Attenuation of islet‐specific T cell responses is associated with C‐peptide improvement in autoimmune type 2 diabetes patients

The clinical efficacy of peroxisome proliferator‐activated receptor gamma (PPAR‐γ) agonists in cell‐mediated autoimmune diseases results from down‐regulation of inflammatory cytokines and autoimmune effector cells. T cell islet autoimmunity has been demonstrated to be common in patients with phenotypic type 2 diabetes mellitus (T2DM) and islet‐specific T cells (T⁺) to be correlated positively with more severe beta cell dysfunction. We hypothesized that the beneficial effects of the PPAR‐γ agonist, rosiglitazone, therapy in autoimmune T2DM patients is due, in part, to the immunosuppressive properties on the islet‐specific T cell responses. Twenty‐six phenotypic T2DM patients positive for T cell islet autoimmunity (T⁺) were identified and randomized to rosiglitazone (n = 12) or glyburide (n = 14). Beta cell function, islet‐specific T cell responses, interleukin (IL)‐12 and interferon (IFN)‐γ responses and islet autoantibodies were followed for 36 months. Patients treated with rosiglitazone demonstrated significant (P < 0·03) down‐regulation of islet‐specific T cell responses, although no change in response to tetanus, a significant decrease (P < 0·05) in IFN‐γ production and significantly (P < 0·001) increased levels of adiponectin compared to glyburide‐treated patients. Glucagon‐stimulated beta cell function was observed to improve significantly (P < 0·05) in the rosiglitazone‐treated T2DM patients coinciding with the down‐regulation of the islet‐specific T cell responses. In contrast, beta cell function in the glyburide‐treated T2DM patients was observed to drop progressively throughout the study. Our results suggest that down‐regulation of islet‐specific T cell autoimmunity through anti‐inflammatory therapy may help to improve beta cell function in autoimmune phenotypic T2DM patients.     

Maternal virus infections in pregnancy and type 1 diabetes in their offspring: Systematic review and meta‐analysis of observational studies

Virus infections are implicated in the development of type 1 diabetes based on epidemiological, clinical, in vitro cell‐based and molecular studies, and animal models. We reviewed the association between virus infections in pregnant women and development of islet autoimmunity or type 1 diabetes in their offspring. We performed a systematic review and meta‐analysis, analysed using random effects models, of human studies from Medline and EMBASE without language restriction. Inclusion criteria were as follows: cohort and case‐control studies measuring viral nucleic acid in blood, stool, urine, or tissue, or serological tests for viruses, in pregnant women whose offspring developed islet autoimmunity and/or type 1 diabetes. All studies required sufficient data to calculate odds ratios and 95% confidence intervals. The 10 studies (4 case control, 6 nested‐case control) that met the eligibility criteria included 2992 participants (953 offspring, 2039 mothers), with varying study design. The 2 outcomes examined were islet autoimmunity (n = 466) and type 1 diabetes (n = 2526). Meta‐analysis showed a significant association between virus infection during pregnancy and clinical type 1 diabetes during childhood (odds ratio 2·16, 95% CI 1·22‐3·80; P = 0·008; heterogeneity X² = 1·65, I² = 40%), but no association with islet autoimmunity (1·45, 0·63‐3·31; P = 0·38; X² = 1·34, I² = 25%). The increased risk of type 1 diabetes following maternal virus infection is consistent with viraemia involving the fetus during pregnancy and suggests a potential causative link between antenatal infection and type 1 diabetes. Larger prospective birth studies with more frequent sampling, and pathogenesis studies, are required to more clearly establish an aetiological link.     

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren’s syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver–kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti‐nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD‐associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE‐cases without known AILD (n = 272), 26 (9·6%) had PBC‐associated autoantibodies, 15 (5·5%) AIH‐associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC‐associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC‐criteria. AMA‐M2 detected by immunoblot was the most common PBC‐associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH‐criteria. The patient with combined AIH/PBC‐serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC‐associated, 12 (10·8%) AIH‐associated autoantibodies and two overlapped. PBC‐associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD‐associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody‐negative and ‐positive patients.     

