HLA-DW2, viral immunity and family studies in multiple sclerosis

The presence of glutamic acid at positions 71 or 74 in pocket 4 of the HLA-DRbeta1 chain is associated with the clinical course of multiple sclerosis

BACKGROUND

Primary progressive multiple sclerosis (PP-MS) differs from relapsing-remitting or secondary progressive MS (RR/SP-MS) in ways suggesting differences in the pathogenic pathways. Susceptibility to both PP-MS and RR/SP-MS is linked to carriage of the HLA molecule DRB1*1501. Several serologically defined HLA-DR groups (DR1, DR4, DR6, and DR9) occur less often in RR/SP-MS than in controls. Some or all of the HLA-DR molecules encoded by alleles in these serologically defined groups have a negatively charged glutamic acid at residue 71 or 74 of the beta1 chain (beta1(71)/beta1(74)). Residues at these positions are important in the formation of pocket 4 in the antigen binding site of the HLA-DR molecule.

OBJECTIVES

To investigate whether the presence of alleles encoding HLA-DR molecules containing glutamic acid at beta1(71)/beta1(74) correlates with the course of MS.

METHODS

HLA-DR and HLA-DQ alleles and genotypes were analysed in 121 MS patients (50 with PP-MS) and 109 controls by molecular typing.

RESULTS

Alleles encoding HLA-DR molecules containing a glutamic acid at beta1(71)/beta1(74) occurred less often in patients with RR/SP-MS than in those with PP-MS or controls. In subjects not carrying the DRB1*1501 allele, a much higher proportion of PP-MS patients carried alleles encoding HLA-DR molecules containing a glutamic acid at beta1(71)/beta1(74) than did RR/SP-MS patients or controls.

CONCLUSIONS

The amino acid residues involved in determining the shape and charge of pocket 4 of the HLA-DR beta1 chain could influence the clinical course of MS by determining protection against RR/SP-MS or susceptibility to the development of PP-MS.

Multiple sclerosis: a modifying influence of HLA class I genes in an HLA class II associated autoimmune disease

Multiple sclerosis (MS) is a presumed autoimmune disease of the central nervous system, shown to be associated with the HLA class II haplotype DRB1*15,DQB1*06. Carrying the HLA class II haplotype DRB1*15,DQB1*06 increases the risk of MS by 3.6. By adopting a polymerase chain reaction (PCR)-based typing technique for HLA class I and class II genes, 200 Swedish MS patients and 210 Swedish healthy controls were analysed for their HLA alleles. Additional HLA class I alleles that increase and decrease the genetic susceptibility to MS were identified. The HLA-A*0301 allele increases the risk of MS (odds ratio=2.1) independently of DRB1*15,DQB1*06. HLA-A*0201 decreases the overall risk (odds ratio= 0.52) and the presence of A*0201 reduces the risk of MS for DRB1*15,DQB1*06 carriers from 3.6 to 1.5. Our findings are the first to identify a major modulating effect of HLA class I alleles on the susceptibility to a human autoimmune disease; a phenomenon that has previously only been observed in animal models.

HLA-DMB gene and HLA-DRA promoter region polymorphisms in Australian multiple sclerosis patients

The MHC region has been shown to contain a susceptibility locus for multiple sclerosis (MS). While the strongest association to date has been between HLA-DRB1*1501 and MS, the exact nature of the MHC association in MS remains unclear. Two candidate polymorphic loci within the MHC class II region, the HLA-DMB gene and the HLA-DRA promoter, which lie close to HLA-DRB1, were therefore examined in an Australian MS population. The HLA-DMB*0103 phenotype was increased in the MS patients (46% vs. 30%) and the frequency of the HLA-DRA promoter A allele was also increased (81% vs. 68%). When the subjects were stratified into HLA-DRB*1501 positive and negative individuals these associations were not significantly different. This is a result of the strong linkage disequilibrium between HLA-DRB*1501 and both HLA-DMB*0103 and the HLA-DRA promoter A allele. The complete linkage between DRB1*1501 and the HLA-DRA promoter A allele indicates that the MS susceptibility haplotype (DRB1*1501-HLA-DQB1*0602-HLA-DQA1* 0102) can be extended out to promoter of the HLA-DRA locus. Interactions between both HLA-DMB and the HLA-DRA promoter and other reported MS susceptibility loci were examined (TCRBV polymorphisms, HLA-DQA1 and HLA-DQB1). Some interactions between specific TCRBV polymorphisms and the HLA-DRA promoter were observed, which is consistent with other published reports suggesting an epistatic interaction between TCRBV and HLA-DRB1.

