Torsten Matthias

Autoantibodies against protective molecules--C1q, C-reactive protein, serum amyloid P, mannose-binding lectin, and apolipoprotein A1: prevalence in systemic lupus erythematosus.

Abstract:  Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of several autoantibodies. Among the multiple factors involved in SLE development, apoptotic defects and impaired clearance of cellular debris have gained considerable interest, as they contribute to autoantigen overload. Several molecules of the innate immunity, also participate in the removal of damaged and apoptotic cells. Among them are C1q, C‐reactive protein (CRP), serum amyloid P protein (SAP), mannose‐binding lectin (MBL), and apolipoprotein A1 (APO A1). To evaluate the prevalence of autoantibodies against CRP, SAP, MBL, APO A1, and C1q among SLE patients, and their relationship with disease activity, a total of 150 SLE patients were screened for the presence of elevated antibody titers against C1q, CRP, SAP, MBL, and APO A1, utilizing the enzyme‐linked immunosorbent assay (ELISA) method. Disease activity was assessed using the ECLAM or SLEDAI scores. The study population comprised two groups of patients: 100 patients with quiescent disease (median ECLAM score 2) comprised the first group, and 50 patients with active disease (median SLEDAI score 16) comprised group 2. Elevated titers of anti‐CRP antibodies were significantly elevated only in group 1 (10% versus 4% of controls). Antibodies against SAP were evaluated only among patients in group 1, and were found at a significant high prevalence (20%). Elevated titers of anti‐MBL antibodies were significantly elevated only in group 1 (15% versus 3.6%); and antibodies directed against APO A1 were significantly elevated in 21% of group 1, and 50% of group 2 patients. Elevated titers of anti‐C1q were evaluated only in group 2, and were found at a significant prevalence of 66%. Significant correlation with disease activity was found only for anti‐APO A1 antibodies, and only in group 1. Several patients harbored more than one of the autoantibodies tested. In patients with SLE, autoantibodies directed against protective molecules, that is, acute‐phase proteins involved in the disposal of cellular and nuclear debris, can be detected. These autoantibodies may play a pathogenic role in the development or perpetuation of autoimmunity in SLE.

Autoantibodies in Nonautoimmune Individuals during Infections

Abstract:  Infections can act as environmental triggers inducing or promoting autoimmune disease in genetically predisposed individuals. Identification of microbial peptides similar to self‐tissues may by molecular mimicry, provide the inducing mechanism for an immune response. The aim of this study was to identify autoantibodies (autoAbs) in nonautoimmune individuals during acute bacterial, viral, or parasitic infections. Specific Abs or specific infections with an increased autoAb load may shed insight into the mechanisms of autoimmune disease. Sera from 88 patients with acute infections (41 bacterial, 23 viral, 17 parasitic, and 7 rickettsial) were tested by the ELISA method for antinuclear antibodies (ANA) 8 Pro, and Abs to thyroid peroxidase (TPO), thyroglobulin, phospholipids, annexin‐V, laminin, anti–Saccharomyces cervisiae (ASCA), and prothrombin, along with 80 normal controls. Elevated titers of Abs to annexin‐V and prothrombin were the most prevalent in viral, parasitic, and rickettsial infections and to laminin in viral and parasitic infections. Elevated titers of ASCA and ANA were found in viral and bacterial infections. Antiphospholipid Abs were found in parasitic and Q‐fever infections. Thirty‐four individuals harbored elevated titers of at least two Abs. An autoAb burden was detected in individuals with hepatitis A, hepatitis B, toxoplasma or Q‐fever infections. In nonautoimmune individuals with various (bacterial, viral, parasitic, and rickettsial) infections, elevated titers of Abs to annexin‐V, prothrombin, laminin, ASCA, ANA, and phospholipids were most frequently detected.

