Phenotype and functionality of follicular helper T cells in patients with acute dengue infection.
Wijesinghe A., Gamage J., Goonewardena H., Gomes L., Jayathilaka D., Wijeratne DT., de Alwis R., Jeewandara C., Wijewickrama A., Ogg GS., Malavige GN.
BACKGROUND: The association of functionality and phenotype of follicular helper T cells (Tfh) with dengue virus (DENV) specific antibody responses and clinical disease severity has not been well studied. METHODS: We investigated the phenotype and functionality of Tfh cells and plasmablasts in adult patients (DF = 18, DHF = 22) with acute dengue (day 4 to 8 since onset of fever) of varying severity using multiparametric flowcytometry. The properties of Tfh cells were correlated with viraemia, disease severity, plasmablast responses and DENV-specific serum antibody responses. We further evaluated the kinetics of neutralizing antibodies (Neut50) throughout the course of illness in order to evaluate their association with clinical disease severity and viraemia. RESULTS: Tfh cells (especially those producing IL-21 and co-expressing PD-1 and ICOS) were found to be significantly expanded (p