Monica V. Talor

Interleukin-17A Is Dispensable for Myocarditis but Essential for the Progression to Dilated Cardiomyopathy

Rationale: One-third of myocarditis cases progresses to dilated cardiomyopathy (DCM), but the mechanisms controlling this process are largely unknown. CD4+ T helper (Th)17 cells have been implicated in the pathogenesis of autoimmune diseases, but the role of Th17-produced cytokines during inflammation-induced cardiac remodeling has not been previously studied. Objective: We examined the importance of interleukin (IL)-17A in the progression of myocarditis to DCM using a mouse model. Methods and Results: Immunization of mice with myocarditogenic peptide in complete Freunds adjuvant induced the infiltration of IL-17A–producing Th17 cells into the inflamed heart. Unexpectedly, IL-17A–deficient mice developed myocarditis with similar incidence and severity compared to wild-type mice. Additionally, IL-17A deficiency did not ameliorate the severe myocarditis of interferon (IFN)&ggr;-deficient mice, suggesting that IL-17A plays a minimal role during acute myocarditis. In contrast, IL-17A–deficient mice were protected from postmyocarditis remodeling and did not develop DCM. Flow cytometric and cytokine analysis revealed an important role for IL-17A in heart-specific upregulation of IL-6, TNF&agr;, and IL-1&bgr; and the recruitment of CD11b+ monocyte and Gr1+ granulocyte populations into the heart. Furthermore, IL-17A–deficient mice had reduced interstitial myocardial fibrosis, downregulated expression of matrix metalloproteinase-2 and -9 and decreased gelatinase activity. Treatment of BALB/c mice with anti–IL-17A monoclonal antibody administered after the onset of myocarditis abrogated myocarditis-induced cardiac fibrosis and preserved ventricular function. Conclusions: Our findings reveal a critical role for IL-17A in postmyocarditis cardiac remodeling and the progression to DCM. Targeting IL-17A may be an attractive therapy for patients with inflammatory dilated cardiomyopathy.

Interleukin-13 Protects Against Experimental Autoimmune Myocarditis by Regulating Macrophage Differentiation

We report here that interleukin (IL)-13 protects BALB/c mice from myocarditis, whether induced by peptide immunization or by viral infection. In contrast to mild disease in IL-4 knockout (KO) BALB/c mice, IL-13 KO BALB/c mice developed severe coxsackievirus B3 (CVB3)-induced autoimmune myocarditis and myocarditogenic peptide-induced experimental autoimmune myocarditis. Such severe disease was characterized by increased cardiac inflammation, increased total intracardiac CD45(+) leukocytes, elevated anti-cardiac myosin autoantibodies, and increased cardiac fibrosis. Echocardiography revealed that IL-13 KO mice developed severe dilated cardiomyopathy with impaired cardiac function and heart failure. Hearts of IL-13 KO mice had increased levels of the proinflammatory and profibrotic cytokines IL-1beta, IL-18, interferon-gamma, transforming growth factor-beta1, and IL-4 as well as histamine. The hallmark of the disease in IL-13 KO mice was the up-regulation of T-cell responses. CD4(+) T cells were increased in IL-13 KO hearts both proportionally and in absolute number. Splenic T cells from IL-13 KO mice were highly activated, and myosin stimulation additionally increased T-cell proliferation. CD4(+)CD25(+)Foxp3(+) regulatory T-cell numbers were decreased in the spleens of IL-13 KO mice. IL-13 deficiency led to decreased levels of alternatively activated CD206(+) and CD204(+) macrophages and increased levels of classically activated macrophages. IL-13 KO mice had increased caspase-1 activation, leading to increased production of both IL-1beta and IL-18. Therefore, IL-13 protects against myocarditis by modulating monocyte/macrophage populations and by regulating their function.

