A Case of a False-Positive Anti-Myeloperoxidase Antibody ELISA in a Patient with Hypothyroidism
- Author:
Mi Kyung JIN
1
;
Kwan Yong SEO
;
Jin Young KANG
;
Ji Young CHOI
;
Se Hee YOON
;
Yong Lim KIM
;
Dong Il WON
;
Sun Hee PARK
Author Information
- Publication Type:Case Report
- Keywords: Hypothyroidism; Anti-thyroid peroxidase antibodg; Anti-myeloperoxi dase antibody
- MeSH: Adult; Antibodies; Antibodies, Antineutrophil Cytoplasmic; Cytoplasm; Diuretics; Dyspnea; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Follow-Up Studies; Hematuria; Humans; Hypothyroidism; Iodide Peroxidase; Pericardial Effusion; Thyroid Gland; Vasculitis
- From:Chonnam Medical Journal 2011;47(1):48-50
- CountryRepublic of Korea
- Language:English
- Abstract: We present a case of a false-positive anti-myeloperoxidase (MPO) antibody result on an ELISA in a patient with anti-thyroid microsomal antibody (TMA)-positive hypothyroidism. A 41-year-old woman presented with dyspnea on exertion. The initial evaluation revealed pericardial effusion associated with hypothyroidism. In addition, microscopic hematuria with normal renal function and positive cytoplasmic anti-neutrophil cytoplasmic antibodies (c-ANCA) on immunofluorescent assay were found. In further evaluation, elevated anti-TMA and MPO antibodies by ELISA. While no definite signs of vasculitis were present, the clinical state improved with thyroid hormone replacement and diuretics. Anti-MPO antibody was still positive in the follow-up tests, and microscopic hematuria persisted. On the basis of previous reports that thyroid peroxidase and MPO molecules contain cross-reactive epitopes that are exposed in denaturated molecules, we suggest that in a patient with anti-TMA-positive hypothyroidism, anti-MPO antibody might also be positive on ELISA without clinical signs of vasculitis.
