Interleukin-2 receptor concentrations in pregnant women with a history of recurrent miscarriage.

BACKGROUND The mechanism by which the maternal immune system tolerates the fetus during pregnancy is unclear. METHODS This study measured interleukin-2 receptor (IL-2R) concentrations in the serum of non-pregnant women (Group 1); healthy first trimester pregnant women (Group 2); pregnant women with a history of recurrent miscarriage whose pregnancies again failed later in the first trimester (Group 3); and first trimester pregnant women with a history of recurrent miscarriage but whose pregnancies on this occasion went successfully to term (Group 4). An initial sample was obtained from all women in Groups 1, 2, 3 and 4. A further sample was obtained 4 weeks later from women in Groups 1, 2 and 4. RESULTS The initial sample showed no significant difference in IL-2R concentrations between Groups 1 and 2. Concentrations were significantly higher in Groups 3 (667 +/- 244 U/ml; P < 0.003) and 4 (730 +/- 360 U/ml; P < 0.05) compared with healthy pregnant women (425 +/- 94). When the second sample was obtained concentrations in Group 4 were found to have fallen so that they no longer differed from Group 2. CONCLUSIONS Our results confirm earlier findings that a successful pregnancy is associated with significantly lower concentrations of IL-2R.