Cells producing antibody to measles and herpes simplex virus in cerebrospinal fluid and blood of patients with multiple sclerosis and controls.

The B cell response against measles and herpes simplex virus (HSV) was evaluated in cerebrospinal fluid (CSF) and peripheral blood from patients with multiple sclerosis (MS) and controls by enumeration of cells secreting anti-measles and anti-HSV antibodies of IgG, IgA and IgM isotypes. We used a nitrocellulose immunospot assay which enables parallel enumeration of numbers of cells secreting total IgG, IgA and IgM. Anti-measles IgG antibody-secreting cells were present in CSF from 21 of 24 MS patients (mean 24 cells/10(4) mononuclear cells), and against HSV in CSF from seven of eight patients (mean 23/10(4) cells). No antibody-secreting cells were detectable in the patients' blood. Ten MS patients examined were negative for cells in CSF and blood producing anti-measles antibodies of IgA and IgM isotypes. Anti-measles IgG antibody secreting cells were also found in CSF from four of 18 controls, and anti-HSV IgG antibody-secreting cells in six of 13, especially in patients with subacute or chronic inflammatory nervous system diseases. Our results confirm that viral antibodies in MS are produced within CSF and that this B cell response is preferentially sequestered to this compartment. Whether this viral B cell response in MS reflects specific activation due to persistence of viral antigens or an epiphenomenon remains to be clarified.     

Kappa/Lambda Ratios In IgG,IgA and IgM of Cerebrospinal Fluid and of Sera in Patients with Multiple Sclerosis

Kappa/lambda (κ/λ) ratios of each immunoglobulin, i.e. IgG, IgA and IgM in cerebrospinal fluid (CSF) and in sera of patients with multiple sclerosis (MS) were analysed by sandwich enzyme linked immunosorbent assay. In CSF κ/λ ratios of IgG of MS patients were significantly (p < 0.05) higher than those of normal controls, whereas the values of IgA and IgM did not differ significantly from those of normal controls. In sera κ/λ ratios of IgG, IgA and IgM did not differ significantly from those of normal controls. Our results suggest that in MS patients abnormal κ/λ ratios are also restricted to IgG components in CSF, as oligoclonal IgG bands are.     

Kappa/lambda ratios in IgG, IgA and IgM of cerebrospinal fluid and of sera in patients with multiple sclerosis

Kappa/lambda (kappa/lambda) ratios of each immunoglobulin, i.e. IgG, IgA and IgM in cerebrospinal fluid (CSF) and in sera of patients with multiple sclerosis (MS) were analysed by sandwich enzyme linked immunosorbent assay. In CSF kappa/lambda ratios of IgG of MS patients were significantly (p less than 0.05) higher than those of normal controls, whereas the values of IgA and IgM did not differ significantly from those of normal controls. In sera kappa/lambda ratios of IgG, IgA and IgM did not differ significantly from those of normal controls. Our results suggest that in MS patients abnormal kappa/lambda ratios are also restricted to IgG components in CSF, as oligoclonal IgG bands are.     

Immunoglobulin G, A, and M--clonal restriction in multiple sclerosis cerebrospinal fluid and serum--analysis by two-dimensional electrophoresis

Immunoglobulin G, A, and M (IgG, IgA, and IgM) were purified from multiple sclerosis (MS) cerebrospinal fluid (CSF) and sera and analyzed by two-dimensional electrophoresis. The light (L)-chains of MS CSF IgG were of limited diversity and dominated by about 30 major spots and many less intense spots. CSF IgG of patients with subacute sclerosing panencephalitis (SSPE) was dominated by 10 to 20 intense L-chain spots. L-chains from patients with fungal, syphilitic, and tuberculous infections of the central nervous system (CNS) ranged from 70 to in excess of 300 spots. The patterns of L-chains in MS CSF and autologous sera were different, indicating amplified synthesis of particular L-chains in MS CNS. Cathodic IgG fractions differing in isoelectric point by 0.1 to 0.3 pH units were isolated. SSPE CSF IgG fractions were dominated by a few L-chain spots, MS CSF fractions contained less than 20 spots, and MS serum fractions contained about 200 spots. MS CSF mu-chains were similar in isoelectric point range to serum but fractionated into discrete spots compared with a diffuse pattern in serum. MS CSF IgA alpha-chain spot overlapped in mobility with serum alpha-chains except a portion of the alpha-chain complex in CSF was shifted cathodically forming discrete spots. The CSF L-chains of both IgM and IgA were completely dissimilar to serum. These studies indicate major limited diversity and compartmentalized CNS synthesis of IgG, IgA, and IgM in MS. The restricted clonal pattern is proposed as consequent to B-cell stimulation by disease-related antigen(s) with limited epitope complexity. The dominance of a small number of L-chains supports results from idiotypic analysis suggesting finite clonal complexity of MS CSF IgG and indicates the feasibility of structural analysis of MS CSF L-chains, particularly amino acid sequence determinations.     

