Lymphoid cell proliferation in renal transplants: biologic and diagnostic implications

Area of Science:

• Nephrology
• Immunology
• Transplantation

Background:

• The location of alloreaction development in kidney transplants is debated.
• Understanding immune cell activity within the kidney is crucial for diagnosis.

Purpose of the Study:

• To investigate the site of alloreaction in kidney transplants.
• To evaluate interstitial inflammatory cell (IIC) proliferation in various kidney conditions.
• To assess the role of T lymphocytes in kidney allograft rejection.

Main Methods:

• Interstitial inflammatory cell (IIC) proliferation was quantified using MIB-1 immunostaining.
• Proliferation rates were compared between acute cell-mediated rejection (ACR), chronic allograft nephropathy (CAN), normal kidneys, and native kidneys.
• T lymphocyte, B lymphocyte, and macrophage proliferation were assessed.

Main Results:

• IIC proliferation rates were significantly higher in ACR compared to normal kidneys, acute tubular necrosis, and non-specific chronic allograft nephropathy.
• Proliferation was predominantly observed in T lymphocytes within ACR kidneys.
• Biopsies with high MIB-1+ IIC rates, indicative of ACR, responded well to anti-rejection therapy.

Conclusions:

• Alloreaction, particularly T lymphocyte proliferation, occurs within the transplanted kidney.
• These findings support the concept of in situ alloimmunization.
• MIB-1 immunostaining for IIC proliferation can aid in diagnosing ACR.