Immunosuppression, Maintenance Therapy
You probably could have guessed that this was coming after the last post. Even though induction therapy plays a large role in reducing the number of acute rejections, when trying to minimize the risk of long term rejection, maintenance therapy is key. Maintenance therapy is the immunosuppressant regimen that the patient will be on for the rest of their lives. A universal limitation on all immunosuppressive drugs is that they are non-antigen specific, and so because this regimen will affect the whole of the patient’s immune response a long period of time, patients must first be assessed based on their immunological risk before any kind of treatment can be started. Patients who have had previous transplants, are young, are African-American, or have an aggressive autoimmune disorder are at a higher risk for rejection and so are typically given higher dosages or more potent maintenance agents. The elderly, first transplant patients, and those without an autoimmune disease are generally low-risk. The immune system naturally breaking down with age is thought to be the reason older patients need less suppression, however, the flip-side of this is that older transplant patients have a longer recovery from the operation. Maintenance immunosuppression agents are usually used in conjunction with one another, especially when their effective mechanisms complement each other. The three main drugs are Calcineurin Inhibitors (CNI), mTOR Inhibitors and other anti-proliferative agents, and just like in induction therapy all of these are usually supplemented with steroids.
Because maintenance therapy is long-term suppression there are many side effects that arise from it, which generally do not arise from induction therapy (due to its very short duration). Above is a table I have found which shows just some of them for the varying drugs that are currently used.
You probably could have guessed that this was coming after the last post. Even though induction therapy plays a large role in reducing the number of acute rejections, when trying to minimize the risk of long term rejection, maintenance therapy is key. Maintenance therapy is the immunosuppressant regimen that the patient will be on for the rest of their lives. A universal limitation on all immunosuppressive drugs is that they are non-antigen specific, and so because this regimen will affect the whole of the patient’s immune response a long period of time, patients must first be assessed based on their immunological risk before any kind of treatment can be started. Patients who have had previous transplants, are young, are African-American, or have an aggressive autoimmune disorder are at a higher risk for rejection and so are typically given higher dosages or more potent maintenance agents. The elderly, first transplant patients, and those without an autoimmune disease are generally low-risk. The immune system naturally breaking down with age is thought to be the reason older patients need less suppression, however, the flip-side of this is that older transplant patients have a longer recovery from the operation. Maintenance immunosuppression agents are usually used in conjunction with one another, especially when their effective mechanisms complement each other. The three main drugs are Calcineurin Inhibitors (CNI), mTOR Inhibitors and other anti-proliferative agents, and just like in induction therapy all of these are usually supplemented with steroids.
Why are patients who are African-American at a higher risk for rejection? Is it just an observed trend or is there a known genetic reason that African-Americans tend to reject the transplant more?
ReplyDeleteIt is an observed trend, however, it is unknown if it results from social or genetic causes. It is still a strong enough trend that it is taken into account when calculating a patient's immunological risk for maintenance therapy.
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