Multiple Sclerosis: Cells Secreting Antibodies Against Myelin-Associated Glycoprotein are Present in Cerebrospinal Fluid

We evaluated the B-cell response in cerebrospinal fluid (CSF) and blood by enumerating cells secreting antibodies to myelin-associated glycoprotein (MAG) and, for reference, to myelin basic protein (MBP), two myelin components which may constitute targets for autoimmune attack in multiple sclerosis (MS). Among 25 untreated MS patients, 12 had cells in CSF secreting anti-MAG IgG antibodies (mean value 1 per 1429 CSF cells) and three also had cells secreting anti-MAG antibodies of the IgM isotype but at lower levels. In CSF from 2 out of 10 MS patients examined, anti-MAG and anti-MBP IgG antibody-secreting cells were present concurrently. Antibody-secreting cells were less frequent in blood and bone marrow, reflecting compartmentalization to CSF. Anti-MAG antibody-secreting cells were found in CSF from only 1 out of 27 control patients. The intrathecal production of anti-MAG and anti-MBP antibodies may be important in the pathogenesis of MS.     

Increased spontaneous immunoglobulin secretion associated with cyclophosphamide-induced immune suppression

Spontaneous immunoglobulin (Ig) secretion by cells from multiple sclerosis (MS) patients (in the progressive phase) treated with monthly pulse doses of cyclophosphamide (CY) (1000–1600 mg/M²) was measured using the protein A plaque assay, to evaluate the effect of CY treatment on B-cell function. Surprisingly, an increase, rather than a decrease, in Ig-secreting cells was seen following CY treatment. CY-treated MS patients averaged 1380±535 spontaneous total (IgM+G+A) Ig plaque-forming cells (PFC) per 1×10⁶ peripheral blood mononuclear cells (MNC), measured at 15–22 days after monthly CY administration, while healthy adults had 280±47 Ig PFC/10⁶ MNC, and MS patients not treated with CY had 300±43 Ig PFC/10⁶ MNC. The observed increase was due to an increase in IgG and IgA PFC. PFC levels remained elevated for 4 weeks following CY treatment, decreasing to control levels by 7–8 weeks post-CY. A small increase in serum IgG level was noted after >12 months of pulse CY therapy; no increase was seen in CSF IgG levels. A preferential decrease in the number of CD4+ T cells was also seen in the CY-treated MS patients. We propose that the observed increase in the number of spontaneous Ig PFC was due to the CY-induced disruption of the CD4+ T cell-mediated control ofin vivo activated B cells.     

T cell dependent differentiation of human B cells: direct switch from IgM to IgE, and sequential switch from IgM via IgG to IgA production.

Ig production by splenic human B cells that express different surface Ig isotypes were analysed in limiting dilution cultures. Therefore, FACS sorted IgM+, IgG+ and IgA1+ B cells were stimulated with PMA-activated EL4 thymoma cells as helper cells in the presence of IL-2 and IL-4. We found that at least every second B cell responded in vitro and secreted the antibody corresponding to its surface Ig isotype. IgE secreting cells developed from surface IgM+ D+ cells (1/31 to 1/167), but not from IgG+ or IgA1+ cells (much less than 1/5000). Negative signalling of the IgM+ B cells by addition of anti-IgM antibodies into the cultures reduced the number of single IgM producing cells by greater than 85%, and completely inhibited IgE switch. In contrast, anti-IgG and anti-IgA antibodies did not reduce the IgE response. The results indicate a direct switch from IgM to IgE secretion in vitro. In contrast to IgE, IgA secreting cells developed from IgM+D+ (1/30 to 1/51) and from IgG+ B cells (1/14 to 1/25). Negative signalling of the IgG+ B cell subset within total B cells by anti-IgG antibodies suppressed the development of IgG as well as IgA producing cells, but did not inhibit IgM and IgE responses. This indicates a sequential switch from IgM via IgG to IgA. Taken together, this study indicates that IgE secreting cells are derived directly from IgM+D+ B cells by non-sequential switching, whereas IgA producing cells preferentially develop by sequential switching via IgG+ B cells.     

