Kidney Transplants and Anti-Semaphorin-3B Mediated Membranous Nephropathy

According to a recent article, a recent study shows evidence that anti-Semaphorin 3B antibodies are pathogenic and therefore patients diagnosed with membranous nephropathy should be monitored after a kidney transplant.

Membranous Nephropathy

Membranous nephropathy is a kidney disorder in which small blood vessels in the kidney (glomeruli) that filter wastes from the blood become inflamed and thickened. As a result, proteins leak from the damaged blood vessels into the urine (proteinuria). For many, loss of these proteins eventually causes signs and symptoms characteristic of nephrotic syndrome.

Symptoms:

The following are symptoms of membranous nephropathy:

  • Edema (swelling) in any area of the body
  • Fatigue
  • Foamy urine
  • Poor appetite
  • Weight gain
  • Excessive urination, usually at night
  • Elevated fat levels in the blood (hyperlipidemia)
  • Increased protein levels in the urine (proteinuria)
  • Decreased protein levels in the blood, particularly of the protein albumin

Research

Researchers performed biopsies on patients’ kidneys at 1 month and 5 months after their kidney transplant. Using immunohistochemistry and confocal microscopy, researchers were able to detect the Semaphorin 3B antigen.

Conclusions

Researchers discovered a boy, who was seven years old, had early recurrence after transplantation, and he had both severe nephrotic syndrome and advanced kidney failure. Using a Western blot analysis of serum, they found the boy had anti-Semaphorin 3B antibodies. This means that recurrence happened just 25 days after his kidney transplantation despite the use of conventional immunosuppressive therapy. Rituximab, a monoclonal antibody, was then used to treat the boy, and after 40 days of treatment, there were no anti-Semaphorin 3B antibodies found in his system.

Researchers, therefore, concluded that anti-Semaphorin 3B antibodies are pathogenic (causing or capable of disease) and patients with membranous nephropathy should be closely monitored after a kidney transplant.