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Autoantibodies against Cytochrome P450 Side-Chain Cleavage Enzyme in Dogs (Canis lupus familiaris) Affected with Hypoadrenocorticism (Addison's Disease).

Boag AM, Christie MR, McLaughlin KA, Syme HM, Graham P, Catchpole B - PLoS ONE (2015)

Bottom Line: In humans with autoimmune Addison's disease (AAD) or autoimmune polyendocrine syndrome (APS), circulating autoantibodies have been demonstrated against enzymes associated with adrenal steroid synthesis.Sex was significantly associated with the presence of P450scc autoantibodies in the case population, with 30% of females testing positive compared with 17% of males (p = 0.037).Significant associations with breed (p = 0.015) and DLA-type (DQA1*006:01 allele; p = 0.017) were also found.

View Article: PubMed Central - PubMed

Affiliation: The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom.

ABSTRACT
Canine hypoadrenocorticism likely arises from immune-mediated destruction of adrenocortical tissue, leading to glucocorticoid and mineralocorticoid deficiency. In humans with autoimmune Addison's disease (AAD) or autoimmune polyendocrine syndrome (APS), circulating autoantibodies have been demonstrated against enzymes associated with adrenal steroid synthesis. The current study investigates autoantibodies against steroid synthesis enzymes in dogs with spontaneous hypoadrenocorticism. Coding regions of canine CYP21A2 (21-hydroxylase; 21-OH), CYP17A1 (17-hydroxylase; 17-OH), CYP11A1 (P450 side-chain cleavage enzyme; P450scc) and HSD3B2 (3β hydroxysteroid dehydrogenase; 3βHSD) were amplified, cloned and expressed as 35S-methionine radiolabelled recombinant protein. In a pilot study, serum samples from 20 dogs with hypoadrenocorticism and four unaffected control dogs were screened by radio-immunoprecipitation assay. There was no evidence of reactivity against 21-OH, 17-OH or 3βHSD, but five dogs with hypoadrenocorticism showed immunoreactivity to P450scc compared with controls. Serum samples were subsequently obtained from 213 dogs diagnosed with hypoadrenocorticism and 110 dogs from a hospital control population. Thirty control dogs were randomly selected to establish a threshold for antibody positivity (mean + 3 × standard deviation). Dogs with hypoadrenocorticism were more likely to be P450scc autoantibody positive than hospital controls (24% vs. 1.2%, respectively; p = 0.0016). Sex was significantly associated with the presence of P450scc autoantibodies in the case population, with 30% of females testing positive compared with 17% of males (p = 0.037). Significant associations with breed (p = 0.015) and DLA-type (DQA1*006:01 allele; p = 0.017) were also found. This cross-sectional study indicates that P450scc autoantibodies are present in a proportion of dogs affected with hypoadrenocorticism.

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Radioimmunoprecipitation assays with canine sera against recombinant radiolabelled adrenal antigens.Radioactivity (counts per minute; CPM) for hypoadrenocorticism cases (n = 20; filled boxes) and control (n = 4; open boxes) serum samples after immunoprecipitation with recombinant canine (A) 21-OH; (B) 17-OH; (C) 3βHSD and (D) P450scc. Data are shown as mean + SEM. Hatched line represents positive threshold (mean + 3SD of control samples), with values above this indicated (*).
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pone.0143458.g002: Radioimmunoprecipitation assays with canine sera against recombinant radiolabelled adrenal antigens.Radioactivity (counts per minute; CPM) for hypoadrenocorticism cases (n = 20; filled boxes) and control (n = 4; open boxes) serum samples after immunoprecipitation with recombinant canine (A) 21-OH; (B) 17-OH; (C) 3βHSD and (D) P450scc. Data are shown as mean + SEM. Hatched line represents positive threshold (mean + 3SD of control samples), with values above this indicated (*).

Mentions: An experiment was performed to investigate autoantibody reactivity to the recombinant canine adrenal antigens with sera from dogs affected with hypoadrenocorticism (n = 20). These dogs were selected from all the samples collected based on blood sampling within three months of diagnosis, and covered a range of breeds, ages and sex. Control dogs (n = 4) had no known history of endocrinopathy, autoimmune disease or neoplasia. No difference in immunoreactivity was seen, comparing cases and controls for 21-OH, 17-OH and 3βHSD (Fig 2A–2C). In contrast, reactivity to P450scc was seen in a proportion of cases (Fig 2D), using the mean + 3SD CPM of the control values as the threshold for positivity. Five cases of hypoadrenocorticism were considered to be P450scc autoantibody positive, consisting of a German shepherd dog, beagle, lurcher, Great Dane and Polish lowland sheepdog, with an age of onset between 1 year and 4 years 7 months and comprising three females and two males.