Effect of cyclosporine on rubella virus-specific immune responses in chronic progressive multiple sclerosis

Cyclosporine A (CsA) has been used in putative autoimmune diseases after sensitization to unknown antigens. We have previously shown that CsA prevented continued activation of T-cells in chronic progressive multiple sclerosis (CPMS) patients. The current study was undertaken to determine whether CsA, or CsA and prednisone (CsA + P) could suppress immune responses to a common recall antigen. Serum antibody levels were higher in all CPMS patients than age-matched normal controls. However, rubella antibody titers in the CsA or CsA + P groups were no different from a placebo-treated CPMS patient group. The lymphocyte responses to inactivated rubella virus of CsA and CsA + P-treated CPMS patients were lower than placebo and control but not statistically different. Therapy with both CSA and CSA + P was associated with significantly lower panel mixed leukocyte responses and Ta1 expression than in the placebo-treated group; CD3, CD4, CD8 antigen expression and active rosette formation by T-cells were similar for the three CPMS groups. These results suggest that while CsA exerts measurable effects on non-specific indicators of cellular immunity in CPMS patients, it may not be as effective in suppressing pre-existent specific immune responses.

Immunogenetic profile of multiple sclerosis in Mexicans

This is the first study on genetic markers in Mexican Mestizos with multiple sclerosis (MS). Patients were born in Mexico, had no family history of MS are middle-class, and have a high-level education. HLA class I, class II determinants, C2, C4, BF, GLO-1, ABO, and Rb red cell systems were analyzed and compared with results of 295 controls. Measles antibodies, glucose, IgG, total proteins, and cell count were measured in cerebrospinal fluid; anti-neuron, T-cell, and B-cell antibodies were determined in serum. MS in Mexican Mestizos was clinically similar to MS reported in high prevalence countries. DRw6, as previously found in Japanese patients, and its subtype, DRw13, were increased in patients in our study (pc = 0.0007, pc = 0.01, respectively), and the combination A3, B7, DR2, was also elevated (pc = 0.003). The polygenicity of the disease is emphasized by the excess of AB group carriers (pc = 0.01). IgG levels were high in patients with DR2 or DRw6 and 67% of the latter had anti-T cell antibodies. Severity of the disease was also related to the DR markers. It is suggested that at least two HLA-DR linked genes and the industrialized environment are important for the expression of MS in Mestizos.

Cell-mediated immunological status in multiple sclerosis patients

In vitro lymphocyte proliferation in response to allogeneic pooled cells, mitogens (PHA, Con A and PWM), and PPD was measured in 67 patients with clinically definite MS and in 67 age and sex-matched controls. Overall, dose-response curves in the two groups were similar, but response to PHA and PWM was significantly greater among patients, and a greater percentage of patients failed to respond to peak and suboptimal PPD concentrations. There was a reduced response to allogeneic pooled cells in Dw2 positive controls, and, in both patients and controls, a tendency towards a higher PPD response in Dw2 positive males. The results suggest that there is some alteration of balance of immune regulation in MS, which is slightly affected by Dw2 status.

HLA and multiple sclerosis: population and families study

Association between HLA and multiple sclerosis (MS) was investigated at the population level on 100 MS patients genotyped for HLA-A, B, C, DR and Bf, Glo, and on 155 patients phenotyped for the same HLA antigens. Association between MS and DR2 was clearly confirmed, although its strength is rather weak. No other genetic marker could be related to the disease, no haplotype nor any allelic combination could be recognized as MS specific, and antigen genotype frequencies among the diseased could not ascertain the mode of inheritance, although dominance is very likely. Computer analysis between HLA, Bf, Glo and age of the patient, sex, age of onset and evolution of MS, impairment indexes, titres of anti-DNA and anti-measles antibodies in CSF did not show any interaction. Twenty sib pairs and two trios of MS were also studied; they showed no significant distortion with the random distribution of haplotypes. DR2 gene frequency, however, was significantly higher in sib pairs showing one or two haplotypes than in HLA different affected siblings. Three crossing-overs were identified which suggest where the HLA-linked MS susceptibility (MSS) gene could be located within the HLA segment, while other epistatic MSS genes or environmental factors are likely to be important.

