Simultaneous Living Donor Kidney and Parathyroid Allotransplantation: First Case Report and Review of Literature

The Challenge of Preoperative Panel Reactive Antibody Positivity in Parathyroid Transplantation

OBJECTIVES

Identifying suitable recipient criteria and matching recipients with appropriate donors are required to increase survival for parathyroid transplant. This study was undertaken to evaluate transplant survival rates while comparing preoperative panel reactive antibody positivity.

MATERIALS AND METHODS

The study included 14 hypoparathyroidism patients who presented to our clinic for parathyroid transplant. Preoperative ABO compatibility and negative cross-match tests were prioritized for recipient-donor matching, and panel reactive antibody screening tests were performed. During the 24-month follow-up, we evaluated medication use and serum calcium, phosphorus, and parathormone levels of patients.

RESULTS

Preoperative panel reactive antibody positivity was assessed in 3 groups. The HLA class I-positive group (mean fluorescence intensity range, 179-1770) showed decreased medication use and stability in serum calcium levels. The HLA class IIpositive (mean fluorescence intensity range, 85-3959) showed decreased medication use by 25% to 50% and returned to their former prescription doses after 12 months. An opposite pattern was observed in 2 patients with panel reactive antibody positivity for both HLA classes (mean fluorescence intensity range, 462-2289), with 1 patient requiring medication for continuing symptoms and the other patient occasionally taking additional magnesium supplementation, despite decreased medication doses after 12 months. Serum calcium levels remained normal, and parathormone and phosphorus levels were elevated.

CONCLUSIONS

Improving patient symptoms and having no requirement for intravenous calcium replacement are priorities, and monitoring serum levels is the next important step. Varied panel reactive antibody positivities and survival rates indicate a requirement, and each HLA class could require a proper limitation for the mean fluorescence intensity. Preoperative mean fluorescence intensity cut-off value should be <900. Higher mean fluorescence intensity values in panel reactive antibody screenings could increase risk of short-term graft survival after parathyroid transplant. Further studies should include immunological risk assessments by individualizing the outcome with donor-specific antibodies.

Is parathyroid allotransplantation a viable option in the treatment of permanent hypoparathyroidism? A review of the literature

BACKGROUND

The standard clinical treatment for hypoparathyroidism, replacement of calcium and vitamin metabolites (calcitriol), has been used for decades; however, evidence points to its inefficiency in acting on the pathophysiology of the disease, which may precipitate or aggravate conditions already related to hypoparathyroidism. Therapies based on recombinant human parathyroid hormone have emerged in recent years but still have low availability due to their high cost. Parathyroid allotransplantation (Pt-a) has been reported as a strategy for treating more severe cases.

METHODS

This narrative review highlights relevant aspects of conventional permanent hypoparathyroidism treatment and provides a comprehensive and critical review of the reports of applications of Pt-a, especially those carried out in recent years. Particular focus is placed on the following key points: parathyroid immunogenicity, immunosuppression regimens (short-term or chronic), techniques to reduce the expression of immunogenic molecules, follow-up time, and reductions in calcium and vitamin D supplementation.

CONCLUSION

Pt-a has been considered a safe and relatively low-cost therapy and is believed to have the potential to cure the disease, in addition to treating symptoms. However, there is considerable heterogeneity in treatment protocols; therefore, more studies are required to improve the standardization of the procedure and thus improve the consistency of outcomes.

Simultaneous Kidney and Parathyroid Transplantation in the Management of Genetic Hypoparathyroidism in a Child

Background.

Genetically determined hypoparathyroidism can lead to life-threatening episodes of hypocalcemia and, more rarely, to end-stage kidney disease at a young age. Parathyroid allotransplantation is the only curative treatment, and in patients already receiving immunosuppression for kidney transplantation, there may be little additional risk involved. We report the first such case in a child.

Methods.

An 11-y-old girl, known to have hypoparathyroidism secondary to an activating pathogenic variant in the calcium-sensing receptor, developed end-stage kidney disease and was started on intermittent hemodialysis. Since the age of 2.5 y, she had been receiving treatment with exogenous synthetic parathyroid hormone (PTH). In June 2019, at the age of 11.8 y, she received a living-donor kidney and simultaneous parathyroid gland transplant from her father. The kidney was implanted into the right iliac fossa, followed by implantation of the parathyroid gland into the exposed rectus muscle.

