Introduction:
Cell adhesion molecules on neutrophils and monocytes play an important role in the immunity of newborns.

Material and methods:
Eighty-two premature infants (47 with early-onset infection and 35 without infection, 37 male and 45 female, 40 delivered vaginally and 42 by Caesarean section) between the 3rd and 7th day of life were assessed for the expression rate of CD11a, CD11b, CD11c, CD18 CD54 and CD62L on granulocytes and monocytes using a Becton Dickinson FACS Canto II flow cytometer. Both groups were analysed for sex, body weight, gestational age, type of delivery and infection, and correlations between adhesion molecules were identified.

Results:
Preterm infants with infection had a significantly higher mean CD62L level than preterm infants without infection. There was also a positive correlation between gestational age and CD11b and CD11c, as well as correlations between CD11b and CD11c, CD11b and CD54, and CD11c and CD54U. In preterm infants without infection, there was a significant correlation between body weight and CD11a level, and correlations between CD11a and CD18, as well as CD11a and CD54. The sex of the preterm infants and type of delivery in both groups had no significant effect on the mean levels of the analysed molecules. There was no significant relationship between the expression of the analysed molecules and the CRP concentration and platelet count in preterm infants with infection.

Conclusions:
1. Early-onset infection in premature infants promotes increased expression of the CD62L molecule, which despite the lack of correlation with the CRP concentration and platelet count may prove useful in the diagnosis of infections. 2. CD11b expression in preterm infants with infections is affected by gestational age, while the expression of CD11a in preterm infants without infections is correlated with body weight. 3. Expression of the analysed molecules in premature neonates does not depend on sex or type of delivery.