482 Analysis of the Immune Status in the Acute Phase of Viral Respiratory Infections in Children

BACKGROUND: Viral infections can cause severe symptoms in the upper and lower respiratory tract. These are very common in childhood and occasionally seem to be an intractable problem. The aim of our study was to investigate the serum cytokine levels and other inflammatory parameters in the acute phase of viral respiratory infections and after 1 month. METHODS: We investigated the peripheral blood cell, leukocyte counts, C-reactive protein (CRP) levels, serology of respiratory viruses and serum IL-1, IL-2, IL-4, IL-6, IL-10, IL-13, IFN-gamma and TNF-α levels in children suffered from acute viral infection (group 1, N = 40) and in healthy controls (group 2, N = 20). RESULTS: Based on serology and direct identification of viruses from nasopharyngeal secretion RSV was detected in 40%, adenovirus in 20%, parainfluenza in 33% and EBV in 7%. In acute phase of infection the patients had moderately elevated leukocyte (9729 ± 658 vs 7405 ± 416, P < 0.05), monocyte count (8.48 ± 0.58% vs 5.84 ± 0.34%, P < 0.001), CRP levels (9.62 ± 3.14 mg/L vs 1.66 ± 0.58 mg/l, P < 0.05) and decreased eosinophil count (2,15 ± 0,34% vs 5,25 ± 0,81%, P < 0,05) and elevated IL-6 (4.28 ± 0.77 pg/mL vs 1.50 ± 0.25 pg/mL, P < 0.01), IL-10 (9.17 ± 2.86 pg/mL vs 1.47 ± 0.28 pg/mL P < 0.05), IL-13 (9.56 ± 2.15 pg/mL vs 1.38 ± 0.24 pg/mL, P < 0.01), IFN-γ (25.36 ± 9.73 pg/mL vs 1.11 ± 0.08 pg/mL, P < 0.05) and IFN-γ /IL-4 ratio (22.13 ± 9.56 vs 1.03 ± 0.08, P < 0.05) compared with controls. One month after the acute phase most inflammatory parameters normalized, monocyte count (8.48 ± 0.58% vs 5.05 ± 0.52%, P < 0.05), IL-6 (4.28 ± 0.77 pg/mL vs 0.80 pg/mL, P < 0.001) and IFN-γ (25.36 ± 9.73 pg/mL vs 5.14 ± 1.8 pg/mL, P < 0.05) levels decreased and eosinophil counts (2.15 ± 0.34% vs 3.62 ± 0.48%, P < 0.05) increased. CONCLUSIONS: Our results show that the protective proinflammatory cytokines, such as IFN-gamma (induced by TNF-α from monocytes) and IL-13, in association with an anti-inflammatory cytokine, IL-10, and mildly elevated other inflammatory parameters are increased in children with acute viral infection. A single parameter, elevated monocyte count, can indicate the viral origin of the infections.