Antenatal betamethasone associates with transient immunodepression in very low birth weight infants.

Background: Antenatal betamethasone (BM) treatment for mothers at risk for premature delivery is effective in reducing neonatal morbidity. Immunodepression, defined as monocyte human leukocyte antigen (HLA)-DR expression <60%, is common in patients in intensive care. In very low birth weight (VLBW) infants, immunodepression correlates with gestational age and may predispose to infections.

Objectives: To evaluate whether timing of antenatal BM associates with immunodepression in VLBW infants.

Methods: We determined monocyte HLA-DR expression by flow cytometry and measured 13 cytokines, cortisol, and BM in plasma from 56 VLBW infants. We calculated total glucocorticoid index as the sum of BM and cortisol at the ratio 33.3:1.

Results: HLA-DR expression both in cord (R(2) = 0.175, p = 0.033, n = 26) and on day 1 (R(2) = 0.125, p = 0.011, n = 51) showed an association with timing of BM. A short interval from BM to birth induced more pronounced and prolonged immunodepression, with lower HLA-DR% on postnatal day 7. On day 3, 25 infants (45%) met the criteria of immunodepression. HLA-DR expression correlated negatively with total glucocorticoid index (cord: R(2) = -0.573, p = 0.003, n = 13; day 1: R(2) = -0.213, p = 0.008, n = 32). Elapsed time from maternal BM correlated positively with concentrations of cytokines IL-6 and IL-10 on day 1.

Conclusions: In VLBW infants, antenatal BM associated with transient immunodepression in a time-dependent manner. Suppression of both anti- and proinflammatory cytokines occurred. These effects may lead to an increased risk for later infections.