Evidence for intrathecal synthesis of autoantibodies in systemic lupus erythematosus with neurological involvement.

The diagnosis of systemic lupus erythematosus (SLE) in a patient who presents with isolated central nervous system (CNS) abnormalities, is a difficult clinical challenge. The pathogenesis of such CNS involvement in SLE is unknown. Twelve patients with active SLE were examined for serum and cerebrospinal fluid (CSF) autoantibodies and compared with 21 patients with headache. Four of six patients with SLE and active CNS presentation had CSF autoantibodies while none of the other SLE patients and the controls had autoantibodies. We describe these four patients in whom immunological work-up revealed CSF antinuclear, anti-DNA, anti-SSA/Ro, anti-SSB/La and antineuronal autoantibodies. A newly devised antibody activity index provided means to demonstrate that the CSF autoantibodies in these patients were produced intrathecally. Beyond the importance of our finding of the potential role of autoantibodies in the pathogenesis of CNS damage in SLE, we propose that CSF analysis for autoantibodies should become an essential part of the diagnostic work-up in autoimmune diseases with CNS involvement.