EFFECTS OF LABOR AND MEDICATION ON MAJOR LYMPHOCYTE SUBSETS IN CORD-BLOOD

It is envisaged that flow cytometric analysis of lymphocyte subsets in cord blood may be used as a biomarker for effects on the immune syste m of exposure to environmental factors. In order to investigate the po ssible application of this parameter, we first studied the effects of other factors that may influence the outcome of subset analysis in cor d blood. FAGS analysis was performed in 112 pairs of umbilical cord bl ood and of peripheral maternal blood sampled at labour. Whereas in mat ernal blood no statistically significant effects of medication during labour on T lymphocyte numbers and NK cells were found, in oxytocin-an d in oxytocin and prostaglandin-treated mothers B cell numbers showed a statistically significant increase, In cord blood, the course of lab our and/or medication during labour were identified as the most import ant factors determining distribution of major lymphocyte subsets. In c ord blood after deliveries without medication or after neuroplegic ana lgesia (NPA), the mean percentage of cord blood T lymphocytes (CD3(+)) was highest (59%) and that of NK lymphocytes (CD3(-)/CD16 + 56(+)) lo west (20%), The mean percentage of T lymphocytes was significantly low er (52%) and that of NK lymphocytes higher (28%) in cord blood where d eliveries were done under NPA in combination with infusion of oxytocin . The combination of NPA with oxytocin and induction of labour by pros taglandin E2 led to a further reduction of T lymphocytes and an increa se of NK cells (39% and 38% respectively), The changes in ratio of T a nd NK lymphocytes were due both to decreasing absolute counts of T lym phocytes and increasing counts of NK lymphocytes. Thus, the effects of labour and/or medication during labour must be taken into account whe n this parameter is applied as a potential biomarker of effects of env ironmental factors on the immune system.