Chronic rejection is a pattern of slow deterioration in a transplanted organ, caused by the development of an immune reaction to the tissue in the organ. It is a form of long-term transplant rejection and is an especially big cause of concern with lung transplants. For reasons researchers do not fully understand, patients undergoing lung transplants are far more likely to experience chronic rejection, and average survival times for lung recipients tend to be shorter than those for other donor organs for this reason.
There are several levels of transplant rejection, classified by how long it takes for rejection to set in. In hyperacute rejection, it becomes evident within minutes of transplant that the recipient's body is reacting badly to the donor organ. Careful matching is done to minimize the risks of rejection, with the goal of identifying any possible conflicts between donor and recipient, but sometimes risks are missed, or deemed acceptable if the alternative is death while waiting for a suitable donor organ.
Acute rejection sets in within 60 days. Chronic rejection occurs after 60 days, and is often slow in onset. Over time, immune reactions to the donor organ cause fibrous tissue to develop and may interfere with the organ's function. In patients with lung transplants, difficulty breathing can develop and the patient's airways may become narrowed and clogged with mucus. The signs of chronic rejection are typically identified during a follow-up medical appointment and medical testing such as imaging studies and biopsies may be required to confirm a diagnosis of rejection.
In addition to using rigorous matching systems for donor organs, doctors also provide patients with medications designed to prevent rejection. These medications suppress immune function, making it harder for the body to attack the donor organ. Chronic rejection sometimes occurs when people take medications intermittently or stop taking them, although in other cases, it occurs despite a patient's careful adherence to the medication regimen.
Potential complications of organ transplant can onset months or years after the transplant procedure. It is important for patients to receive regular medical evaluations after transplant and to follow directions from their doctors with care. If patients notice signs of rejection, they should immediately see a doctor for a thorough examination and evaluation. Catching rejection early provides patients with more treatment options, including an opportunity to intervene before the only treatment is a new organ to replace the failing transplant.
