Multifocal motor neuropathy: association of anti-GM1 IgM antibodies with clinical features.

OBJECTIVE: To determine the prevalence and specificity of antibodies against single gangliosides and ganglioside complexes in serum from 88 patients with multifocal motor neuropathy (MMN) and to study the association with clinical features. METHODS: ELISA was used to detect immunoglobulin (Ig)M, IgG, and IgA antibodies against GM1, GM2, GD1a, GD1b, GM1b, GT1a, GT1b, GQ1b, GalNAc-GD1a, and the glycolipid SGPG; absorption studies were performed to study cross-reactivity. Presence of antibodies against ganglioside complexes consisting of any of combinations of GM1, GM2, GD1a, GD1b, GT1b, and GQ1b was also tested. RESULTS: Anti-GM1 IgM, IgG, and IgA antibodies were detected in serum from 43%, 1%, and 5% of patients with MMN. Anti-GM2 IgM antibodies were detected in 6% and anti-GD1b IgM antibodies in 9% of patients. Patients with MMN with anti-GM1 IgM antibodies had more severe weakness (p < 0.01), more disability (p < 0.01), and more axon loss (p = 0.05) than patients without anti-GM1 IgM antibodies. Anti-GM1 IgM antibody titers correlated with Medical Research Council scores (correlation coefficient = 0.43; p < 0.0001). Anti-GD1b IgM antibody activity was associated with reduced vibration sense (p < 0.01). Absorption studies showed that anti-GD1b and anti-GM2 IgM antibodies cross-reacted with GM1. Antibodies against ganglioside complexes were not detected. Complexes containing GD1a, GD1b, GT1b, or GQ1b with GM1 lowered antibody activity against GM1. CONCLUSION: Anti-ganglioside IgM antibodies in MMN display limited specificity and are associated with severity and clinical characteristics. Results of this study suggest that anti-GM1 IgM antibodies may play a role in MMN pathogenesis.

Detection of anti-MAG antibodies in polyneuropathy associated with IgM monoclonal gammopathy.

BACKGROUND: Detection of serum antibodies to myelin-associated glycoprotein (MAG) by Western blot (WB) is a valuable assay to diagnose a distinct type of demyelinating polyneuropathy with immunoglobulin M (IgM) monoclonal gammopathy. In this study, the diagnostic accuracy of a new and more practical ELISA to detect these antibodies was validated. METHODS: Routine WBs from 2 independent laboratories and ELISA were used to detect anti-MAG IgM in serum from 207 patients with neuropathy and controls. The sensitivity and specificity of these assays were compared and related to the patient clinical and electrophysiologic characteristics. RESULTS: In ELISA, anti-MAG antibodies were found in serum from 49 (72%) of 68 patients with demyelinating polyneuropathy and IgM monoclonal gammopathy. However, in this subgroup of patients, only 30 (44%) and 37 (54%) were positive in the 2 WBs. All of the patients positive in the 2 WBs were also positive in ELISA. A high correlation was found for IgM activity in ELISA to MAG and sulfate-3-glucuronyl paragloboside (SGPG) (Spearman rho = 0.72, p < 0.0001), supporting the notion that the shared sulfated glucuronic acid moiety of MAG and SGPG is preserved. Most patients positive in anti-MAG ELISA had a slowly progressive sensory-motor demyelinating polyneuropathy, even if the WB was negative. In control groups, however, 4 WB-negative patients with a nondemyelinating monoclonal gammopathy-related polyneuropathy were positive in anti-MAG ELISA. The remaining samples were negative in ELISA. CONCLUSION: ELISA is more sensitive than Western blot to diagnose anti-myelin-associated glycoprotein related polyneuropathy, although a positive serology may be found in other forms of polyneuropathy as well.

Cross-reactive anti-galactocerebroside antibodies and Mycoplasma pneumoniae infections in Guillain-Barré syndrome.

Anti-galactocerebroside (GalC) antibodies are reported to be present in GBS patients with preceding Mycoplasma pneumoniae (MP) infection. We investigated the presence of anti-GalC reactivity in serum of a large group of GBS patients using ELISA and compared this with healthy controls and individuals with an uncomplicated MP infection. Anti-GalC antibody reactivity was present in 12% of the GBS patients. Furthermore, anti-GalC antibodies were associated with MP infections, a relatively mild form of the disease and demyelinating features. Anti-GalC antibodies cross-reacted with MP antigen. In conclusion, anti-GalC antibodies in GBS patients may be induced by molecular mimicry with MP.

Structure of Campylobacter jejuni lipopolysaccharides determines antiganglioside specificity and clinical features of Guillain-Barré and Miller Fisher patients.

