Higher Frequency of CD4(+)CXCR5(+)ICOS(+)PD1(+) T Follicular Helper Cells in Patients With Infectious Mononucleosis

Follicular helper T (Tfh) cells are recognized as a distinct CD4(+)helper T cell subset, and mainly dysregulated in the autoimmune disease, whether it plays a role in the infectious mononucleosis (IM) diseases is unknown. In this study, we found that the CD4(+)CXCR5(+) Tfh cells were not significantly changed, but the CD4(+)CXCR5(+)ICOS(+) and CD4(+)CXCR5(+)ICOS(+)PD1(+) Tfh subsets were significantly increased in the IM patients, and all these cells were significantly changed after antiviral therapy. Second, only the numbers of CD4(+)CXCR5(+)ICOS(+)PD1(+) Tfh cells correlated with the Epstein-Barr virus (EBV) DNA load, negatively correlated with the numbers of naive B cells and amount of IL-21, and positively correlated with the numbers of plasma cells, memory B cells, and atypical lymphocytes. Third, the frequency of CD4(+)CXCR5(+)ICOS(+)PD1(+) Tfh subset was significantly higher in lymphadenectasis or hepatosplenomegaly patients, and associated with the level of alanine aminotransferase (ALT). All together, our findings discovered this CD4(+)CXCR5(+)ICOS(+)PD1(+) Tfh cell subset might play an important role in the pathogenesis of IM.