Plasma levels of Interleukin-6 and Interleukin-10 in preterm neonates evaluated for sepsis

In a prospective study, plasma interleukin-6 (IL-6) and interleukin-10 (IL-10) levels were measured by enzyme-linked immunosorbent assay in 45 premature neonates (25-34 weeks gestational age) with signs and symptoms of suspected sepsis at 0, 12 and 24 h; C-reactive protein (CRP) was measured at 0-24 h after enrolment. Six subjects were excluded due to insufficient blood sampling. The remaining 39 neonates were assigned to one of three groups: 25 newborns with sepsis (blood culture positive), seven with pneumonia (positive results on broncho-alveolar lavage fluid culture and characteristic chest radiography) and seven with necrotising enterocolitis (NEC) (characteristic intestinal and radiological signs according to the criteria of Bell et al.). A group of 20 healthy preterm neonates represented control subjects. On admission, higher levels of IL-6, IL-10 and CRP were observed in neonates with sepsis: IL-6 (median 1500 pg/ml, range 487-10000 pg/ml), IL-10 (median 113 pg/ml, range 70-196 pg/ml), CRP (median 22 mg/l, range 4-80 mg/l); pneumonia: IL-6 (median 1500 pg/ml, range 747-8000 pg/ml, IL-10 (median 84 pg/ml, range 76-92 pg/ml), CRP (median 10 mg/l, range 8-33 mg/l) and NEC: IL-6 (median 6650 pg/ml, range 1595-7950 pg/ml), IL-10 (median 80 pg/ml, range 61-147 pg/ml), CRP (median 3 mg/l, range 2.8-8 mg/l) as compared to controls (IL-6 median 208 pg/ml, range 198-349 pg/ml; IL-10 median 36 pg/ml, range 19-50 pg/ml; CRP median < 2 mg/l) (P < 0.05). In neonates with sepsis, IL-6 levels were significantly correlated with IL-10 levels (r = 0.65; P = 0.04) at the time of the second sample. The highest IL-6 levels were observed at onset, while IL-10 was predominant 12 h later. On admission, IL-10 and CRP levels were significantly higher in non-survivors (IL-10 median 507 pg/ml, range 422-753 pg/ml; CRP median 123 mg/l, range 20-219 mg/l) than in survivors (IL-10 median 76 pg/ml, range 61-143 pg/ml; CRP median 8 mg/l range 3-46 mg/l), while IL-10 levels were significantly higher (P < 0.05) also 12 h after admission (non-survivors: IL-10 median 600 pg/ml, range 538-800 pg/ml; survivors: IL-10 median 74 pg/ml, range 53-161 pg/ml). IL-6 and IL-10 levels were significantly correlated with CRP levels on admission (r = 0.45; P = 0.05). CONCLUSION: Preterm neonates with sepsis, pneumonia or necrotising enterocolitis showed increased interleukin-6, interleukin-10 and C-reactive protein levels. High interleukin-10 concentration was associated with mortality and could be an early indicator of prognosis.