Spontaneous antibody-secreting human blood lymphocytes detected with a protein A plaque assay.

Spontaneous antibody-secreting lymphocytes in human peripheral blood were detected and counted by a protein A plaque assay. The level of plaque-forming cells (PFC) in peripheral blood was significantly higher in patients with immune disorders (per 10(6) lymphocytes: IgG PFC, 2,654 +/- 684; IgA PFC, 1,727 +/- 327; IgM PFC, 403 +/- 92) than in normal controls (per 10(6) lymphocytes: IgG PFC, 327 +/- 56; IgA PFC 633 +/- 128; IgM PFC, 215 +/- 105). There was no direct correlation between the PFC numbers of different Ig classes.     

Monoclonal IgM, IgA and IgG in the serum of a single individual: immunofluorescence identification of cells producing the immunoglobulins.

Monoclonal IgM(?) and IgA(?) in the serum of patient CM were previously shown to share identical, individually specific (Ind) or idiotypic antigenic determinants. A component in the IgG fraction of CM's serum was shown by one of the assay systems to also share Ind determinants with the IgA and IgM. Recent experiments have indicated that the CM IgG monoclonal protein also shares identical Ind determinants with the other two CM immunoglobulins (Ig). These results suggested that the variable regions of the heavy and light chains of the three different classes of Ig were very similar. A direct immunofluorescence assay was used in this study on bone marrow smears of patient CM obtained at two different dates to identify the cells producing these Ig. The reaction of antisera specific for Ind determinants demonstrated that most plasma cells, whether containing IgM, IgA, or IgG, stained with the anti-Ind antisera; this occurred irrespective of whether the anti-Ind antisera were generated to the patient's IgM or IgA. The reaction with isotypic antisera revealed cell populations containing either IgM, IgA, or IgG and a significant cell population containing both IgM and IgA. The common occurrence of IgM and IgA-containing cells which synthesize monoclonal Ig with shared Ind determinants provides evidence consistent with the IgM-IgA pathway of differentiation of antibody-producing cells. Further, the tendency toward decreasing numbers of IgM-staining cells with concomitant increasing numbers of IgA and IgG-containing cells suggests that the clones of cells producing these Ig were derived from a single precursor cell.     

T-Cell Helper Activity and B-Cell Function of Synovial and Blood Lymphocytes from Patients with Rheumatoid Arthritis or Other Forms of Chronic Arthritis

The helper effect of T cells on B-cell immunoglobulin (Ig) responses induced by pokeweed mitogen (PWM) or purified protein derivative of tuberculin (PPD) was studied in lymphocytes from synovial fluid (SF) and blood of nine patients with rheumatoid arthritis (RA) and eight patients with other forms of chronic arthritis. In PWM cultures the helper effect of SF T cells on Ig responses (IgG, IgM, IgA) of autologous and allogeneic blood B cells was lower than that of blood T cells (P less than 0.01). This decrease was more pronounced in patients with RA than in patients with non-RA. In PPD cultures no significant difference was found between the helper effect of SF T cells and blood T cells on the Ig responses of allogeneic blood B cells or on the IgG response of autologous blood B cells, whereas the helper effect of SF T cells on the IgM and IgA responses of autologous blood B cells was decreased. The Ig responses to PWM or PPD in cocultures of autologous blood B and T cells were not significantly different between patients and healthy controls. The PWM- and PPD-induced Ig responses of SF B cells were lower than those of blood B cells when cocultured with autologous blood T cells. SF B cells produced IgG but usually little IgM and IgA. Thus there was a dysfunction of SF B cells and of SF T cells in a PWM-driven system, but a fairly good helper function of SF T cells in a PPD-driven system.     