Autoantibodies against Cytochrome P450 Side-Chain Cleavage Enzyme in Dogs (Canis lupus familiaris) Affected with Hypoadrenocorticism (Addison's Disease).

Boag AM, Christie MR, McLaughlin KA, Syme HM, Graham P, Catchpole B - PLoS ONE (2015)

Radioimmunoprecipitation assays with canine sera against recombinant radiolabelled adrenal antigens.Radioactivity (counts per minute; CPM) for hypoadrenocorticism cases (n = 20; filled boxes) and control (n = 4; open boxes) serum samples after immunoprecipitation with recombinant canine (A) 21-OH; (B) 17-OH; (C) 3βHSD and (D) P450scc. Data are shown as mean + SEM. Hatched line represents positive threshold (mean + 3SD of control samples), with values above this indicated (*).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664467&req=5

pone.0143458.g002: Radioimmunoprecipitation assays with canine sera against recombinant radiolabelled adrenal antigens.Radioactivity (counts per minute; CPM) for hypoadrenocorticism cases (n = 20; filled boxes) and control (n = 4; open boxes) serum samples after immunoprecipitation with recombinant canine (A) 21-OH; (B) 17-OH; (C) 3βHSD and (D) P450scc. Data are shown as mean + SEM. Hatched line represents positive threshold (mean + 3SD of control samples), with values above this indicated (*).
Mentions: An experiment was performed to investigate autoantibody reactivity to the recombinant canine adrenal antigens with sera from dogs affected with hypoadrenocorticism (n = 20). These dogs were selected from all the samples collected based on blood sampling within three months of diagnosis, and covered a range of breeds, ages and sex. Control dogs (n = 4) had no known history of endocrinopathy, autoimmune disease or neoplasia. No difference in immunoreactivity was seen, comparing cases and controls for 21-OH, 17-OH and 3βHSD (Fig 2A–2C). In contrast, reactivity to P450scc was seen in a proportion of cases (Fig 2D), using the mean + 3SD CPM of the control values as the threshold for positivity. Five cases of hypoadrenocorticism were considered to be P450scc autoantibody positive, consisting of a German shepherd dog, beagle, lurcher, Great Dane and Polish lowland sheepdog, with an age of onset between 1 year and 4 years 7 months and comprising three females and two males.

Bottom Line: In humans with autoimmune Addison's disease (AAD) or autoimmune polyendocrine syndrome (APS), circulating autoantibodies have been demonstrated against enzymes associated with adrenal steroid synthesis.Sex was significantly associated with the presence of P450scc autoantibodies in the case population, with 30% of females testing positive compared with 17% of males (p = 0.037).Significant associations with breed (p = 0.015) and DLA-type (DQA1*006:01 allele; p = 0.017) were also found.

View Article: PubMed Central - PubMed

Affiliation: The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom.

ABSTRACT
Canine hypoadrenocorticism likely arises from immune-mediated destruction of adrenocortical tissue, leading to glucocorticoid and mineralocorticoid deficiency. In humans with autoimmune Addison's disease (AAD) or autoimmune polyendocrine syndrome (APS), circulating autoantibodies have been demonstrated against enzymes associated with adrenal steroid synthesis. The current study investigates autoantibodies against steroid synthesis enzymes in dogs with spontaneous hypoadrenocorticism. Coding regions of canine CYP21A2 (21-hydroxylase; 21-OH), CYP17A1 (17-hydroxylase; 17-OH), CYP11A1 (P450 side-chain cleavage enzyme; P450scc) and HSD3B2 (3β hydroxysteroid dehydrogenase; 3βHSD) were amplified, cloned and expressed as 35S-methionine radiolabelled recombinant protein. In a pilot study, serum samples from 20 dogs with hypoadrenocorticism and four unaffected control dogs were screened by radio-immunoprecipitation assay. There was no evidence of reactivity against 21-OH, 17-OH or 3βHSD, but five dogs with hypoadrenocorticism showed immunoreactivity to P450scc compared with controls. Serum samples were subsequently obtained from 213 dogs diagnosed with hypoadrenocorticism and 110 dogs from a hospital control population. Thirty control dogs were randomly selected to establish a threshold for antibody positivity (mean + 3 × standard deviation). Dogs with hypoadrenocorticism were more likely to be P450scc autoantibody positive than hospital controls (24% vs. 1.2%, respectively; p = 0.0016). Sex was significantly associated with the presence of P450scc autoantibodies in the case population, with 30% of females testing positive compared with 17% of males (p = 0.037). Significant associations with breed (p = 0.015) and DLA-type (DQA1*006:01 allele; p = 0.017) were also found. This cross-sectional study indicates that P450scc autoantibodies are present in a proportion of dogs affected with hypoadrenocorticism.

Show MeSH
Related in: MedlinePlus