Interleukin-10 (IL-10) is one of the cytokines implicated in the pathogenesis of diffuse large B-cell lymphoma (DLBCL) in which it acts as auto/paracrine growth factor for lymphoma growth. T-cell non-Hodgkin lymphoma (NHL) is a heterogeneous disease, the biological basis of which is not fully understood. Some evidence suggests that IL-10 might be associated with the progression of T-cell NHLs and that IL-10 may be involved in a rescue effect, protecting T cells from apoptotic cell death associated with upregulated bcl-2 expression. The current study evaluated the impact of IL-10 gene (IL10) polymorphism on the response to chemotherapy and survival in T-cell NHL. IL10 polymorphisms were determined in 108 patients with T-cell NHL. The response to chemotherapy was not dependent on IL10 polymorphism, while survival differed significantly according to IL10 polymorphism. The group with ATA haplotype showed superior overall survival (61.2 +/- 5.9% vs. 21.2 +/- 11.7%, P = 0.001) and failure-free survival (35.0 +/- 5.7% vs. 13.2 +/- 8.7%, P = 0.001) compared to those without ATA haplotype. The ATA haplotype was identified as a favourable prognostic factor compared to non-ATA haplotype (P = 0.037, hazard ratio 2.1), together with international prognostic index (IPI) in a multivariate model for overall survival. In conclusion, IL10 polymorphism may affect the survival of T-cell NHL patients.