Identification of a specific HLA DR2 Ia molecule as a restriction element for measles virus-specific HLA class II-restricted cytotoxic T cell clones

By using a panel of HLA-D-defined subtypes of HLA-DR2 HCL with known beta chain structural variabilities, we have demonstrated that HLA-DR2, OKT4+ cytotoxic T lymphocyte (CTL) clones specific for measles virus are apparently restricted to a distinct DR beta chain. The presence of this DR beta 2 molecule correlated precisely with the susceptibility of measles virus-infected HLA-DR2 HCL to lysis by these CTL clones. These studies demonstrate that delineation of HLA-DR2 into various subgroups can have a functional significance that parallels the structural differences within the HLA-D region. These results are discussed in the context of the possible association of HLA class II-restricted, measles virus-specific CTL and multiple sclerosis.

Histocompatibility antigens in familial multiple sclerosis in a high-risk area of the disease

Fourteen Finnish families, each with two or more cases of multiple sclerosis (MS), were analysed for HLA antigens. Seventy family members were studied. They were all born in a high-risk area of MS and came from families with an unusually high frequency of MS. The frequencies of B7, B12 and DR2 were increased both in patients and their healthy relatives, whereas A1, B8 and DR1 were decreased in patients. MS patients shared the HLA haplotypes more often than expected.

Family studies in multiple sclerosis: HLA haplotypes of affected sib-pairs

The occurrence of multiple sclerosis (MS) in several members of families has been observed in 4.8% of 105 MS patients from a limited epidemiological area of Rostock. Typing of the HLA antigens in 4 affected sib-pairs showed two identical HLA haplotypes in 3 of the pairs: 1 pair shared one haplotype. These findings point to a dominant mode of inheritance of the disease susceptibility gene together with the HLA haplotype. The assessment of family studies in MS is discussed.

Lymphocyte blast transformation responses to mitogens and specific antigens in different clinical phases of multiple sclerosis: a follow-up study

28 MS patients were studied at least 5 times for lymphocyte blast transformation responses to several mitogens (PHA, Con, PWM) and specific antigens (PPD, herpes simplex, measles, mumps, rubella), the mean duration of the follow-up being 15.3 months. Comparison of responses during remissions, exacerbations and ACTH treatment revealed no straight-forward association between the strength of response and clinical disease activity. Mitogen responses did not differ among various disease phases, but the PPD response was significantly lower during exacerbations than during remissions and still lower during ACTH treatment (P less than 0.05, Wilcoxon paired test). In responses to viral antigens, there was the same trend as in the PPD response. However, there were great individual differences in the behaviour of all antigen and mitogen induced lymphocyte responses. As a group, MS patients also showed more changes in their PHA mitogen responses during the follow-up than 8 control subjects followed similarly (P less than 0.005, F-test). The variation coefficient of the PHA response was also correlated with the maximal difference in the Fog neurologic deficit scale during the follow-up time (r = 0.460, P less than 0.05). However, patients with greatest clinical changes most often also received ACTH treatment, which may affect the results. The follow-up results of individual patients revealed that some had quite regular patterns of decreasing responses during disease relapses, whereas others had more irregular wide fluctuations of responses.

Histocompatibility (HLA) antigens and eye diseases other than uveitis

In recent years, numerous studies on the possible associations of histocompatibility (HLA) antigens with various eye diseases other than uveitis have been carried out. This paper presents, discusses and evaluates the results of these studies. Undoubtedly, apart from acute anterior uveitis, HLA-typing has very limited usefulness in the practice of clinical ophthalmology. Many reported HLA associations with other eye diseases have not been confirmed by subsequent studies. However, a sizable residuum of highly significant and reproducible associations between HLA antigens and several eye diseases remains, suggesting that HLA-typing in patients with these diseases may contribute to the understanding of pathogenesis and etiology and may prove a valuable prognostic indicator for some diseases.

Power of the affected-sib-pair method to defect disease susceptibility loci of small effect: an application to multiple sclerosis

The distribution of marker locus identity-by-descent scores in affected sib pairs provides a powerful tool for detecting the presence of a linked non-Mendelian disease susceptibility locus. This basic approach is here extended to include a trio of sibs. A special type of sib trio consisting of two affected and one unaffected sib is investigated. It is shown that compared to affected-sib-pairs, trios with the above configuration are less efficient in detecting the presence of a linked disease susceptibility locus. When the generalized two-allele single locus model is fitted to sib pairs affected with multiple sclerosis, an estimate of the recombination fraction of 0.21 between the putative disease susceptibility locus and the HLA complex is obtained. However, this transmission model is deemed inadequate since a recombination fraction this large is inconsistent with the variety of HLA associations observed at the population level.