A quarter of patients with type 1 diabetes have co‐existing non‐islet autoimmunity: the findings of a UK population‐based family study

Individuals with type 1 diabetes (T1D) are at increased risk of coeliac disease (CD), autoimmune thyroiditis and autoimmune gastritis, but the absolute risks are unclear. The aim of this study was to investigate the prevalence of autoantibodies to tissue transglutaminase (TGA), thyroid peroxidase (TPOA) and gastric H⁺/K⁺‐ATPase (ATPA) and their genetic associations in a well‐characterized population‐based cohort of individuals with T1D from the Bart's–Oxford family study for whom islet autoantibody prevalence data were already available. Autoantibodies in sera from 1072 patients (males/females 604/468; median age 11·8 years, median T1D duration 2·7 months) were measured by radioimmunoassays; HLA class II risk genotype was analysed in 973 (91%) using polymerase chain reaction with sequence specific primers (PCR‐SSP). The prevalence of TGA (and/or history of CD), TPOA and ATPA in patients was 9·0, 9·6 and 8·2%, respectively; 3·1% had two or more autoantibodies. Females were at higher risk of multiple autoimmunity; TGA/CD were associated with younger age and TPOA with older age. ATPA were uncommon in patients under 5 years, and more common in older patients. Anti‐glutamate decarboxylase autoantibodies were predictive of co‐existing TPOA/ATPA. TGA/CD were associated with human leucocyte antigen (HLA) DR3‐DQ2, with the DR3‐DQ2/DR3‐DQ2 genotype conferring the highest risk, followed by DR4‐DQ8/DR4‐DQ8. ATPA were associated with DR3‐DQ2, DRB1*0404 (in males) and the DR3‐DQ2/DR4‐DQ8 genotype. TPOA were associated with the DR3‐DQ2/DR3‐DQ2 genotype. Almost one‐quarter of patients diagnosed with T1D aged under 21 years have at least one other organ‐specific autoantibody. HLA class II genetic profiling may be useful in identifying those at risk of multiple autoimmunity.     

Relationship between natural and infection‐induced antibodies in systemic autoimmune diseases (SAD): SLE,SSc and RA

Infection or vaccine‐induced T cell‐dependent immune response and the subsequent high‐affinity neutralizing antibody production have been extensively studied, while the connection between natural autoantibodies (nAAbs) and disease‐specific antibodies has not been thoroughly investigated. Our goal was to find the relationship between immunoglobulin (Ig)M and IgG isotype nAAbs and infection or vaccine‐induced and disease‐related autoantibody levels in systemic autoimmune diseases (SAD). A previously described indirect enzyme‐linked immunosorbent assay (ELISA) test was used for detection of IgM/IgG nAAbs against citrate synthase (anti‐CS) and F4 fragment (anti‐F4) of DNA topoisomerase I in 374 SAD samples, with a special focus on systemic lupus erythematosus (SLE) (n = 92), rheumatoid arthritis (n = 73) and systemic sclerosis (n = 157) disease groups. Anti‐measles IgG and anti‐dsDNA IgG/IgM autoantibodies were measured using commercial and in‐house indirect ELISA tests. In all SAD groups the anti‐measles IgG‐seropositive cases showed significantly higher anti‐CS IgG titers (P = 0·011). In anti‐dsDNA IgG‐positive SLE patients, we detected significantly higher levels of anti‐CS and anti‐F4 IgG nAAbs (P = 0·001 and < 0·001, respectively). Additionally, we found increased levels of IgM isotypes of anti‐CS and anti‐F4 nAAbs in anti‐dsDNA IgM‐positive SLE patients (P = 0·002 and 0·016, respectively). The association between IgG isotypes of pathogen‐ or autoimmune disease‐related antibodies and the IgG nAAbs may underscore the immune response‐inducible nature of the diseases investigated. The relationship between protective anti‐dsDNA IgM and the IgM isotype of anti‐F4 and anti‐CS may provide immunoserological evidence for the beneficial roles of nAAbs in SLE patients.     

Doubly Reactive INS‐IGF2 Autoantibodies in Children with Newly Diagnosed Autoimmune (type 1) Diabetes

The splice variant INS‐IGF2 entails the preproinsulin signal peptide, the insulin B‐chain, eight amino acids of the C‐peptide and 138 unique amino acids from an ORF in the IGF2 gene. The aim of this study was to determine whether levels of specific INS‐IGF2 autoantibodies (INS‐IGF2A) were related to age at diagnosis, islet autoantibodies, HLA‐DQ or both, in patients and controls with newly diagnosed type 1 diabetes. Patients (n = 676), 0–18 years of age, diagnosed with type 1 diabetes in 1996–2005 and controls (n = 363) were analysed for specific INS‐IGF2A after displacement with both cold insulin and INS‐IGF2 to correct for non‐specific binding and identify double reactive sera. GADA, IA‐2A, IAA, ICA, ZnT8RA, ZnT8WA, ZnT8QA and HLA‐DQ genotypes were also determined. The median level of specific INS‐IGF2A was higher in patients than in controls (P < 0.001). Irrespective of age at diagnosis, 19% (126/676) of the patients had INS‐IGF2A when the cut‐off was the 95th percentile of the controls (P < 0.001). The risk of INS‐IGF2A was increased among HLA‐DQ2/8 (OR = 1.509; 95th CI 1.011, 2.252; P = 0.045) but not in 2/2, 2/X, 8/8, 8/X or X/X (X is neither 2 nor 8) patients. The association with HLA‐DQ2/8 suggests that this autoantigen may be presented on HLA‐DQ trans‐heterodimers, rather than cis‐heterodimers. Autoantibodies reactive with both insulin and INS‐IGF2A at diagnosis support the notion that INS‐IGF2 autoimmunity contributes to type 1 diabetes.     

