Background: Phototherapy is widely used in neonatal units for treatment of hyperbilirubinemia. Although phototherapy usually controls hyperbilirubinemia successfully, it is not without side effects, some of which are as yet unknown.
Objective: The purpose of our study is to investigate the influence of phototherapy used in the treatment of neonatal hyperbilirubinemia on the levels of T-lymphocyte subsets (CD3+, CD4+ and CD8+).
Subjects and Methods: The study group included 20 term newborns with hyperbilirubinemia (group 1) and the control group included 20 age- and sex- matched healthy term newborns (group 2). The hyperbilirubinemic newborns were further classified into group 1a (before phototherapy) and group 1 b (48 hours after phototherapy). Blood samples were collected from hyperbilirubinemic newborns before phototherapy and 48 hours after exposure to phototherapy, and samples were collected from controls at time of examination. The percentages of T-lymphocyte subsets were measured in the samples using appropriate methods.
Results: The percentage of CD3+ lymphocyte subset was significantly lower in term neonates 48 h after exposure to phototherapy. The percentage of CD4+ and CD8+ lymphocyte subsets were decreased 48h after exposure to phototherapy, but these findings were not statistically significant.
Conclusion: The results demonstrated that in addition to the well-known positive effect of phototherapy on the neonatal serum bilirubin level, this treatment may have affection on the function of the immune system in newborns.
Key words: Hyperbilirubinemia, phototherapy, lymphocytes subsets, immunity