Nervous system disease, immunological features, and HLA phenotype in Sjögren's syndrome.

Twenty seven patients with primary or possible Sjögren's syndrome with neurological manifestations were compared immunologically with 21 patients with Sjögren's syndrome with an intact nervous system. Patients with Sjögren's syndrome were divided into seropositive and seronegative subgroups with respect to the occurrence of one or more autoantibodies (antinuclear antibodies, rheumatoid factor, antibodies to SS-B) in their serum samples. This study of 48 patients indicates that the spectrum of nervous system disease in seronegative and seropositive subgroups is almost indistinguishable. No significant differences were found in the occurrence of circulating immune complexes, the levels of serum complement C3 and C4, or serum IgA, IgM, and beta 2 microglobulin with respect to the neurological manifestations. The serum IgG level, however, was significantly higher in the patients with Sjögren's syndrome with intact nervous systems than in those with neurological manifestations. No significant association was found between the HLA phenotype and nervous system disease. The occurrence of HLA-B8 and DR3 antigens was, however, significantly higher in those patients with antibodies to SS-B than in those without. This finding supports the suggestion that HLA-B8/DR3 may modulate autoantibody responses rather than disease expression in Sjögren's syndrome.