<prompt> Most unstable leprosy is ?BBBLBTTT  <response>: Ans. isai.e., BBStable forms of leprosy - polar forms of leprosy, i.e., Tuberculoid leprosy TT and lepromatous leprosy LL.Unstable forms of leprosy - Borderline forms of leprosy, i.e., Borderline tuberculoid BT, borderline BB and Borderline lepromatous BL. BB is the most unstable form. 