To study the putative shift of a Th1 to a Th2 immune response in pregnancy and its reversal post partum in healthy women and patients with rheumatoid arthritis (RA).
Peripheral blood mononuclear cells (PBMC) were examined by FACS analysis for the expression of activation markers CD25 and HLA-DR and chemokine receptors CXCR3 and CCR4 on CD4+ and CD8+ T cells in four healthy women and four patients with RA. Samples were analysed once in the third trimester and six and 12 weeks post partum. Eight healthy non-pregnant women served as controls.
No reduction of CD25 and HLA-DR+ T cells occurred in the third trimester, but a significant increase was observed post partum in healthy women and an even greater increase in patients. Proportions of T cells expressing the CXCR3 or CCR4 marker were similar in patients and controls during pregnancy, whereas a significant increase occurred post partum. The ratio of CXCR3+ to CCR4+ cells remained unchanged during the observation period and did not differ significantly from that in non-pregnant controls.
A shift from a Th1 to a Th2 immune response was not detected in the circulation of healthy pregnant women or pregnant patients. The significant increase of T cell activation after pregnancy warrants further investigation into the mechanisms of adjustment of the immune system post partum and its clinical correlates in rheumatic patients.