Associations of B cell‐activating factor (BAFF) and anti‐BAFF autoantibodies with disease activity in multi‐ethnic Asian systemic lupus erythematosus patients in Singapore

To measure the levels of B cell‐activating factor (BAFF) and endogenous anti‐BAFF autoantibodies in a cohort of multi‐ethnic Asian systemic lupus erythematosus (SLE) patients in Singapore, to determine their correlation with disease activity. Serum samples from 121 SLE patients and 24 age‐ and sex‐matched healthy controls were assayed for BAFF and anti‐BAFF immunoglobulin (Ig)G antibody levels by enzyme‐linked immunosorbent assay (ELISA). The lowest reliable detection limit for anti‐BAFF‐IgG antibody levels was defined as 2 standard deviations (s.d.) from blank. Correlation of serum BAFF and anti‐BAFF IgG levels with disease activity [scored by SLE Activity Measure revised (SLAM‐R)], and disease manifestations were determined in these 121 patients. SLE patients had elevated BAFF levels compared to controls; mean 820 ± 40 pg/ml and 152 pg ± 45/ml, respectively [mean ± standard error of the mean (s.e.m.), P < 0·01], which were correlated positively with anti‐dsDNA antibody levels (r = 0·253, P < 0·03), and SLAM‐R scores (r = 0·627, P < 0·01). In addition, SLE patients had significantly higher levels of anti‐BAFF IgG, which were correlated negatively with disease activity (r = –0·436, P < 0·01), levels of anti‐dsDNA antibody (r = –0·347, P < 0·02) and BAFF (r = –0·459, P < 0·01). The majority of patients in this multi‐ethnic Asian SLE cohort had elevated levels of BAFF and anti‐BAFF antibodies. Anti‐BAFF autoantibody levels correlated negatively with clinical disease activity, anti‐dsDNA and BAFF levels, suggesting that they may be disease‐modifying. Our results provide further information about the complexity of BAFF pathophysiology in different SLE disease populations and phenotypes, and suggest that studies of the influence of anti‐cytokine antibodies in different SLE populations will be required when selecting patients for trials using targeted anti‐cytokine therapies.     

Screening for insulinoma antigen 2 and zinc transporter 8 autoantibodies: a cost‐effective and age‐independent strategy to identify rapid progressors to clinical onset among relatives of type 1 diabetic patients

In first‐degree relatives of type 1 diabetic patients, we investigated whether diabetes risk assessment solely based on insulinoma antigen 2 (IA‐2) and zinc transporter 8 (ZnT8) antibody status (IA‐2A, respectively, ZnT8A) is as effective as screening for three or four autoantibodies [antibodies against insulin (IAA), glutamate decarboxylase 65 kDa (GAD) glutamate decarboxylase autoantibodies (GADA) and IA‐2A with or without ZnT8A] in identifying children, adolescents and adults who progress rapidly to diabetes (within 5 years). Antibodies were determined by radiobinding assays during follow‐up of 6444 siblings and offspring aged 0–39 years at inclusion and recruited consecutively by the Belgian Diabetes Registry. We identified 394 persistently IAA⁺, GADA⁺, IA‐2A⁺ and/or ZnT8A⁺ relatives (6·1%). After a median follow‐up time of 52 months, 132 relatives developed type 1 diabetes. In each age category tested (0–9, 10–19 and 20–39 years) progression to diabetes was significantly quicker in the presence of IA‐2A and/or ZnT8A than in their joint absence (P < 0·001). Progression rate was age‐independent in IA‐2A⁺ and/or ZnT8A⁺ relatives but decreased with age if only GADA and/or IAA were present (P = 0·008). In the age group mainly considered for immune interventions until now (10–39 years), screening for IA‐2A and ZnT8A alone identified 78% of the rapid progressors (versus 75% if positive for ≥ 2 antibodies among IAA, GADA, IA‐2A and ZnT8A or versus 62% without testing for ZnT8A). Screening for IA‐2A and ZnT8A alone allows identification of the majority of rapidly progressing prediabetic siblings and offspring regardless of age and is more cost‐effective to select participants for intervention trials than conventional screening.     

