Autoantibodies and neuropsychiatric events in lupus

Within the study window, 133 of the 412 patients (32.3 percent) had at least one NP event and 47 (11.4 percent) had two or more events. In total, the events encompassed 14 of the 19 recognized NP syndromes. The proportion of NP events directly attributed to SLE varied from 15 percent (32 of 214) to 36 percent (77 of 214), depending on the attribution model used. Testing for autoantibodies uncovered an association between anti-ribosomal P antibodies and psychosis. Seven patients had psychosis that was attributed to SLE and nearly half of these patients had anti-P antibodies. In addition, the presence of another lupus antibody called lupus anticoagulant was linked to cerebrovascular disease, particularly nonischemic stroke. There was no statistically significantly link with NP events and other lupus autoantibodies, including anticardiolipin, anti-A2-glycoprotein I and anti-NR2 glutamate receptor antibodies.

As Dr. Handy acknowledges, despite the association between these laboratory tests and specific NP events occurring around the time of diagnosis of SLE, these intriguing findings have questionable clinical applications, due to the low sensitivity of antibody tests for NP disease. What's more, the study itself had a number of limitations. For one, due to the lack of specificity of most of the NP events, composite arbitrary rules for attribution had to be developed. For another, many of the NP events attributed to SLE were infrequent, restricting the statistical power of the analysis. Despite its limitations, however, this study provides novel information on the prevalence of specific autoantibodies in an international sample of recently diagnosed SLE patients. "Future studies will be conducted to determine the reproducibility of these findings in an expanded disease inception cohort," Dr. Handy states, "and to examine whether any of these autoantibodies predict the subsequent development or course of NP events over time."

Article: "Autoantibodies and Neuropsychiatric Events at the Time of Systematic Lupus Erythematosus Diagnosis," J.G. Hanly, M.B. Urowitz, F. Siannis, V. Farewell, C. Gordon, S.C. Bae, D. Isenberg, M.A. Dooley, A. Clarke, S. Bernatsky, D. Gladman, P.R. Fortin, S. Manzi, K. Steinsson, I.N. Bruce, E. Ginzler, C. Aranow, D.J. Wallace, R. Ramsey-Goldman, R. van Vollenhoven, G. Sturfelt, O. Nived, J. Sanchez-Guerrero, G.S. Alarcon, M. Petri, M. Khamashta, A. Zoma, J. Font, K. Kalunian, J. Douglas, Q. Qi, K. Thompson, and J.T. Merrill, for the Systemic Lupus International Collaborating Clinics, Arthritis & Rheumatism, March 2008.