Normal levels of interleukin 6 and 8 in serum and urine in asymptomatic healthy children

Abstract

Objective: To determine the interleukins (IL) 6 and 8 levels in serum and urine in the healthy pediatric population, and to establish our laboratory reference values. Material and methods: Study, in healthy children without urinary tract infection. We analyse the following variables: sex, age, to be oldest or youngest than 1 year, and IL-6 and IL-8 levels in serum and urine (ELISA). We evaluate the basic statistics for quantitative variables. It compare the independent samples by means of Mann-Whitney U test, and its correlation with the Pearson test. Results:We have studied 52 children (40 males, 76.92%). The mean of age was 51.31 + 47.98 months (1-149 months), and it didn?t have differences according to sex, or to be oldest and youngest than 1 year of age. The mean values of IL (and confidence interval IC: 95%), and the upper limit of normality, respectively were for serum IL-6: 0.49 (IC: 0-1,05), and 3.95 pg/mL; urine IL-6: 0,17 (IC: 0-0,51), 1,83 pg/mL; serum IL-8: 136,66 (IC: 0,74-272,58), 974,58 pg/mL; and urine IL-8: 47,23 (14,71-79,75), 242,39 pg/mL. It didn?t have differences neither between both sex nor age groups, except urine IL-8 mean levels greater in youngest of 1 year of age, with a negative correlation between this variable and age (p<0,05). Moreover, it exist a positive and very significant correlation of urine IL-6 and 8 (p<0,001), and serum and urine IL-8 (p<0,01). Conclusions: In healthy pediatric population, it didn?t observe differences according to sex in IL-6 and IL-8 levels, but the urine IL-8 production is greater in more little children. It observe significant serum and urine IL-8 levels in healthy children, making questionable its validity in urinary tract infection diagnosis. Finally, it exist an excellent correlation between urinary IL-6 and IL-8 in normal conditions.