Decreased phagocytic capacity of cord blood monocytes in second- and third-born multiplets

To assess the risk to second- and third-borns of developing perinatal infections based on a diminished first-line immune response in comparison to the first-born.

11 sets of twins and 2 sets of triplets (27-39 weeks of gestation, 740-3,560 g birth weight) admitted consecutively to our neonatal care unit were investigated. All were delivered by cesarean section. Phagocytosis and the expression of TNF-alpha and IL-1 in cord blood were determined immediately and 72 h after birth from peripheral blood monocytes by FACS analysis and ELISA.

In all second- and third-borns, phagocytosis of cord blood monocytes was significantly decreased in comparison to the first-borns (p < 0.001, p < 0.015). 72 h after birth phagocytosis determined from peripheral blood showed no significant difference between the first-borns and the second- and third-borns. Cytokine expression revealed no significant differences dependent on birth order.

We suggest that the observed temporarily diminished first-line immune response of second- and third-born multiplets might be the result of a short-term reduced cellular oxygenation during delivery, but has no influence on further immunological deficiency leading to a higher risk of perinatal infections.