The increased type-1 and type-2 chemokine levels in children with acute RSV infection alter the development of adaptive immune responses

Severe RSV infections and frequent recurrence could be related to the altered polarization of type-2/type-1 T cells. This increases the importance of determining distinctive chemokines and chemokine receptor profiles on memory T cells. We analyzed systemic adaptive T cell response in the acute (n=17) and convalescent phase (n=7) of RSV-infected children, in the acute (n=11) and convalescent phase (n=6) of children with other viral respiratory infections (adenovirus and influenza virus), and in healthy children (n=18). Expression of CCR4 and CXCR3 on effector-memory (T_EM) and central-memory (T _CM) T cells was compared between tested groups. Serum concentrations of specific chemokines were determined. High CXCL10 levels were detected in acutely infected children regardless of virus pathogen, whereas increased CCL17 production was RSV-specific. Higher percentages of CCR4⁺ CD4 T _EM cells in acute RSV infection were accompanied with higher percentages of CXCR3⁺ CD8 T_EM cells, whereas the development of long-lived memory CXCR3⁺ CD4 and CD8 T_CM cells seems to be compromised, as only children with other viral infections had higher percentages in the convalescent phase. Presence of type-2 and type-1 adaptive antiviral immune response, together with insufficient development of long-lived type-1 T cell memory, could play an important role in RSV pathogenesis and reinfection.