CD44 and common variable immunodeficiency: As previously shown, CD21low B cells are associated with autoimmune phenomena [50], and it is thus feasible to speculate on the immunoregulatory role of PD-1highCXCR5+ CD8 T cells in patients with complex form of CVID, similarly to the regulatory function of the CD44+CD122+Ly49+ CD8 T cells shown in the murine model of autoimmune encephalomyelitis, which also upregulated the Cxcr5 gene [36].