The use of ion exchange chromatography for demonstration of rubella-specific IgM antibodies

IgM and IgG immunoglobulins of human sera were separated by stepwise column chromatography in QAE-Sephadex A-25 ion exchanger gel bed. The procedure resulted within 30 min in a fraction suitable for direct titration of rubella-specific IgM antibodies by haemagglutination inhibition test. The method proved to be a useful diagnostic tool for primary rubella. Serum samples of 13 individuals with previously acquired immunity, 152 patients with a recent rubella-like illness, and 194 pregnant women exposed to rubella infection were tested for the presence of rubella-specific IgM antibodies. Sera of individuals with previous immunity proved to be negative for specific IgM antibodies. Specific IgM titre was demonstrated in the blood of all the 25 patients with significant titre-rise tested because of rubella-like illness, and also in the sera of additional 8 patients whose serum samples were taken too late for demonstration of a rise in titre. Significant titre-rises were found in 5 women exposed to rubella infection, but only two of them exhibited rubella-specific IgM antibodies. The absence of specific IgM antibodies refers presumably to subclinical reinfection in the other three cases.     

The significance of specific IgM antibody in the diagnosis of rubella employing the immunofluorescence technique

The applicability of the immunofluorescence (IF) test to the diagnosis of primary rubella infection was investigated. The test is based on the detection of rubella-specific antibodies in the IgM fraction of immunoglobulins. The results indicate the usefulness of the IF test for the diagnosis of primary rubella infection on a single serum specimen collected at a proper time. The test is also of value in the differentiation of primary infection from reinfection, since in reinfection no rubella-specific antibodies are found in the IgM fraction. The test is also valuable for the detection of fetal infection in utero since the persistence of IgM antibodies in pregnant women is indicative of fetal infection.     

Serological Assessment of Rubella During Pregnancy

In 45 patients with rubella-like illnesses during pregnancy serological tests showed that the clinical diagnosis had been accurate in only 20. Since only 16 of these patients had presented for laboratory investigations within a week of the onset of symptoms, the value of haemagglutination-inhibition tests was considerably reduced; the diagnosis in these cases was confirmed by complement-fixation and rubella-specific IgM tests.Of 172 patients exposed to a rubella-like illness, only 17 were seronegative; 105 sought advice within two weeks of exposure, and therefore the haemagglutination-inhibition antibody tests were useful in determining immunity. Since the clinical diagnosis of rubella was proved incorrect in a number of cases, these pregnancies were saved. Hence both doctors and patients should report both exposure to and rubella-like illnesses as early as possible, so that laboratory investigations may be carried out without delay.     

Letter: Spontaneous pelvic thrombosis in the postmenopausal woman.

An epidemic of rubella reached its peak in the Atlantic provinces in 1974, subsiding in early 1975. With the exception of Quebec the remainder of Canada showed a reverse trend, with a large increase in the numbers of cases reported in the first 41/2 months of 1975. The Halifax virus laboratory reported 106 serologically proven cases of rubella in 1974, 44 of them in pregnant women. In the aftermath of the epidemic many infants were born with the congenital rubella syndrome (CRS). A study carried out from Sept. 1, 1974 through Apr. 30, 1975 showed an 80% correlation between clinical diagnosis and the presence of rubella-specific IgM antibodies in 35 of these infants. Of the 23 infants in whom the diagnosis of CRS was made by laboratory or clinical findings or both, laboratory criteria were met in 20 (87.0%), clinical criteria in 19 (82.6%) and both laboratory and clinical criteria in 16 (69.6%).     

Immunoglobulin subclasses of antibodies to human T-cell leukemia/lymphoma virus I-associated antigens in acquired immune deficiency syndrome and lymphadenopathy syndrome

