Abstract

Deviating cytokine patterns, as a consequence of aberrant immunoregulation, is implicated to be of aetiopathogenetic importance in systemic lupus erythematosus (SLE). To evaluate the possibility of anti-cytokine autoantibody-mediated cytokine regulation/dysregulation, IgG class autoantibodies against cytokines (IL-1beta, IL-6, IL-10, TNFalpha and TGFbeta(1)) were analysed by enzyme-linked immunosorbent assay (ELISA) in serial serum samples from clinically well-characterized SLE patients and in normal human sera (NHS). Anti-TNFalpha autoantibody levels were lower in patients with active disease compared to inactive disease (P<0.001) as well as to NHS (P<0.001). The anti-TNFalpha antibody levels correlated inversely to the SLE disease activity index (SLEDAI) (r(2)=0.07, P<0.01), whereas anti-TGFbeta antibodies were raised in SLE and correlated positively to levels of complement factor C1q (r(2)=0.08, P<0.005). Generally raised anti-cytokine antibody levels and correlations to disease activity measures were found in one individual. Inverse correlations were found comparing SLEDAI scores and autoantibodies to TNFalpha (r(2)=0.92) and IL-6 (r(2)=0.86) and positive correlations were found between levels of anti-TNFalpha and C1q (r(2)=0.86) and C3 (r(2)=0.90). We show, for the first time, a coincidence between reduced anti-TNFalpha autoantibody levels and disease exacerbation in SLE, which is of interest regarding aetiopathogenesis and disease control.