Anti-GM1 and anti-sulfatide antibodies in patients with systemic lupus erythematosus, Sjögren's syndrome, mixed cryoglobulinemia and idiopathic systemic vasculitis.

OBJECTIVES: Over the last two decades, increasing interest has been focused on the association between autoimmune polyneuropathies and anti-neuronal autoantibodies in immune-mediated polyneuropathy. The possible appearance of these autoantibodies in systemic diseases that are not limited to the nervous system has not been fully addressed yet. METHODS: We evaluated 32 patients with systemic lupus erythematosus, 34 patients with hepatitis C virus-associated mixed IgM-k/IgG cryoglobulinemia, 19 with small vessel ANCA-associated vasculitis, and 20 patients with Sjögren's syndrome by means of an immunoenzyme method of anti-neuronal autoantibody detection. RESULTS: As compared to normals, a significant increase (p < 0.001) in plasma titers of both IgM and IgG anti-GM1 ganglioside and IgM and IgG anti-sulfatide was observed in patients with systemic lupus erythematosus, mixed cryoglobulinemia and Sjög-ren's syndrome. Idiopathic systemic vasculitis patients were found to have significantly increased levels of anti-sulfatide IgG autoantibodies (p < 0.001). Clinical and electrophysiologic studies revealed that abnormal titers of anti-neuronal antibodies were associated with evidence of neuropathy in patients with systemic lupus erythematosus and ANCA-related vasculitis (p < 0.05) as well as in patients with mixed cryoglobulinemia and Sjögren's syndrome (p < 0.001). CONCLUSION: Anti-GM1 and anti-sulfatide antibodies are frequently found in patients with small vessel ANCA-associated vasculitis and other multi-organ immune-mediated diseases. Upon detection of these antibodies, accurate neurologic examination should be carried out due to the significant association that can be found between these serologic abnormalities and the involvement of the peripheral nervous system as also detected by electrophysiologic studies. This study supports the unexpected possibility that anti-neuronal reactivity may be a direct trigger of neurologic injury in these systemic disorders.

[Anti-GM1 and anti-sulphatide antibodies in systemic idiopathic vasculitis, systemic lupus erythematosus and mixed cryoglobulinaemia: Serum detection and clinical and electrophysiologic correlations]. / Gli anticorpi anti-GM1 ed anti-solfatidi nelle Vasculiti sistemiche primitive, nel Lupus eritematoso sistemico e nella Crioglobulinemia mista: dosaggio sierico e correlazioni clinico-elettromiografiche.

BACKGROUND: In the last two decades increasing interest has been focused on the association between autoimmune polyneuropathies and high titers of anti-nervous serum autoantibodies. High titer of IgG anti-GM1 antibody could be detected in Guillain Barre' syndrome and in chronic painful axonal sensory immune-mediated polyneuropathy. The possible occurrence of anti-nervous autoantibodies in autoimmune diseases not limited to the nervous system is still under study. METHODS: We evaluated 29 patients with systemic lupus erythematosus (SLE), 19 with biopsy-proven renal involvement, 28 patients with mixed IgM-K/IgG polyclonal cryoglobulinaemia (18 with glomerulonephritis) and 19 with small-sized vessel ANCA-associated vasculitis (12 with renal involvement) by using a sensitive immunoenzyme method of autoantibody detection. RESULTS: Compared to controls (1/176+/-1/205; 1:204+/-1:103), we found a significant increase in plasma IgM and IgG anti-GM1 titers (1:643+/-1:531; 1:444+/-1:309) in SLE patients (p<0.0001). We also found IgM (1:3032+/-1:2844) and IgG (1:1560) anti-sulphatide titers to be higher than the control group (p<0.0001). Mean plasma IgM and IgG anti-GM1 titers of the cryoglobulinaemic patients were 1:524+/-1:403 and 1:501+/-1:415, respectively, once again higher than the controls (p<0.0001). Mean plasma IgM and IgG anti-sulphatide titers in this group were 1:1864+/-1:1189 and 1:1350 (p<0.0001). We found idiopathic systemic vasculitis patients to have significantly increased levels of anti-sulphatides IgG class autoantibodies (1:1400; p<0.0001). We found no correlation with the serologic markers for vasculitis or the clinical or histologic extent of renal involvement. Electrophysiologic studies revealed that in 38% of SLE patients (p<0.005), 61% of cryoglobulinaemic patients (p<0.01) and 42% of ANCA-related vasculitic patients (p<0.01) the abnormal titers of antineuronal antibodies were associated with clinical or subclinical evidence of neuropathy. CONCLUSIONS: In patients with systemic idiopathic or secondary vasculitis anti-GM1 and anti-sulphatide antibodies can frequently be found. Their presence should prompt an accurate neurological examination because these serologic abnormalities are significantly associated with neurologic, often subclinical, involvement. Antineuronal reactivity might be the epiphenomenon of primary phylogistic damage, which exposes normally segregated neuronal epitopes or be directly involved in triggering neurological injury.