Major histocompatibility complex class II expression and parathyroid autoantibodies in primary hyperparathyroidism

Therapeutic applications of the selective high affinity ligand drug SH7139 extend beyond non-Hodgkin's lymphoma to many other types of solid cancers

SH7139, the first of a series of selective high affinity ligand (SHAL) oncology drug candidates designed to target and bind to the HLA-DR proteins overexpressed by B-cell lymphomas, has demonstrated exceptional efficacy in the treatment of Burkitt lymphoma xenografts in mice and a safety profile that may prove to be unprecedented for an oncology drug. The aim of this study was to determine how frequently the HLA-DRs targeted by SH7139 are expressed by different subtypes of non-Hodgkin’s lymphoma and by other solid cancers that have been reported to express HLA-DR. Binding studies conducted with SH7129, a biotinylated analog of SH7139, reveal that more than half of the biopsy sections obtained from patients with different types of non-Hodgkin’s lymphoma express the HLA-DRs targeted by SH7139. Similar analyses of tumor biopsy tissue obtained from patients diagnosed with eighteen other solid cancers show the majority of these tumors also express the HLA-DRs targeted by SH7139. Cervical, ovarian, colorectal and prostate cancers expressed the most HLA-DR. Only a few esophageal and head and neck tumors bound the diagnostic. Within an individual’s tumor, cell to cell differences in HLA-DR target expression varied by only 2 to 3-fold while the expression levels in tumors obtained from different patients varied as much as 10 to 100-fold. The high frequency with which SH7129 was observed to bind to these cancers suggests that many patients diagnosed with B-cell lymphomas, myelomas, and other non-hematological cancers should be considered potential candidates for new therapies such as SH7139 that target HLA-DR-expressing tumors.

Inflammatory infiltrates in parathyroid tumors

CONTEXT

Inflammatory infiltrates are sometimes present in solid tumors and may be coupled to clinical behavior or etiology. Infectious viruses contribute to tumorigenesis in a significant fraction of human neoplasias.

OBJECTIVE

Characterize inflammatory infiltrates and possible viral transcription in primary hyperparathyroidism.

DESIGN

From the period 2007 to 2016, a total of 55 parathyroid tumors (51 adenomas and 4 hyperplasias) with prominent inflammatory infiltrates were identified from more than 2000 parathyroid tumors in the pathology archives, and investigated by immunohistochemistry for CD4, CD8, CD20 and CD45 and scored as +0, +1 or +2. Clinicopathological data were compared to 142 parathyroid adenomas without histological evidence of inflammation. Transcriptome sequencing was performed for 13 parathyroid tumors (four inflammatory, 9 non-inflammatory) to identify potential viral transcripts.

RESULTS

Tumors had prominent germinal center-like nodular (+2) lymphocytic infiltrates consisting of T and B lymphocytes (31%) and/or diffuse (+1-2) infiltrates of predominantly CD8+ T lymphocytes (84%). In the majority of cases with adjacent normal parathyroid tissue, the normal rim was unaffected by the inflammatory infiltrates (96%). Presence of inflammatory infiltrates was associated with higher levels of serum-PTH (P = 0.007) and oxyphilic differentiation (P = 0.002). Co-existent autoimmune disease was observed in 27% of patients with inflammatory infiltrates, which in turn was associated with oxyphilic differentiation (P = 0.041). Additionally, prescription of anti-inflammatory drugs was associated with lower serum ionized calcium (P = 0.037).

CONCLUSIONS

No evidence of virus-like sequences in the parathyroid tumors could be found by transcriptome sequencing, suggesting that other factors may contribute to attract the immune system to the parathyroid tumor tissue.

Chronic autoimmune atrophic gastritis associated with primary hyperparathyroidism: a transversal prospective study

DESIGN

The coexistence of chronic autoimmune atrophic gastritis (CAAG) and primary hyperparathyroidism (PHPT) has been described previously, even if its extent and underlying mechanisms remain poorly understood. We therefore prospectively evaluated this association in two series of patients, one with CAAG and the other with sporadic PHPT.

