Evaluation of viral load and anticoenemia as markers for relapse cytomegalovirus infection in renal transplant recipients

Cytomegalovirus (CMV) is a pathogen, commonly found in the donors and recipients of solid organ transplantation. CMV is one of the major causes of morbidity and mortality in these patients. Relapsing episodes of CMV infection occur in 23-33% of transplant patients which is likely a reflection of incomplete suppression of viral replication following antiviral treatment with intravenous ganciclovir. We have studied CMV DNA load and antigenemia as markers for relapse of CMV infection in 49 renal transplant patients out of 68 with CMV infection who received a course of intravenous ganciclovir among 300 transplants carried out between january of 2001 and june of 2005. Viral load and antigenemia were measured in blood samples obtained before, during and at the completion of treatment. We also studied different viral load as predictors of relapse CMV infection. Twelve (24.5%) of 49 recipients developed relapsing CMV infection. The relapsing group had higher viral loads after treatment than the no relapsing group. There was no difference in antigenemia level between both groups. The viral loads before and during the treatment, the age and sex of donors and recipients, inmunosupresion, percentage of seronegative recipients with seropositive donors, duration of the therapy and the percentage of patients with heavy inmunosupression were similar in the two groups, but the incidence of acute rejection was higher in the relapsing group. We also evaluated the range of viral load after treatment which is able to trigger the relapse of CMV infection. We conclude that CMV DNA load after treatment is a useful marker for individualizing antiviral treatment of CMV infection in renal transplant recipients. Acute rejection is a risk factor to the relapsing CMV infection.