Persistent hepatotropic viral infections are a common etiologic agent of chronic liver disease. Unresolved infection can be attributed to nonfunctional intrahepatic CD8+ T-cell responses. In light of dampened CD8+ T-cell responses, liver disease often manifests systemically as immunoglobulin (Ig)-related syndromes due to aberrant B-cell functions. These two opposing yet coexisting phenomena implicate the potential of altered CD4+ T-cell help. Elevated CD4+ forkhead box P3–positive (Foxp3+) T cells were evident in both human liver disease and a mouse model of chemically induced liver injury despite marked activation and spontaneous IgG production by intrahepatic B cells. While this population suppressed CD8+ T-cell responses, aberrant B-cell activities were maintained due to expression of CD40 ligand on a subset of CD4+ Foxp3+ T cells. In vivo blockade of CD40 ligand attenuated B-cell abnormalities in a mouse model of liver injury. A phenotypically similar population of CD4+ Foxp3+, CD40 ligand–positive T cells was found in diseased livers explanted from patients with chronic hepatitis C infection. This population was absent in nondiseased liver tissues and peripheral blood. Conclusion: Liver disease elicits alterations in the intrahepatic CD4+ T-cell compartment that suppress T-cell immunity while concomitantly promoting aberrant IgG mediated manifestations. (Hepatology 2017;65:661-677).
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We are grateful to the donors and their families of the Emory Transplant Center for invaluable consented participation in this study. We thank the Emory Transplant Center team: surgical and nursing staff, coordinators, and Shine Thomas for their assistance and cooperation. We thank Victoria M. Velazquez, J. Brett Mendel, Young-Jin Seo, and Aryn Price for critical reading of the manuscript and fruitful scientific discussions. We thank Kiran Gill and Barbara Cervasi of the Emory Vaccine Center Flow Cytometry and Pathology Cores for technical assistance throughout the study.
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