CD4 and asthma: Natural and induced Tregs have many subsets with the most well-understood being those that express CD4, CD25, and FoxP3 (CD4+CD25+ FoxP3+ Tregs), which had acquired notable attention because of their role in a variety of autoimmune pathologies, inflammatory disorders such as asthma and colitis, and immune responses to tissue transplants, tumors, and various infectious agents pathologies [8].