Histocompatibility types and antiviral antibodies in a diverse group of individuals

A study was made of the possible relationship between histocompatibility (HLA) antigens of the A and B loci and antibodies to cytomegalovirus, influenza A (victoria strain), measles, rotavirus, vaccinia, and varicella/zoster. A large and diverse group of unselected individuals was studied. A possible relationship was detected between the presence of the antigen B15 and a lack of circulating measles antibodies. The study group was divided into three sections: (a) healthy individuals, (b) "renal disease" patients awaiting renal transplantation, and (c) patients with various types of "other disease," mainly of an immunological nature. Significantly elevated titers to cytomegalovirus and varicella/zoster were found in the two diseased groups, but these elevated titers could not be linked with the presence or absence of any particular HLA A or B antigen.

Virus antibodies in Parkinson's disease. Herpes simplex and measles virus antibodies in serum and CSF and their relation to HLA types

Serum and cerebrospinal fluid (CFS) immunoglobulin G (IgG) antibodies to herpes simplex (HSV) and measles viruses were assayed with a radioimmunoassay in 56 patients with idiopathic Parkinson's disease and in a similar number of age- and sex-matched controls with other neurological diseases. As a group, the patients with Parkinson's disease had a significantly increased serum antibody level against HSV, but measles virus antibody levels were similar in both groups. Both in the Parkinson's group and in the control group, the levels of the total IgG in CSF were within normal limits and the CSF antibodies to HSV and measles virus paralleled the serum antibody titers relative to the total IgG serum-to-CSF ratios. This indicates no increased intrathecal antibody production in either group. In 48 patients with Parkinson's disease who were HLA-typed, no association of viral antibody levels with particular HLS antigens were noted. The findings suggest that HSV is not present within the central nervous system of the patients with Parkinson's disease. The increase HSV antibody level seen in Parkinson's disease patients may reflect a more general disturbance of the patients' immune functions.

Lymphocyte blast transformation and antibody responses after vaccination with inactivated mumps virus vaccine

Mumps antibody response and the development of cell-mediated immunity (CMI) to mumps antigen as assayed by the lymphocyte blast transformation method were studied after immunization with an inactivated mumps vaccine in seven sero-negative and ten sero-positive subjects. The transformation response of peripheral blood lymphocytes to mumps antigen generally appeared by 20 weeks post vaccination and reached levels found in sero-positive subjects years after mumps infection. There was no clear-cut correlation between the magnitude of blast transformation and antibody responses.

HLA family studies and multiple sclerosis: A common gene, dominantly expressed

All available Australian families with more than one member suffering multiple sclerosis (MS) were HLA typed. As with all other individual published studies, convincing evidence for linkage between the HLA system and disease was not obtained. An analysis of 100 published affected sib-pairs and 17 cousin-pairs, however, established the existence of an HLA-linked disease susceptibility gene for MS, which is likely to be dominantly expressed. Dominance was also supported by the finding of only three HLA-DR2 (Dw2) homozygous individuals out of 60 unrelated patients which enabled rejection of a recessive gene hypothesis (p less than 0.02). Analysis of the sib-pair data strongly suggested that this MS gene is not rare in the normal population and may be as common as DR2.

Cell-mediated immunity to viral antigens and tuberculin in multiple sclerosis

Lymphocyte transformation responses to measles, mumps, herpes simplex and parainfluenza virus antigens and purified protein derivative of tuberculin were determined in both 78 normal controls and 40 patients with multiple sclerosis, 16 of whom were studied serially. Patients with multiple sclerosis showed significantly reduced responses to all antigens except herpes simplex. Impaired responses occurred at all stages of clinical activity, but were lowest during recovery from an acute exacerbation or in patients with chronic disease. The transformation responses to measles, mumps and parainfluenza virus antigens correlated significantly with the numbers of circulating T cells, which, similarly, showed parallel fluctuations with disease activity.

