First, we found a higher frequency of CXCR5− Tph (Fig. 2A, C), CXCR5−ICOS+ Tph (Fig. 2D, F) and CXCR5−ICOS+PD-1+ Tph (Fig. 2G, J) in children with allergic asthma. Here, TPH1 is linked to allergic asthma.