Antibodies to Microtubule-Associated Protein 2 in Patients With Neuropsychiatric Systemic Lupus Erythematosus

Objective. Microtubule-associated protein 2 (MAP-2), a cellular protein restricted to neurons, is important in the control of cytoskeletal integrity and other neuronal functions. We undertook this study to examine the presence of autoantibodies to MAP-2 in neuropsychiatric systemic lupus erythematosus (NPSLE). Methods. Sera from 100 patients with SLE, 74 patients witli other neurologic disorders and injuries (including cerebrovascular accidents, brain trauma, brain tumors, and demyelinating disorders), and 60 normal controls were examined both by enzyme immunoassays and by Western immunoblotting for autoantibodies to MAP-2. Sera designated positive for antibodies to MAP-2 were required to be positive in both assays. Results. Seventeen percent of SLE patients had autoantibodies to MAP-2, in contrast to 4% of neurologic injury/disease control patients (P = 0.028) and 1.7% of normal controls. In SLE, anti-MAP-2 positivity in both assays was associated with neuropsychiatric symptoms in 76.5% of patients, whereas the absence of anti-MAP-2 was associated with neuropsychiatric symptoms in 19.7% of patients (P = 0.0002). The neuropsychiatric symptoms in the former group included psychosis, seizure, neuropathy, and cerebritis. Conclusion. Autoantibodies to MAP-2, a neuron-restricted cytoskeletal protein, appear to be another immune marker for NPSLE.