Serum and CSF soluble CD26 and CD30 concentrations in healthy pediatric surgical outpatients.

Activated T-helper type 1 (Th1) lymphocytes induce a cellular type immune response, and Th2 lymphocytes, a humoral or antibody-mediated type immune response. Soluble CD26 (sCD26) and soluble CD30 (sCD30) are regarded as markers of Th1 and Th2 lymphocyte activation, respectively. Serum from 112 generally healthy pediatric surgical patients and cerebrospinal fluid (CSF) from 39, aged 1-17 years were measured for sCD26 and sCD30 using an enzyme-linked immunosorbent assay method. The detection limit for sCD26 was 6.8 ng/ml and for sCD30, 1.9 IU/ml. For serum sCD26 and sCD30, 2.5% and 97.5% percentiles constituted the reference limits, and the 95% credible intervals for the percentiles were calculated using regression models with a Bayesian approach. A significant between-gender difference was observed (P = 0.015) in serum sCD26 concentration, of which the lower limits ranged between 273 and 716 ng/ml for girls and 235 and 797 ng/ml for boys. The upper limits ranged between 1456 and 1898 ng/ml for girls and between 1419 and 1981 ng/ml for boys. Moreover, the concentrations of sCD26 increased in infants and children up to 10 years in girls and 12 years in boys. After this however, the values decreased. The serum sCD30 concentration was highest among the youngest infants aged 1 year (80-193 IU/ml), after which a consistent age-related decrease was found. The lowest values were found at the age of 17 years (10-89 IU/ml). A significant between-gender difference in sCD30 concentration was observed (P = 0.019). sCD26 and sCD30 concentrations were low in the CSF samples analyzed: 13.3 ng/ml (median); range 8.3-51.5 ng/ml and 7.6 IU/ml; 2.1-18.5 IU/ml, respectively. Reference limits for serum sCD26 in children aged 1-17 years were established as being 235-1800 ng/ml in toddlers and 400-1800 ng/ml in female adolescents and 700-2000 ng/ml in male adolescents. For sCD30; reference limits of 80-190 IU/ml were established in the youngest age group and 10-90 IU/ml in adolescents.