METHODS

From January 2005 to March 2012, 107 histologically confirmed CAAG patients and 149 PHPT patients were consecutively enrolled. Routine laboratory assays included serum calcium, parathyroid hormone (PTH), plasma gastrin and chromogranin A (CgA). In CAAG patients with high PTH levels, ionized calcium and 25(OH)-vitamin D were evaluated. All CAAG and hypergastrinemic PHPT patients received an upper gastrointestinal endoscopy. Exclusion criteria were familial PHPT, MEN1 syndrome, treatment with proton pump inhibitor drugs, Helicobacter pylori infection and renal failure.

RESULTS

Of the 107 CAAG patients, nine (8.4%) had PHPT and 13 (12.1%) had secondary hyperparathyroidism stemming from vitamin D deficiency. Among the 149 PHPT patients, 11 (7.4%) had CAAG. Gastrin and CgA levels were similar in the CAAG patients with vs those without hyperparathyroidism (either primary or secondary), and calcium and PTH levels were similar in the PHPT patients with vs those without CAAG.

CONCLUSIONS

This study confirms a non-casual association between PHPT and CAAG. The prevalence of PHPT in CAAG patients is threefold that of the general population (8.4 vs 1-3%), and the prevalence of CAAG in PHPT patients is fourfold that of the general population (7.4 vs 2%). The mechanisms underlying this association remain unknown, but a potential role for autoimmunity is suggested.

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.

Anti-parathyroid and anti-calcium sensing receptor antibodies in autoimmune hypoparathyroidism

The parathyroid glands are an infrequent target for autoimmunity, the exception being autoimmune polyglandular syndrome type 1, in which autoimmune hypoparathyroidism is the rule. Antibodies that are directed against the parathyroid cell surface calcium-sensing receptor (CaSR) have recently been recognized to be present in the serum of patients with autoimmune hypoparathyroidism. In some individuals, these anti-CaSR antibodies have also been shown to produce functional activation of the receptor, suggesting a direct pathogenic role in hypocalcemia. Additionally, a few hypercalcemic patients with autoimmune hypocalciuric hypercalcemia owing to anti-CaSR antibodies that inhibit receptor activation have now been identified. Other novel parathyroid autoantigens are starting to be elucidated, suggesting that new approaches to treatment, such as CaSR antagonists or agonists (calcilytics/calcimimetics), may be worthwhile.

The syndrome of gastric carcinoid and hyperparathyroidism: a family study and literature review

OBJECTIVE

To present evidence supporting the hypothesis that the coexistence of gastric carcinoids (GCs) and hyperparathyroidism may represent a distinct clinical entity, not related to multiple endocrine neoplasia type 1 (MEN1).

METHODS

We studied a cohort of five young siblings (age range 26-42 years), one of whom had been found to have GC and hyperparathyroidism. All siblings underwent serial gastroscopies for the assessment of gastric neuroendocrine cell proliferations over a mean follow-up period of 31.2 months. Imaging, biochemical and hormonal as well as molecular genetic investigations were performed in the direction of MEN1 syndrome. The literature was searched for cases with coexistence of GCs and hyperparathyroidism not associated with MEN1.

RESULTS

Four of the siblings, all male, were found to have GCs in a background of Helicobacter pylori-associated chronic atrophic gastritis and pernicious anaemia, with no serological evidence of gastric autoimmunity. In two of them, asymptomatic hyperparathyroidism was also present. Screening for MEN1 gene mutations or large deletions was negative, and hormone and imaging investigations did not support a diagnosis of familial MEN1 syndrome. A literature search revealed sporadic reports of cases with GC and hyperparathyroidism not attributable to MEN1.

CONCLUSIONS

The association of GCs and hyperparathyroidism appears to constitute a distinct syndrome that can be encountered in genetically predisposed individuals, and should not be regarded as 'atypical' or 'incomplete' expression of MEN1. Its prevalence and aetiology should be the subject of future studies. Screening for hyperparathyroidism seems to be justified in patients with GC of any type.