Medical question: Please a doctor answer this, online doctors?

Thyroid is for metabolic activity. The T is for Thyroxine and the 4 says there are 4 iodine molecules on it. There is also T3 which just has one less iodine. T-lymphocytes are part of the immune system. That T comes from the immune cells maturing in the thymus of a person. They are completely different diseases and affect completely different systems.