Objective To analyze the correlation between EBV DNA load and programmed death receptor 1 (PD-1), programmed death receptor 1 ligand (PD-L1), cytotoxic T lymphocyte associated antigen 4 (CTLA-4), T cell immunoglobulin and ITIM domain pro. tein (TIGIT) in children with infectious mononucleosis (IM).Methods A total of 120 IM children treated in Shuangyashan People'sHospital from January 2020 to January 2023 were selected as the observation group, and 120 healthy children who underwent physicalexamination were selected as the healthy group. The expressions of PD-1, PD-L1, CTLA-4 and TIGIT were detected, and the expressiondifferences between the observation group and the healthy group were analyzed. According to the median blood EBV DNA load of chil.dren with IM, 68 cases were assigned into low EBV DNA load group (< 6.3×105 copies/mL) and 52 cases into high EBV DNA load group (≥6.3×105 copies/mL). The clinical features and expression differences in PD-1, PD-L1, CTLA-4 and TIGIT were compared be. tween the two groups, and the correlation of EBV DNA load with PD-1, PD-L1, CTLA-4, and TIGIT were analyzed.Results The ex. pression levels of PD-1, PD-L1, CTLA-4, and TIGIT in B lymphocytes of the observation group were (5.66±0.87)% , (6.95±1.12)% ,(4.34±0.58)%, and (7.43±0.98)%, respectively, which were significantly higher than those of the healthy group [(0.790.13)%, (0.88±0.27)%, (0.43±0.08)%, (1.24±0.35)%, respectively] (P<0.05). The expression levels of PD-1, PD-L1, CTLA-4, and TIGIT in B lympho. cytes of IM children were (6.78±1.12)%, (7.64±1.43)%, (5.85±0.83)%, and (8.54±1.43)%, respectively, which were significantly higherthan those of IM children in the recovery period [(4.72±0.68)%, (5.51±0.79)%, (3.23±0.46)%, (6.17±0.96)%, respectively] (P<0.05).The high EBV DNA load group had longer duration of fever , higher incidence of fever, lymphadenopathy, acute hematological compli.cations, higher white blood cell count, lymphocyte count (LYM), atypical lymphocytes, and higher expression levels of serum amyloid A(SAA), C-reactive protein (CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH)than the low EBV DNA load group (P<0.05). In children with IM, EBV DNA load was significantly positively correlated with fever dura.tion, white blood cell count, LYM, atypical lymphocytes, SAA, CRP, LDH, ALT, and AST (P<0.05). The expression levels of PD-1, PD-L1, CTLA-4, and TIGIT in B lymphocytes of the high EBV DNA load group were significantly higher than those of the low EBV DNAload group (P<0.05). Conclusion The overexpression of immunosuppressive factors PD-1, PD-L1, CTLA-4, and TIGIT in B lympho.cytes is significantly associated with EBV DNA load in children with IM, which can be used for the evaluation of IM in children. |