Risk factors for cytomegalovirus infection and disease in renal transplant recipients: HLA-DR7 and triple therapy

Role of Immunogenetics in the Outcome of HCMV Infection: Implications for Ageing

The outcome of host-virus interactions is determined by a number of factors, some related to the virus, others to the host, such as environmental factors and genetic factors. Therefore, different individuals vary in their relative susceptibility to infections. Human cytomegalovirus (HCMV) is an important pathogen from a clinical point of view, as it causes significant morbidity and mortality in immunosuppressed or immunosenescent individuals, such as the transplanted patients and the elderly, respectively. It is, therefore, important to understand the mechanisms of virus infection control. In this review, we discuss recent advances in the immunobiology of HCMV-host interactions, with particular emphasis on the immunogenetic aspects (human leukocyte antigens, HLA; killer cell immunoglobulin-like receptors, KIRs; immunoglobulin genetic markers, GM allotypes) to elucidate the mechanisms underlying the complex host-virus interaction that determine various outcomes of HCMV infection. The results, which show the role of humoral and cellular immunity in the control of infection by HCMV, would be valuable in directing efforts to reduce HCMV spurred health complications in the transplanted patients and in the elderly, including immunosenescence. In addition, concerning GM allotypes, it is intriguing that, in a Southern Italian population, alleles associated with the risk of developing HCMV symptomatic infection are negatively associated with longevity.

HLA-DQ3 is a probable risk factor for CMV infection in high-risk kidney transplant patients

BACKGROUND

Cytomegalovirus (CMV) infection in transplant patients with special risk factors remains a major hazard. CMV-seronegative recipients with seropositive donors have the highest risk of developing acute CMV disease. We suggest that the HLA-type may influence the occurrence and the severity of primary CMV infection of these recipients and the measurement of the special HLA-types may be useful in the prediction of acute infection.

METHODS

Since 1999 1213 cadaver kidney transplantations have been performed in our clinic. 163 of 1213 recipients were CMV-seronegative (13%) and 129 of them received the kidney from seropositive donors. All 129 patients received CMV infection prophylaxis. Of 129 CMV-seronegative patients 49 developed acute CMV infection (38%) during the first posttransplant year. CMV infection was diagnosed by CMV antigenemia test and serologic measurements (ELISA). The particular HLA-genotypes of the recipients were studied before the transplantation. The occurrence and the severity of CMV infection was investigated in association with HLA-types.

RESULTS

We found different acute CMV infection distribution in the careers and non-careers of investigated HLA-types: HLA-A2, HLA-B12, HLA-Cw7, HLA-DR6 and HLA-DR11, but the differences were not significant in these HLA-types (P = 0.26, P = 0.37, P = 0.83, P = 0.07 and P = 0.37). While investigating HLA-DQ3, we found that of 68 DQ3-positive patients 32 (47%), of 61 DQ3-negative patients 17 (28%) had acute CMV infection and this difference was found to be significant. This result was confirmed by univariate and multivariate Cox Regression (P = 0.001) and the appropriate significance level was considered by Bonferroni correction.

CONCLUSIONS

HLA-DQ3 was found to be an independent predictor of CMV infection. Our data suggest that patients positive for HLA-DQ3 are more susceptible to CMV infection than a comparable group of patients negative for HLA-DQ3. This result was not due to rejection and/or treatment for rejection and was not influenced by induction therapy. Although we found more symptomatic infections among DQ3+ patients the difference was not significant (P = 0.19). Comparing the gender proportion among all 1213 kidney recipients and among CMV-seronegative recipients we found that the proportion of males is significantly higher among CMV-seronegative recipients (P < 0.001).

Cytomegalovirus disease after prophylaxis with oral ganciclovir in renal transplantation: the importance of HLA-DR matching

This study assessed the incidence of cytomegalovirus (CMV) disease and associated outcomes after oral ganciclovir prophylaxis in renal transplantation. A retrospective analysis was performed of all adult renal transplant recipients at a single transplant center transplanted between August 16, 1996, and December 31, 2000. CMV disease prophylaxis included ganciclovir 1000 mg orally thrice daily prescribed for 90 d in D-/R+ cases and 180 d in D+/R- and D+/R+ cases. Forty (9.1%) of 470 patients studied were diagnosed with CMV disease, which varied significantly by CMV serostatus and number of HLA-DR matches. The highest incidence of disease, 26.2%, was in D+/R- patients with zero HLA-DR matches. Five-year graft survival was 56.8% with CMV disease compared with 79.1% without (P < 0.001). Five-year graft survival with CMV disease was 75.9% with one or two HLA-DR matches versus 16.2% with zero HLA-DR matches (P < 0.001). CMV remains an important factor in long-term graft survival after oral ganciclovir prophylaxis. However, we have observed that the adverse impact of CMV disease on graft survival is apparent only in patients with zero HLA-DR matches. These results call for the development of new CMV disease prophylaxis and treatment strategies in patients with zero HLA-DR matches. In addition, organ allocation policies discouraging combining CMV-seropositive donors and zero HLA-DR matches may be worth consideration.