Patients with systemic lupus erythematosus with high plasma levels of sFasrisk relapse

Objective. We related soluble Fas (sFas) levels to the Systemic Lupus Eryth ematosus Disease Activity Index (SLEDAI) in a longitudinal series of plasma samples of patients with SLE to evaluate the relation between excessive pr oduction of sFas and disease activity. Methods. We generated 21 monoclonal antibodies against Fas. Two Of these we re used to develop and validate a sensitive sandwich ELISA for the longitud inal analysis of sFas levels in plasma of 30 patients and 25 controls. Results. At the start of followup, a significant elevation (p < 0.0001) was found in sFas levels in SLE (1167 +/- 337 pg/ml sFas) compared to controls (618 +/- 98 pg/ml sFas). Also, at the start of the followup a significant difference (p = 0.0028) existed between patients who were going to have a r elapse (1236 +/- 402 pg/ml sFas) during followup and patients who were not (809 +/- 276 pg/ml sFas). While sFas did not fluctuate with disease activit y in individual patients, we found a strong correlation (r = 0.75, p < 0.00 01) between sFas and SLEDAI, but only at the time of relapse, when we analy zed the patients as a group. Conclusion. In individual patients with SLE, sFas does not fluctuate with d isease activity. However, patients with high plasma levels of sFas are at r isk of relapse.