Studies looking at peripheral blood lymphocyte subsets in FGID have not identified differences in regulatory T-cells [14] or lymphocyte subsets, but have found increased levels of B-cells expressing IgG or co-stimulatory molecules CD80 or CD86 and T-cells expressing β7+HLADR+ and CD69+ in IBS-patients compared to controls [15-17]. Here, CD80 is linked to irritable bowel syndrome.