THE TUMOR-NECROSIS-FACTOR FAMILY OF RECEPTORS LIGANDS IN THE SERUM OFPATIENTS WITH RHEUMATOID-ARTHRITIS/

We investigated the serum concentration of the tumour necrosis factor (TNF) family ligands (TNF-alpha and TNF-beta) and their soluble recept ors (sTNF-R p55 and sTNF-R p75) in 66 patients with rheumatoid arthrit is (RA) and 14 healthy subjects as a control group, using an enzyme-li nked immunosorbent assay (ELISA), We examined a possible association b etween the serum levels of these proteins and RA activity according to the Mallya & Mace scoring system and Ritchie's index. We also evaluat ed the correlation between the serum levels of ligands and their solub le receptors as well as the ligands and receptors concentration and th e duration of the disease, TNF-alpha, sTNF-R p55 and sTNF-R p75 were d etectable in the serum of all 66 patients and 14 healthy individuals. In contrast, TNF-beta was measurable in only 14 (21.9%) patients with RA and in none of the control subjects. The highest TNF-alpha, sTNF-R p55 and sTNF-R p75 levels were found in those patients in stage 4 of t he disease, and the lowest in the control group. We found a positive c orrelation between sTNF-R p55 and sTNF-R p75 concentrations and Ritchi e's index and no correlation with TNF-alpha and TNF-beta, TNF-alpha, s TNF-R p55 and sTNF-R p75 serum levels correlated positively with the d uration of the disease, but levels of TNF-beta did not. We observed a positive correlation between the concentrations of TNF-alpha with sTNF -R p55 and with sTNF-R p75, as well as between both soluble receptors, In contrast, we have not observed any correlation between the serum l evel of TNF-beta with TNF-alpha, sTNF-R p55, and sTNF-R p75, Our studi es indicate that TNF-alpha, sTNF-R p55 and sTNF-R p75, but not TNF-bet a (lymphotoxin alpha) are good markers of RA activity and that these p roteins play an important role in the pathogenesis of this disease.