Autoantibodies against recombinant human steroidogenic enzymes 21-hydroxylase, side-chain cleavage and 17alpha-hydroxylase in Addison's disease and autoimmune polyendocrine syndrome type III.
OBJECTIVE
To evaluate the frequency of autoantibodies (Ab) against 21 hydroxylase (21OH), side-chain cleavage (SCC) and 17alpha-hydroxylase (17OH), in Addison's disease (AD) and autoimmune polyendocrine syndrome type III (APSIII).


METHODS
We used radiobinding assays and in vitro translated recombinant human (35)S-21OH, (35)S-SCC or (35)S-17OH and studied serum samples from 29 AD (18 idiopathic, 11 granulomatous) and 18 APSIII (autoimmune thyroid disease plus type 1 diabetes mellitus, without AD) patients. Results were compared with those of adrenocortical autoantibodies obtained with indirect immunofluorescence (ACA-IIF).


RESULTS
ACA-IIF were detected in 15/18 (83%) idiopathic and in 1/11 (9%) granulomatous AD subjects. 21OHAb were found in 14/18 (78%) idiopathic and in the same (9%) granulomatous AD subject. A significant positive correlation was shown between ACA-IIF and 21OHAb levels (r(2)=0.56, P<0.02). The concordance rate between the two assays was 83% (24/29) in AD patients. SCCAb were found in 5/18 (28%) idiopathic (4 of whom were also positive for 21OHAb) and in the same (9%) granulomatous AD subject. 17OHAb were found in only 2/18 (11%) idiopathic and none of the granulomatous AD patients. Two APSIII patients were positive for ACA-IIF, but only one was positive for 21OHAb and SCCAb. 17OHAb were found in another two APSIII patients.


CONCLUSIONS
Measurement of 21OHAb should be the first step in immune assessment of patients with AD and individuals at risk for adrenal autoimmunity, in addition to ACA-IIF. Due to their low prevalence in AD, measurement of SCCAb and 17OHAb should be indicated only for 21OHAb negative patients and/or for those with premature ovarian failure, regardless of ACA-IIF results.
de Carmo Silva
R
R
Division of Endocrinology, Department of Medicine, Universidade Federal de Sâo Paulo, Escola Paulista de Medicina, Sâo Paulo, SP, Brazil. rcarmo@mandic.com.br
Kater
C E
CE
Dib
S A
SA
Laureti
S
S
Forini
F
F
Cosentino
A
A
Falorni
A
A
D000224:Addison Disease / Q000276:immunology*; D000302:Adrenal Cortex / Q000276:immunology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis*; D001327:Autoimmune Diseases / Q000276:immunology*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000276:immunology*; D004700:Endocrine System Diseases / Q000276:immunology*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000276:immunology; D012016:Reference Values; D013254:Steroid 17-alpha-Hydroxylase / Q000276:immunology*; D013255:Steroid 21-Hydroxylase / Q000276:immunology*; D013577:Syndrome
D001323:Autoantibodies; D011994:Recombinant Proteins; D013255:Steroid 21-Hydroxylase; D013254:Steroid 17-alpha-Hydroxylase; D002786:Cholesterol Side-Chain Cleavage Enzyme