Ganglioside mimicry in the lipopolysaccharide (LPS) fraction of Campylobacter jejuni isolated from Guillain-Barré syndrome (GBS) and Miller Fisher syndrome (MFS) patients was compared with isolates from patients with an uncomplicated enteritis. The antibody response to C. jejuni LPS and gangliosides in neuropathy patients and controls was compared as well. LPS from GBS and MFS-associated isolates more frequently contained ganglioside-like epitopes compared to control isolates. Almost all neuropathy patients showed a strong antibody response against LPS and multiple gangliosides in contrast to enteritis patients. Isolates from GBS patients more frequently had a GM1-like epitope than isolates from MFS patients. GQ1b-like epitopes were present in all MFS-associated isolates and was associated with anti-GQ1b antibody reactivity and the presence of oculomotor symptoms. These results demonstrate that the expression of ganglioside mimics is a risk factor for the development of post-Campylobacter neuropathy. This study provides additional evidence for the hypothesis that the LPS fraction determines the antiganglioside specificity and clinical features in post-Campylobacter neuropathy patients.

Cytomegalovirus infections and anti-GM2 antibodies in Guillain-Barré syndrome.

To investigate whether antecedent cytomegalovirus (CMV) infections in patients with Guillain-Barré syndrome are associated with the presence of specific antiganglioside antibodies, acute phase serum samples from 130 patients with Guillain-Barré syndrome and 200 controls were tested. Anti-GM2 IgM antibodies were found more often in patients with Guillain-Barré syndrome with CMV infection (22%) than in patients without the infection (2%) (P = 0.003). CMV infections may elicit anti-GM2 antibodies in susceptible patients, which may contribute to the pathogenesis of Guillain-Barré syndrome associated with CMV.

Campylobacter jejuni infections and anti-GM1 antibodies in Guillain-Barré syndrome.

The group of patients with Guillain-Barr'e syndrome (GBS) is very heterogenous with regard to antecedent infections, immunological parameters, clinical manifestations, and response to treatment. In this study, the presumed pathogenic factors anti-GM1 antibodies and Campylobacter jejuni infections were related to the clinical characteristics. Serum from 154 patients with GBS, 63 patients with other neurological diseases (OND), and 50 normal controls (NC) were tested for the presence of antibodies against GM1 and C. jejuni. Anti-GM1 antibodies were detected in 31 (20%) GBS patients, 5 (8%) OND patients, and in none of the NC. Evidence for a recent C. jejuni infection was found in 49 (32%) GBS patients and less often in OND patients (11%) or NC (8%). In GBS patients, the presence of anti-GM1 antibodies was significantly associated with C. jejuni infections. The subgroup of GBS patients with anti-GM1 antibodies suffered more often from a rapidly progressive and more severe neuropathy with predominantly distal distribution of weakness, without deficits of cranial nerves or sensory disturbances. The subgroup with C. jejuni infection also more often had a severe pure motor variant of GBS. Recovery of the patients with anti-GM1 antibodies and C. jejuni infections was not as good after plasma exchange compared with intravenous immunoglobulins.

The influence of T cells on homogeneous immunoglobulins in sera of athymic nude mice during aging.

In this study, results are presented which are in agreement with predictions made on basis of the 'three-stage hypothesis' on the development of benign monoclonal gammapathy (BMG). In a T-cell depletion model. C57BL/Ka nude mice were shown to develop single and multiple homogeneous immunoglobulins (H-Ig) during aging in the highest frequencies known so far. Ninety per cent of the C57BL/Ka nude mice displayed one or more H-Ig at 12 months of age. In a T-cell supplementation model, infusion of corticosteriod resistant T cells into 9-month-old BALB/c nude mice resulted in a decrease in the frequency of H-Ig from 43% at 9 months down to 20% at 15 months of age. In contrast, the frequency of H-Ig in the control group increased from 40% at 9 months up to 68% at 12 months. The results show that normally functioning T cells are essential for the generation of a normal, heterogeneous Ig spectrum; they further support the validity of the three-stage hypothesis with regard to the role of an impairment of the T immune system in the pathogenesis of BMG.

The influence of H-2 genetic factors on the development of benign monoclonal gammopathy in ageing H-2 congenic C57BL and BALB mice.

The role of H-2 genetic factors in the development of benign monoclonal gammopathy (BMG) was investigated in six H-2 congenic C57BL and BALB strains (C57BL/10.ScSn and BALB.B: H-2b; B10.D2 and BALB/c: H-2d; B10.BR and BALB.K: H-2k) during ageing. The frequencies of homogeneous immunoglobulins (H-Ig), both single and multiple, in the three C57BL strains were higher than those in the corresponding three BALB strains. No relationship was found with a particular H-2 haplotype. The most frequent H-Ig isotype within the C57BL strains was IgG2a, within BALB.B and BALB.K mice IgG3 and in BALB/c mice IgG1. Categorization of the monoclonal gammopathies (MG) on the basis of their origin showed a single transient monoclonal B-cell proliferation in 2-5% and 3-9% of the C57BL and BALB mice positive for H-Ig, respectively. Multiple myeloma or B-cell lymphoma were found to be responsible for about 1% of the paraproteinaemias in all strains. Persistent, non-progressive MG, most likely BMG, was detected in 70-81% and 39-46% of the C57BL and BALB mice positive for H-Ig, respectively. The remaining 14-24% and 50-58% of the, respectively, C57BL and BALB mice positive for H-Ig could not be evaluated in time. The H-2 haplotypes under investigation were not associated with the onset, occurrence, multiplicity, persistence or isotype of the MG developing in these H-2 congenic C57BL and BALB strains during ageing.