Polyfunctional Cytomegalovirus-Specific Immunity in Lung Transplant Recipients Receiving Valganciclovir Prophylaxis

Abstract

†Palmer and Weinhold contributed equally to the manuscript.Cytomegalovirus (CMV) is a common opportunistic infection after lung transplant. Despite effective antiviral medications to treat CMV, invasive CMV disease contributes to lung allograft dysfunction and worse survival. Efforts to prevent CMV have led to the use of valganciclovir prophylaxis for increasingly longer periods after transplant. A pivotal concern with long-term antiviral prophylaxis is that it may prevent or delay the development of CMV-specific immunity and increase the subsequent risk of late onset disease. To address this issue, we conducted a pilot study to determine if CMV-specific immunity was detectable in lung transplant recipients at risk for CMV while on antiviral prophylaxis. Utilizing polychromatic flow cytometry panels, CMV-specific immunity was determined by peripheral blood CD4 and CD8 T cell expression of cytokines in response to the HLA restricted CMV peptides pp65 and IE-1. We determined CMV seropositive lung transplant recipients on valganciclovir for a median of 6 months from transplant have a detectable polyfunctional CMV-specific T cell response which is comparable to seropositive recipients not on antiviral medications and to healthy seropositive nontransplant controls. Thus, valganciclovir prophylaxis does not appear to impair the development of CMV-specific immunity in lung transplantation.

Prospective Analysis of Human Cytomegalovirus DNAemia and Specific CD8+ T Cell Responses in Lung Transplant Recipients

“…In particular, we observed that, in a small fraction of four R+ LuTRs, high-level HCMC DNAemia occurred in spite of stable responses. In the control of HCMV replication, the importance of CD8+ T cell specificity, that is, the spectrum of viral proteins to which responses are directed, has been highlighted previously (21,23,(28)(29)(30)(31). Furthermore, it has been demonstrated that virus-specific CD4+ T helper cells are necessary for the generation and maintenance of CD8+ T cells (24,28,(30)(31)(32)(33).…”

“…In the control of HCMV replication, the importance of CD8+ T cell specificity, that is, the spectrum of viral proteins to which responses are directed, has been highlighted previously (21,23,(28)(29)(30)(31). Furthermore, it has been demonstrated that virus-specific CD4+ T helper cells are necessary for the generation and maintenance of CD8+ T cells (24,28,(30)(31)(32)(33). The QuantiFERON R -CMV assay (Cellestis GmbH, a QIAGEN company) is designed to stimulate CD8+ T cells specifically with a mixture of multiple HCMV peptides and therefore does not allow the specific targeted epitope to be identified or CD4+ T cell functionality to be evaluated (25,34).…”

Polyfunctional T-Cell Signatures to Predict Protection from Cytomegalovirus after Lung Transplantation

“…Details of sample collection and storage of peripheral blood mononuclear cells have been previously published and are also provided in the online supplement (9).…”

“…Compensation beads were used, and data were acquired immediately with a LSRII flow cytometer (Becton-Dickinson, San Jose, CA). Additional details of the methods to assess CMV-specific immunity and gating strategy are provided in the online supplement, are displayed in Figure 1, and have been previously published (9).…”

“…T-cell polyfunctionality is operationally defined by the simultaneous measurement of three or more antigen-driven effector functions within a single cell, including production of IL-2, tumor necrosis factor-a (TNF-a), IFN-g, and expression of the degranulation marker CD107a. Our group has previously profiled polyfunctional T cells by flow cytometry after stimulation by CMV pp65 and by IE-1 peptide pools in immunosuppressed lung transplantation recipients (9). Because of the importance of T-cell polyfunctionality in high-quality vaccine immunity and control of HIV infection (10-12), we hypothesized that a polyfunctional CMV-specific immune response would discriminate CMV risk and provide a novel and clinically relevant diagnostic test.…”