Serum Neopterin, β2-Microglobulin, Soluble Interleukin-2 Receptors, and Immunoglobulin Levels in Healthy Adolescents

Serum biomarkers, such as neopterin, β₂-microglobulin (B2M), and soluble interleukin-2 receptors (sIL-2R), are elevated in viral infections, including HIV-1 infection, and in inflammatory conditions, autoimmune disease, and malignancies. For many of these conditions, serum levels correlate with disease activity. Application of these biomarkers in adolescents is limited by a lack of information on the range and determinants of variability (age, sex, race) for serum levels of these important molecules in this age group. To address this question, we analyzed serum samples from a well-characterized heterogeneous population of 111 healthy adolescents. White children had significantly higher serum levels of sIL-2R and IgM and lower levels of IgG (P≤ 0.001) than black children. Boys had higher sIL-2R and B2M levels (P< 0.005) and lower IgM levels (P< 0.05) than girls. No significant age effect on B2M or neopterin level was observed over the age range of 12–19 years included in this analysis. However, stratification by race showed that serum sIL-2R level was significantly associated with age among whites, but not among blacks. Values of these biomarkers in this population are compared with age-stratified values in the previously analyzed 20- to 69-year-old population from whose households the adolescent subjects were recruited.