Shrivastava S, TrehanPati N, Patra S, Kottilil S, Pande C, Trivedi SS, Sarin SK. Increased regulatory T cells and impaired functions of circulating CD8 T lymphocytes is associated with viral persistence in Hepatitis B virus-positive newborns.
J Viral Hepat 2013;
20:582-91. [PMID:
23808997 DOI:
10.1111/jvh.12078]
[Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/18/2012] [Indexed: 12/27/2022]
Abstract
Hepatitis B Virus (HBV) infection in infancy or early childhood leads to high rate of persistent infection (25-90%). The immunological basis of high rate of viral persistence in vertically acquired HBV infections is not completely understood. CD8 T cells play a pivotal role in clearing the Hepatitis B virus infection in adults. Herein, we sought to delineate the role of T cells in viral persistence in HBsAg+ve newborns. At birth peripheral and cord blood of HBsAg+ve (N = 12), HBsAg-ve (N = 10) and healthy newborns (HC: N = 15) were evaluated for T-cell frequency and functionality by flow cytometry. No significant differences were observed in the frequency of CD8 and CD4 T cells in all the three groups. However, significantly higher frequency of FoxP3 expressing regulatory T cells were observed in HBsAg+ve (63.79%) compared with HBsAg-ve (28.12%) and HC (11.06%) (P < 0.05). Moreover, HBsAg+ve newborns showed functional defect in CD8 T cells by decreased IFN-γ production and lower CD107A expression (cytotoxic capacity) compared with HBsAg-ve and HC, which positively correlated with decreased TCRζ-chain expression CD8 T cells (r(2) > 0.93, P < 0.05). Despite equal frequency of CD8 T cells in all the three groups, CD8 T cells in HBsAg+ve newborns are dysfunctional. An expansion of regulatory T cells and impaired TCR signalling may represent the immune tolerant state of the adaptive immune system in response to chronic HBV infection.
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