Cytomegalovirus antibody status of donor/recipient does not influence the incidence of bronchiolitis obliterans syndrome in lung transplantation

Background: We have previously reported that prophylaxis for cytomegalovirus (CMV) infection does not influence the incidence of bronchiolitis obliterans syndrome (BOS) at 2 years. The effect of CMV infection (without evidence of disease) on BOS is still not well understood. Moreover, the incidence and risk factors for development of BOS in CMV-antibody-negative donor/recipient matches in lung transplantation have not been described. The aim of this study is to determine the incidence of BOS in lung transplant patients with CMV-antibody-negative (-) donors (D) and recipients (R), and to evaluate the risk factors that predispose to BOS in this sub-group. Method: A retrospective study of data from the transplant database of our center was performed. All single-lung (SL), double-lung (DL) and heart-lung block (HL) transplant patients who survived >2 years post-transplant were included in the study group. They were grouped as follows: D-/R-, n = 102; D-/R-, n = 70; D+/R-, n = 33, and D+/R+, n = 92. Results: The 3-year BOS-free survival rates were 65%, 56%, 58% and 67%, respectively, and the incidence rates of BOS at 5 years post-transplant in the different groups were 57%, 62%, 78% and 55% (p > 0.05). In the D-/R- group, the significant risk factor for developing BOS was three or more episodes of acute rejection (P = 0.02). The mean numbers of acute rejection episodes per 100 patients-days within the first 6 months were 1.28, 1.06, 0.50 and 1.11 (p < 0.001 overall) for the four groups, respectively. Conclusion: Although CMV is believed to be a risk factor for BOS, its absence did not affect the occurrence or incidence of BOS in lung transplant patients. The main risk factor for BOS in the CMV-antibody-negative population remains the number of acute rejection episodes within the first 6 months after transplantation.