Calcium-sensing receptor autoantibodies in primary hyperparathyroidism.
BACKGROUND
Mutations in the extracellular calcium-sensing receptor (CaSR) gene are known to be implicated in some cases of primary hyperparathyroidism. However, not all patients display such mutations and so the mechanisms of primary hyperparathyroidism are still largely unknown. An autoimmune origin has been suggested, as autoantibodies against the CaSR have been detected in some patients. The aim of our study was to investigate the presence of CaSR autoantibodies in a large cohort of patients with primary hyperparathyroidism.


METHODS
Seventy-five patients were tested for the presence of anti-parathyroid antibodies using an immunoblotting assay with the recombinant extracellular domain of the human CaSR and an immunofluorescence technique with parathyroid adenoma.


RESULTS
Five of 75 (6.7%) patients had CaSR autoantibodies. There was no statistically significant difference in the decrease of parathyroid hormone (PTH) level after surgery between patients with or without autoantibodies. Histological examination of parathyroid tissue did not show greater lymphocytic infiltration in patients with autoantibodies than in those without.


CONCLUSIONS
This study confirmed that some patients with primary hyperparathyroidism displayed CaSR autoantibodies. The pathophysiological role of these autoantibodies in hyperparathyroidism needs to be further elucidated.
Charrié
Anne
A
University of Lyon, F-69002 Lyon, France.
Chikh
Karim
K
Peix
Jean-Louis
JL
Berger
Nicole
N
Decaussin
Myriam
M
Veber
Sophie
S
Bienvenu
Jacques
J
Lifante
Jean-Christophe
JC
Fabien
Nicole
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000276:immunology*; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology / Q000473:pathology / Q000601:surgery; D002118:Calcium / Q000097:blood; D015331:Cohort Studies; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D044169:Receptors, Calcium-Sensing / Q000276:immunology*
D001323:Autoantibodies; D010281:Parathyroid Hormone; D044169:Receptors, Calcium-Sensing; D002118:Calcium