Results.

The kidney graft showed immediate function while the intrinsic serum PTH level remained low at 3 ng/L. Exogenous PTH infusion was reduced on day 6 posttransplantation to stimulate PTH production by the new gland, which resulted in improving intrinsic PTH concentrations of 28 ng/L by day 9. Twelve months after transplantation, PTH levels remain in normal range and the kidney graft function is stable with a serum creatinine of 110 μmol/L.

Conclusions.

Simultaneous living donation and transplantation of a kidney and a parathyroid gland into a child is safe and feasible and has the potential to cure primary hypoparathyroidism as well as kidney failure.

Parathyroid Allotransplantation: A Systematic Review

Background: To date, there is no satisfactory treatment for patients with calcium and vitamin D supplementation refractive hypoparathyroidism. Parathyroid allotransplantation by design is a one-time cure through its restoration of the parathyroid function and, therefore, could be the solution. A systematic literature review is conducted in the present paper, with the aim of outlining the possibilities of parathyroid allotransplantation and to calculate its efficacy. Additionally, various transplantation characteristics are linked to success. Methods: This review is carried out according to the PRISMA statement and checklist. Relevant articles were searched for in medical databases with the most recent literature search performed on 9 December 2021. Results: In total, 24 articles involving 22 unique patient cohorts were identified with 203 transplantations performed on 148 patients. Numerous types of (exploratory) interventions were carried out with virtually no protocols that were alike: there was the use of (non-) cryopreserved parathyroid tissue combined with direct transplantation or pretreatment using in vitro techniques, such as culturing cells and macro-/microencapsulation. The variability increased further when considering immunosuppression, graft histology, and donor–recipient compatibility, but this was found to be reported in its entirety by exception. As a result of the large heterogeneity among studies, we constructed our own criterium for transplantation success. With only the studies eligible for our assessment, the pooled success rate for parathyroid allotransplantation emerged to be 46% (13/28 transplantations) with a median follow-up duration of 12 months (Q1–Q3: 8–24 months). Conclusions: Manifold possibilities have been explored around parathyroid allotransplantation but are presented as a double-edged sword due to high clinical diverseness, low expertise in carrying out the procedure, and unsatisfactory study quality. Transplantations carried out with permanent immunosuppression seem to be the most promising, but, in its current state, little could be said about the treatment efficacy with a high quality of evidence. Of foremost importance in pursuing the answer whether parathyroid allotransplantation is a suitable treatment for hypoparathyroidism, a standardized definition of transplantation success must be established with a high-quality trial.

MANAGEMENT OF ENDOCRINE DISEASE: Postsurgical hypoparathyroidism: current treatments and future prospects for parathyroid allotransplantation

BACKGROUND

Permanent postsurgical hypoparathyroidism (POSH) is a major complication of anterior neck surgery in general and of thyroid surgery in particular. Depending on diagnostic criteria, up to 10% of patients undergoing bilateral thyroid surgery develop POSH. This leads to a multitude of symptoms that decrease the quality of life and burden the healthcare provision through complex needs for medication and treatment of specific complications, such as seizures and laryngospasm.

METHODS

Narrative review of current medical treatments for POSH and of the experience accumulated with parathyroid allotransplantation.

RESULTS

In most patients, POSH is controlled with regular use of calcium supplements and active vitamin D analogues but a significant proportion of patients continue to experience severe symptoms requiring repeated emergency admissions. Replacement therapy with synthetic PTH compounds (PTH1-34, Natpara® and PTH1-84, teriparatide, Forsteo®) has been assessed in multicentre trials, but the use of this medication is restricted by costs and concerns related to the risk of development of osteosarcoma. Based on recent case reports of successful allotransplantation of parathyroid tissue between siblings, there is renewed interest in this technique. Data on selection of donors, parathyroid cell preparation before allotransplantation, site and timing of transplantation, need for immunosuppression and long-term outcomes are reviewed.

