TNF and non-Hodgkin lymphoma: For patients treated with thiopurines or anti-TNF-α therapy, SIRs for NHL were significantly increased among patients on combination therapy with both drug classes (SIR 5.7; 95% CI 2.7 to 11.9), while monotherapy with thiopurines also increased the risk of NHL with SIR 2.8 (95% CI 1.4 to 5.7).