Immunoglobulin G (IgG) and IgM antibodies to human T-cell leukemia/lymphoma virus-I (HTLV-I)-associated membrane antigens (HTLV-I-MA) were assayed by indirect cytospin immunofluorescence, and IgG and IgM antibodies to purified HTLV-I were assayed by enzyme-linked immunosorbent assay in sera from 119 immunologically well-characterized promiscuous male homosexuals in The Netherlands, of whom 9 suffered from acquired immune deficiency syndrome (AIDS), 18 suffered from lymphadenopathy syndrome (LAS), and 5 suffered from gay bowel syndrome. Antibodies to HTLV-I-MA were present in four of nine AIDS patients, including one patient with antibodies to purified HTLV-I. Antibodies to HTLV-I-MA were present in 6 of 18 LAS patients, including 3 patients with antibodies to purified HTLV-I. Of five patients with gay bowel syndrome, one had IgG and IgM antibodies to HTLV-I-MA. Of the four HTLV-I seropositive AIDS patients, two had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, one had only IgG antibodies, and one had only IgM antibodies. Of the six HTLV-I seropositive LAS patients, four had IgG and IgM antibodies to HTLV-I or HTLV-I-MA, and two had only IgM antibodies. In the sera from 27 healthy homosexuals with and 60 without T-cell subset imbalances, no antibodies to HTLV-I or HTLV-I-MA were detected.     

Waldenstr?m's macroglobulinemia: review of 45 cases.

Of 168 patients with monoclonal IgM in the serum 45 (27%) had Waldenström''s macroglobulinemia. The mean age at diagnosis was 66 years. Generalized weakness, fatigue and bleeding manifestations were the usual chief complaints. Lymphadenopathy and hepatosplenomegaly were frequent. Moderate or severe anemia was noted in 29 patients, 9 had abnormal liver function, 8 had cold agglutinemia and 7 had cryoglobulinemia. Two patients had false-positive VDRL tests. The serum concentration of IgM usually exceeded 1000 mg/dl. Comparison of IgM values obtained by immunoquantitation and electrophoresis showed two types of discrepancy: readings were too high by immunoquantitation when IgM of low molecular weight was present, and readings were too low when, probably, IgM/IgG complexes were present or the serum was hyperviscous. Bence Jones protein was detected in 71% of the urine samples tested but the concentration was usually low, exceeding 200 mg/24 h in only nine instances. The mean survival time from the time of diagnosis for the 24 patients who died was 49.5 months and for the patients who are still alive, 43 months. Survival seemed to be related to the presence of azotemia, hypoalbuminemia and abnormal liver function.     

The role of IgG avidity in diagnosis of cytomegalovirus infection in newborns and infants

To evaluate the value of IgG avidity in diagnosis of congenital cytomegalovirus (CMV) infection in newborns and infants we collected serum samples from 40 infants under 12 months of age with suspected congenital CMV infection. Sera were tested for IgM, IgG and IgG avidity. For 25 of them, virus isolation and/or polymerase chain reaction (PCR) on urine specimens were performed. Thirteen (32.5%) patients showed the presence of CMV IgM antibodies, 3 (7.5%) had equivocal IgM result, and 24 (60.0%) patients had IgG antibodies only. Using IgG avidity, CMV infection (low avidity index-AI) was documented in 61.5% IgM positive and 54.2% IgM negative patients. Eight of nine (88.8%) IgM positive patients were positive either on virus isolation or PCR. In IgM negative patients, 46.6% urine cultures were positive for CMV and 66.6% were PCR positive. According to age, IgG avidity demonstrated acute/recent primary CMV infection in 58.8% patients younger than three months compared with 91.7% and 81.8% in 3-6 and 6-12 months old babies, respectively. In conclusion, IgG avidity is useful in diagnosis of CMV infection either in IgM positive or IgM negative children older than 3 months of age. In infants less than 3 months, transplacentally derived maternal IgG antibodies of high avidity influence on the IgG avidity result. In these children, CMV infection should be confirmed by direct virologic methods such as virus isolation or PCR.     

Significance of Isolated Positive IgM Serologic Results by Enzyme Immunoassay for Coccidioidomycosis

Serologic testing is important for diagnosis of coccidioidomycosis. Many methods are available for diagnostic testing. Enzyme immunoassay (EIA) can be performed quickly and locally but has the potential for false-positive results in patients manifesting a positive EIA for immunoglobulin M (IgM) antibodies and a negative EIA for immunoglobulin G (IgG). We retrospectively reviewed the charts of 405 patients with coccidioidal serologic testing performed between 1999 and 2003. Of 706 EIAs, 37 (5%) produced test results for 28 patients that showed isolated IgM positivity. Among these 28 patients, 24 (86%) had positive serologic findings by other methods (complement fixation or immunodiffusion or both), and 7 (25%) had positive microbiologic or histopathologic findings. All 4 (14%) patients without other positive serologic results had diagnostic tests with positive microbiologic or histopathologic results. No false-positive IgM assays were observed. We conclude that the false-positive rate of the EIA IgM is low, and that an isolated positive EIA IgM should prompt further follow-up and diagnostic testing. J. T. Currier was a Visiting Research Trainee at the Division of Infectious Diseases, Mayo Clinic, Scottsdale, AZ.     

