IVIg + cyclophosphamide + rATG

This is a combination therapy consisting of three agents:

• Intravenous immunoglobulin (IVIg): A pooled human antibody preparation used for immune modulation and replacement in various autoimmune, inflammatory, and immunodeficiency conditions. It acts by modulating the immune response through multiple mechanisms including neutralization of autoantibodies, inhibition of complement activation, and modulation of Fc receptor function.
• Cyclophosphamide: An alkylating agent with potent immunosuppressive properties. It suppresses both B-cell and T-cell function by cross-linking DNA strands, leading to cell death in rapidly dividing lymphocytes.
• Rabbit anti-thymocyte globulin (rATG): A polyclonal antibody preparation derived from rabbits immunized with human thymocytes. It depletes circulating T lymphocytes via complement-dependent lysis and opsonization for phagocytosis.

This combination is used as an aggressive immunosuppressive regimen in severe or refractory autoimmune diseases (such as certain neuroinflammatory disorders), transplant rejection prophylaxis/treatment, or other settings where profound suppression of the adaptive immune system is required. The rationale for combining these agents is to target multiple arms of the immune response—humoral (B cells/antibodies) and cellular (T cells)—to achieve disease control when monotherapy or less intensive regimens are insufficient.