CD4 and Autoimmunity: The non-elevation of CD4+CXCR5+ICOS−PD-1+ Tfh cells in IgAV and its downregulation in patients presenting abdominal dominant symptoms may reflect a pathogenic mechanism during IgAV development, specifically the development of abdominal symptoms in IgAV; which would inhibit the potential immunosuppressive activity of Tfh cells, and thus shift the balance toward enhanced autoimmunity.