L. Sirota et al., Phototherapy for neonatal hyperbilirubinemia affects cytokine production by peripheral blood mononuclear cells, EUR J PED, 158(11), 1999, pp. 910-913
The capacity of peripheral blood mononuclear cells (PBMC) to produce interl
eukin (IL) IL-1 beta, IL-2, IL-3, IL-6, IL-10 and tumor necrosis factor-alp
ha (TNF alpha.) was examined in term newborns with hyperbilirubinemia after
24 hours' exposure to phototherapy (wave length 425-475 nm). The results w
ere compared with those fi om untreated neonates. Fifty newborns spontaneou
sly delivered at terrm were included in the study. Blood samples were colle
cted from 20 newborns before and 24 h after phototherapy. The control group
consisted of 30 neonates examined on two consecutive days, PBMC isolated f
rom blood samples were incubated in vitro for cytokine production. The conc
entration of cytokines in the supernatants was tested using ELISA kits: (fo
r IL-1 beta, IL-6, IL-10 and TNF alpha), or by bioassays (for IL-2 and IL-3
). Phototherapy caused a 70% increase in IL-2 secretion (123 +/- 27 vs 208
+/- 30 units/ml. P < 0.01) and 56% in IL-10 production (1.07 +/- 0.19 vs 1.
67 +/- 0.33 ng/ml, P < 0.03), whereas the spontaneous secretion of IL-1 bet
a was reduced by 43% (13.7 +/- 2.3 vs 7.3 +/- 1.7 ng/ml, P < 0.02). In the
control group the secretion of these cytokines was similar on the two conse
cutive days and did not differ significantly from secretion in the other gr
oup before phototherapy. On the other hand, lipopolysaccharide induced TNF
alpha production was higher on the second day in the two groups of newborns
irrespective of phototherapy (388 +/- 58 vs 683 +/- 88 pg/ml, P < 0.001, i
n the control group and 384 +/- 75 vs 588 +/- 91, P < 0.05, before and afte
r phototherapy). The synthesis of IL-3 and IL-6 did not change significantl
y between the two days of the study. The results demonstrate that in additi
on to the well-known nn positive effect of phototherapy on the neonate seru
m bilirubin level. this treatment affects the function of the immune system
in newborns via alterations in cytokine production.