Background: To examine whether genetic factors are involved in the development of acute rejection (AR), we investigated a (CA)m(CT)n repeat in the 3'-flanking region of the interleukin (IL)-2 gene.
Method: We genotyped 290 heart transplant recipients with and without AR (International Society for Heart and Lung Transplantation criteria > or =3A) and 101 controls.
Results: The frequency of allele 135 of the repeat and its genotype distribution (carriers/noncarriers) were significantly associated with freedom from AR (P=0.03 and P=0.02, respectively). We also found interaction between allele 135 and HLA-DR matching. More carriers of allele 135 with no or one mismatch remained free from AR compared to patients without the allele (P=0.01). This was not found in the HLA-DR group with two mismatches.
Conclusion: HLA-DR matching might only be effective in reducing AR after heart transplantation in recipients who carry allele 135 of the (CA)m(CT)n repeat in the 3'-flanking region of the IL-2 gene.