CXCR5 and in situ carcinoma: Only a small number of studies have investigated the frequency of Tfh subsets in MS, and findings have thus far been inconsistent.8, 15 In the present study, there was no significant difference between individuals with CIS and HC as regards the frequency of total CXCR5+FoxP3− Tfh cells nor of the Tfh1, Tfh2, Tfh17 and Tfh17.1 subsets, expressed as a percentage of Tfh cells, CD4+ T cells or PBMC.