Complement as a predictor of further miscarriage in couples with recurrent miscarriages

BACKGROUND: The clinical significance of complement is unclear in patients with unexplained recurrent miscarriage, though low levels of complement 3 (C3) and/or complement 4 (C4) are reported to be associated with the antiphospholipid syndrome (aPS). We therefore investigated whether C3 and C4 have a predictive value for subsequent miscarriages. METHODS: In total, 215 patients with a history of two consecutive first-trimester miscarriages and no abnormal chromosomes in either partner, no uterine anomalies and no antiphospholipid (aPL) antibodies were examined. Blood tests for C3, C4, total haemolytic complement (CH50), immunoglobulin G (IgG), immunoglobulin A (IgA) and immunoglobulin M (IgM) were performed before subsequent pregnancy. Patients were then followed up without treatment, and their pregnancy outcomes were compared with their previous blood test results. RESULTS: From 215 pregnant patients, 45 subsequently miscarried, whereas the remainder had a live birth. There was no relation with serum CH50, IgG, IgA and IgM levels, but C3 and C4 levels in patients with subsequent miscarriage were significantly higher than in those whose pregnancy was successful. CONCLUSION: In patients with two previous miscarriages, C3 and C4 levels were higher in those women who had a third miscarriage, than in women that went on to have a live birth.     

Anti-phosphatidylserine/prothrombin antibodies are not frequently found in patients with unexplained recurrent miscarriages

OBJECTIVE: To determine whether the presence of anti-phosphatidylserine/ prothrombin antibodies (anti-PS/PT) can be a major factor in otherwise unexplained recurrent miscarriages. PATIENTS AND METHODS: Eighty-one consecutive patients with history of 2 or more recurrent miscarriages were studied. Patients with history of overt thrombotic events were not included. Patients were examined for plausible causes of miscarriages, and titer of IgG, IgM and IgA anti-PS/PT were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Thirty-five patients had one or more plausible causes of recurrent miscarriages, including 12 positive for well-established anti-phospholipid antibodies, such as anti-beta2-glycoprotein I. None of the patients included in this study was found to be positive for anti-PS/PT. CONCLUSION: Detection of anti-PS/PT in addition to other anti-phospholipid antibodies does not seem to aid in the evaluation of patients with unexplained recurrent miscarriages.     

反复自然流产患者外周血调节性T细胞Foxp3的表达

评价原因不明复发性流产(unexplained recurrent miscarriage,URM)患者外周血CD4+CD25+调节性T细胞中Foxp3的表达。以正常生育非孕妇女(n=20)为对照,以URM(n=25)为研究对象,采用实时荧光定量PCR分析外周血单个核细胞Foxp3转录水平;以流式细胞术分析外周血CD4+CD25+T细胞Foxp3翻译水平。结果:实时荧光定量PCR显示,URM患者的Foxp3转录水平明显低于正常对照组(P<0.01)。流式细胞仪分析显示URM组外周血中CD4+CD25+T细胞Foxp3翻译水平显著低于正常对照组(P<0.01)。URM患者外周血调节性T细胞Foxp3表达降调可能参与URM的发病。     

Immunology: Chlamydial immunoglobulin IgG and IgA antibodies in serum and semen are not associated with the presence of Chlamydia trachomatis DNA or rRNA in semen from male partners of infertile couples

The role of Chlamydia (C.) trachomatis in male infertility iscontroversial. The objective of this study was to determinethe prevalence of asymptomatic C.trachomatis infections in malepartners of infertile couples, and to compare this result withthe presence of chlamydial antibodies in serum and semen. C.trachomatiswas detected in five of 50 semen specimens (10%) by either polymerasechain reaction for C.trachomatis DNA or direct DNA probing forC.trachomatis rRNA. There was no association between the detectionof C.trachomatis in semen and the presence of chlamydial antibodiesin serum or semen. Chlamydial serum antibodies were neitherassociated with antisperm serum antibodies nor with pathologicalstandard semen parameters. These results indicate that the assessmentof chlamydial immunoglobulin IgG and IgA antibodies in serumor semen is of limited use in male infertility work-up, in contrastto its significance in female tubal infertility. The presenceof C.trachomatis in semen emphasizes the potential risk of transmissionduring artificial insemination and other assisted reproductivetechniques, and underlines the importance of sensitive directdetection methods in this group of patients.     

