CXCR3 and infection: Although Tfh makes only a small contribution to the total pool of p24+ cells during AHI due to their low frequency (Fig. 1B)(77), CXCR3+ Tfh had the highest frequency of p24+ cells by S4/5 of AHI (median 0.16%) (Fig. 6D), a change from S3 when there were no differences in infection frequency between populations (Fig. S12H).