Association of adiponectin, interleukin (IL)-1ra, inducible protein 10, IL-6 and number of islet autoantibodies with progression patterns of type 1 diabetes the first year after diagnosis

The progression of type 1 diabetes after diagnosis is poorly understood. Our aim was to assess the relation of disease progression of juvenile‐onset type 1 diabetes, determined by preserved beta cell function the first year after diagnosis, with systemic cytokine concentrations and number of autoantibodies. Juvenile patients (n = 227) had a meal‐stimulated C‐peptide test 1 and 6 months after diagnosis. On the basis of the C‐peptide course for the duration of 1–6 months, four progression groups were defined: patients with persistently low beta cell function (‘stable‐low’), rapid progressers, slow progressers and remitters. Serum concentrations of adiponectin, interleukin (IL)‐1ra, inducible protein 10 (IP‐10), IL‐6 and glutamic acid decarboxylase (GAD), IA‐2A and islet‐cell antibodies (ICA) were measured at 1, 6 and 12 months. We found that adiponectin concentrations at 1 month predicted disease progression at 6 months (P = 0·04). Patients with low adiponectin had a higher probability of becoming remitters than rapid progressers, odds ratio 3·1 (1·3–7·6). At 6 and 12 months, adiponectin differed significantly between the groups, with highest concentrations among stable‐low and rapid progressers patients (P = 0·03 and P = 0·006). IL‐1ra, IP‐10 and IL‐6 did not differ between the groups at any time‐point. The number of autoantibodies differed significantly between the groups at 1 month (P = 0·04), where rapid progressers had the largest number. There was no difference between the groups in human leucocyte antigen‐associated risk. We define progression patterns distinguishing patients diagnosed with low beta cell function from those with rapid decline, slow decline or actual increase in beta cell function, pointing to different mechanisms of disease progression. We find that adiponectin concentration at 1 month predicts, and at 6 and 12 months associates with, distinct progression patterns.     

Childhood thyroid autoimmunity and relation to islet autoantibodies in children at risk for type 1 diabetes in the diabetes prediction in skåne (DiPiS) study

Abstract

Background: The aim was to determine prevalence and age at seroconversion of thyroid autoimmunity in relation to islet autoantibodies, gender and HLA-DQ genotypes in children with increased risk for type 1 diabetes followed from birth.

Methods: In 10-year-old children (n?=?1874), blood samples were analysed for autoantibodies against thyroid peroxidase (TPOAb), thyroglobulin (TGAb), glutamic acid decarboxylase 65 (GADA), Zink transporter 8 (ZnT8R/W/QA), insulinoma-associated protein-2 (IA-2A), insulin (IAA) and HLA-DQ genotypes. Prospectively collected samples from 2 years of age were next analysed for TPOAb, and TGAb and, finally, in confirming samples at 11–16 years of age along with TSH and FT4. Frequencies were tested with Chi-square or Fischer’s exact tests, autoantibody levels with Wilcoxon and correlations between autoantibody levels with Spearman’s rank correlation test.

Results: The prevalence of thyroid autoimmunity was 6.9%, overrepresented in girls (p?<?.001) also having higher TPOAb levels at 10 years (p?=?.049). TPOAb was associated with GADA (p?=?.002), ZnT8R/W/QA (p?=?.001) and IA-2A (p?=?.001) while TGAb were associated with ZnT8R/W/QA (p?=?.021). In boys only, TPOAb were associated with GADA (p?=?.002), IA-2A (p?=?.001), ZnT8R/W/QA (p?=?.001) and IAA (p?=?.009), and TGAb with GADA (p?=?.013), IA-2A (p?=?.005) and ZnT8R/W/QA (p?=?.003). Levels of IA-2A correlated to both TPOAb (p?=?.021) and to TGAb (p?=?.011). In boys only, levels of GADA and TGAb correlated (p?=?.009 as did levels of IA-2A and TPOAb (p?=?.013). The frequency and levels of thyroid autoantibodies increased with age. At follow-up, 22.3% had abnormal thyroid function or were treated with thyroxine.

Conclusions: Thyroid autoimmunity and high TPOAb levels were more common in girls. In contrast, in boys only, there was a strong association with as well as correlation between levels of thyroid and islet autoantibodies. It is concluded that while girls may develop autoimmune thyroid disease (AITD) independent of islet autoantibodies, the risk for thyroid disease in boys may be linked to concomitant islet autoimmunity.     