Renal graft dysfunction during infection with cytomegalovirus: association with IgM lymphocytotoxins and HLA-DR3 and DR7.

Of 121 consecutive adult recipients of cadaver renal transplants who were treated with low dose steroids and azathioprine, 23 developed active cytomegalovirus infections. These 23 patients were divided into three groups on the basis of their symptoms related to the infection: five patients had no renal, respiratory, or haematological abnormalities; seven had renal dysfunction; and nine had renal dysfunction plus respiratory or haematological abnormalities. Two patients were regarded as a separate group because their infections occurred two to four weeks after graft nephrectomy. All but three of the patients produced IgM or IgG lymphocytotoxins during their infections. In the patients with mild infections and in control patients without infections, however, these lymphocytotoxins were predominantly IgG antibodies that were not precipitated by 3.5% macrogol (polyethylene glycol). In contrast, 12 of the 16 patients with renal dysfunction during their infections had broadly reactive IgM lymphocytotoxins. These IgM lymphocytotoxins lysed T as well as B lymphocytes at 22 degrees C and were precipitated by 3.5% macrogol, suggesting that they were circulating as immune complexes. Rheumatoid factors were found in sera from nine patients with cytomegalovirus infections, seven of whom developed leukopenia or pneumonia, or both, in addition to renal dysfunction. Some of these immune responses associated with cytomegalovirus infection in transplant recipients may be genetically controlled since 10 of 11 patients positive for HLA-DR3 or DR7 produced IgM lymphocytotoxins.     

BK antibody and virus-specific IgM responses in renal transplant recipients,patients with malignant disease,and healthy people.

Haemagglutination-inhibition (HAI) antibodies to BK virus, including BK-virus-specific IgM, were determined before and after renal transplantation in 20 patients, in 57 patients with malignant disease, and in 66 healthy controls, Before transplantation 11 of the renal transplant recipients were seronegative, but eight later serocconverted, two before and six after transplantation. Twenty of the patients with malignant disease and 22 controls were also seronegative. The geometric mean titre of BK HAI antibodies was significantly higher among transplanted patients (1/180) than among controls (1/90). BK-virus-specific IgM antibody was detected in seven renal transplant recipients, six patients with malignant disease, and 13 healthy controls. In transplant recipients BK-virus-specific IgM antibody usually persisted throughout the duration of the study, and studies on controls from whom second serum samples were available suggested that they too had persistent BK-virus-specific IgM responses. The geometric mean titre of BK-virus-specific IgM HAI antibody was significantly greater in post-transplantation sera (1/223) than in control sera (1/28). The specificity of the detection of BK-virus-specific IgM HAI antibody was confirmed by direct visualisation of antibody by immune electron microscopy. The persistence of BK-virus-specific IgM suggested that BK virus continued to provide an antigenic stimulus. Nevertheless, there was no obvious association between the serological findings and any clinical features, and prospective studies will be needed to elucidate any such association.     

Salivary diagnosis of measles: a study of notified cases in the United Kingdom, 1991-3.

OBJECTIVES--To validate a method for salivary diagnosis of measles and to assess the diagnostic accuracy of notified cases of measles. DESIGN--Blood and saliva samples were collected within 90 days of onset of symptoms from patients clinically diagnosed as having measles and tested for specific IgM by antibody capture radioimmunoassay. SETTING--17 districts in England and one in southern Ireland during August 1991 to February 1993. SUBJECTS--236 children and adults with measles notified by a general practitioner. RESULTS--Specific IgM was detected in serum in only 85 (36%) of the 236 cases. In cases associated with outbreaks and tested within six weeks of onset, 53/57 (93%) of samples were IgM positive, thereby confirming the sensitivity of serum IgM detection as a marker of recent infection. The serological confirmation rate was lower in cases with a documented history of vaccination (13/87; 15%) than in those without (70/149; 47%) and varied with age, being lowest in patients under a year, of whom only 4/36 (11%) were confirmed. Measles specific IgM was detected in 71/77 (92%) of adequate saliva samples collected from patients with serum positive for IgM. In cases where measles was not confirmed, 6/101 had rubella specific IgM and 5/132 had human parvovirus B19 specific IgM detected in serum. CONCLUSIONS--The existing national surveillance system for measles, which relies on clinically diagnosed cases, lacks the precision required for effective disease control. Saliva is a valid alternative to serum for IgM detection, and salivary diagnosis could play a major role in achieving measles elimination. Rubella and parvovirus B19 seem to be responsible for a minority of incorrectly diagnosed cases of measles in the United Kingdom and other infectious causes of measles-like illness need to be sought.     

