A longitudinal study of autoantibodies against cytochrome P450 side-chain cleavage enzyme in dogs ( Canis lupus familiaris ) affected with hypoadrenocorticism (Addison’s disease)

OBJECTIVE: Immunoglobulin G (IgG) antibodies to the steroidogenic enzymes 21-hydroxylase (21OH) and side-chain cleavage enzyme (SCC) are important diagnostic markers for autoimmune Addison's disease and autoimmune polyendocrine syndromes (APS) types I and II. The characterization of autoantibody (IgG) subclasses may reveal information on how tIssue destruction takes place; therefore, IgG subtypes of anti-21OH and anti-SCC antibodies from sera of patients with Addison's disease, APS I and APS II were determined using recombinant 21OH and SCC. METHODS: SCC(51-521) and his-SCC(51-521) were expressed by pET-scc in the Escherichia coli strain BL21 Star (DE3) and inclusion bodies were purified. Full-length, human 21OH fused to an N-terminal 6x histidine affinity tag was expressed in insect cells by using the baculovirus expression system bac-to-bac. Western blots were used to investigate the IgG subtype(s) of the autoantibodies against 21OH and SCC in patients and healthy blood donors. RESULTS: All anti-SCC positive sera (n=10) contained autoantibodies of the IgG1 subclass, while four out of ten also contained IgG3. All anti-21OH positive sera (n=16) had autoantibodies exclusively against IgG1. Sera from 20 healthy subjects did not show any reactivity against 21OH or SCC. CONCLUSIONS: The finding of a predominating IgG1 response against 21OH and SCC may suggest that T helper (Th) cells of the Th1 subclass are involved in destruction of the adrenal cortex in patients with autoimmune Addison's disease.

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II. Adrenal Cortex and Steroid 21-Hydroxylase Autoantibodies in Children with Organ-Specific Autoimmune Diseases: Markers of High Progression to Clinical Addison’s Disease

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.82.3.3849 ◽

1997 ◽

Vol 82 (3) ◽

pp. 939-942

Author(s):

Corrado Betterle ◽

Marina Volpato ◽

Bernard Rees Smith ◽

Jadwiga Furmaniak ◽

Shu Chen ◽

...

Keyword(s):

Autoimmune Diseases ◽

Adrenal Cortex ◽

Addison’S Disease ◽

Adrenal Function ◽

Side Chain ◽

Addison's Disease ◽

Side Chain Cleavage ◽

Chain Cleavage ◽

Organ Specific ◽

Cleavage Enzyme

Abstract Adrenal cortex autoantibodies (ACA) were measured by immunofluorescence in 808 children with organ-specific autoimmune diseases without adrenal insufficiency. ACA were found in 14 children (1.7%), mostly in hypoparathyroidism (48%). Ten ACA-positive and 12 ACA-negative children were followed up for a maximum of 10 yr by evaluation of adrenocortical function (ACTH test) and autoantibody status. In all patients steroid-producing cell autoantibodies were assessed by immunofluorescence and autoantibodies to steroid 21-hydroxylase, 17α-hydroxylase, and cytochrome P450 side-chain cleavage enzyme by immunoprecipitation assay. All 10 ACA-positive patients were positive for 21-hydroxylase autoantibodies. Six were positive for steroid-producing cell autoantibodies and 5 also for autoantibodies to 17α-hydroxylase and/or P450 side-chain cleavage enzyme. Overt Addison’s disease developed in 9 (90%) ACA/21-OH-antibody-positive children after 3–121 months, and 1 remaining child had subclinical hypoadrenalism. By contrast, all ACA/21-OH antibody-negative children maintained normal adrenal function. Adrenal failure was not related to ACA titres, sex, adrenal function, type of preexisting autoimmune disorder, or human leucocyte antigens D-related status. In conclusion, in children with autoimmune endocrine diseases, ACA/21-hydroxylase autoantibodies are important predictive markers for the development of Addison’s disease.

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