EVIDENCE FOR REDUCED TH1 FUNCTION IN NORMAL-PREGNANCY - A HYPOTHESIS FOR THE REMISSION OF RHEUMATOID-ARTHRITIS

Objective. The mechanisms underlying the pregnancy induced remission o f rheumatoid arthritis (RA) remain unclear. We assessed the hypothesis that it reflects systemic physiologic changes in immune response duri ng gestation. Methods. We used in vitro whole blood culture systems st imulated with either lipopolysaccharide or phytohemagglutinin to asses s cytokine secretion of cells from healthy pregnant and control donors . Results. Interleukin 2 (IL-2) production was decreased during pregna ncy, more so in the 3rd trimester, and soluble tumor necrosis factor ( TNF) receptor p55 and p75 was increased, again most significantly in t he 3rd trimester. TNF-alpha and IL-1 beta were unchanged. Conclusion. These findings are consistent with the hypothesized downregulation of Th1 responses during pregnancy. Further studies to assess the relation ship with fetal/maternal HLA class II disparity, and eventually the pr esence or absence of remission in actual patients with RA, are require d.