Circulating organ-specific
autoantibodies are serological markers of destruction or impairment of the relevant endocrine tissue cells and may be associated with abnormal
hormone levels with or without clinical evidence of overt disease. We sought organ-specific cardiac
antibodies in patients with
autoimmune polyendocrinopathy because of increasing evidence that the heart has endocrine characteristics (secretion of
atrial natriuretic peptide [
ANP] and other
peptide hormones). Serum samples from 166 patients with polyendocrinopathy, 80 with autoimmunity confined to one gland, and 200 healthy blood donors were tested for these
antibodies by means of immunofluorescence on human heart. Skeletal muscle was used to identify cross-reacting
antibodies. Organ-specific cardiac
antibodies were detected in significantly more of the patients with
autoimmune polyendocrinopathy (28 [17%]) than of those with autoimmunity confined to one gland (1 [1%]) or of normal subjects (7 [3.5%]; p = 0.0001). Among the patients with
autoimmune polyendocrinopathy, the prevalence of systemic
hypertension was higher in those with cardiac
autoantibodies than in those without (5/28 [18%] vs 2/80 [3%]; p = 0.01); the same was true for a family history of
hypertension (11 [42%] vs 5 [7%]; p = 0.0001). There were no significant differences in mean basal or stimulated
ANP concentrations between patients with or without
antibodies or between patients and controls. 5 of the 22 antibody-positive patients had
ANP concentrations outside the normal range, but these disturbances were not associated with systemic
hypertension or a family history of the disorder. Patients with
autoimmune polyendocrinopathy can have organ-specific cardiac
antibodies, which may represent novel serological markers for an autoimmune form of systemic
hypertension in the absence of overt
cardiac disease.