Humoral immune response in patients with IgA and IgM glomerulonephritis.

A single dose of inactivated mumps virus vaccine was administered to male patients with IgA glomerulonephritis (IgA-GN), IgM glomerulonephritis (IgM-GN) and to healthy males. Antibodies to mumps virus were determined using an enzyme-linked immunosorbent assay. Patients with IgA-GN showed a higher and more sustained IgG and IgA antibody response compared to patients with IgM-GN or healthy controls. Before vaccination, patients with IgM-GN had higher levels of IgG antibodies than the controls or those with IgA-GN. However, the IgA antibody and IgG responses after vaccination were low. IgM antibody responses did not vary among the groups studied. It is concluded that patients with IgA-GN are high responders for IgA and IgG antibody production. Patients with IgM-GN are low responders, especially for IgA antibody.     

Lymphocyte Populations in the Cerebrospinal Fluid and Peripheral Blood of Patients with Multiple Sclerosis and Optic Neuritis

The cerebrospinal fluid (CSF) and peripheral blood (PB) of patients with multiple sclerosis (MS), optic neuritis (ON), and aseptic meningitis (AM) were studied with respect to the percentage of B cells (using membrane Ig fluorescence), T cells, and T-cell subpopulations (using a rosetting technique or monoclonal antibodies). In the PB of all three patient groups there were normal B-cell levels but a significant decrease in T cells compared with PB of normal individuals. In the CSF the B cells were reduced but the T cells elevated when compared with the PB of the patients, and these differences were statistically significant. The level of total T cells was not influenced by disease activity in MS or ON, but there was a significant reduction of suppressor cells in PB during disease activity in MS patients. In CSF there were also fewer suppressor cells during active disease, but the reduction was not statistically significant. Differences in B and T cells in CSF and PB indicate that the immune reactions within the central nervous system are at least partially isolated from the rest of the immune system. The changes in the T-cell subpopulations in MS support the evidence for an immunoregulatory defect in this disease.     

The clinical condition of IgA-deficient patients is related to the proportion of IgD- and IgM-producing cells in their nasal mucosa

Nasal biopsy specimens from 15 adult patients with selective IgA deficiency but normal IgG-subclass levels were examined by immunohistochemistry for the presence of immunocytes producing various Ig isotypes. The mucosal samples were completely IgA-deficient except in two cases where 0.9% and 8.4% IgA cells were found, respectively (normal, 69.8%). Numerous IgG- (mainly IgG1-) producing cells were present in 10 samples; in five of these there were additional IgM- but virtually no IgD-producing cells, whereas in the other five a marked dominance of the IgD over the IgM isotype was seen. The latter category of patients had more upper airways infections (recurrent acute rhinosinusitis, otitis media, and tonsillitis) than the former, who had no recurrent upper respiratory tract infections except one patient with recurrent acute rhinosinusitis. The five remaining samples, which contained very few Ig-producing cells, were derived from patients with even more frequent infections than those showing IgD predominance. Our results indicate that IgM acts as a compensatory secretory Ig in the upper respiratory tract of some IgA-deficient subjects. However, immunoregulatory events favouring local IgD responses apparently do not support mucosal defence satisfactorily, either because local production of IgM is hampered or because IgD (which is not a secretory Ig) blocks complement-dependent reactions mediated by IgG and IgM antibodies within the mucosa.     

B cells and antibodies in MS

When the B-cell response was examined by enumeration of immunoglobulin (Ig)-secreting cells, normal cerebrospinal fluid (CSF)--in contrast to previous beliefs--contained IgG-secreting cells, indeed at an 8-fold higher proportion per 10(4) mononuclear cells (MNC) than blood. As expected, the proportion of IgG-producing cells was greatly increased in MS CSF. Evaluation of antibody (Ab) responses at the cellular level, thereby bypassing draw-backs inherent in determinations of circulating Ab levels, such as Ab binding to target, revealed that in one MS patient group, 57% had, in CSF, cells secreting IgG Ab against myelin basic protein (MBP) and, in another MS group, 55% had, in CSF, cells producing IgG Ab against myelin-associated glycoprotein (MAG); both MBP and MAG are possible targets for immune attack in MS. Anti-MBP and anti-MAG IgG antibody-secreting cells could occur in parallel or independently. They were rarely detected in blood, reflecting strong sequestration in CNS CSF. Their possible role in MS pathogenesis is envisaged in light of recently suggested coupling between polyclonal B-cell hyperresponsiveness and antigen-driven specific responses in autoimmune-prone individuals.     

