Genomic polymorphisms of the innate immune system and allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-HSCT) is largely employed for treating patients affected by many hematological disorders, but despite the considerable improvement in the treatment of its complications, graft-versus-host disease and infections remain important causes of morbidity and mortality. Innate immunity is crucial in the immune defense against infections after allo-HSCT, and in the biological reactions leading to graft-versus-host disease. Thus, the innate immune system plays an important role in allo-HSCT clinical outcome. It is known now that cytokine gene polymorphisms greatly influence the outcome of allo-HSCT. In addition, genetic variability of some pattern-recognition receptors and antimicrobial peptides represent a promising field to be researched for allo-HSCT impact. Furthermore, more recent work suggests the importance of genetic variability between donor and recipient in the killer cell immunoglobulin-like receptors of the natural killer cells on the allo-HSCT outcome. This article discusses the main cytokines and innate immune gene polymorphisms influencing allo-HSCT outcome, presents new innate immune genes with promising expectations and points at the importance of genetic variability in natural killer cells in allo-HSCT outcome.