Alterations in the immune system of patients with imminent preterm labour.

Premature labour is the major cause of perinatal morbidity and mortality. The aetiology of most cases of preterm labour remains unknown. We tried to estimate whether immunological changes are present in patients with preterm labour. Fourteen patients with imminent preterm labour and 12 healthy women with uncomplicated pregnancies were included in the study. The specific lymphocyte antigens were determined using direct staining with monoclonal antibodies and analysed by flow cytometry. We observed that CD8+ lymphocyte percentage was significantly lower in the group of patients with preterm labour when compared to controls (p < 0.001). This deficit was related to T CD8+11b+ suppressor lymphocytes, while the percentage of T CD8+11b- cytotoxic lymphocytes did not differ in both studied groups. Furthermore, the percentage of T CD3+ lymphocytes was significantly lower and that of B CD19+ cells higher in the study group when compared to controls. Similarly, the percentage of CD4+45RA naive cells was higher in the group of patients with imminent preterm labour, while the percentage of memory CD4+45RO+ cells was lower in the study group in comparison with the control group. These observations suggest that alterations in maternal immunological parameters can be associated with the mechanisms mediating preterm labour. Copyright 2000 S. Karger AG, Basel