Specific Anti-CMV Reactivity in BAL: A Useful Tool

Purpose: Cytomegalovirus is a major complicating opportunistic infection and a significant cause of morbidity and mortality in solid organ transplant recipients, particularly in lung transplant recipients (LTRs). Different protocols based on profilaxis or preemptive treatments of CMV infections are in use in lung transplant centres. In the view of preemptive treatment accurate diagnostic tests that identify high-risk patients have a great interest. Aim of the present study was to evaluate peripheral and lung CMV-specific T-cell response and the incidence of viral infection/reactivation in a cohort of de novo LTRs longitudinally followed for 6/12 months post-transplant. Methods and Materials: 21 LTRs, undergoing surveillance bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy at 1, 3, 6 and 12 months post-transplant or according to clinical need, were enrolled. Blood samples were collected at the time of BAL. gamma-FN+ T-cells in PBMC and BAL lymphocytes were determined by means of ELISPOT assay in the presence or absence of CMV antigens or mitogens. CMVspecific response was expressed as percentage of the maximal response obtained with mitogens. CMV viral load was assessed in both blood samples and BAL at the same time. According to internal preemptive protocol patients were treated with i.v. ganciclovir or oral valganciclovir when viral load was above the following cut off values: > 300.000 DNA copies/ml of peripheral blood, > 100.000 DNA copies/ml of BAL.Results: Over the 92 samples examined, CL-ELISPOT on BAL had a specificity of 84% and a sensitivity of 63% in detecting protection toward infection/reactivation (3 false positive samples only) while CL-ELISPOT performed on peripheral blood was not as specific as the BAL one. Conclusions: Anti-CMV specific reactivity on BAL can be easily and routinely assessed by ELISPOT and allows the identification of patients at a higher risk of infection. On the basis of this pilot study the routine assessment of specific anti-CMV reactivity on BAL will be performed as an adjunct to our preemptive protocol.