The Number of Regulatory T Cells Correlates with Hemodynamic Improvement in Patients with Inflammatory Dilated Cardiomyopathy After Immunoadsorption Therapy

Inflammatory DCM (iDCM) may be related to autoimmune processes. An immunoadsorption (IA) has been reported to improve cardiac hemodynamics. The benefit of IA is probably related to the removal of autoantibodies. A recent study suggests additional effects of IA on the T cell–mediated immune reactions, especially on regulatory T cells (Tregs). In this prospective study, the correlation between the level of Tregs and improvement of myocardial contractility in response to IA in patients with iDCM was investigated. Patients (n = 18) with iDCM, reduced left ventricular (LV) ejection fraction (<35%), were enrolled for IA. Before and 6 months after IA, LV systolic function was assessed by echocardiography, and blood levels of Tregs were quantified by FACS analysis. Patients (n = 12) with chronic ischaemic heart failure and comparable reduced LV‐EF served as controls. IA improved LV‐EF in 12 of 18 patients at 6‐month follow‐up. These patients were classified as ‘IA responder’. In 6 patients, LV‐EF remained unchanged. At baseline, IA responder and non‐responder subgroups showed similar values for C‐reactive protein, white blood cells, lymphocytes and T helper cells, but they differ for the number of circulating Tregs (responder: 2.32 ± 1.38% versus non‐responder: 4.86 ± 0.28%; P < 0.01). Tregs increased significantly in the IA responders, but remained unchanged in the IA non‐responders. In patients with ischaemic cardiomyopathy, none of these values changed over time. A low level of Tregs in patients with chronic iDCM may characterize a subset of patients who do best respond to IA therapy.     

Human neonatal thymectomy induces altered B‐cell responses and autoreactivity

An association between T‐cell lymphopenia and autoimmunity has long been proposed, but it remains to be elucidated whether T‐cell lymphopenia affects B‐cell responses to autoantigens. Human neonatal thymectomy (Tx) results in a decrease in T‐cell numbers and we used this model to study the development of autoreactivity. Two cohorts of neonatally thymectomized individuals were examined, a cohort of young (1–5 years post‐Tx, n = 10–27) and older children (>10 years, n = 26), and compared to healthy age‐matched controls. T‐cell and B‐cell subsets were assessed and autoantibody profiling performed. Early post‐Tx, a decrease in T‐cell numbers (2.75 × 10⁹/L vs. 0.71 × 10⁹/L) and an increased proportion of memory T cells (19.72 vs. 57.43%) were observed. The presence of autoantibodies was correlated with an increased proportion of memory T cells in thymectomized children. No differences were seen in percentages of different B‐cell subsets between the groups. The autoantigen microarray showed a skewed autoantibody response after Tx. In the cohort of older individuals, autoantibodies were present in 62% of the thymectomized children, while they were found in only 33% of the healthy controls. Overall, our data suggest that neonatal Tx skews the autoantibody profile. Preferential expansion and preservation of Treg (regulatory T) cell stability and function, may contribute to preventing autoimmune disease development after Tx.     

Accelerated progression from islet autoimmunity to diabetes is causing the escalating incidence of type 1 diabetes in young children

The incidence of type 1 diabetes is rising worldwide, particularly in young children. Since type 1 diabetes is preceded by autoimmunity to islet antigens, there must be a consequent increase in the incidence of islet autoimmunity in young children or a more rapid rate of progression to diabetes once islet autoimmunity initiates. This study was to determine whether the incidence of islet autoimmunity or the rate of progression from autoimmunity to diabetes onset has changed over a 20-year period in children genetically predisposed to type 1 diabetes. Between 1989 and 2010, children who were first-degree relatives of patients with type 1 diabetes and who were born in Germany were prospectively followed from birth without intervention. A total of 324 children (BABYDIAB study) born between 1989 and 2000 and 216 children (TEDDY study) born between 2004 and 2010 with matched HLA genotypes were recruited before age 3 months and included for analysis. Children were followed for the development of autoantibodies to insulin, GAD, and IA-2, and for progression to diabetes. The cumulative frequency of diabetes by age 4 years was 2.5% (95% CI 0.8-4.2%) in BABYDIAB children and 6.2% (95% CI 2.3-10.1%) in TEDDY children (p = 0.03). The cumulative frequency of islet autoantibodies by age 4 years was similar in the children from both studies (11.3% vs 13.9%). Progression to diabetes from the development of islet autoantibodies was markedly increased in autoantibody-positive children from the more recently recruited TEDDY cohort (50% progression within 85.2 months for BABYDIAB children vs 9.6 months for TEDDY children; p = 0.009), also if children were further selected on the basis of high-risk HLA genotypes or the development of autoantibodies to multiple islet antigens (p = 0.01). The findings suggest that recent increasing incidence of type 1 diabetes in young children could be due to weakening of mechanisms that normally regulate autoimmune destruction of islet beta cells.     

