Soluble CD95 concentrations are increased in patients with severe systemiclupus erythematosus, but not in their first degree relatives

Objective-Plasma concentrations of soluble CD95 (sCD95) are raised in patie nts with systemic lupus erythematosus (SLE) before clinical relapses become manifest. Increased sCD95 concentrations may therefore be a familial chara cteristic that is associated with susceptibility to severe disease. To test this, sCD95 concentrations were measured in healthy first degree relatives of patients with severe and non-severe SLE. Methods-Seventy seven first degree relatives of 26 patients with severe, an d 72 relatives of 25 patients with non-severe lupus were studied. Controls were 42 first degree relatives of 17 patients with chronic cutaneous lupus erythematosus (CCLE) and 63 partners of the patients with their first degre e relatives. Severe lupus was defined as both multi-organ disease and cyclo phosphamide treatment, non-severe lupus as neither. Organ damage was assess ed with the SLICC-ACR index, disease activity with SLEDAI. Results-Soluble CD95 concentrations in relatives of patients with severe SL E were similar to those in relatives of patients with non-severe SLE, relat ives of patients with CCLE, and controls (median (interquartile range) sCD9 5 concentration 0.59 (0.52-0.66) v 0.57 (0.50-0.63), 0.56 (0.51-0.71), and 0.55 (0.49-0.61) ng/ml, p=0.25, p=0.94, and p=0.17, respectively). Increase d concentrations of sCD95, however, were found in patients with severe SLE compared with those in patients with non-severe SLE, patients with CCLE, an d control relatives (0.77 (0.70-0.97) v 0.60 (0.54-0.67), 0.57 (0.54-0.71), and 0.57 (0.52-0.63) ng/ml, respectively, p<0.001). Concentrations of sCD9 5 were significantly correlated with damage index scores (r(s)=0.47, p<0.01 ). Basic and clinical characteristics of patients with SLE, including SLEDA I scores, could not explain these observations. Conclusion-Soluble CD95 concentrations are associated with severity of the disease and not with susceptibility for severe SLE.