Serum allergen‐specific IgA is not associated with natural or induced tolerance to egg in children

The role of specific IgA (sIgA) in oral immunotherapy (OIT) and natural tolerance to foods is poorly understood. We aimed to study serum sIgA in induced and natural tolerance to egg. Children aged 5–16 years diagnosed with IgE‐mediated egg allergy were recruited. After egg challenge, patients were classified as transient (TEA) or persistent (PEA) egg‐allergic. PEA children were further divided into oral immunotherapy (PEA‐OIT) or egg avoidance (PEA‐EA). Allergy/tolerance was reassessed 9–12 months later (T1) in PEA‐EA. Serum sIgA to ovalbumin and ovomucoid were determined at inclusion in all patients and repeated in PEA at T1. 21 TEA and 52 PEA children were recruited (28 PEA‐OIT, 24 PEA‐EA). Serum sIgA remained unchanged after OIT. TEA and PEA had similar serum sIgA. No specific trend on serum sIgA was observed in five PEA‐EA who developed natural tolerance over follow‐up. Thus, serum sIgA seems not to be associated with induced or natural egg tolerance.     

Maintenance of tolerance to cow''s milk in atopic individuals is characterized by high levels of specific immunoglobulin G4

BACKGROUND: The central role of specific IgE in cow's milk allergy (CMA) is well documented. However, less is known about the function of other immunoglobulin isotypes in allergy and tolerance to cow's milk proteins (CMPs). OBJECTIVE: To determine differences in the antibody responses that are associated with allergy and tolerance to cow's milk in allergic, atopic and non-atopic individuals of different age groups. METHODS: Nineteen infants (<1 year), 18 children (6-14 years) and 41 adults (21-68 years) were included. Each age group was comprised of subjects with CMA, atopic individuals without a history of CMA and non-atopic subjects. Levels of specific IgE, IgG4, IgG1 and IgA to whole cow's milk and the six most abundant individual CMPs were determined in plasma by ELISA. For comparison, specific IgE and IgG4 were measured to ovomucoid and house dust mite (HDM) in individuals allergic for the respective allergens, and in atopic and non-atopic subjects without allergy. RESULTS: In infants and children with CMA, alphas1-casein and beta-lactoglobulin induced the highest specific IgE response, whereas alphas1-casein was the most allergenic CMP in adult patients. Specific IgG4 and IgG1 responses were the highest to alphas1-casein and beta-lactoglobulin in all age groups, while kappa-casein and alpha-lactalbumin induced the highest levels of IgA. CMP-specific IgG4 was higher in atopic children and adults without CMA, as compared with non-atopic individuals. A similar difference between tolerant atopic and non-atopic subjects was observed for IgG4 specific to ovomucoid, whereas HDM-specific IgG4 was not detectable in these subjects. CONCLUSION: Maintenance of tolerance to cow's milk in atopic children and adults without CMA is associated with elevated levels of specific IgG4, in combination with low specific IgE. The up-regulation of specific IgG4 in tolerant atopic individuals may be related to the type of allergen and its regular dose of exposure.     

Altered production of IgE and IgA induced by IL-4 in peripheral blood mononuclear cells from patients with IgA nephropathy.

In order to elucidate the factors responsible for altered immunoglobulin production in patients with IgA nephropathy (IgAN), the in vitro effects of IL-4 and interferon-gamma (IFN-gamma) on the synthesis of IgE and IgA by peripheral blood mononuclear cells (PBMC) were studied. Spontaneous IgE and IgA synthesis by PBMC was significantly increased in patients with IgA nephropathy compared with controls. The maximum amounts of IgA and IgE synthesis by PBMC after stimulation with IL-4 were almost the same both in patients with IgAN and in controls. The enhancement rate of IL-4-induced IgE and IgA synthesis was significantly lower in IgAN than in the controls, suggesting in vivo preactivation of PBMC in IgAN patients. IFN-gamma suppressed IgA and IgE synthesis by PBMC from IgAN patients as well as controls. However, the suppressive effect on IgE synthesis was less prominent in patients with IgAN. These results suggested that altered IL-4 action might be involved in the development of IgA nephropathy.     

