In adult participants who self-identified as having seasonal allergies, the bacterial formulation B. longum MM2, B. bifidum G9–1, and L. gasseri KS-13 was associated with a significant improvement in rhinoconjunctivitis-specific quality of life during allergy season when compared with the placebo group (p = 0.0092).185 Changes in the immune parameters tested (serum total IgE and Treg percentage), from baseline to week 6 were similar for both the intervention and placebo groups such that the mechanism of action remains unclear. Here, IGHE is linked to allergic disease.