Antibodies to polyclonal IgA,IgA1, and IgA2 and isotype-specific immune complexes in IgA nephropathy

The concentrations of serum IgG and IgM antibodies to polyclonal IgA (IgA_p), IgA₁, and IgA₂ were determined by enzyme immunoassay in 31 patients with IgA nephropathy and 30 healthy controls. Patients with IgA nephropathy had significantly raised concentrations of serum IgA compared to controls (Mann-WhitneyU test,P=0.001) and increased concentrations of conglutinin-binding IgA immune complexes (P=0.024). No differences in the median concentrations of IgG and IgM anti-IgA antibodies were found between the patients and the controls. In serum samples from healthy controls there was a significant positive correlation between IgM anti-IgA_p and IgA immune complex concentrations (P=0.05), which contrasted with the finding of an inverse correlation between IgM anti-IgA_p and IgA immune complex concentrations in patients with IgA nephropathy (P<0.05). In addition, the concentrations of conglutinin binding IgM immune complexes in serum were found to correlate with the concentration of IgM anti-IgA_p (0.010<P<0.025), IgM anti-IgA₁, and IgM anti-IgA₂ (P«0.005 for both) in patients with IgA nephropathy but not in controls. IgM anti-IgA antibodies may be important in augmenting the clearance of IgA immune complexes from the serum of patients with IgA nephropathy.     

Analysis of IgG subclass production in cell cultures from IgA deficient patients and in normal controls as a function of age

IgA deficient individuals may also have low serum levels of IgG subclasses, especially IgG2. In the present study we examined the development of plasma cells producing IgM, IgA or IgG, and the IgG1 and IgG2 subclasses, following lipopolysaccharide (LPS) and pokeweed mitogen (PWM) stimulation of mononuclear cells (MNC) from normal and IgA deficient individuals as a function of age. Studies of blood MNC from 38 normal donors (age range 2-44 years) revealed an age-related distribution pattern of mu, gamma, alpha, gamma 1 and gamma 2 plasma cells produced in mitogen-stimulated and control cultures. Decreased IgA responses to both LPS and PWM were consistently observed in cultures of MNC from all of the nine children with IgA deficiency. When compared with age-matched controls the IgG response was also diminished in PWM stimulated cultures, whereas the IgM responses were normal. The IgG deficit was due to reduced responses for the gamma 1 and gamma 2 subclasses, and was most pronounced for IgG2; IgG2 plasma cell differentiation was particularly depressed in LPS cultures. In contrast to normal adult cells, blood MNC from the nine children with IgA deficiency and age-matched controls (2-17 years) yielded more IgG1 than IgG2 plasma cells in both control and LPS cultures, while the pattern of response to PWM was similar in all groups (gamma 1 greater than gamma 2). A good concordance was found between the level of secreted Ig in the culture supernatants and the relative number of IgM or, IgG and IgA plasma cells identified by immunofluorescence staining of cytoplasmic immunoglobulins.     

Genital secretory immune response to chronic simian immunodeficiency virus (SIV) infection: a comparison between intravenously and genitally inoculated rhesus macaques.

The humoral and genital secretory immune response to chronic SIV infection was compared between female Rhesus macaques inoculated by i.v. or intravaginal routes. Total IgG levels in serum were 10-fold higher in SIV-infected animals when compared with uninfected controls. Vaginal washes from normal macaques contained predominantly IgA and IgG, while those from SIV-infected animals contained high levels of IgG. The SIV-infected animals had high titres of SIV-specific IgG in serum, with lower but detectable IgA and IgM responses. The genital secretory immune response to SIV was similar in intravenously and intravaginally inoculated animals. The anti-SIV response in the vaginal washes consisted mainly of IgG. Within the lamina propria of the reproductive tract of animals chronically infected with SIV there were essentially no IgA or IgG plasma cells and only a small number of IgM plasma cells, while two normal animals had large numbers of IgA plasma cells. These results suggest that the mucosal immune system of the female reproductive tract is impaired in chronic SIV infection.     