Association of interleukin 22 gene polymorphisms and serum IL‐22 level with risk of systemic lupus erythematosus in a Chinese population

The aim of this study was to investigate the association between the single‐nucleotide polymorphisms (SNPs) of the interleukin 22 (IL‐22) gene and systemic lupus erythematosus (SLE) in a Chinese population. Three IL‐22 SNPs (rs2227485, rs2227513 and rs2227491) were genotyped using SNaPshot SNP genotyping assays and identified by sequencing in 314 SLE patients and 411 healthy controls. The IL‐22 level of serum was assessed by enzyme‐linked immunosorbent assay (ELISA) kits. Data were analysed by spss version 17.0 software. We found that rs2227513 was associated with an increased risk of SLE [AG versus AA: adjusted odds ratio (aOR) = 2·24, 95% confidence interval (CI) = 1·22–4·12, P = 0·010; G versus· A: adjusted OR = 2·18, 95% CI = 1·20‐3·97, P = 0·011]. Further analysis in patients with SLE showed that the AG genotype and G allele were associated with an increased risk of renal disorder in SLE (G versus A: aOR = 3·09, 95% CI = 1·30–7·33, P = 0·011; AG versus· AA: aOR = 3·25, 95% CI = 1·35–7·85, P = 0·009). In addition, the concentration of IL‐22 was significantly lower in the rs2227513 AG genotype compared with AA genotype (P = 0·028). These results suggest that rs2227513 polymorphism might contribute to SLE susceptibility, probably by decreasing the expression of IL‐22.     

Rituximab‐induced interleukin‐15 reduction associated with clinical improvement in rheumatoid arthritis

Rituximab therapy alters all aspects of B‐cell participation in the disturbed immune response of rheumatoid arthritis patients. To determine the impact of B‐cell depletion on other immune compartments, we analysed levels of soluble and surface interleukin‐15 (IL‐15) along with the frequency of IL‐15‐related subsets after rituximab treatment. We then studied the correlation of observed changes with clinical activity. Heparinized blood samples from 33 rheumatoid arthritis patients were collected on days 0, 30, 90 and 180 after each of three rituximab cycles. Serum cytokine levels were determined by ELISA. Interleukin‐15 trans‐presentation was analysed by cytometry. Flow cytometry with monoclonal antibodies was performed to analyse circulating cell subsets. Interleukin‐15 was detected in the serum of 25 patients before initiating the treatment. Rituximab then progressively reduced serum IL‐15 (138 ± 21 pg/ml at baseline, 48 ± 18 pg/ml after third cycle, P = 0·03) along with IL‐17 (1197 ± 203 pg/ml at baseline, 623 ± 213 pg/ml after third cycle, P = 0·03) and tended to increase the frequency of circulating regulatory T cells (3·1 ± 1 cells/μl at baseline, 7·7 ± 2 cells/μl after third cycle). Rituximab also significantly decreased IL‐15 trans‐presentation on surface monocytes of patients negative for IL‐15 serum (mean fluorescence intensity: 4·82 ± 1·30 at baseline, 1·42 ± 0·69 after third cycle P = 0·05). Reduction of serum IL‐15 was associated with decrease in CD8⁺ CD45RO⁺/RA⁺ ratio (1·17 ± 0·21 at baseline, 0·36 ± 0·06 at third cycle, P = 0·02). DAS28, erythrocyte sedimentation rate and C‐reactive protein correlated significantly with CD8⁺ CD45RO⁺/RA⁺ ratio (R = 0·323, R = 0·357, R = 0·369 respectively, P < 0·001). Our results suggest that sustained clinical improvement after rituximab treatment is associated with IL‐15/memory T‐cell‐related mechanisms beyond circulating B cells.     

