Association between chronic lung allograft dysfunction and human Cytomegalovirus UL40 peptide variants in lung-transplant recipients.

Natural-Killer cells play an important role in the pathogenesis of chronic lung allograft dysfunction (CLAD) in lung-transplant recipients. Activating NKG2C+ and inhibitory NKG2A+ NK cells proliferate in response to human Cytomegalovirus (HCMV) infection via the presentation of virally encoded UL40 peptides on HLA-E molecules. We aimed to clarify whether infection with HCMV strains carrying different UL40 peptide variants is associated with the development of CLAD. We included 82 lung-transplant recipients, 18 patients developing CLAD and 64 matched control patients without CLAD. In all patients 1 episode of high-level HCMV-replication occurred. HCMV UL40 variants and Natural-Killer-cell proliferation with distinct UL40 peptides were assessed. The VMTPRTLIL variant was significantly overrepresented in patients developing CLAD (p < 0.0001) and lead to a significantly lower proliferation of inhibitory NKG2A+ cells, compared to the VMAPRTLIL, VMAPRTLVL and VMAPRTLLL variants (p < 0.0001). Thus, HCMV UL40 variants may contribute to development of CLAD over the NK cell response.