Severity of infections in IgA deficiency: correlation with decreased serum antibodies to pneumococcal polysaccharides and decreased serum IgG2 and/or IgG4

In order to define abnormalities of humoral immunity which determine susceptibility to respiratory tract infections in IgA-deficient adults, serum IgG subclass concentrations, and serum concentrations of pneumococcal antibodies and Haemophilus influenzae type B (Hib) antibodies sera from IgA-deficient adults with and without susceptibility to respiratory tract infections were compared. Infection susceptibility was not related to the degree of IgA deficiency, but was related to deficiency of IgG4 and, to a lesser extent, IgG2, as well as to low basal serum concentrations of pneumococcal polysaccharide antibodies. The combination of IgG2 and/or IgG4 deficiency and a non-protective basal serum concentration of antibody against two or more pneumococcal polysaccharides was present in the serum of six of 12 (50%) patients with severe infections, but only one of 44 (2%) patients without infections. Furthermore, the preservation of antibody responses against the most immunogenic pneumococcal polysaccharide type 3, but not against the less immunogenic types 7F, 9N and 14, in patients with severe infections suggested that abnormalities of pneumococcal polysaccharide antibody responses might include defects of affinity maturation.     

IgA肾病组蛋白H3K4三甲基化和DNA甲基化基因修饰的相关性

目的: 探讨IgA肾病(IgAN)外周血单个核细胞(PBMCs)组蛋白H3赖氨酸4 (H3K4)三甲基化与DNA甲基化之间的关系。方法: 采用染色质免疫共沉淀联合芯片技术(ChIP-chip)对40例IgAN患者和40例健康者的PBMCs H3K4三甲基化进行高通量筛选,染色质免疫共沉淀-实时定量聚合酶链反应 (ChIP-qPCR) 验证芯片结果,定量反转录聚合酶链反应(qRT-PCR)检测阳性基因的mRNA表达水平,采用甲基化DNA免疫共沉淀定量聚合酶链反应(MeDIP-qPCR)检测DNA甲基化水平。结果: IgAN病人PBMCs 基因组H3K4三甲基化水平升高,基因组DNA甲基化水平降低。 4个阳性基因H3K4三甲基化水平和DNA甲基化水平与正常对照组相比,显著差异(P<0.05)。结论: IgAN患者PBMCs基因组H3K4三甲基化和DNA甲基化水平存在显著改变,DNA甲基化和组蛋白H3K4三甲基化基因修饰存在相互作用。     

PCR检测沙眼衣原体与习惯性流产和女性不孕相关性研究

本文应用聚合酶链反应技术（ＰＣＲ），对１２０例不孕和１００例查体妇女的宫颈内膜标本进行沙眼衣原体检测，以了解女性沙眼衣原体感染与自发流产的关系，并与一般细胞培养法进行了比较。结果：不孕妇女中沙眼衣原体感染率为１８．３％，显著高于对照组（８％Ｐ＜０．０５），并且自发流产３次、４次的妇女沙眼衣原体阳性率明显高于对照组（Ｐ＜０．０１）．敏感性也较一般培养法高（Ｐ＜０．０１）。本研究提示：沙眼衣原体感染与自发性习惯性流产关系十分密切，而且ＰＣＲ法在检测沙眼衣原体感染方面较一般培养法更敏感、快速，是早期诊断生殖道沙眼衣原体感染的一项有价值的方法。     

Delineation of producing ability of IgG and IgA subclasses by naive B cells in newborn infants and adult individuals

