History of antithymocyte globulin
Antithymocyte globulin (ATG) was originally developed as one of various tested preparations of antilymphocyte globulin (ALG) specifically generated against humanMechanism of immunosuppression
As an rATG, thymoglobulin consists of polyclonal antibodies, which, unlike monoclonal antibodies, target a large variety of immune cell surface proteins, including B and T lymphocyte, natural killer cell, and plasma cell surface antigens. However, its efficacy as an immunosuppressive agent is primarily through rapid induced apoptosis of CD3+ T cells present in the bloodstream. Even at low levels of concentration (up to 1 ug/mL), rATG T-cell depletive ability is still sound, but higher concentrations of ATG can induce lysis of T lymphocytes through the classical complement pathway along with B cell and NK cell depletion as well . Thymoglobulin has also demonstrated the ability to induce expression of a number of regulatory cell markers ''in vitro'', including CD25, GITR, and CTLA-4 (aka CD152, functions as immune checkpoint, downregulates immune response). Recent research has suggested that Thymoglobulin may also contribute to T-cell anergy, in which T-cells remain inactive, though further research must be done to confirm this interaction.Clinical applications
Thymoglobulin is commonly used to prevent and treat acute rejection and increase graft survival in solid organ transplantation (SOT), especially kidney, liver, pancreas, and heart transplantation. As multiple studies have demonstrated both its efficacy and safety in a clinical setting, it is also used in different minimization regimens to reduce the application of higher risk immunosuppressive agents such as corticosteroids and calcineurin inhibitors (CNIs) in solid organ transplantation. Because both corticosteroids and CNIs have been found to potentially cause long-term adverse effects in the body, a multitude of studies have been conducted to examine the efficacy of thymoglobulin in SOT either with minimal usage or without the use of either agent. Findings have indicated that use of thymoglobulin alone minimizes risk of adverse effects and thus improves long-term outcomes for transplant patients. Thymoglobulin is also an effective agent for preventing graft-vs.-host disease in patients receiving haematopoietic stem cell transplantation (HSCT). GVHD is a condition in which immune cells within the graft attack host cells and cause tissue damage. It is considered a major obstacle to successful HSCT. The T-cell depleting activity of thymoglobulin has proved to be useful in preventing GVHD. Multiple studies have indicated that thymoglobulin is favored in comparison to other induction agents for patients who have increased risk of developing post-transplant complications, such as elderly patients, patients undergoing a repeat transplantation, and patients in which minimization of use of steroids or CNIs post-operation is recommended.References
{{Reflist Polyclonal antibodies Sanofi