the role of t helper 9(th9) against infectious diseases

background and aims: infectious diseases are disorders caused by organisms such as bacteria, viruses, fungi or parasites .the th9 subset develops in response to combined signals from tgf-b and il-4 among a cacophony of other cytokines in the extracellular milieu.t helper 9 (th9) cells,a novel cd4 t cell subset, seem to play a complex role in the outcome of specific immune responses. in this article, we aim to review the role of these cells in infectious disease.methods:in this mini-review research,we study 25novel articles since 2009 to 2014 about the the role of t helper9 in some infectious diseases.result: pleural mesothelial cells promoted th9 cell differentiation by presenting antigen. it was differentiated th17 but not th9 cells significantly elevated in the development of cvb3-induced vmc. the microenvironment of vmc seemed to contribute to the differentiation and proliferation of th17rather than th9 cells. having reviewed the limited number of articles considering this relevance, we came to this result that lymphatic filariasis and mycobacterium tuberculosis infections confirmed the existence of relationship. in addition, rapamycin resistant murine th9 cells have a stable in vivo phenotype and inhibit graft-versus-host reactivity but concerning viral myocarditis,th9 cells could not protect against it. conclusion:the accurate molecular mechanisms underlying the generation and differentiation of human th9 cells are not elucidated completely. th9 cells exhibit ag-specific expansion in a chronic helminth infection (lymphatic filariasis), but in relevance to viral myocarditis,th9 cells did not show efficient role against it.anyway, whether th9 cells participate in the protection against infections warrants further research