A significant increase in CXCR5+ CD4+ memory T cells (CXCR5+ CCR7+ PD1– ICOS− CD45RO+ CD28+ CD127+ CD4+) was observed in active PsA patients compared to PsV patients, as well as in the PsV-AT group compared to PsV-BT group. The gene discussed is ICOS; the disease is ataxia telangiectasia.