Allotransplantation of Cryopreserved Parathyroid Tissue for Severe Hypocalcemia in a Renal Transplant Recipient

We report the successful allotransplantation of cryopreserved parathyroid tissue to reverse hypocalcemia in a kidney transplant recipient. A 36-year-old male received a second deceased donor kidney transplant, and 6 weeks later developed severe bilateral leg numbness and weakness, inability to walk, acute pain in the left knee and wrist tetany. His total calcium was 2.6 mg/dL and parathormone level 5 pg/mL (normal 10-60 pg/mL). He underwent allotransplantation of parathyroid tissue cryopreserved for 8 months into his left brachioradialis muscle. Immunosuppression included tacrolimus (target C(0) 10-12 ng/mL), mycophenolate mofetil and steroids. Within 2 weeks, the left knee pain, leg weakness and numbness resolved, and by 1 month he could walk normally. After a peak at month 2, his parathyroid hormone (PTH) level fell to < 10 pg/mL; therefore at month 3 he received a second parathyroid transplant from the same donor. Eight months later (11 months after initial graft) he has a total calcium of 9.3 mg/dL, PTH level 15 pg/mL and is clinically asymptomatic. The amount of parathyroid tissue needed to render a patient normocalcemic is not known. In our case, the need for second transplant suggests that the amount of tissue transferred for an allograft may need to be substantially greater than for an autograft.