Lymphocyte blast transformation responses and viral antibodies in relation to HLA antigens in multiple sclerosis

Fifty four clinically stable multiple sclerosis (MS) patients and 54 age- and sex-matched control subjects were HLA-typed, and their responses to herpes simplex, measles, mumps and rubella antigens were examined by the lymphocyte blast transformation test and by serum antibody titrations. Blast transformation response to purified tuberculin (PPD), mitogen phytohaemagglutinin (PHA), pokeweed mitogen (PWN) and concanavalin A (Con A) and spontaneous proliferation of lymphocytes were also studied. MS patients differed from controls by higher antibody levels to measles and rubella viruses and by lower specific blast transformation responses to rubella and measles antigens. When the relative strength of transformation responses was measured, mumps and herpes simplex responses were also lower in MS patients than in controls. In addition, spontaneous lymphocyte proliferation of MS patients in 6-day cultures was lower than that of control lymphocytes. In mitogen stimulations there were no differences between whole groups, but the oldest patients had lower responses to PHA and Con A than their matched controls. The frequency of HLA-Dw2 was 56.6% in MS patients and 32.1% in controls. The patients with and without Dw2 differed from each other only by a lower specific response to PPD in the Dw2-positive group. The immunological response of Dw2-positive controls resembled that of MS patients: low transformation response to viral antigens, low spontaneous proliferation and elevated measles antibodies. This finding supports the function of a genetically determined type of immune responsiveness with low cell-mediated immunity and high levels of certain viral antibodies as one susceptibility factor in multiple sclerosis.

Transfer factor in treatment of multiple sclerosis

A 2-year prospective double-blind trial of the treatment of multiple sclerosis patients with the leucocyte extract, transfer factor (TF), obtained from leucocytes of relatives living with the patient, was conducted. 60 patients with definite MS, of whom 58 completed the trial, were divided into two equal groups, one of which received TF and the other placebo. The groups were evenly balanced with respect to sex ratios, disability, duration of disease, ratio of moderate to severe cases, and HLA phenotype. Neurological, electrophysiological, and immunological assessments were done at the start of the trial and every 6 months thereafter. The results indicated that (1) TF retarded but did not reverse progression of the disease; (2) a significant difference between treatment and placebo groups was not apparent with 18 months after the start of the trial; and (3) treatment was effective only in those patients with mild to moderate disease activity.

Lymphocyte blast transformation responses in measles infection

Lymphocyte blast transformation responses were studied in eight patients with natural measles infection. A specific response to purified measles virus antigen and a weaker response to crude measles virus antigen were found after infection. The response to purified measles antigen appeared 1-3 weeks after the beginning of the rash, when the great number of proliferating mononuclear cells found in the peripheral blood during the rash was declining. In the first weeks after onset of the rash also leucocyte and lymphocyte numbers were decreased, and specific responses to purified tuberculin (PPD) and to rubella and mumps virus antigens were suppressed. In mitogen stimulation tests there was no significant suppression of phytohaemagglutinin and concanavalin responses in this small series, but the response to pokeweed mitogen was decreased. The responses to antigens other than measles virus antigens recovered in parallel with the increase of the measles-specific response.

Genetic segregation of multiple sclerosis and histocompatibility (HLA) haplotypes

The possibility that a gene determining susceptibility to multiple sclerosis (MSS) may be closely linked to the major histocompatibility locus (HLA) is suggested by observation of a loose association between multiple sclerosis (MS) and certain HLA determinants. In the present study, the possible association was analyzed by studying the segregation of MS and the HLA haplotypes in families with more than one case of MS. Analysis of 48 published families revealed that the haplotype shared by those with MS within the family was also shared by those without clinical signs of MS at close to the 50% frequency expected by chance. Thus, we were unable to demonstrate that MS is associated with one HLA defined parental haplotype. We discussed reasons for this apparent failure to demonstrate existence of an MSS gene using available multiplex MS families.

Has myelin basic protein received a fair trial in the treatment of multiple sclerosis?

Autosensitization to some central nervous system antigen still remains one of the best hypotheses for the continuing pathogenesis of multiple sclerosis (MS). Enough is now known about the cause, pathogenesis, and treatment of experimental allergic encephalomyelitis (EAE) to test this hypothesis. Reports of therapeutic failure of the encephalitogen myelin basic protein (BP) in the treatment of MS have their counterparts in similar therapeutic failures in EAE. Only highly inbred strain 13 guinea pigs respond consistently to BP therapy, and this only when BP is administered in relatively high doses. Noninbred guinea pigs respond much less well to simple BP therapy, and monkeys hardly at all. In both strains of monkeys so far studied, a nonspecific adjunctive factor--an antibiotic in Macaca mulatta and a steroid in Macaca fascicularis--is also required. Accordingly, human trials of the therapeutic efficacy of BP in MS should include its administration in large concentrations together with an adjunctive agent.