Increased prevalence of autoimmunity in Turner syndrome – influence of age

Individuals with Turner syndrome (TS) are prone to develop autoimmune conditions such as coeliac disease (CD), thyroiditis and type 1 diabetes (T1DM). The objective of the present study was to examine TS of various karyotypes for autoantibodies and corresponding diseases. This was investigated in a prospective cross‐sectional study of Danish TS patients (n = 107, median age 36·7 years, range: 6–60 years). A medical history was recorded and a blood sample was analysed for autoantibodies against gliadin, transglutaminase, adrenal cortex, intrinsic factor, anti‐thyroid peroxidase (anti‐TPO) and glutamic‐acid‐decarboxylase 65 (GAD‐65). Autoantibodies were present in 58% (n = 61) of all patients, whereof 18% (11) had autoantibodies targeting more than one organ. Patients with autoantibodies were significantly older than those without (P = 0·001). Anti‐TPO was present in 45% (48) of patients, of whom 33% (16) were hypothyroid. Overall, 18% (19) presented with CD autoantibodies, of whom 26% (five) had CD. Anti‐TPO and CD autoantibodies co‐existed in 9% (10). Immunoglobulin A deficiency was found in 3% (three) of patients, who all had CD autoantibodies without disease. Among four patients with anti‐GAD‐65 none had T1DM, but two were classified as having T2DM. One patient had adrenocortical autoantibodies but not adrenal failure. Autoantibodies against intrinsic factor were absent. Anti‐GAD‐65 was increased in isochromosomal karyotypes (3/23 versus 1/84, P = 0·008) with no other association found between autoantibodies and karyotype. In conclusion, TS girls and women face a high prevalence of autoimmunity and associated disease with a preponderance towards hypothyroidism and CD. Thus, health care providers dealing with this patient group should be observant and test liberally for these conditions even before clinical symptoms emerge.     

Evaluation of membrane‐bound and soluble forms of human leucocyte antigen‐G in systemic sclerosis

Systemic sclerosis (SSc) is a complex disease characterized by immune dysregulation, extensive vascular damage and widespread fibrosis. Human leucocyte antigen‐G (HLA‐G) is a non‐classic class I major histocompatibility complex (MHC) molecule characterized by complex immunomodulating properties. HLA‐G is expressed on the membrane of different cell lineages in both physiological and pathological conditions. HLA‐G is also detectable in soluble form (sHLA‐G) deriving from the shedding of surface isoforms (sHLA‐G1) or the secretion of soluble isoforms (HLA‐G5). Several immunosuppressive functions have been attributed to both membrane‐bound and soluble HLA‐G molecules. The plasma levels of sHLA‐G were higher in SSc patients (444·27 ± 304·84 U/ml) compared to controls (16·74 ± 20·58 U/ml) (P < 0·0001). The plasma levels of transforming growth factor (TGF)‐β were higher in SSc patients (18 937 ± 15 217 pg/ml) compared to controls (11 099 ± 6081 pg/ml; P = 0·003), and a significant correlation was found between TGF‐β and the plasma levels of total sHLA‐G (r = 0·65; P < 0·01), sHLA‐G1 (r = 0·60; P = 0·003) and HLA‐G5 (r = 0·47; P = 0·02). The percentage of HLA‐G‐positive monocytes (0·98 ± 1·72), CD4⁺ (0·37 ± 0·68), CD8⁺ (2·05 ± 3·74) and CD4⁺CD8⁺ double‐positive cells (14·53 ± 16·88) was higher in SSc patients than in controls (0·11 ± 0·08, 0·01 ± 0·01, 0·01 ± 0·01 and 0·39 ± 0·40, respectively) (P < 0·0001). These data indicate that in SSc the secretion and/or shedding of soluble HLA‐G molecules and the membrane expression of HLA‐G by peripheral blood mononuclear cells (PBMC) is clearly elevated, suggesting an involvement of HLA‐G molecules in the immune dysregulation of SSc.     

Helicobacter pylori infection in patients with selective immunoglobulin a deficiency

Selective immunoglobulin A (IgA) deficiency (IgAD) is the most common primary immunodeficiency in the western world. The aim of the study was to investigate the prevalence and clinical characteristics of Helicobacter pylori‐infected dyspeptic patients with IgAD. Case samples were drawn from all subjects ≥ 12 years of age (n = 104729) who had undergone serum total IgA measurements during 2004–14 for any reason at Leumit Healthcare Services (Israel) and had serum total IgA < 0·07 g/l. The control group was comprised of a random sample of remaining patients with a case–control ratio of 10 controls for each case. The dyspeptic diseases were identified and retrieved from Leumit Health Care Services electronic database using specific ICD‐9‐CM diagnostic codes. The case group included 347 subjects and the control group 3470 subjects. There were no significant differences in the prevalence of patients with dyspepsia [84 (24·2%) versus 821 (23·6%) for cases and controls, respectively]. Additionally, there was no difference in a proportion of dyspeptic H. pylori‐positive subjects [59 (17·1%) versus 524 (15·1%)] between the case and control groups. Only 59 (17%) among the 347 IgAD patients underwent gastroscopy. A significantly larger proportion of case subjects experienced several forms of gastritis [13 (61·9%) versus 38 (21·6%), P < 0·001), duodenal ulcers [seven (33·3%) versus 19 (10·8%); P = 0·01] and nodular lymphoid hyperplasia (NLH) [two (9·5%) versus none; P = 0·011]. IgAD is not associated with increased prevalence of H. pylori‐associated dyspepsia; nevertheless, H. pylori‐infected dyspeptic IgAD subjects experience more EGD‐proved gastritis, duodenal ulcers and NLH.     

