View source for Organ transplantation and immunosuppression

Following [[organ transplantation]], lifelong immunosuppression is required to prevent [[transplant rejection]]. Modern post-transplant immunosuppressive therapy has reduced the incidence of rejection to < 10%. It’s important to individualise the choice and dose of immunosuppressants to achieve adequate immunosuppression as well as the least amount of side effects and complications. This is very difficult as there is no biomarker for adequate immunosuppression. It’s usually best to err at the side of giving too much immunosuppression, rather than risking an organ.

== Complications ==
Chronic immunosuppression increases the risk for infections, [[cardiovascular disease]], [[diabetes mellitus]], and malignancy. Common infections include [[candidiasis]], [[PCP]], BK polyomavirus infection, JC polyomavirus infection, [[CMV]], <abbr>[[EBV]]</abbr>, and [[tuberculosis]].

Common malignancies include [[non-Hodgkin lymphoma]], nonmelanoma skin cancer, and virally induced cancers like [[Kaposi sarcoma]], <abbr>[[HCC]]</abbr>, and [[vulvar carcinoma]]. Patients must be annually screened for these malignancies.

Cardiovascular disease is a major cause of death and graft loss, and so modifiable risk factors for CVD must be addressed.

== Kidney transplant immunosuppression ==
Generally, the immunosuppression consists of an initial induction therapy followed by maintenance. Induction usually consists of [[methylprednisolone]] + another drug, which may be basiliximab (anti-IL2), [[antithymocyte globulin]] (ATG), [[rituximab]], or [[IVIG]].

Maintenance therapy usually consists of [[prednisolone]], [[tacrolimus]], and [[mycophenolate mofetil]]. Calcineurin inhibitors like tacrolimus are considered the most important component of kidney transplant immunosuppression.

The serum concentration of these immunosuppressant drugs should be regularly monitored to ensure them being in the therapeutic window.

== Liver transplant immunosuppression ==
A calcineurin inhibitor, especially tacrolimus, is the most important component of liver transplant immunosuppression. Other components include [[corticosteroids]] and [[mycophenolate mofetil]]. These are generally started postoperatively and then tapered down and discontinued after a few months as part of induction therapy. If calcineurin inhibitor-induced nephrotoxicity is a concern, the mTOR inhibitor [[sirolimus]] may be used instead of calcineurin.

Unlike kidney transplantation, liver transplantation may not require lifelong immunosuppression. Some physicians will give stable and low-risk patients an option of an immunosuppressant-free trial period, which, if successful and without rejection, may be lifelong but continuously monitored.

== Antimicrobial prophylaxis ==
Patients should receive antibiotic, antiviral, and in some cases antifungal prophylaxis for the first 6 months after transplant. This includes [[TMP-SMX]] for [[PCP]], antivirals for [[HSV]], [[HZV]], and [[CMV]], as well as inactivated vaccines for [[influenza]], [[pneumococcus]], and [[hepatitis B]].
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