CD154‐expressing CMV‐specific T cells associate with freedom from DNAemia and may be protective in seronegative recipients after liver or intestine transplantation

Abstract

Cell‐mediated immunity to CMV, if known, could improve antiviral drug therapy in at‐risk children and young adults with LT and IT. Host immunity has been measured with CMV‐specific T cells, which express IFNγ, but not those which express CD154, a possible substitute for IFNγ. CMV‐specific CD154+ T cells and their subsets were measured with flow cytometry after stimulating PBL from recipient blood samples with an overlapping peptide mix of CMV‐pp65 antigen for up to 6 hours. CMV‐specific CD154+ T cells co‐expressed IFNγ in PBL from three healthy adults and averaged 3.8% (95% CI 3.2%‐4.4%) in 40 healthy adults. CMV‐specific T cells were significantly lower in 19 CMV DNAemic LT or IT recipients, compared with 126 non‐DNAemic recipients, 1.3% (95% CI 0.8‐1.7) vs 4.1 (95% CI 3.6‐4.6, P < .001). All T‐cell subsets demonstrated similar between‐group differences. In logistic regression analysis of 46 training set samples, 12 with DNAemia, all obtained between days 0 and 60 from transplant, CMV‐specific T‐cell frequencies ≥1.7% predicted freedom from DNAemia with NPV of 93%. Sensitivity, specificity, and PPV were 83%, 74%, and 53%, respectively. Test performance was replicated in 99 validation samples. In 32 of 46 training set samples, all from seronegative recipients, one of 19 recipients with CMV‐specific T‐cell frequencies ≥1.7% experienced DNAemia, compared with 8 of 13 recipients with frequencies <1.7% (P = .001). CMV‐specific CD154+ T cells are associated with freedom from DNAemia after LT and IT. Among seronegative recipients, CMV‐specific T cells may protect against the development of CMV DNAemia.

Impaired T-cell and antibody immunity after COVID-19 infection in chronically immunosuppressed transplant recipients

“…Further, CD154 was also co-expressed with IL-6 in B-cells (Figure 1b). Thus, CD154 was used as a surrogate for S-reactive IFN+T-cells, and S-reactive IL-6+B-cells in all subsequent assays using nonpermeabilizing CD154 staining described previously 18,21 .…”

“…Consistent with this increased risk in Tr patients, CMV infection was associated with decreased T-cell immunity to this virus in Tr patients with COVID-19. Frequencies of CMV-specific T-cells which express CD154 after stimulation with the pp65 antigenic peptide mixture were measured as described previously, in 61 subjects 18 . CMV-specific T-cell frequencies were significantly lower in 16 Tr recipients with COVID-19 compared with 13 healthy Tr recipients (0.5+/-0.4% vs 1.5+/-0.5%, p=3E-05, Figure 4a).…”

“…We have modeled our assay on clinical assays which measure antiviral T-cell immunity by employing a single marker. These assays use either IFN or CD154 as a marker of antigen-specific T-cells [18][19][20]22,23 . CD154 can substitute for IFN because it is co-expressed in viral antigen-specific T-cells 18,24 .…”

“…A clinically usable test design is exemplified by assays to measure T-cell response to cytomegalovirus (CMV). These assays use unselected peptide mixtures representing the entire antigenic sequence of interest, a single activation marker, and no costimulators [18][19][20] . Here, we describe a minimal marker assay to characterize S-reactive T-and B-cells in healthy unexposed subjects and COVID-19 patients most of whom were hospitalized, with an emphasis on chronically immunosuppressed solid organ transplant recipients.…”

CRISPR-Cas9-Edited Tacrolimus-Resistant Antiviral T Cells for Advanced Adoptive Immunotherapy in Transplant Recipients

“…40 CD154 is also induced upon antigen recognition by the T cell receptor (TCR) 41 and has been reported to be expressed on T cells protective against CMV. 42 We found CMV-specific CD154 upregulation on CD4 + (Figure 4O) but also on a subset of CD8 + T cells (Figure 4Q). CD154-expressing CD4 + (Figure 4P) and CD8 + T cells (Figure 4R) were more frequent among FKBP12 KO CMV TCPs cultured in tacrolimus compared with their unmodified counterpart (Figures 4P and 4R).…”