<p>Organ-specific autoimmunity constitutes a large health problem, where both the clinical management and our understanding of the pathogenetic mechanisms need to improve. Women with Addison's disease have abnormally low levels of dehydroepiandrosterone (DHEA), its sulphate ester (DHEA-S) and androgens relative to age, and many patients complain of physical and mental fatigue and low stress tolerance. To define a suitable dose, the effect of oral DHEA replacement was evaluated in women with Addison's disease. </p><p> DHEA was administered for three months to nine women with Addison's disease in either of two doses, 50 mg (n=5) or 200 mg (n=4). A dose of 50 mg restored the DHEA(S) and androgen levels to normal without altering the insulin sensitivity, body composition or serum lipid profile.</p><p> Autoimmune polyendocrine syndrome type I (APS I) is a rare but useful model disorder of autoimmunity, characterised by multiple organ-specific autoimmune manifestations and high-titre autoantibodies and with adrenocortical insufficiency, Addison's disease, as one of its cardinal manifestations. Approximately 10-20% of APS I patients suffer from autoimmune hepatitis, which carries a high mortality, if untreated. The presence of putative antigenic targets in the liver was investigated.</p><p> Cytochrome P4501A2 (CYP1A2) and aromatic L-amino acid decarboxylase (AADC) were identified as hepatic autoantigens with the use of APS I sera for immunofluorescent staining of normal human liver, Western blot of microsomal and cytosol fractions of human liver homogenate, and immunoprecipitation of <i>in vitro</i> transcribed and translated radioactively labelled proteins. The presence of CYP1A2- and AADC-antibodies was significantly correlated to AIH, and CYP1A2 antibodies inhibited enzyme activity <i>in vitro</i>.</p><p><i> In conclusion</i>, a daily replacement dose of 50 mg of DHEA sufficiently restores levels of DHEA, DHEA(S) and androgens in women with Addison's disease, without severe side-effects. We have further identified CYP1A2 and AADC as hepatic autoantigens associated with autoimmune hepatitis in APS I.</p>

Organ-specific autoimmunity constitutes a large health problem, where both the clinical management and our understanding of the pathogenetic mechanisms need to improve. Women with Addison's disease have abnormally low levels of dehydroepiandrosterone (DHEA), its sulphate ester (DHEA-S) and androgens relative to age, and many patients complain of physical and mental fatigue and low stress tolerance. To define a suitable dose, the effect of oral DHEA replacement was evaluated in women with Addison's disease. DHEA was administered for three months to nine women with Addison's disease in either of two doses, 50 mg (n=5) or 200 mg (n=4). A dose of 50 mg restored the DHEA(S) and androgen levels to normal without altering the insulin sensitivity, body composition or serum lipid profile. Autoimmune polyendocrine syndrome type I (APS I) is a rare but useful model disorder of autoimmunity, characterised by multiple organ-specific autoimmune manifestations and high-titre autoantibodies and with adrenocortical insufficiency, Addison's disease, as one of its cardinal manifestations. Approximately 10-20% of APS I patients suffer from autoimmune hepatitis, which carries a high mortality, if untreated. The presence of putative antigenic targets in the liver was investigated. Cytochrome P4501A2 (CYP1A2) and aromatic L-amino acid decarboxylase (AADC) were identified as hepatic autoantigens with the use of APS I sera for immunofluorescent staining of normal human liver, Western blot of microsomal and cytosol fractions of human liver homogenate, and immunoprecipitation of in vitro transcribed and translated radioactively labelled proteins. The presence of CYP1A2- and AADC-antibodies was significantly correlated to AIH, and CYP1A2 antibodies inhibited enzyme activity in vitro. In conclusion, a daily replacement dose of 50 mg of DHEA sufficiently restores levels of DHEA, DHEA(S) and androgens in women with Addison's disease, without severe side-effects. We have further identified CYP1A2 and AADC as hepatic autoantigens associated with autoimmune hepatitis in APS I.