Systemic Lupus Erythematosus Patients Contain Significantly Less IgM against Mono-Methylated Lysine than Healthy Subjects

Post-translational modifications on proteins are important in biological processes but may create neo-epitopes that induce autoimmune responses. In this study, we measured the serum IgG and IgM response to a set of non-modified or acetyl- and methyl-modified peptides corresponding to residues 1–19 of the histone 3 N-terminal tail in systemic lupus erythematosus (SLE) patients and healthy subjects. Our results indicated that the SLE patients and healthy subjects produced antibodies (Abs) to the peptides, but the two groups had different Ab isotype and epitope preferences. Abs to the non-modified form, H3_1–19, were of the IgG isotype and produced by SLE patients. They could not recognize the scrambled H3_1–19, which contained the same amino acid composition but a different sequence as H3_1–19. In comparison, healthy subjects in general did not produce IgG against H3_1–19. However, about 70% of the healthy subjects produced IgM Abs against mono-methylated K9 of H3_1–19 (H3_1–19K9me). Our further studies revealed that ε-amine mono-methylated lysine could completely inhibit the IgM binding to H3_1–19K9me, but lysine had no inhibitory effect. In addition, the IgM Abs could bind peptides containing a mono-methylated lysine residue but with totally different sequences. Thus, mono-methylated lysine was the sole epitope for the IgM. Interestingly, SLE patients had much lower levels of this type of IgM. There was no obvious correlation between the IgM levels and disease activity and the decreased IgM was unlikely caused by medical treatments.We also found that the IgM Abs were not polyreactive to dsDNA, ssDNA, lipopolysaccharide (LPS) or insulin and they did not exist in umbilical cord serum, implying that they were not natural Abs. The IgM Abs against mono-methylated lysine are present in healthy subjects but are significantly lower in SLE patients, suggesting a distinct origin of production and special physiological functions.     

Serological Study of Bartonella henselae in Cat Scratch Disease in Japan

It has become clear that Bartonella henselae is a common cause of cat scratch disease (CSD). The indirect fluorescence antibody (IFA) test for detection of IgG and IgM antibodies to B. henselae concerning CSD showed that 5 (50%) of 10 patients with CSD had a serum IgG antibody titer of 1:128 or more and that 2 (20%) patients had a serum IgM antibody titer of 1:20 or more. One of 7 asymptomatic members of patients' families (14%) had IgG antibody to B. henselae at a titer of 1:256. IgM antibody to B. henselae was not detected in sera from the patients' families. Both IgG and IgM antibodies to B. henselae were not detected in sera from the healthy control group. These data suggest that B. henselae may be a cause of CSD in Japan.     

Anti-Rhinosporidial Antibody Levels in Patients with Rhinosporidiosis and in Asymptomatic Persons,in Sri Lanka

The only report hitherto, from India in 1982, on anti-rhinosporidial antibody levels in patients with rhinosporidiosis recorded that antibody was not detected in Indian patients. The present report describes the use of the dot-ELISA assay of serum anti-rhinosporidial IgG, IgM and IgA and salivary sIgA in patients with diverse clinical presentations, in rural asymptomatic persons who had bathed in ground waters that probably harboured the causative pathogen, Rhinosporidium seeberi, and in laboratory persons who were exposed to R. seeberi. Ultrasonic extracts of purified endospores and sporangia of R. seeberi were used as antigen. The geometric mean (reciprocal) titres of serum antibody detected in patients were IgM 142.1, IgG 178.5, IgA 84.6, with ranges of 0-640, 30-960 and 0-160 respectively, salivary sIgA titres ranged from 0 to 18 with a mean of 4.6. The levels of antibody had no correlation with the site, the number of sporangia, duration and recurrence of the disease. Asymptomatic persons from the same endemic area as patients showed mean titres of IgM 89.6, IgG 69.1, IgA 95.5, with salivary sIgA titres of 3.1. Asymptomatic personnel who had been working in a laboratory where rhiniosporidial work was being done, showed mean titres of 169.6 IgM, 62.8 IgG, and 6.5 salivary sIgA. These results indicate that an anti-rhinosporidial antibody response occurs in rhinosporidial patients, as well as in asymptomatic persons who were exposed to R. seeberi in the environment. Anti-R. seeberi antibody does not appear to be protective in rhinosporidiosis since appreciable titres were present in patients with recurrent, single, multiple or disseminated lesions of long duration.     

