Flow cytometric assessment of anti-neuronal antibodies in central nervous system involvement of systemic lupus erythematosus and other autoimmune diseases.

The objective of this study is to evaluate the association between anti-neuronal antibody (anti-NA) and central nervous system (CNS) manifestations of systemic lupus erythematosus (SLE) and other rheumatic diseases using a flow cytometric method. Anti-NA was measured by flow cytometry in serum and cerebrospinal fluid (CSF) samples from patients with SLE (n=44 for serum, n=17 for CSF), other rheumatic diseases (n=64 for serum, n=21 for CSF) and from healthy controls (n=65 for serum, n=18 for CSF). Serum anti-NA was more frequently observed in SLE (31.8%, 14/44) than in other rheumatic diseases (4.7%, 3/64, P<0.001) or in healthy controls (0%, 0/65, P<0.00001). In SLE patients, the frequency of serum anti-NA was significantly higher in CNS-SLE (76.5%, 13/17) than in non CNS-SLE (3.7%, 1/27, P<0.000001). CSF anti-NA was detected in 88.2% (15/17) of CNS-SLE and was more frequently detected in CNS-SLE (15/17, 88.2%) than in other rheumatic diseases with CNS involvement (1/21, 4.8%, P<0.000001) or in healthy controls (0/18, P<0.000001). In conclusion, serum anti-NA was more frequently found in CNS-SLE than in non CNS-SLE, other rheumatic diseases or in healthy controls. The frequency of CSF anti-NA in CNS-SLE was significantly higher than in other rheumatic diseases with CNS involvement or in healthy controls.