Autologous mixed lymphocyte reaction (AMLR) in man. XVI. The AMLR and monoclonal antibody-defined T cell subsets and HNK 1 + natural killer cells in normal human pregnancy

Abstract

Peripheral blood mononuclear cells from 27 pregnant women and 10 age-matched non-pregnant women were examined for monoclonal antibody-defined T cells, immunoregulatory T-cell subsets, natural killer cells, activated T cells and surface Ig + B lymphocytes using a fluorescence-activated cell sorter (FACS analyzer). The autologous mixed lymphocyte reaction (AMLR) and in vitro influence of interleukin 1 (IL-1) and interleukin 2 (IL-2) on the AMLR were also studied. No significant difference was observed in the proportions of Leu 3 + (helper/inducer phenotype) and Leu 2 + (suppressor/cytotoxic) T cells during all three trimesters of pregnancy and in post-partum period when compared to non-pregnant healthy control women. T cells expressing DR antigen (evidence of T-cell activation) were significantly increased during second trimester ( P < 0.002) and in post-partum period ( P < 0.05). However, Tac + T cells (IL-2 receptor positive T cells, another but distinct marker for T cell activation) were normal throughout pregnancy and in the post-partum period. Leu 7 + (HNK 1 +) lymphoid cells (containing a population of natural killer cells) were normal during all 3 trimesters of pregnancy but were increased during post-partum period. Surface Ig + B cells were comparable to control group throughout pregnancy and during post-partum period. The AMLR was significantly deficient ( P < 0.01) during first and third trimester of pregnancy. In vitro addition of purified IL-2 restored the AMLR to the baseline levels of the controls but the AMLR was still lower than the levels in controls with IL-2. The addition of IL-1 to IL-2 containing cultures, further enhanced the AMLR in all groups but the responses were significantly lower in first and third trimester and post-partum group when compared to controls with IL-1 and IL-2 combined. This would suggest that in addition to deficient AMLR, there is partial deficiency of response to IL-2 during first and third trimester of pregnancy.