In particular, a lower percentage of the homing receptor integrin-β7+ (β7) and CD86+ DCs, as well as a higher percentage of the C-C chemokine receptor type 7+ (CCR7) and of the marker of immune tolerance and suppression indoleamine 2,3-dyoxigenase (IDO) were observed in COVID-19 patients. The gene discussed is CCR7; the disease is COVID-19.