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Interferon autoantibodies associated with AIRE deficiency decrease the expression of IFN-stimulated genes.

Kisand K, Link M, Wolff AS, Meager A, Tserel L, Org T, Murumägi A, Uibo R, Willcox N, Trebusak Podkrajsek K, Battelino T, Lobell A, Kämpe O, Lima K, Meloni A, Ergun-Longmire B, Maclaren NK, Perheentupa J, Krohn KJ, Scott HS, Husebye ES, Peterson P - Blood (2008)

Bottom Line: Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection.We also report unexpected increases in serum CXCL10 levels in APECED.Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of General and Molecular Pathology, University of Tartu, Tartu, Estonia.

ABSTRACT
Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection. Combining genome-wide expression array with real time RT-PCR assays, we here demonstrate that antibodies against IFN-alpha cause highly significant down-regulation of interferon-stimulated gene expression in cells from APECED patients' blood by blocking their highly dilute endogenous IFNs. This down-regulation was lost progressively as these APECED cells matured in cultures without neutralizing autoantibodies. Most interestingly, a rare APECED patient with autoantibodies to IFN-omega but not IFN-alpha showed a marked increase in expression of the same interferon-stimulated genes. We also report unexpected increases in serum CXCL10 levels in APECED. Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

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Effect of APECED sera on ISG expression and STAT1 phosphorylation. (A) Expression of ISGs in control monocytes incubated in 20% autologous sera with the addition of 2% APECED sera-positive (Ab+) or -negative (Ab−) for IFN-α antibodies, or with control serum (Ctrl) for 18 hours. *P < .05 between IFN-α antibody–positive APECED patients and healthy controls. (B) U937 cells were treated with 1000 U/mL IFN-α for 15 minutes or with the same concentration of IFN-α preincubated with 2%, 5%, or 10% of APECED (A1-A5) or 10% of control (C1-C3) sera, stained for intacellular pSTAT1 and measured by flow cytometry. (C) Control PBMCs were incubated with 50% of serum samples from APECED patients positive (Ab+) or negative (Ab−) for IFN-α antibodies, healthy controls (Ctrl), or SLE patients for 15 minutes and stained for intracellular pSTAT1 to test for IFN activity in the sera (left panel). Control PBMCs were incubated with 50% of serum samples from an APECED patient negative for IFN-α autoantibodies (A3), an SLE patient with IFN activity, or two healthy controls for 15 minutes with or without the addition of neutralizing anti–IFN-α antibody or isotype control antibody as indicated, and stained for intracellular pSTAT1 (right panel).
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Figure 3: Effect of APECED sera on ISG expression and STAT1 phosphorylation. (A) Expression of ISGs in control monocytes incubated in 20% autologous sera with the addition of 2% APECED sera-positive (Ab+) or -negative (Ab−) for IFN-α antibodies, or with control serum (Ctrl) for 18 hours. *P < .05 between IFN-α antibody–positive APECED patients and healthy controls. (B) U937 cells were treated with 1000 U/mL IFN-α for 15 minutes or with the same concentration of IFN-α preincubated with 2%, 5%, or 10% of APECED (A1-A5) or 10% of control (C1-C3) sera, stained for intacellular pSTAT1 and measured by flow cytometry. (C) Control PBMCs were incubated with 50% of serum samples from APECED patients positive (Ab+) or negative (Ab−) for IFN-α antibodies, healthy controls (Ctrl), or SLE patients for 15 minutes and stained for intracellular pSTAT1 to test for IFN activity in the sera (left panel). Control PBMCs were incubated with 50% of serum samples from an APECED patient negative for IFN-α autoantibodies (A3), an SLE patient with IFN activity, or two healthy controls for 15 minutes with or without the addition of neutralizing anti–IFN-α antibody or isotype control antibody as indicated, and stained for intracellular pSTAT1 (right panel).

Mentions: We next tested for acute effects of the neutralizing autoantibodies after incubating monocytes from healthy donors in medium containing 20% autologous plasma and 2% APECED or control sera for 18 hours. Expression of all the ISGs tested was significantly down-regulated by all the APECED sera that contained anti–IFN-α neutralizing autoantibodies, but not by the one specific for IFN-ω (Figure 3A). If fetal calf serum was used instead of autologous serum, no differences in ISG expression were seen in monocytes cultured in the presence of APECED or control sera (data not shown). Evidently, human plasma contains low levels of type I IFNs that can be blocked by the patients' neutralizing autoantibodies.


Interferon autoantibodies associated with AIRE deficiency decrease the expression of IFN-stimulated genes.