Evaluation of immunoglobin isotype specific to Leishmania in tegumentary American leishmaniasis

Leishmania-specific immunoglobulin subclass response was evaluated in 133 patients infected with Leishmania braziliensis. The indirect immunofluorescent antibody test (IFAT) was employed with amastigotes of L. mexicana amazonensis as antigen. Among the 133 sera obtained at consultation for diagnosis of active lesions, IgM was detected in 54 following absorption with Staphylococcus aureus Cowan strain I, and in 5 sera prior to absorption. IgM reactive with Leishmania antigen was only found in sera from patients whose lesions had evolved over the past two months or less. Leishmania-specific IgG was detected in all sera prior to absorption. Sera obtained at the time of recurrence or after complete healing of lesions presented only specific IgG. The combined use of the Montenegro skin test and specific IgM increased the sensitivity of immunodiagnostic methods in patients with lesions of less than 2 months duration. Normal control volunteers were negative for specific IgM and unreactive to Montenegro skin testing. Among 16 patients with non-leishmanial lesions, 3 with sporotrichosis showed IgG reactive with Leishmania; none, including 4 with lesions of less than two months duration, showed specific IgM. We conclude that in patients infected with L. braziliensis the presence of specific IgG and IgM is associated with the time of lesion evolution and the primary or recurrent nature of the lesions. In addition, the combined use of IgM titer and Montenegro reactivity is of potential utility in the diagnosis of early lesions.     

Idiotypic and antiidiotypic T and B lymphocytes in myasthenia gravis.

The prevalence of Id and anti-Id T and B cells as measured by their reactivities with two human mAb, one antiacetylcholine receptor mAb and one anti-Id mAb, was studied in 38 patients with myasthenia gravis and in 27 healthy individuals. Id and anti-Id T cells were estimated by enumerating the numbers of cells secreting IFN-gamma in response to 10 pg/ml of the human mAb. T cell stimulation, measured as numbers of IFN-gamma-secreting cells that exceeded the mean + 2 SD of controls, was induced by the Id mAb in 78.9% of the patients and in 7.4% of the controls, whereas the anti-Id mAb-stimulated T cells in 55.3% of the patients and in 3.7% of the controls. The mean value of the Id and anti-Id-reactive T cells in the patients was 18.3/10(5) and 10.1/10(5) PBMC, respectively. B cells secreting IgM antibodies binding to the human mAb were increased in patients with myasthenia gravis compared to healthy controls. Seventy-five percent of the patients and 12% of the controls had B cells secreting IgM antibodies binding to the Id mAb, although 89% of the patients and 16% of the controls had B cells secreting IgM antibodies binding to the anti-Id mAb. The mean value of B cells secreting IgM antibodies binding to Id or anti-Id mAb in the patients were 7.4 cells/10(6) and 5.5 cells/10(6) PBMC, respectively. We conclude that Id and anti-Id T and B cells are present in myasthenia gravis. These methods allow a quantitative estimation of T and B cells with defined specificities and thus a way of mapping the repertoire of lymphocytes.     