Environmental triggers of autoimmune thyroiditis

Autoimmune thyroiditis is among the most prevalent of all the autoimmunities. Autoimmune thyroiditis is multifactorial with contributions from genetic and environmental factors. Much information has been published about the genetic predisposition to autoimmune thyroiditis both in experimental animals and humans. There is, in contrast, very little data on environmental agents that can serve as the trigger for autoimmunity in a genetically predisposed host. The best-established environmental factor is excess dietary iodine. Increased iodine consumption is strongly implicated as a trigger for thyroiditis, but only in genetically susceptible individuals. However, excess iodine is not the only environmental agent implicated as a trigger leading to autoimmune thyroiditis. There are a wide variety of other synthetic chemicals that affect the thyroid gland or have the ability to promote immune dysfunction in the host. These chemicals are released into the environment by design, such as in pesticides, or as a by-product of industry. Candidate pollutants include polyaromatic hydrocarbons, polybrominated biphenols, and polychlorinated biphenols, among others. Infections are also reputed to trigger autoimmunity and may act alone or in concert with environmental chemicals. We have utilized a unique animal model, the NOD.H2(h4) mouse to explore the influence of iodine and other environmental factors on autoimmune thyroiditis.

Identification of Novel Serological Biomarkers for Inflammatory Bowel Disease Using Escherichia coli Proteome Chip

Specific antimicrobial antibodies present in the sera of patients with inflammatory bowel disease (IBD) have been proven to be valuable serological biomarkers for diagnosis/prognosis of the disease. Herein we describe the use of a whole Escherichia coli proteome microarray as a novel high throughput proteomics approach to screen and identify new serological biomarkers for IBD. Each protein array, which contains 4,256 E. coli K12 proteins, was screened using individual serum from healthy controls (n = 39) and clinically well characterized patients with IBD (66 Crohn disease (CD) and 29 ulcerative colitis (UC)). Proteins that could be recognized by serum antibodies were visualized and quantified using Cy3-labeled goat anti-human antibodies. Surprisingly significance analysis of microarrays identified a total of 417 E. coli proteins that were differentially recognized by serum antibodies between healthy controls and CD or UC. Among those, 169 proteins were identified as highly immunogenic in healthy controls, 186 proteins were identified as highly immunogenic in CD, and only 19 were identified as highly immunogenic in UC. Using a supervised learning algorithm (k-top scoring pairs), we identified two sets of serum antibodies that were novel biomarkers for specifically distinguishing CD from healthy controls (accuracy, 86 ± 4%; p < 0.01) and CD from UC (accuracy, 80 ± 2%; p < 0.01), respectively. The Set 1 antibodies recognized three pairs of E. coli proteins: Era versus YbaN, YhgN versus FocA, and GabT versus YcdG, and the Set 2 antibodies recognized YidX versus FrvX. The specificity and sensitivity of Set 1 antibodies were 81 ± 5 and 89 ± 3%, respectively, whereas those of Set 2 antibodies were 84 ± 1 and 70 ± 6%, respectively. Serum antibodies identified for distinguishing healthy controls versus UC were only marginal because their accuracy, specificity, and sensitivity were 66 ± 5, 69 ± 5, and 61 ± 7%, respectively (p < 0.04). Taken together, we identified novel sets of serological biomarkers for diagnosis of CD versus healthy control and CD versus UC.

Significance of Prediagnostic Thyroid Antibodies in Women with Autoimmune Thyroid Disease

