A robust immunoassay for anti-interferon autoantibodies that is highly specific for patients with autoimmune polyglandular syndrome type 1

Abstract

For normal controls (n=100) CPS without competition were 31,237+/-17,328 CPS while after subtracting the competition value, the results were -6563+/-10,303 CPS. The initial APS1 patient (used to create the index as 1.0) gave 394,063 CPS without competition and a delta of 363,662+/-31,587 CPS with competition. Scatchard plot analysis of this patient sample revealed a high avidity for IFN-alpha (K(d) of 0.5 nM). The CPS, delta, and index for 6/7 APS1 patients were strongly positive and 3 standard deviations or more above that of the normal controls. Using a cut-off of 2 standard deviations above normal controls, relatives of APS1 patients were negative for type I interferon autoantibodies as were 71 patients with Addison's disease (non-APS1) and 141 Type 1 diabetes patients. This simple high throughput competitive europium time resolved fluorescence assay had a sensitivity of > or =86% or greater and a specificity of >99.5%.

Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy

“…Mutation analysis of the AIRE gene is the most direct way to confirm the diagnosis; however, the process can be time-consuming and expensive if the associated mutations are not common. Instead, autoantibodies directed against type I interferons (especially IFN-ω and IFN-α) can be used for APECED diagnosis [16][17][18][19][20][21]. High-titer neutralizing autoantibodies against type I IFNs are detectable in AIRE-deficient children as early as a few months of age, before the appearance of clinical symptoms or organ-specific autoantibodies [18,22,23].…”

“…The anti-cytokine autoantibodies stand out due to their high prevalence and early emergence [18,22,70]. Neutralizing autoantibodies specific for type I IFNs in APECED were discovered in 2006 by Meager and coworkers [16], and their diagnostic value was appreciated soon [17,19,20,28]. Although these autoantibodies influence interferon-stimulated gene expression in vivo and in vitro [32], AD Addison's disease, AIH autoimmune hepatitis, AL alopecia, CMC chronic mucocutaneous candidiasis, ED enamel dysplasia, GID gastro-intestinal dysfunction, HP hypopathyroidism, HT hypothyroidism, IFN interferon, IL interleukin, ILD interstitial lung disease, OF ovarian failure, PA pernicious anemia, T1D type 1 diabetes, TIN tubulo-interstitial nephritis, VIT vitiligo a Autoantibodies diagnostic for APECED (AIRE-deficiency) or with good positive predictive value for specific manifestations of the syndrome are indicated in bold there is no solid evidence to indicate that APECED patients have an increased susceptibility to viral diseases, such as has been described in patients with inborn errors impairing type I and III IFN function [32,130].…”

“…Low-titer autoantibodies to type I IFNs can also be found in diseases that are accompanied by increased IFN production (i.e., systemic lupus erythematosus, genetic interferonopathies, and during HIV or HCV infection); however, autoantibody production never reaches the levels observed in APECED patients and the antibodies are rarely neutralizing [25,26]. IFN-binding autoantibodies have been analyzed using an enzyme-linked immunosorbent assay (ELISA) [16,27], europium-based immunoassay [20], radioligand binding assay (RLBA) [28], Luminex [29] and luciferasebased immunoprecipitation system (LIPS) [30,31]. Additionally, bioassays such as the antiviral neutralizing assay (AVINA) [16,17,32] and reporter-based cell assays [33] that enable the determination of the neutralizing capacity of the autoantibodies have been reported.…”

Murine High Specificity/Sensitivity Competitive Europium Insulin Autoantibody Assay

“…We have recently described a europium competitive assay for autoantibodies reacting with interferon-a that specifically detects autoantibodies present in patients with the autoimmune polyendocrine syndrome type I. 19 With the competitive fluid-phase step this assay is extremely specific, and patients with related autoimmune disorders (e.g., isolated Addison's disease) are negative. Thus we believe this format of europium detection combined with ELISA format and fluid-phase competition is generalizable, including detection of human autoantibodies.…”

The Next Big Idea

“…48 George's laboratory, in collaboration with DAISY has participated in development and validation of multiple serologic assays for detection of islet autoimmunity, [49][50][51][52][53][54][55][56][57][58][59] celiac disease, [60][61][62][63][64][65] and other autoimmune disorders. 54,[66][67][68][69][70][71][72] DAISY has contributed significantly to the ''discovery'' of celiac disease as a common disease in the U.S. general population 65,[73][74][75][76] and special groups. [77][78][79] We have extensively studied the relationship between islet autoimmunity and celiac autoimmunity [77][78][79][80][81] and begun to disentangle the common mechanisms of islet autoimmunity and celiac, thyroid, adrenal, parietal cell, and rheumatoid autoimmunities.…”