Diagnosis of HCV related acute hepatitis by serial determination of IgM to HCV: a preliminary observation

OBJECTIVE: To verify whether serial determination of titre of IgM to HCV core protein (HCV IgM) may be useful to distinguish acute hepatitis C (AHC) from reactivation of chronic hepatitis C (r-CHC), we studied 18 consecutive patients with AHC (identified by seroconversion to anti-HCV) and 15 consecutive patients who had been anti-HCV positive for at least one year at the time of reactivation. METHODS: Samples of serum were obtained from all patients on hospitalisation and every 5 days during the follow-up and stored at -80 degrees C: 54 samples of serum for the AHC group and 41 for the r-CHC group. Titres of HCV IgM were calculated as Index values by a commercially available enzyme immunoassay (HCV-IgM EIA 2.0, Abbott Laboratories, North Chicago, IL, USA). RESULTS: No difference was observed between the two groups of patients as regards age, sex, risk factors for the acquisition of HCV infection, clinical and biochemical data on presentation, prevalence of cases with detectable viremia or distribution of HCV genotypes. HCV IgM was detected with an Index value of 350 or more in only 1 (6.7%) in the r-CHC group and in 17 (94.4%) in the AHC group (p<0.01). Moreover, during the early phase of the illness we observed a wide variation in the HCV IgM Index values in AHC and consistent values in r-CHC. CONCLUSIONS: Our data indicate that AHC is characterised by high and variable titres of HCV IgM during the acute phase of the illness, which may be considered diagnostic, whereas in r-CHC the IgM titre remains stable and rarely reaches a high level.     

Eye muscle antibodies in endocrine exophthalmos. Clinical and serological observations

Serum samples were obtained from 65 patients with endocrine exophthalmos class I-V. In 33/65 patients who were treated either with prednisone or with ciclosporin, blood was sampled before, during and after therapy. Antibodies against eye muscle were determined during the course of immunosuppressive therapy in order to have an objective parameter of the therapeutic effect. To ascertain the specificity of the reaction both eye and abdominal muscles were used as antigens in an ELISA system. Both IgG and IgM antibodies were detected. In 45/65 patients (71%) eye muscle antibodies were positive before starting therapy. Antibodies were mostly detected in patients with active disease. Patients with exophthalmos of recent onset always had IgM antibodies whereas patients with chronic exophthalmos were mostly IgG positive. Patients with relapse showed mostly IgG but also IgG and IgM positivity in 2 cases. In 58% of cases only IgG antibodies were found whereas in 34% both IgG and IgM were detected and in 8% only IgM antibodies. There was no association between antibodies directed against eye muscle and thyroid microsomal and thyroglobulin antibodies or with the state of thyroid function. Furthermore there was no correlation between exophthalmos classes and eye muscle antibody binding activity. The antibody level declined during therapy with prednisone or with ciclosporin but rose again 8-12 weeks after stopping the drug in patients with progressive disease.     

Deposition of IgM and complement at the dermoepidermal junction in acute and chronic cutaneous graft-vs-host disease in man.

The presence of cutaneous immunoglobulin and complement was investigated in 88 patients with and without graft-vs-host disease (GVHD) after transplantation of bone marrow from HLA identical siblings for the treatment of acute leukemia or aplastic anemia. For comparison, skin biopsies from the patients obtained before transplantation, from 58 healthy individuals (mostly marrow donors) and from four syngeneic marrow recipients were studied. A direct immunfluorescent staining technique was used. Dermo-epidermal IgM deposits were found in 11% of healthy individuals and patients before grafting but were present in 86% of patients with chronic and 39% of patients with acute GVHD. Patients with allogeneic grafts who never had GVHD or who had recovered from it and patients with syngeneic grafts showed findings not different from those in healthy individuals. Findings similar to those with IgM, although less striking, were made for C3, i.e., patients who had chronic or acute GVHD had a high incidence and intensity of C3 deposits at the dermo-epidermal junction. This observation raises the possibility that humoral immunity is involved in the development of GVHD.     

Immunoglobulin M. Specific for Measles and Mumps in Multiple Sclerosis

Sera from 43 patients with multiple sclerosis were tested by immunofluorescence. Sera from patients with active multiple sclerosis included four with measles virus-specific immunoglobulin M (measles IgM) and two with mumps virus-specific IgM (mumps IgM). In one case each mumps IgM and measles IgM seem to have persisted for two and a half years and three years respectively. In a comparable group of 43 patients with other nervous diseases measles IgM was found in only one serum, and among 43 normal patients no measles or mumps IgM was found.Herpes simplex virus-specific IgM (herpes simplex IgM) was distributed among all three groups. Anticellular IgM was also found, predominantly in active multiple sclerosis, and persisted in two sera for two and a half years.