Cross-Reactive Epitopes on β2-Glycoprotein-I and Saccharomyces cerevisiae in Patients with the Antiphospholipid Syndrome

Abstract:  Anti‐Saccharomyces cerevisiae antibodies (ASCA), directed against the phosphopeptidomannan (PPM) part of the cell wall of the yeast, have been identified as an important and specific serological marker for Crohns disease. We evaluated the prevalence and properties of ASCA in APS patients. Thirty‐one out of 155 APS patients tested positive for ASCA (20.0%), compared to 5.0% in healthy controls (P < 0.05). The presence of ASCA was not associated with any specific manifestation of APS. The ASCA found to be the population of anti‐β2GPI antibodies (Abs). Affinity purified anti‐β2GPI from ASCA‐positive sera on a β2GPI column, bound specifically the PPM, as shown by direct binding and competition assays (95‐98%). The PPM inhibited differentially the anti‐β2GPI binding to β2GPI. Since the anti‐β2GPI anti‐PPM could bind only native form of β2GPI and not the recombinant form, we assume that these specific anti‐β2GPI subpopulations of Abs are directed to the glycosylated site of the molecule. In conclusion, a subpopulation of anti‐β2GPI is specific to the glycosylated site of the β2GPI molecule that cross‐reacts with PPM.

Identification of Thrombin Antibodies in Patients with Antiphospholipid Syndrome

Abstract: Venous or arterial thrombosis, abortion, and the presence of antiphospholipid antibodies (aPL) define the criteria for the antiphospholipid syndrome (APS). A heterogeneous group of antibodies against phospholipids and plasma proteins may influence several coagulation pathways and lead to thrombophilia. We investigated the presence of antibodies to thrombin (Thr) in patients with aPL and reviewed their clinical manifestations. IgG and IgM titers of aPL were measured by ELISA (Aesku.Diagnostics, Wendelsheim, Germany). Lupus anticoagulants (LA) were measured according to the criteria of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. One hundred twenty patients were identified with LA or anticardiolipin (aCL). Of the 120 patients, 98 (82%) had primary APS and 22 (18%) had secondary APS. Further, 76/120 (63%) were suffering from thromboembolic manifestations, mostly venous thrombosis. Anti‐thrombin‐IgG was detected in 20%, and anti‐thrombin‐IgM was detected in 23% of the patients. The presence of anti‐thrombin antibodies was closely related to the presence of anti‐β2‐glycoprotein‐I (β2‐GP‐I) (96%), aCL (97%), and LA (87%), and less well to the presence of anti‐phosphatidylserine/prothrombin /Ser/Pro) antibodies (71%) or anti‐prothrombin antibodies (Pro) (50%). Sixty‐seven percent of the patients with anti‐Thr‐IgG suffered from thromboembolic complications, mostly arterial thrombosis. The rate of thrombosis was higher for these patients than for patients with anti‐β2‐GP‐I antibodies (37/60, 62%), LA (50/79, 63%), or anti‐Ser/Pro antibodies (18/28, 64%). Anti‐thrombin antibodies were found in 20% of patients with aPL; 67% of these patients were admitted with thrombotic manifestations of APS. The presence of anti‐thrombin antibodies was closely associated with the presence of aCL and anti‐β2‐GP‐I antibodies. The sensitivity of the test for anti‐thrombin antibodies for the diagnosis of APS was higher than the sensitivity of the anti‐prothrombin assay and similar to the sensitivity of the anti‐Ser/Pro assay.

Diagnostic Challenges in Celiac Disease and the Role of the Tissue Transglutaminase–Neo-Epitope

The diagnosis of celiac disease (CD) remains a clinical challenge based on the incomplete specificity and sensitivity rates of current non-invasive tests. Furthermore, histological assessments fail to identify all overt cases and, in particular, do not manifest pathognomonic alterations in silent cases. Accordingly, the majority of CD cases are diagnosed with great delay. Recent research into the pathogenesis of CD, allowed us to identify a neo-antigen that appears to be the most promising serological tool for the detection of anti-tissue transglutaminase as well as anti-gliadin antibodies.

