Tissue Expression of Interleukin 2 (IL-2) and IL-2 Receptor (IL-2Rα/CD25) in non-Hodgkin B-cell Lymphomas in Children Correlations With Clinical Data

The study aimed at analysis of tissue expression of interleukin 2 (IL-2) and subunit a of its receptor (IL-2R alpha/CD25) in B-cell non-Hodgkin lymphomas (B-cell NHLs) in children as related to selected clinical data. The studies were performed on an archival tissue material originating from children with B-cell NHLs (n = 26) using avidin-biotin-peroxidase complex method and in-situ hybridization with biotinylated tyramine amplification signal (ImmunoMax technique). As compared with non-neoplastic lesions, in B-cell NHLs a significantly higher expression was noted of both IL-2 and IL-2R alpha. In children with B-cell NHLs, frequency of IL-2 detection was 62%, and that of IL-2R alpha, 46%. Using hybridocytochemistry, presence of mRNA for IL-2 could be detected, but not mRNA for IL-2R alpha in children with B-cell NHLs. A significant direct relationship was demonstrated between expressions of IL-2 and IL-2R alpha in children with B-cell NHLs. No significant relationships could be detected between expression of IL-2 and/or IL-2R alpha on one hand and histopathologic diagnosis, tumor location, age, or sex in B-cell NHLs on the other. The new element in the results involved demonstration of significant differences in shorter survival of children with B-cell NHLs, as related to cellular expression of IL-2 and IL-2R alpha (CD25). Comparing the expected percentage of patients at risk, children with CD25-positive tissue expression had a significantly lower chance to survive longer time than children with IL-2-positive tissue expression. The positive relationship between tissue expression of IL-2R alpha and the shorter survival of children with B-cell NHLs should prompt further investigations to identify other risk factors in patients with this type of tumors in children.