Background:Infection is one of the leading causes of morbidity and mortality in liver transplant (LT) recipients. Since the immunosuppressive regimen currently used after LT reduces the T cell responses in adaptive immunity but effectively maintains the humoral components of innate immunity, polymorphisms in host immunoregulatory genes associated with humoral immunity may influence the development of different clinical forms of infectious complications after LT.

Methods:80 consecutive LT recipients were employed and studied for postoperative infections, i.e., the incidence of CMV infection and bacteremia within 4 weeks of receiving a LT. By using the genomic DNA isolated from either the peripheral blood or the liver mononuclear cells of the patients, FcΓRIIa[131H/R], FcΓRIIIa[158F/V], and C1qA[276A/G] polymorphisms were determined by performing PCR. The observed genetic polymorphisms were analyzed with respect to the clinical outcomes.

Results:We observed statistically significant differences in the overall survival and incidence of bacteremia in the LT recipients with F carrier genotype for FcΓRIIIa (n=40) and in the patients with VV genotype (n=36) (p=0.036 and p=0.002, respectively). In ABO compatible or identical group (n=65), a higher incidence of bacteremia (n=8/32, 25%) was observed in the patients with F carrier genotype for FcΓRIIIa than in VV homozygous patients (n=1/29, 3.4%) (p=0.019). In ABO incompatible group (n=15), the incidence of bacteremia was significantly higher in the patients with F carrier genotype for FcΓRIIIa (n=4/8, 50%) than in VV homozygous patients (n=0/7, 0%) (p=0.035). In addition, the survival rate was higher in the patients with R carrier genotype for FcΓRIIa (n=8) than in the HH homozygous patients (n=7) (1-year survival rate was 87.5% and 57.4%, respectively) (p=0.037). C1qA polymorphisms did not influence either survival or the infection rate in any of the patient subgroups, probably reflecting the reduced complement components including C1q in patients with severe cirrhosis. We did not observe any differences in the incidence of CMV infection with respect to the 3 gene-polymorphisms.

Conclusions:Polymorphisms in FcΓR genes in LT recipients were observed to be greatly associated with the susceptibility or resistance to bacterial infections. LT recipients with either FcΓRIIIa F carrier or FcΓRIIa HH genotypes, who are individuals with high risk of bacteremia, may need intensive prophylactic antibiotic therapies.

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