Measles antibodies and histocompatibility types in multiple sclerosis

Measles antibody titres and HLA antigens were determined in 71 White and 11 Coloured multiple sclerosis (MS) patients and 71 White and 11 Coloured age and sex-matched controls. Measles antibody titres were determined by the hemagglutination inhibition test and HLA antigens were determined serologically by a micro-lymphocytotoxicity test. Measles antibody titres were significantly higher in MS than in control cases and this was true for both female and male patients. No association was observed between the HLA antigens, especially HLA-A3 or HLA-B7 and measles antibody titres in the sera of MS patients or controls.

Strong linkage disequilibrium between HLA-Dw2 and and BfS in multiple sclerosis and in the normal population

An increased frequency of the S allele of Properdin factor B (BfS) was found amongst 162 patients with multiple sclerosis (MS) compared with 470 normal controls. This increase was shown to be due to a strong linkage disequilibrium (LD) between BfS and HLA-Dw2 in 77 patients typed for both systems (delta = 3.84%, P = .0002). The same LD was demonstrated amongst 100 normal controls (delta = 2.24%, P = .0049) and 31 patients with idiopathic demyelination of the peripheral nervous system (IDPN). A total of 70 haplotypes with HLA-Dw2 were encountered (40 MS, seven IDPN and 23 normal controls) and all contained BfS. In the MS patient group, a much weaker association was noted between BfS and HLA-B7 suggesting either that the Bf locus is musch closer to the HLA-D than the HLA-B locus or (and) that HLA-D and Bf products selectively interact (perhaps on the surface of B lymphocytes) with evolutionary advantage or disadvantage resulting from certain allelic combinations. Strong associations between BfS1 and HLA-Bw21 (P = .0000) and BfF1 and HLA-B18 (P = .0001), both previously reported, were confirmed in the current study. No increase in the frequency of a glyoxalase (GLO) allele was found amongst the MS patients and no LD was encountered between HLA-Dw2 and a GLO allele. The possibility that the HLA-Dw2, BfS disequilibrium has resulted from a selective advantage conferred on the general community but at the expense of increasing susceptibility to MS should be considered.

Genetic basis of multiple sclerosis: HLA antigens, disease progression, and oligoclonal IgG in CSF

The HLA antigens B7 and Dw2 occurred at elevated frequencies in 105 multiple sclerosis (MS) patients (49 and 47%, respectively), compared to healthy controls (29 and 30%), especially in MS patients with oligoclonal CSF-IgG (51 and 50%), in cases with CSF-IgG index values above 1.5 (64 and 64%), and in those with the most malignant course of the disease (47 and 59%). Normal or only slightly elevated frequencies of B7 and Dw2 were found in MS patients without oligoclonal CSF IgG (35 and 29%), normal CSF-IgG index (43 and 39%), and the most benign course (42 and 37%). No correlation was found between the HLA type and measles virus antibody titers in serum or a measles virus antibody response within the CNS.

HLA antigens in the Landry-Guillain-Barré syndrome and chronic relapsing polyneuritis

Forty-four patients with inflammatory demyelinating polyneuritis (22 with Landry-Guillain-Barré syndrome, 6 with subacute polyneuritis, and 16 with chronic relapsing polyneuritis) were typed for genetic markers in and around the HLA region of chromosome 6. Patients with chronic relapsing polyneuritis showed a definite association with HLA-AW30 and AW31 and probable associations with HLA-B8, HLA-DW3, and glyoxalase I. No significant associations were demonstrated with the Landry-Guillain-Barré syndrome although an increase in glyoxalase I was significant if combined with the results of typing in chronic relapsing polyneuritis. The total patient group showed significant increases in HLA-AW30, HLA-AW31, and HLA-DW3. The results support the view that HLA-linked genetic factors influence susceptibility to chronic relapsing polyneuritis and may contribute to the differences in clinical patterns observed in inflammatory demyelination of the peripheral nervous system.

Relapsing neuropathy due to tetanus toxoid. Report of a case

A unique case history is presented, of a 42-year-old patient who has suffered three episodes of a demyelinating neuropathy, each of which followed an injection of tetanus toxoid. The clinical features on each occasion were characteristic of acute idiopathic polyneuropathy; a rapid onset of a mainly motor neuropathy with eventual recovery. Nerve conduction studies performed during the second and third episodes demonstrated grossly slowed motor conduction velocities. The sural nerve was biopsied after the third episode, and the features seen on light and electron microscopy included prominent hypertrophic changes, mononuclear cells associated with most "onion bulbs" and macrophage mediated demyelination. Studies of blastogenesis and macrophage migration inhibition, showed T lymphocyte responsiveness to both peripheral nerve myelin and tetanus toxoid. Typing for antigens of the HLA system indicated that the patient was homozygous for HLAB8.