Polymorphism in interleukin 21 gene is associated with decreased susceptibility to diffuse large B cell lymphoma.

Interleukin 21 (IL-21) plays a key role in innate and adaptive immunity. Polymorphisms in IL-21 gene may be greatly involved in various diseases. The aim of the study was to investigate the association between IL-21 genetic polymorphisms and the susceptibility to diffuse large B cell lymphoma (DLBCL). IL-21 -2498G/A and +78A/G polymorphisms were examined in 221 DLBCL patients and 243 healthy controls. We found that distributions of -2498GA genotype and -2498AA genotype were clearly decreased in DLBCL cases compared to healthy donors (odds ratio [OR] = 0.71, 95% confidence interval [CI] = 0.43-0.92, P = 0.021; OR = 0.36, 95 % CI = 0.15-0.48, P < 0.001; data were adjusted for age and sex). Stratification analyses revealed that patients with advanced Ann Arbor stages (III+IV) had further decreased percentage of -2498AA genotype than those with primary stages (OR = 0.31, 95% CI = 0.13-0.87, P = 0.023; data were adjusted for age and sex). In addition, we evaluated the possible effect of IL-21 polymorphisms on gene expression by examining serum level of IL-21 in patients and controls. Data revealed that subjects carrying -2498AA genotype had significantly higher serum level of IL-21 than those with GG genotype or GA genotype. These data suggest that IL-21 -2498G/A polymorphism is associated with decreased susceptibility to DLBCL and may increase serum level of IL-21.