What is the success rate of allotransplantation (allotransplantation) for parathyroid issues?

Success Rate of Parathyroid Allotransplantation

Parathyroid allotransplantation has a success rate ranging from 55-70% based on the most recent evidence, with graft function typically lasting 6-12 months, though some cases show functionality for up to 3 years.

Overview of Parathyroid Allotransplantation

Parathyroid allotransplantation involves transplanting parathyroid tissue from a donor to a recipient with hypoparathyroidism. This procedure has emerged as a treatment option for patients with therapy-refractory hypoparathyroidism, particularly following extensive neck surgery.

Success Rates from Clinical Evidence

• In a 2007 study of 85 patients who underwent 116 allotransplantations, 55.1% of allografts retained endocrine function for more than 2 months 1
• A 2016 study reported a 70% success rate at a mean follow-up of 12 months 2
• A 2024 report of 3 patients showed that all experienced dramatic symptomatic improvement, though 2 required repeated procedures 3

Duration of Graft Function

• Mean cellular allograft survival was reported as 6.35±13.08 months 1
• Some cases demonstrate longer functionality:
  • A 2009 case report showed graft functionality for at least 20 months 4
  • A 2016 case report documented normal calcium and PTH levels for nearly 3 years after transplantation 5

Factors Affecting Success

Donor Selection and Tissue Preparation

• Parathyroid tissue is typically obtained from patients undergoing parathyroidectomy for secondary or tertiary hyperparathyroidism 1, 3
• Cultivation techniques can reduce HLA expression, potentially reducing immunogenicity:
  • After 6 weeks of cultivation and freezing, parathyroid cells showed decreased HLA class I ABC expression and absence of HLA class II positive cells 1

Transplantation Techniques

• Various approaches exist:
  • Direct tissue transplantation to recipient's forearm 5
  • Microencapsulation of parathyroid tissue 4
  • Cell suspension transplantation after short-term cultivation 2

Immunosuppression Requirements

• Approaches vary from:
  • Full immunosuppression for living-donor transplantation 5
  • Short-term immunosuppression (prednisolone for 10 days) 2
  • Microencapsulation techniques that may eliminate the need for immunosuppression 4

Clinical Applications

Indications for Parathyroid Allotransplantation

Parathyroid allotransplantation may be considered in:

• Persistent hypoparathyroidism after extensive neck surgery 5
• Cases refractory to conventional medical therapy (calcium and vitamin D supplementation) 5, 4
• Patients with severely impaired quality of life due to hypocalcemic symptoms 5

Benefits

• Restoration of normal calcium homeostasis 5
• Reduction or elimination of calcium and vitamin D supplementation 5, 2
• Significant improvement in hypocalcemic symptoms 3
• Improved quality of life 5

Limitations and Considerations

• Need for repeat procedures in some patients to maintain symptom control 3
• Variability in graft survival duration 1
• Lack of standardized protocols for:
  • Optimal amount of parathyroid tissue to transplant 3
  • Immunosuppression regimens 3
  • Uniform definition of graft viability 3

Conclusion

While parathyroid allotransplantation shows promise as a treatment for refractory hypoparathyroidism with success rates of 55-70%, the procedure remains experimental with variable outcomes. The most successful cases demonstrate functionality for several months to years, but many patients require repeated procedures or return to medical management over time.