A successful transplant does not end with the donated organ surgically connected to the recipient. The next big challenge comes from our immune system designed to identify and attack anything it recognises as foreign.

Rejection occurs when the recipient’s immune system mounts an attack against the transplanted organ. This happens because immune cells recognise differences between the donor and recepient Blood-group tissue in compatibility. Tissue matching and blood group typing before transplantation help reduce this risk, but cannot eliminate it completely.

Rejection can occur at different times.

Hyperacute rejection can occur within minutes to hours and is rarely seen these days due to better cross match techniques

Acute rejection usually develops over days to months, although it can occur later if immunosuppression is inadequate.

Chronic rejection develops gradually and can lead to progressive loss of organ function over months or years.

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Importantly, rejection does not always cause obvious symptoms. A transplanted kidney may show a rising creatinine before the patient feels anything.

Blood tests for donor-specific antibodies, imaging and, when necessary, a biopsy can help confirm the diagnosis.

The cornerstone of preventing rejection is immunosuppressive medication. Drugs such as tacrolimus, mycophenolate and corticosteroids reduce the immune response sufficiently to protect the transplant.

The challenge is achieving the right balance: too little immunosuppression can result in rejection, while too much increases the risk of infections, cancers and medication-related complications.

Patients play a crucial role in protecting their transplant. Taking medicines consistently, attending regular follow-ups, monitoring prescribed tests and promptly reporting symptoms or medication problems are essential. Patients should never stop or change immunosuppressive medicines on their own, even when they feel completely well.

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A transplant is therefore not simply an operation—it is a lifelong partnership between the patient, the transplant team and the immune system.

With careful monitoring and appropriate treatment, many episodes of rejection can be detected early and successfully managed, allowing a donated organ to provide years, and often decades, of meaningful life.

-Dr. Rohan Augustine is a Consultant - Nephrology, Transplant Physician, at Manipal Hospital Old Airport Road, Bengaluru