INTRODUCTION Antibodies to thyroglobulin (Tg), thyroperoxidase (TPO), and TSH receptor (TSH-R) are prevalent in autoimmune thyroid diseases. We aimed to assess whether females with Graves disease or Hashimoto thyroiditis are more likely than age-matched controls to have thyroid antibodies before clinical diagnosis and to measure the timing of antibody seroconversion. METHODS This was a nested case-control study using the Department of Defense Serum Repository and the Defense Medical Surveillance System, 1998-2007. We assessed thyroid antibodies in the serum of 522 female, active-duty, military personnel including: 87 Graves disease cases, 87 Hashimoto thyroiditis cases, and 348 age matched controls. One serum sample was available at the time of the clinical diagnosis (±6 months); three additional samples were retrieved from the repository up to 7 yr before the clinical diagnosis, for a total of 2088 samples. RESULTS In Hashimoto thyroiditis, TPO antibodies were found in about 66% of the cases at all time points. Tg antibodies showed a similar stationary trend, at a lower prevalence of about 53%at all time points. No TSH-R antibodies were found. In Graves disease, TPO antibodies gradually increased from 31% at 5-7 yr prior to diagnosis to 57% at diagnosis and Tg antibodies from 18 to 47%. TSH-R antibodies were present before diagnosis and showed an increasing prevalence from 2, 7, 20, to 55%. CONCLUSIONS Antibodies to Tg, TPO, and TSH-R precede by years the development of the diagnostic autoimmune thyroid diseases phenotype. Overall, the presence of thyroid antibodies in apparently healthy individuals should not be neglected.

Antibodies to selected minor target antigens in patients with anti-neutrophil cytoplasmic antibodies (ANCA).

In patients with anti‐neutrophil cytoplasmic antibodies (ANCA)‐associated vasculitis, indirect immunofluorescence (IF) distinguishes between cytoplasmic (C‐ANCA) and perinuclear (P‐ANCA) neutrophil staining patterns. In patients with primary systemic vasculitis such as Wegeners granulomatosis, microscopic polyangiitis and Churg–Strauss syndrome, these IF staining patterns correspond broadly with antibodies to the two major antigens: the C‐ANCA pattern is associated generally with antibodies to serine protease 3 (PR3) and the P‐ANCA pattern with antibodies to myeloperoxidase (MPO). However, some sera positive for ANCA by IF are negative for anti‐PR3 and anti‐MPO antibodies, suggesting the presence of antibodies to minor antigens of PMN granules. We tested sera from a previously well‐defined clinical cohort of patients for antibodies to four possible minor antigens: bactericidal permeability increasing protein, elastase, cathepsin G and lactoferrin. IF‐positive (+) sera had significantly higher antibody frequencies to the minor antigens than did the IF‐negative (–) sera (P < 0·01). Patients with IF+ PR3‐MPO‐ sera showed the most varied reactivity to the minor antigens. Among the IF+ groups, the IF+ PR3+/MPO‐ sera showed the lowest reactivity to the minor antigens. Patients with well‐defined ANCA specificities, e.g. the PR3‐ANCA response associated with Wegeners granulomatosis, are less likely than are other patient subsets to have antibodies to minor antigen targets. Autoantibodies to these minor antigens contribute to the overall pattern of ANCA identified by IF and help to explain why the correlation between IF and enzyme immunoassays show discrepancies. While the pathophysiological significance of antibodies to minor target antigens needs further evaluation, they may be markers of inflammation associated with disease processes.

Cardiac fibroblasts mediate IL-17A–driven inflammatory dilated cardiomyopathy

IL-17A stimulates cardiac fibroblasts to produce inflammatory mediators critical for the recruitment and differentiation of myeloid cells during inflammatory dilated cardiomyopathy.

Antibodies to saccharomyces cerevisiae in Crohn's disease: higher titers are associated with a greater frequency of mutant NOD2/CARD15 alleles and with a higher probability of complicated disease.