Association of CT60 cytotoxic T lymphocyte antigen-4 gene polymorphism with thyroid autoantibody production in patients with Hashimoto's and postpartum thyroiditis

Strong genetic contribution has been demonstrated to influence the development of autoimmune thyroid disease (AITD) as well as thyroid autoantibody production. In order to assess the relation between CT60 cytotoxic T lymphocyte antigen‐4 (CTLA‐4) gene polymorphism and thyroid autoantibody production, we investigated 180 consecutive newly diagnosed patients with two forms of AITD, 105 with Hashimoto's thyroiditis (HT) and 75 with postpartum thyroiditis (PPT). We evaluated thyroid function, measured antibodies against thyroid peroxidase (TPO) and thyroglobulin (Tg), and determined CT60 CTLA‐4 gene polymorphism. In HT, TPO antibody median value was significantly lower in the AA compared to the AG and GG genotypes (65, 122 and 319 U/ml, P < 0·005), while the Tg antibody median value was lower in the AA compared to the AG genotype (91 and 189 U/ml, P < 0·02). In PPT, the frequency of thyroid autoantibody‐positive patients was higher among G‐allele‐carrying genotypes (P < 0·04). Similar to HT, the TPO antibody median value was lower in the AA compared to the AG and GG genotypes (12, 130 and 423 U/ml, P < 0·006). Hypothyroid PPT patients were more often thyroid autoantibody‐positive (P < 0·005) and the TPO antibody median value was higher compared to hyperthyroid PPT patients (500 and 32 U/ml, P < 0·0001). The frequency of the G‐allele was significantly higher among hypothyroid patients (P < 0·05). Our data suggest that in both HT and PPT, the CT60 CTLA‐4 gene polymorphism contributes importantly to thyroid autoantibody production. In PPT, the genotype also seems to influence thyroid function, as patients with the polymorphous allele are more prone to develop hypothyroid form of PPT.     

Increased killer B cells in chronic HCV infection may lead to autoimmunity and increased viral load

Regulatory B (B_reg) cells are characterized by various membrane markers and the secretion of different inhibitory cytokines. A new subset of B_reg cells was identified as CD5^hi Fas‐ligand (FasL)^hi. Their main reported role is to suppress anti‐viral and anti‐tumour immune responses, and, hence they have been dubbed ‘killer’ B cells. In this study, we aim to assess the role of these cells in chronic hepatitis C virus (HCV) infection, and determine if they contribute to the increased viral load and persistence of HCV and its related autoimmunity. (i) FasL expression on CD5^hi B cells is increased significantly in HCV‐infected patients compared to healthy individuals [28·06 ± 6·71 mean fluorescence intensity (MFI) ± standard error of the mean (s.e.m.), median = 27·9 versus 10·87 ± 3·97 MFI ± s.e.m., median = 10·3, respectively, P <  0·0001]. (ii) Killer B cells from HCV patients increased autologous CD4⁺ T cell apoptosis compared to the apoptosis in healthy individuals [39·17% ± 7·18% mean ± standard deviation (s.d.), median = 39·6 versus 25·92 ± 8·65%, mean ± s.d., median = 24·1%, P <  0·0001, respectively]. A similar increase was observed in CD8⁺ T cell apoptosis (54·67 ± 15·49% mean ± s.d., median = 57·3 versus 21·07% ± 7·4%, mean ± s.d., median = 20%, P = 0·0006, respectively). (iii) By neutralizing FasL with monoclonal anti‐FasL antibodies, we have shown that the induction of apoptosis by killer B cells is FasL‐dependent. (iv) Increased expression of FasL on CD5^hi B cells is correlated positively with an increased viral load and the presence of anti‐nuclear antibodies and rheumatoid factor in HCV. This is the first study in which killer B cells have been suggested to play a pathogenic role in HCV. They seem to be involved in HCV's ability to escape efficient immune responses.