Kisand K, Link M, Wolff AS, Meager A, Tserel L, Org T, Murumägi A, Uibo R, Willcox N, Trebusak Podkrajsek K, Battelino T, Lobell A, Kämpe O, Lima K, Meloni A, Ergun-Longmire B, Maclaren NK, Perheentupa J, Krohn KJ, Scott HS, Husebye ES, Peterson P - Blood (2008)

Effect of APECED sera on ISG expression and STAT1 phosphorylation. (A) Expression of ISGs in control monocytes incubated in 20% autologous sera with the addition of 2% APECED sera-positive (Ab+) or -negative (Ab−) for IFN-α antibodies, or with control serum (Ctrl) for 18 hours. *P < .05 between IFN-α antibody–positive APECED patients and healthy controls. (B) U937 cells were treated with 1000 U/mL IFN-α for 15 minutes or with the same concentration of IFN-α preincubated with 2%, 5%, or 10% of APECED (A1-A5) or 10% of control (C1-C3) sera, stained for intacellular pSTAT1 and measured by flow cytometry. (C) Control PBMCs were incubated with 50% of serum samples from APECED patients positive (Ab+) or negative (Ab−) for IFN-α antibodies, healthy controls (Ctrl), or SLE patients for 15 minutes and stained for intracellular pSTAT1 to test for IFN activity in the sera (left panel). Control PBMCs were incubated with 50% of serum samples from an APECED patient negative for IFN-α autoantibodies (A3), an SLE patient with IFN activity, or two healthy controls for 15 minutes with or without the addition of neutralizing anti–IFN-α antibody or isotype control antibody as indicated, and stained for intracellular pSTAT1 (right panel).
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Related In: Results  -  Collection

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Figure 3: Effect of APECED sera on ISG expression and STAT1 phosphorylation. (A) Expression of ISGs in control monocytes incubated in 20% autologous sera with the addition of 2% APECED sera-positive (Ab+) or -negative (Ab−) for IFN-α antibodies, or with control serum (Ctrl) for 18 hours. *P < .05 between IFN-α antibody–positive APECED patients and healthy controls. (B) U937 cells were treated with 1000 U/mL IFN-α for 15 minutes or with the same concentration of IFN-α preincubated with 2%, 5%, or 10% of APECED (A1-A5) or 10% of control (C1-C3) sera, stained for intacellular pSTAT1 and measured by flow cytometry. (C) Control PBMCs were incubated with 50% of serum samples from APECED patients positive (Ab+) or negative (Ab−) for IFN-α antibodies, healthy controls (Ctrl), or SLE patients for 15 minutes and stained for intracellular pSTAT1 to test for IFN activity in the sera (left panel). Control PBMCs were incubated with 50% of serum samples from an APECED patient negative for IFN-α autoantibodies (A3), an SLE patient with IFN activity, or two healthy controls for 15 minutes with or without the addition of neutralizing anti–IFN-α antibody or isotype control antibody as indicated, and stained for intracellular pSTAT1 (right panel).
Mentions: We next tested for acute effects of the neutralizing autoantibodies after incubating monocytes from healthy donors in medium containing 20% autologous plasma and 2% APECED or control sera for 18 hours. Expression of all the ISGs tested was significantly down-regulated by all the APECED sera that contained anti–IFN-α neutralizing autoantibodies, but not by the one specific for IFN-ω (Figure 3A). If fetal calf serum was used instead of autologous serum, no differences in ISG expression were seen in monocytes cultured in the presence of APECED or control sera (data not shown). Evidently, human plasma contains low levels of type I IFNs that can be blocked by the patients' neutralizing autoantibodies.

Bottom Line: Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection.We also report unexpected increases in serum CXCL10 levels in APECED.Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

View Article: PubMed Central - PubMed

Affiliation: Institute of General and Molecular Pathology, University of Tartu, Tartu, Estonia.

ABSTRACT
Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection. Combining genome-wide expression array with real time RT-PCR assays, we here demonstrate that antibodies against IFN-alpha cause highly significant down-regulation of interferon-stimulated gene expression in cells from APECED patients' blood by blocking their highly dilute endogenous IFNs. This down-regulation was lost progressively as these APECED cells matured in cultures without neutralizing autoantibodies. Most interestingly, a rare APECED patient with autoantibodies to IFN-omega but not IFN-alpha showed a marked increase in expression of the same interferon-stimulated genes. We also report unexpected increases in serum CXCL10 levels in APECED. Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

Show MeSH
Related in: MedlinePlus