Lymphocytotoxic antibodies in systemic lupus erythematosus are associated with disease activity irrespective of the presence of neuropsychiatric manifestations.

OBJECTIVES: To evaluate the association of the presence of lymphocytotoxic, anti-beta2-glycoprotein I (anti-beta2-GPI) and anti-ribosomal P (anti-P) antibodies in patients with systemic lupus erythematosus (SLE), presenting or not neuropsychiatric (NP) manifestations, stratified according to the activity of the disease.

METHODS: A total of 138 patients with SLE (59 with active NPSLE, 49 with active non-NPSLE, and 30 with inactive disease) and 57 healthy controls were studied. Disease activity was assessed by the SLE Disease Activity Index (SLEDAI). The presence of lymphocytotoxic antibodies was assessed using a complement-dependent lymphocytotoxicity assay. The presence of anti-beta2-GPI and anti-P antibodies was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS: Lymphocytotoxic antibodies were detected primarily in patients with active disease, that is in 35 out of 59 (59.3%) NPSLE and 23 out of 49 (46.9%) non-NPSLE patients, whereas only four out of 30 (13.3%) inactive SLE patients and none of the healthy controls exhibited the autoantibody. The frequency of lymphocytotoxic antibodies in active SLE patients, considered as a whole or stratified into NPSLE or non-NPSLE, was significantly increased in relation to inactive SLE patients (p<0.001 for each comparison). No significant difference was observed when comparing active NPSLE with non-NPSLE patients. No associations were observed between the presence of anti-beta2-GPI or anti-P antibodies and the activity of SLE or the presence of lymphocytotoxic antibodies.

CONCLUSIONS: Lymphocytotoxic antibodies occurred more frequently in patients with active SLE than in patients with inactive disease, irrespective of the presence of NP manifestations, a finding that is similar to classical biomarkers of lupus activity (anti-dsDNA and complement). These results indicate that the assessment of the presence of lymphocytotoxic antibodies may be an additional useful tool for the evaluation of SLE activity.