CONCLUSION

A prospective trial to assess the efficacy of parathyroid allotransplantation in patients with severely symptomatic protracted post-surgical hypoparathyroidism is warranted.

Prospective Nonrandomized Comparison Between Open and Robot-Assisted Kidney Transplantation: Analysis of Midterm Functional Outcomes

Introduction: To compare short- and midterm outcomes of the first 55 patients undergoing robot-assisted kidney transplant (RAKT) with patients undergoing open kidney transplant (OKT) during the same period in a tertiary care hospital. Materials and Methods: Data of all end-stage renal disease patients undergoing renal transplant were prospectively maintained. All graft kidneys were harvested laparoscopically. Both RAKT and OKT were performed using standardized techniques, and all RAKTs were performed by a single experienced robotic surgeon. Chi-square test/Fisher exact test was done for categorical data, and Mann-Whitney U test was done for continuous data. Discrete variables were expressed in absolute numbers and percentages. For all tests, p < 0.05 was considered significant. All results were expressed as mean ± standard deviation or median with range. Results: Between April 2016 and September 2018, 55 patients underwent RAKT. The same was compared with 152 patients who underwent OKT. The two groups were comparable in terms of age, gender, and body mass index. Duration on hemodialysis was significantly higher in the RAKT group, and hemoglobin and donor kidney glomerular filtration rate was significantly better in the RAKT group. Requirement of perioperative analgesia was significantly less in the RAKT group. Rewarm ischemia time was significantly longer in the RAKT group. The fall in serum creatinine was slower in RAKT group till 3 months. The serum creatinine levels were statistically similar in the two cohorts at 3 months (p = 0.082), which was maintained at median 29 months of follow-up (p = 0.067). Tacrolimus levels on postoperative day 2 were found to be significantly higher in RAKT cohort (17.98 ± 14.41) vs OKT cohort (11.38 ± 6.93). Surgical-site infections were rare in the RAKT group. Conclusions: RAKT confers advantage of decreased wound morbidity with similar functional outcomes compared with OKT in midterm. It looks promising; however, long-term follow-up of larger numbers of patients is needed.

Correction of both immunodeficiency and hypoparathyroidism by thymus transplantation in complete DiGeorge syndrome

Combined immune deficiency due to athymia in patients with complete DiGeorge syndrome can be corrected by allogeneic thymus transplantation. Hypoparathyroidism is a frequent concomitant clinical problem in these patients, which persists after thymus transplantation. Cotransplantation of allogeneic thymus and parental parathyroid tissue has been attempted but does not achieve durable correction of the patients' hypoparathyroidism due to parathyroid graft rejection. Surprisingly, we observed correction of hypoparathyroidism in one patient after thymus transplantation. Immunohistochemical analysis and fluorescence in situ hybridization confirmed the presence of allogeneic parathyroid tissue in the patient's thymus transplant biopsy. Despite a lack of HLA-matching between thymus donor and recipient, the reconstituted immune system displays tolerance toward the thymus donor. Therefore we expect this patient's hypoparathyroidism to be permanently cured. It is recognised that ectopic parathyroid tissue is not infrequently found in the thymus. If such thymuses could be identified, we propose that their use would offer a compelling approach to achieving lasting correction of both immunodeficiency and hypoparathyroidism.

Importance of HLA typing, PRA and DSA tests for successful parathyroid allotransplantation

Parathyroid allotransplantation is increasingly practiced for patients who have permanent hypoparathyroidsm. Parathyroid allotransplantation success is varied, and no defined criteria about immunologic monitoring for pre-/post-transplantation follow-up. This study sought to evaluate the possible role of immunological tests. Four unrelated recipients and one living donor who have chronic kidney disease were evaluated for HLA-typing, PRA, CXM tests to conduct parathyroid allotransplantation. Parathyroid glands were obtained and resected from the donor, then cells were isolated and cryopreserved. Upon histologic examination, cells were cultivated and injected into muscle of four recipients. Recipient's were followed for parathormone and calcium levels for four years. PRA screening were monitored and de novo DSA was evaluated as well. In two of the recipients, allografts continued to be functional more than four years. In one recipient, allograft remained functional for two years and another recipient lost function after one year. Two out four were negative for de novo DSA and three out of four of the recipients remained negative for PRA. Neither HLA-matching nor de novo DSA positivity and PRA screenings seems significant for successfull parathyroid allotransplantation. This study has considerable potential for immunological monitoring of parathyroid allotransplantation.

