In this study, the impact of polymorphisms in the genes of proinflammatory (IL-β, TNF-α, IL-6, IFN-γ), anti-inflammatory (transforming growth factor [TGF]-β, IL-10, IL-Ra), and other immunoregulatory factors (FcγRIIa, NOS3) along with the conventional risk factors on the rate of hematopoietic recovery and first episodes of bacterial, viral, or invasive fungal infections in 102 patients with β-thalassaemia major who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) with relatively uniform protocols at our center from June 1995 to June 2004 with a minimum follow-up of at least 2 years were studied retrospectively for 180 days after hematopoietic stem cell transplantation (HSCT).