Chronic rejection

Chronic Rejection refers to the long-term and often irreversible response of the immune system to a transplanted organ, such as a kidney, liver, heart, or lung. Unlike acute rejection, which can occur days to weeks after transplantation, chronic rejection can take months to years to become apparent. This process is characterized by the gradual loss of function of the transplanted organ, leading to its eventual failure. The mechanisms behind chronic rejection are complex and involve both cellular and humoral immune responses against the transplanted tissue.

Causes and Mechanisms

The exact causes of chronic rejection are not fully understood, but it is believed to involve a combination of immune and non-immune factors. Immune-related causes include the continuous recognition of the transplanted organ as foreign by the recipient's immune system, leading to a chronic inflammatory response. Non-immune factors may include drug toxicity, infections, and the physical stress of the transplantation itself.

The mechanisms of chronic rejection primarily involve:

• Vascular Endothelial Damage: Damage to the blood vessels of the transplanted organ, leading to fibrosis and scarring.
• Fibrosis: The thickening and scarring of connective tissue, often resulting from chronic inflammation.
• B-Cell and T-Cell Mediated Immunity: The activation of immune cells against the transplanted organ, contributing to its deterioration.

Symptoms

Symptoms of chronic rejection vary depending on the organ involved but generally include:

• Decreased organ function
• Fatigue
• Weight loss
• Fluid retention
• High blood pressure

Diagnosis

Diagnosis of chronic rejection involves a combination of clinical assessment, laboratory tests, and imaging studies. Biopsy of the transplanted organ is often considered the gold standard for diagnosing chronic rejection.

Treatment

Treatment options for chronic rejection are limited. The main approach is to adjust immunosuppressive therapy to try to reduce the immune response against the transplanted organ. In some cases, re-transplantation may be considered, although this comes with its own set of challenges.

Prevention

Prevention strategies focus on minimizing risk factors for chronic rejection, including:

• Careful matching of donor and recipient
• Effective management of immunosuppressive medication to avoid under or over-immunosuppression
• Regular monitoring for signs of rejection

Prognosis

The prognosis for patients experiencing chronic rejection varies widely and depends on the organ transplanted, the severity of the rejection, and the response to treatment. Chronic rejection remains a leading cause of long-term transplant failure.

See Also

• Transplant Rejection
• Immunosuppression
• Organ Transplantation