Puliani G, Hasenmajer V, Sciarra F, et al. - As calcium signaling is identified to have a pivotal role in immune response, researchers sought to evaluate immune function in patients affected by hypoparathyroidism. A case-control cross-sectional study, named the Evaluation of iMmune function in Postsurgical and AuToimmune HYpoparathyroidism (NCT04059380), was performed including 20 patients with postsurgical hypoparathyroidism (12 females) and 20 age- and gender-matched controls. Patients with hypoparathyroidism were identified exhibiting reduced monocytes, regulatory, naive and total CD4 + T lymphocytes, which linked with total calcium, ionized calcium, and PTH levels, and were noted to have higher CD3 −CD56 + natural killer (NK) cell count, which inversely linked with calcium, PTH, and vitamin D levels. In addition, they had reduced TNF and GM-CSF gene expression and reduced circulating TNF levels. This study, for the first time, delineated the immune changes in patients with hypoparathyroidism receiving conventional therapies, indicating the immunoregulatory role of PTH and proposing an explanation for the raised susceptibility to infections observed in epidemiological studies.