Neonatal B cells with the naive (sIgD⁺) phenotype are able to generate IgG- and IgA-producing cells as well as IgM production in the presence of memory CD4⁺ T cells expressing L-selectin (CD62L) in pokeweed mitogen-stimulated cultures. We used this system to examine comparatively the ability of naive B cells to produce IgG and IgA subclasses in newborn infants and adult individuals. Naive B cells were enriched from both donors on the basis of sIgD positivity, and memory (CD45RO⁺) CD4⁺ T cells with CD62L expression were isolated from adults. We here demonstrate some differences in profiles of IgG and IgA subclass production between neonatal and adult naive B cells. In neonatal B cells, IgG1 and IgG3 were predominantly produced, but IgG2 and IgG4 production was virtually absent. Similar to neonatal B cells, adult naive B cells produced mainly IgGq and IgG3, although memory (sIgD’) B cells from adults secreted all of the IgG subclasses. It should be noted that low but detectable levels of IgG2 and IgG4 were found in adults’naive B cell cultures. Although IgA produced by neonatal B cells was exclusively IgA1, IgA2-secreting cells were identifiable in adult naive B cells. The results suggest that further class switch of naive B cells to IgG2, IgG4 and IgA2 in addition to IgG1 and IgG3 may be controlled by their own age-dependent maturation process.     

Rescue of IgM,IgG, and IgA production in common varied immunodeficiency by T cell-independent stimulation with Epstein-Barr virus

We previously defined three categories of B-cell defects in common varied immunodeficiency (CVI): failure to produce IgG and IgA in response to T cell-dependent (TD) stimulation byStaphylococcus bacteria (Sac) plus pokeweed mitogen or B-cell inducing factor (BIF), failure to produce any immunoglobulin, and failure of Sac-induced proflieration and differentiation. The present study includes the responses of 22 CVI patients to T cell-independent (TI) stimulation by Epstein-Barr virus (EBV). In the majority of patients, EBV-stimulated B cells showed normal proliferation and IgM production. In addition, IgG and IgA production was in the range of that for EBV-stimulated normal cells in many patients. Among 11 patients with no TD production of immunoglobulin of any isotype, two showed normal IgM secretion in response to EBV and five others had significant but subnormal responses. Four patients never had humoral responses despite repeated testing and removal of potentially suppressing T cells and monocytes. Concanavalin A stimulation of the T cells from all the patients tested resulted in the production of B-cell inducing factor at higher levels than for normal donor T cells, as assayed on normal Sac-stimulated B cells. These results show that many cases of B-cell defects in CVI patients involving TD production of IgM, switching to TD production of IgG and IgA, and mitogen responses to Sac are not absolute defects. The B cells will respond normally to some stimuli.     

Targeting C3a/C5a receptors inhibits human mesangial cell proliferation and alleviates immunoglobulin A nephropathy in mice

Complement activation has a deep pathogenic influence in immunoglobulin (Ig)A nephropathy (IgAN). C3a and C5a, small cleavage fragments generated by complement activation, are key mediators of inflammation. The fragments exert broad proinflammatory effects by binding to specific receptors (C3aR and C5aR, respectively). However, no studies thus far have investigated the effects of C3a, C5a and their receptors on IgAN. We observed that C3aR and C5aR antagonists repressed IgA‐induced cell proliferation and interleukin (IL)‐6 and monocyte chemotactic protein 1 (MCP‐1) production in cultured human mesangial cells (HMCs). Furthermore, an IgAN mouse model induced by Sendai virus infection was employed to investigate the effects of C3aR and C5aR on IgAN in vivo for the first time. Wild‐type (WT) and several knock‐out mouse strains (C3aR^–/– or C5aR^–/–) were immunized intranasally with increasing doses of inactivated virus for 14 weeks and were subjected to two intravenous viral challenges during the time‐period indicated. In the Sendai virus‐induced IgAN model, C3aR/C5aR‐deficient mice had significantly reduced proteinuria, lower renal IgA and C3 deposition, less histological damage and reduced mesangial proliferation compared with WT mice. Both C3aR deficiency and C5aR deficiency, especially C3aR deficiency, inhibited renal tumour necrosis factor (TNF)‐α, transforming growth factor (TGF)‐β, IL‐1β, IL‐6 and MCP‐1 expression significantly. However, C3aR/C5aR‐deficient and WT mice with IgAN did not differ with respect to their blood urea nitrogen (BUN) and serum creatinine levels. Our findings provide further support for the idea that C3aR and C5aR are crucially important in IgAN, and suggest that pharmaceutically targeting C3aR/C5aR may hold promise for the treatment of IgAN.