The cloning and sequencing of thyroid-stimulating hormone (TSH) receptor (TSHR), combined with advances in molecular techniques, have facilitated the understanding of the interaction of the TSHR antibodies (TSHRAbs) with the TSHR at the molecular level and have allowed the delineation of their clinical role. TSHRAbs in vivo are functionally heterogeneous; the stimulating TSHRAbs cause hyperthyroidism and diffuse goiter in patients with Graves' disease, whereas, the blocking TSHRAbs cause hypothyroidism in some patients with autoimmune hypothyroidism and are the cause of transient neonatal hypothyroidism. Measuring TSHRAbs has potential clinical implications in differential diagnosis of Graves' disease, predicting the outcome of Graves' disease after antithyroid drug treatment, and predicting the fetal/neonatal hyperthyroidism or neonatal hypothyroidism. The existence of epitope heterogeneity in a patient, i.e., of stimulating TSHRAbs with epitopes other than on the N-terminal region of the extracellular domain, is significantly associated with favorable long-term clinical response to antithyroid drug treatment. Measuring these subtypes for thyroid-stimulating antibody (TSAb) has potential clinical impli-cations, for example, in predicting responsiveness to treatment in untreated patients with Graves' disease.
Autoantibodies/*immunology ; Epitopes/immunology ; Graves Disease/diagnosis/immunology/therapy ; Humans ; Hyperthyroidism/diagnosis/*immunology/therapy ; Hypothyroidism/diagnosis/*immunology/therapy ; Immunoglobulins, Thyroid-Stimulating ; Receptors, Thyrotropin/*immunology

Propylthiouracil (PTU) is known to be a potential cause of antineutrophil cytoplasmic antibody (ANCA) positive small vessel vasculitis, resulting in glomerulonephritis and diffuse alveolar hemorrhage (DAH). Herein, we describe a 25-year-old pregnant woman who developed a perinulcear ANCA (p-ANCA) and myeloperoxidase ANCA (MPO-ANCA) positive DAH during PTU therapy. The patient improved after corticosteroid therapy and discontinuation of the PTU. Methimazole was prescribed in spite of the risk of recurrence of DAH because of the pregnancy. The patient is currently free from pulmonary problems. Our case shows that the alternative agent, methimazole, can be used to treat hyperthyroidism in a pregnant patient with PTU associated DAH.
Tomography, X-Ray Computed ; *Pulmonary Alveoli ; Propylthiouracil/*adverse effects/therapeutic use ; *Pregnancy Complications, Hematologic ; Pregnancy ; Hyperthyroidism/blood/complications/*drug therapy ; Humans ; Hemoptysis/*chemically induced/diagnosis/immunology ; Female ; Diagnosis, Differential ; Bronchoscopy ; Antithyroid Agents/*adverse effects/therapeutic use ; Antibodies, Antineutrophil Cytoplasmic/*blood ; Adult