Prevalence of CCR5Δ32 polymorphism in long-term survivors of heart transplantation

BackgroundCC chemokine receptor 5 (CCR5) contributes to the alloimmune response following solid organ transplantation. In individuals homozygous for the CCR5Δ32 mutation, the receptor is inactive and lymphocyte recruitment and leukocyte trafficking during rejection are inhibited. A significant improvement in graft survival following renal transplantation has been observed in homozygous CCR5Δ32 patients, although conflicting data exist. To determine whether CCR5Δ32 homozygous heart transplant recipients may also benefit compared to those with a normally functioning CCR receptor, the proportion of patients with CCR5Δ32 mutation was examined in a large cohort of patients surviving for a long period after heart transplantation.MethodsThe prevalence of CCR5 genotype was identified in patients who had survived ≥ 7 years after heart transplantation. Genotyping was performed centrally by polymerase chain reaction (PCR).ResultsA total of 555 patients were recruited at three heart transplant centers in Germany. Of these, 442 patients (79.6%) were homozygous for the wild-type allele, 106 (19.1%) were heterozygous for CCR5Δ32 and 7 (1.3%) were homozygous for CCR5Δ32. No statistically significantly differences were observed between the incidence of CCR5Δ32 homozygosity in the study population and the estimated incidence in the normal population.ConclusionsIn the absence of a control arm, it cannot be established if homozygous carriers of the CCR5Δ32 allele experience a long-term survival benefit following heart transplantation that may be masked by underrepresentation of the CCR5Δ32 allele in recipients of a heart transplant. To answer this question, the prevalence of CCR5Δ32 homozygosity needs to be established in patients awaiting heart transplantation.