In human neonates and preterm infants, fungal infections produce significant morbidity and mortality. Human adult lymphocytes activated by Interleukin-2 (IL-2) closely adhere and inhibit the growth of hyphae forms ofCandida albicans. We hypothesized that neonatal lymphocytes, have decreased adherence to hyphae and therefore decreased capacity to inhibit the growth of C. albicans.

Methods: Lymphocytes were isolated from 10 adult peripheral blood samples, and the cord blood of 10 term, and 10 preterm infants by differential centrifugation, and placed in RPMI-1640 culture medium with IL-2 (1000u/ml) for 7 days. The lymphocytes were then Labelled with [51Cr] Chromium. The labelled lymphocytes were incubated with the hyphae form ofCandida albicans for 1 hr. Binding of the lymphocytes was assessed by [51Cr] incorporation. Data are presented as the mean ± SD.

Results: Lymphocytes from both preterm and term cord blood demonstrated significantly less binding of the Candida albicans than did lymphocytes from adult blood (expressed as percent cell binding: term 33.3 ± 10.5, preterm 15.0 ± 8.4, adult 55 ± 5.02 p=0.0006 by ANOVA).

Conclusion: We conclude that neonatal lymphocytes are deficient in their capacity to adhere to C. albicans hyphae compared to adult lymphocytes. The preterm lymphocytes are more deficient than the term. This deficiency may contribute to the increased susceptibility to candida infections in this age group.