Isolation and Purification of Th9 Cells for the Study of Inflammatory Diseases in Research and Clinical Settings.

Th9 cells are associated with atopic and inflammatory diseases, and their increased levels and function correlate with the severity of symptoms in various inflammatory disorders including asthma, food allergy, atopic dermatitis, ulcerative colitis, and psoriatic arthritis. Thus, clinical trials are warranted to evaluate the role of Th9 cells in allergic diseases with the goal of controlling these ailments.Circulating T cells (naïve or memory CD4+ T cells) purified from human blood and expanded using anti-CD3 and anti-CD28 antibodies can be treated with appropriate cytokines in order to polarize them to the Th9 phenotype as evidenced by their production of IL-9. When treated in vitro with cholecalciferol or 1,25(OH) vitamin D3, cells polarized under Th9 conditions significantly downregulate production of IL-9. The percentage of polarized Th9 memory cells from patients treated with steroids or other modalities can be monitored during clinical trials and compared to control populations.