We report a case of 65-year-old male patient with primary hyperparathyroidism (PHPT) who was admitted to the hospital for autoimmune manifestations (including autoimmune hepatitis and autoantibody development) and exhibited subsequent clinical and paraclinical improvement after parathyroidectomy. By flow cytometry, the expression of PTH receptor 1 (PTHR1) on B lymphocytes of peripheral blood was documented to be higher than that in healthy controls. After parathyroidectomy, autoimmune manifestations improved, while PTH1R expression on B-lymphocytes increased. The possible role of the dynamics of B-lymphocyte PTHR1 in the development of this autoimmune phenomenon is discussed.