Patients' views about parathyroid transplantation for post-thyroidectomy hypoparathyroidism

BACKGROUND

Permanent hypoparathyroidism (hypoPT) represents the most common postoperative complication associated with total thyroidectomy. Current treatment relies on high-dose calcium and/or vitamin D supplementation, but often this is insufficient and some patients remain symptomatic. Parathyroid allotransplantation is a new therapeutic option described recently in the literature. This study aims to investigate the patients' acceptability of parathyroid transplantation as a potential new treatment for hypoPT.

METHOD

Online survey of members of HypoParaUK, a support group for individuals affected by hypoPT.

RESULTS

Responses were received from 252 hypoPT patients. Majority declared to experience severe symptoms despite regular medical treatment. On a severity scale of 0-5, symptoms that were most troublesome were fatigue (3.8), low sense of well-being (3.5), and numbness/tingling (2.9). On a scale of 0-10, on average, their current quality of life (QoL) was 5 ± 3 and they expected this would improve to 7 ± 2 with correction of their hypoPT. Forty-four percent of patients were extremely interested in a potential technique involving intramuscular injection of parathyroid cell suspension compared to just 14% who were interested in the more invasive procedure of implantation of a parathyroid allograft into the forearm. The main concerns expressed were related to the possible need for immunosuppressive therapy.

CONCLUSION

Patients with severe symptomatic hypoPT seem interested to consider participation in a clinical trial exploring the feasibility and success rate of parathyroid transplantation.

[Not Available]

Parathormone (PTH), produced by parathyroid glands, is the main regulator of calcium homeostasis. Hypoparathyroidism (hypoPT), due to decrease of PTH production, is a rare disease. Symptoms are multiple, altering function of several organs and leading to a decrease of quality of life. Acquired etiologies, including thyroïdectomy, the main cause of hypoPT, can be distinguished from congenital etiologies, including genetic defects. HypoPT, which is classically treated by supplementation by calcium and active vitamin D, can now be treated by recombinant injection in certain indications as a poor control under classical therapy. Here are summarized current knowledge on etiologies, epidemiology, clinical manifestations and management of hypoPT.

Living-donor parathyroid allotransplantation for therapy-refractory postsurgical persistent hypoparathyroidism in a nontransplant recipient - three year results: a case report

Background

Therapy-refractory persistent hypoparathyroidism after extensive neck surgery is a rare but severe complication. Parathyroid allotransplantation may represent a definitive treatment option.

Case presentation

A 32-year old female was referred to our hospital with intractable persistent hypocalcemia after neck surgery for papillary thyroid cancer. Despite optimal medical treatment including calcium and vitamin D supplementation and even hormonal replacement therapy hypocalcemic symptoms failed to improve. The quality of life was considered very low. In light of the unsuccessful medical therapy and the young age of the patient parathyroid allotransplantation seemed an attractive treatment option to restore normal calcium homeostasis despite of the need for immunosuppressive therapy after the procedure. Therefore, we performed living-donor allotransplantation of two healthy parathyroid glands to the recipient’s left forearm. The surgical intervention was successful. Neither the donor nor the recipient showed any complications. In the postoperative course clinical symptoms of hypocalcemia significantly improved whereas serum calcium and parathyroid hormone (PTH) levels progressively increased into the normal range. Former intense replacement therapy could be discontinued completely in a stepwise fashion. To date, nearly three years after transplantation, the patient remains asymptomatic with normal serum levels of calcium and PTH.

Conclusion

Successful living-donor parathyroid allotransplantation for postsurgical hypoparathyroidism represents an innovative therapeutic strategy that could provide the definitive treatment in those patients in which the disease is therapy-refractory. The procedure can be justified even in nontransplant recipients. Retrieval of parathyroid glands from healthy donors is feasible and safe.