Differential requirements for induction of total immunoglobulin and physiological rheumatoid factor production by human peripheral blood B cells

Rheumatoid factors (RFs) are autoantibodies directed against the Fc part of IgG. Considerable evidence exists that there are two classes of RFs, pathological and physiological. Whereas pathological RFs are associated with disease, physiological RFs are considered to be a normal component of the immune response. RF(+) precursor B cells present as part of the B cell repertoire of healthy individuals are held responsible for the production of physiological RFs, which is a transient phenomenon with a clear correlation with an initiating stimulus such as immunization or exposure to an infection. Here we demonstrate a difference in the regulatory control of total Ig and RF production by peripheral blood (PB) B cells of both healthy controls (HC) and patients with rheumatoid arthritis (RA). Highly purified B cells from HC and patients with RA were cocultured with T cells stimulated with immobilized anti-CD3 mAb. Similar to IgM production, IgM-RF production was shown to be dependent on CD40 cross-linking. However, activation of PB B cells in the CD40 system in the presence of IL-2, IL-4, IL-10, combinations of these cytokines or supernatant of anti-CD3-stimulated T cells failed to induce detectable IgM-RF, whereas total IgM production was considerable. From these results we conclude that conditions to activate physiological RF(+) B cells require additional contact besides CD40--CD40L interactions between T and B cells. Since the requirements for RF production were similar using PB B cells from HC and patients with RA it is suggested that the regulatory properties of RF(+) precursors in the PB B cell compartment is equal among these groups. Together, these results indicate that conditions for the induction of total Ig and physiological RFs are different.     

T cells from multiple sclerosis patients recognize multiple epitopes on Self-IgG

The highly diversified variable regions of immunoglobulin (Ig) molecules contain immunogenic determinants denoted idiotopes. We have previously reported that T cells from multiple sclerosis (MS) patients recognize IgG from autologous cerebrospinal fluid (CSF), and mapped a T-cell epitope to an IgG idiotope. To test the ability of CSF IgG molecules to elicit a broad polyclonal T-cell response in MS, we have analysed T-cell responses in the blood and CSF against idiotope peptides spanning complementarity determining region (CDR) 3 and somatic mutations within the variable regions of monoclonal CSF IgG. Consistent with a diversified idiotope-specific T-cell repertoire, CD4(+) T cells from both patients recognized several idiotope peptides presented by HLA-DR molecules. Mutations were critical for T-cell recognition, as T cells specific for a mutated CDR1 peptide did not recognize corresponding germline-encoded peptides. One T-cell clone recognized both an idiotope peptide and the B-cell clone expressing this idiotope, compatible with endogenous processing and presentation of this idiotope by B cells. These results suggest that mutated CSF IgG from MS patients carry several T-cell epitopes, which could mediate intrathecal IgG production and inflammation in MS through idiotope-driven T-B-cell collaboration.     

High levels of immunoglobulin E and a continuous increase in immunoglobulin G and immunoglobulin M by age in children with newly diagnosed type 1 diabetes

The incidence of type 1 diabetes (T1D) is increasing, either because of environmental factors accelerating onset of the disease or because of inducement of autoimmune diabetes in children who previously were at lower risk. High levels of immunoglobulin (Ig), specifically, IgM and IgA, and a low level of IgG were reported in adult patients; however no studies have analyzed the increasing incidence in relation to Ig levels. Our aim was to describe Ig in children newly diagnosed with diabetes and in their healthy siblings. Children with T1D expressed significantly lower IgG (p < 0.01) and higher IgA levels (p = 0.045), whereas no differences in IgE or IgM (p > 0.5) levels were found. Age-specific levels were unchanged over a 9-year period. In patients and siblings IgG, IgA and IgE increased by age (p < 0.001); which was in contrast to IgM (p > 0.05). The continued increase in IgG levels by age indicates that adult levels are reached later than in previously studied cohorts, thereby indicating a slower maturation of the immune system.