Abstract: 【Abstract】 Objective To investigate changes in expression of plasma soluble CD100 （sCD100） and membrane-bound CD100 （mCD100） on peripheral T cells in patients with herpes zoster, and to observe the regulatory function of exogenous CD100 on CD8+ T cells. Methods A total of 53 patients with herpes zoster attending the Zhumadian Central Hospital from July 2019 to April 2021 were enrolled, so were 25 age- and sex-matched healthy controls. Anticoagulated venous blood samples were collected, plasma and peripheral blood mononuclear cells were isolated, plasma sCD100 levels were detected by enzyme-linked immunosorbent assay, and mCD100 expression on CD4+ and CD8+ T cells was determined by flow cytometry. After the purification of CD8+ T cells, the secretion levels of cytotoxic molecules and cytokines by CD8+ T cells were measured and compared between herpes zoster patients and controls. Some purified CD8+ T cells from herpes zoster patients were stimulated with recombinant human CD100 and recombinant varicella-zoster virus glycoprotein, and the effect of recombinant human CD100 on the secretion of cytotoxic molecules and cytokines by CD8+ T cells was investigated. Comparisons between groups were conducted by t test. Results Plasma sCD100 levels were significantly lower in the herpes zoster group （1.12 ± 0.23 ng/ml） than in the control group （1.31 ± 0.28 ng/ml, t = 2.97, P = 0.004）, the proportion of mCD100 + CD8+ T cells was significantly higher in the herpes zoster group （17.41% ± 4.26%） than in the control group （14.69% ± 3.70%, t = 2.52, P = 0.014）, and no significant difference in the proportion of mCD100 + CD4+ T cells was found between the two groups （2.52% ± 0.58% vs. 2.32% ± 0.56%, t = 1.27, P = 0.208）. The herpes zoster group showed significantly decreased mRNA expression of perforin and granzyme B in, and lower secretion levels of perforin, granzyme B, interferon-γ and tumor necrosis factor-α by CD8+ T cells compared with the control group （all P < 0.05）. After stimulation with recombinant human CD100, levels of perforin, granzyme B, interferon-γ and tumor necrosis factor-α in the culture supernatant of CD8+ T cells （43.68 ± 14.12, 126.8 ± 22.92, 12.79 ± 3.66, 310.0 ± 79.90 pg/ml, respectively ） were significantly higher than those in non-stimulated group （34.55 ± 10.78, 99.04 ± 10.44, 9.53 ± 2.00, 275.6 ± 68.04 pg/ml, respectively, all P < 0.05）. Conclusion There was an imbalance between sCD100 and mCD100 expression in patients with herpes zoster, and exogenous sCD100 may enhance the cytotoxicity of CD8+ T cells in herpes zoster patients.

Key words: Herpes Zoster, CD8-positive T-lymphocytes, CD100, Immunoregulation