Stage I tumors are confined to a single lymphatic region or a single lymphoid organ such as the spleen. Stage II tumors involve two or more lymphoid regions or lymphoid organs, but all on one side of the septum. Stage III tumors involve lymphoid areas or lymphoid organs on both sides of the septum. Stage IV tumors involve a wide range of non-lymphoid organs. Each stage of Hodgkin’s disease is divided into two subtypes A and B according to the presence of the following symptoms: Subtype A: no fever, night sweats, and unexplained weight loss of 10% or more within 6 months; Subtype B: fever, night sweats, and unexplained weight loss of 10% or more within 6 months.