Thyronamine (TAM) sind eine neue Molekülklasse, die endokrinologische und metabolische Prozesse miteinander vereinen. Der biologisch aktive Metabolit 3-Iod-L-Thyronamin (3-T1AM) wird durch eine kombinierte Deiodierung und Decarboxylierung von Schilddrüsenhormonen (TH) gebildet. Existierende Methoden zum Nachweis und zur Quantifizierung von 3-T1AM im menschlichen Serum sind immer noch umstritten. Auch die an der Biosynthese vermutlich beteiligte TH-Decarboxylase konnte noch nicht identifiziert werden. Für die Identifizierung und Quantifizierung von TH und TAM Profilen wurde die Flüssigchromatographie-Tandem-Massenspektrometrie (LC-MS/MS) verwendet. In der bisherigen präanalytischen Aufarbeitung liefern weder Flüssig-Flüssig- noch Festphasenextraktionen reproduzierbare Ergebnisse des 3-T1AM-Gehalts im Serum. Mit der Entwicklung eines spezifischen Extraktionsverfahrens und nachfolgender Detektion mittels LC-MS/MS gelang der gleichzeitige Nachweis der häufigsten TH im humanen Serum. Parallel dazu wurden monoklonale Antikörper gegen 3-T1AM entwickelt, auf deren Basis ein quantitativer 3-T1AM Chemilumineszenz-Immunoassay entstand. Ergebnisse aus klinischen Kollektiven zeigen, dass 3-T1AM im Serum im nM Konzentrationsbereich vorkommt und dass 3-T1AM bei Patienten außerhalb der Schilddrüse produziert wird. Viele Forscher gehen davon aus, dass die aromatische L-Aminosäure Decarboxylase (AADC) die Synthese von TAM über Decarboxylierung von TH katalysiert. Diese Hypothese wurde durch Inkubation von rekombinanter humaner AADC mit TH getestet. In keinem der Experimente konnte AADC die Decarboxylierung von TH katalysieren. Zusammenfassend ist die Bestimmung von 3-T1AM im Serum mittels LC-MS/MS aufgrund der nicht reproduzierbaren präanalytischen Probenaufbereitung problematisch. In dieser Arbeit wird der erste MAb-basierte 3-T1AM assay vorgestellt, der 3-T1AM zuverlässig in humanem Serum quantifiziert. Die AADC ist wahrscheinlich nicht an der Biosynthese von TAM beteiligt. / Thyronamines (TAM) are a new class of molecules linking endocrinology and metabolism. Combined deiodination and decarboxylation of thyroid hormones (TH) generates a biologically active ‘cooling’ metabolite, 3-iodo-L-thyronamine (3-T1AM).. It remains controversial, which methods are able or not to reliably detect 3-T1AM in human serum, and the presumed TH decarboxylase is still elusive. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the simultane-ous identification and quantification of TH and TAM profiles in biological samples. Several preanalytical methods were tested for complete extraction of 3-T1AM in human serum. Thus far, neither liquid-liquid nor solid-phase extraction methods allowed reproducible extraction of 3-T1AM from human serum samples in the preanalytical sample workup. Nevertheless, a rapid and sensitive extraction procedure was developed for detection of the major TH by LC-MS/MS in a single human serum sample. In parallel, monoclonal antibodies (MAb) targeting 3-T1AM were developed and characterized, and a highly specific quantitative 3-T1AM MAb-based chemiluminescence immunoassay was developed. Studies in clinical cohorts provide evidence that 3-T1AM is present in human serum in the nM concentration range and that 3-T1AM is produced extrathyroidally. Many researchers have reasoned that the aromatic L-amino acid decarboxylase (AADC) mediates TAM synthesis via decarboxylation of TH. This hypothesis was tested by incubating recombinant human AADC with several TH. In all tested conditions, AADC failed to catalyze the decarboxylation of TH. These in vitro observations are supported by the finding that 3-T1AM is also present in plasma samples of patients with AADC deficiency. In summary, 3-T1AM detection in serum using LC-MS/MS encounters preanalytical problems. The first MAb-based 3-T1AM CLIA is presented, which reliably quantifies 3-T1AM in human serum. AADC is likely not involved in TAM biosynthesis.