Background Both antibodies to Saccharomyces cerevisiae (ASCA) and carriage of two mutated NOD2/CARD15 alleles are associated with ileal Crohns disease (CD) and complications requiring bowel surgery. We assessed the ASCA titer as a marker of CD clinical behavior. Methods In a cross‐sectional study, we phenotyped 117 unrelated CD patients. Titers (Units, U) of ASCA IgG and IgA were measured and patients were genotyped for three high‐risk NOD2/CARD15 alleles. Multiple logistic regression and Cox regression analyses were used to assess the association of factors to CD phenotype and time to surgery. Results ASCA seropositivity was associated with younger age at diagnosis, ileal disease, and complicated (stricturing or penetrating) behavior. There was a dose–response between the number of mutant NOD2/CARD15 alleles and the prevalence and titers of ASCA. The ASCA titer and tobacco use were associated with ileal disease independently of NOD2/CARD15 status. The ASCA titer (odds ratio (OR): 2.7 per 25 U, 95% confidence interval (CI): 1.5‐46.7) and ileal disease were associated with stricturing/penetrating behavior, independently of NOD2/CARD15 status. Patients with ileal CD and ASCA titers of 41 U and 60 U needed 10 and 5 years of disease, respectively, to accumulate a 50% risk of complications. Conclusions ASCA+ patients had a greater frequency of mutant NOD2/CARD15 alleles. Nonetheless, higher ASCA titers were associated with higher probabilities of ileal CD and stricturing/penetrating behavior independently of NOD2/CARD15 status. Higher ASCA titers were associated with more rapid development of complications. This quantitative marker may prove useful in risk‐stratifying patients to more aggressive antiinflammatory therapies. (Inflamm Bowel Dis 2007)

Role of CYP2E1 Immunoglobulin G4 Subclass Antibodies and Complement in Pathogenesis of Idiosyncratic Drug-Induced Hepatitis

ABSTRACT Idiosyncratic drug-induced hepatitis (IDDIH) is the third most common cause for acute liver failure in the United States. Previous studies have attempted to identify susceptible patients or early stages of disease with various degrees of success. To determine if total serum immunoglobulin subclasses, CYP2E1-specific subclass autoantibodies, complement components, or immune complexes could distinguish persons with IDDIH from others exposed to drugs, we studied persons exposed to halogenated volatile anesthetics, which have been associated with IDDIH and CYP2E1 autoantibodies. We found that patients with anesthetic-induced IDDIH had significantly elevated levels of CYP2E1-specific immunoglobulin G4 (IgG4) autoantibodies, while anesthetic-exposed healthy persons had significantly elevated levels of CYP2E1-specific IgG1 autoantibodies. Anesthetic IDDIH patients had significantly lower levels of C4a, C3a, and C5a compared to anesthetic-exposed healthy persons. C1q- and C3d-containing immune complexes were significantly elevated in anesthetic-exposed persons. In conclusion, our data suggest that anesthetic-exposed persons develop CYP2E1-specific IgG1 autoantibodies which may form detectable circulating immune complexes subsequently cleared by classical pathway activation of the complement system. Persons susceptible to anesthetic-induced IDDIH develop CYP2E1-specific IgG4 autoantibodies which form small, nonprecipitating immune complexes that escape clearance because of their size or by direct inhibition of complement activation.

Iodination of murine thyroglobulin enhances autoimmune reactivity in the NOD.H2h4 mouse

Autoimmune thyroiditis in humans has been linked to excess iodine intake. A causative relationship between dietary iodine and thyroiditis has been clearly established in animal models of thyroiditis, including the NOD.H2h4 mouse strain, which develops enhanced thyroiditis spontaneously after supplementation of drinking water with sodium iodide. To assess the mechanisms by which iodine may contribute to disease pathogenesis, we have purified hypoiodinated thyroglobulin (Lo‐I Tg) from the thyroids of mice fed methimazole and potassium perchlorate. This preparation contained only a trace of iodine and was poorly reactive to monoclonal antibody 42C3, which has been shown previously to distinguish hypoiodinated from normal Tg. A cloned T cell line 2D11 from a diseased NOD.H2h4 mouse proliferated in response to normal Tg, but not to Lo‐I Tg. Serum antibodies from NOD.H2h4 mice with thyroiditis were poorly reactive to Lo‐I Tg. To determine that these changes were due specifically to iodine content, Lo‐I Tg was reiodinated in vitro. Reiodination of Lo‐I Tg partially re‐established the reactivity of NOD.H2h4 serum antibodies. The data demonstrate that the reactivity of thyroglobulin‐specific antibodies and certain T cells are dependent on the iodine content of thyroglobulin. These findings suggest that iodine contributes to autoimmune thyroiditis in the NOD.H2h4 mouse by directly enhancing the antigenicity of thyroglobulin.