Leukocyte Immunoglobulin-Like Receptors as New Players in Autoimmunity

Leukocyte immunoglobulin-like receptors (LILR) are a family of at least 13 receptors mainly expressed on lymphoid and myelomonocytic cells. They are involved in the activation of the immune system. Inhibitory LILR (termed LILRB) signal through immunoreceptor tyrosine-based inhibitory motives in the cytoplasmic domain, whereas LILRA with short cytoplasmic domains are stimulatory receptors. Polymorphisms and deletions of leukocyte immunoglobulin-like receptors have been shown to be associated with autoimmune disorders, and some of the receptors are involved in the generation of regulatory T cells. Therefore, leukocyte immunoglobulin-like receptors may be central in the pathogenesis of autoimmunity. The data linking these receptors to autoimmune diseases is reviewed here.

Novel trends in celiac disease.

Celiac disease (CD) is one of the most common food intolerances in developed world. It affects genetically susceptible individuals and has severe consequences if it remains undiagnosed. A disease known for more than a century, it is still the focus for experts from various fields of research and development. Geneticists, pathologists, immunologists, food engineers and dieticians share their knowledge and expertise to improve the conditions of CD patients. With new insights in the pathomechanism of gluten processing and antigen presentation in CD, it was possible to improve the diagnostic antigen mimicking the primary epitope in CD. These celiac neo-epitopes are comprised of a complex of gliadin peptides crosslinked with transglutaminase (tTg). They are an early diagnostic marker for CD which occurs up to 6 months earlier than classical markers known to miss a certain amount of CD patients.

Neo-epitope tissue transglutaminase autoantibodies as a biomarker of the gluten sensitive skin disease — Dermatitis herpetiformis

BACKGROUND The deamidated gliadin peptides (DGP) cross linked to human tissue transglutaminase (tTg) comprises a novel neo-epitope structure (Neo-tTg) for serological screening of celiac disease (CD). Our aim is to verify anti-Neo-tTg IgA and IgG in adults with dermatitis herpetiformis (DH). METHODS Multi-centric retrospective evaluation of the IgA/G autoantibodies in sera of DH patients on a regular diet (n=40) and a gluten restricted diet (GRD, n=53) and control adults with autoimmune skin diseases (n=107) by ELISA. RESULTS The sensitivities of Celicheck Neo IgA/G (76%, 95% CI 67-84%) and the Neo tTg-A (85%, 95% CI 70-97%) ELISA were significantly greater than that of tTg-A (56%, 95% CI 46-67%), eTg-A (62%, 95% CI 52-72%), DGP-A (55%, 95% CI 55-65%), DGP-G (61%, 95% CI 51-71%), Glia-A (55%, 95% CI 45-65%) and Glia-G (56%, 95% CI 46-66%) ELISA. The specificities of all 8 ELISA were in the range of 90-100%. The area under the curve (AUC) of receiver operator characteristic curve (ROC) for the two Neo-tTg ELISA (0.863 and 0.949) were higher than the AUCs for ROCs of tTg, DGP and eTG ELISA (range between 0.657 and 0.783). The autoantibody levels of DH patients on a normal diet were significantly higher than those on GRD in the Celicheck Neo IgA/IgG, NeotTg-A; tTg-A and the eTg-A; ELISA (p<0.01) and of no significance in the DGP and Gliadin ELISA. CONCLUSION Neo-epitope IgA autoantibodies represent a new and sensitive serological marker of DH.

Anti-ribosomal-P antibodies accelerate lupus glomerulonephritis and induce lupus nephritis in naïve mice

BACKGROUND Lupus nephritis is known to be associated with several antibodies including autoantibodies that target the DNA, C1q and histone, α-actinin, and the nucleosome. In addition, circulating anti-phosphoribosomal protein antibodies (anti-Ribos.P) were found to be associated with lupus nephritis. STUDY OBJECTIVE We have assessed the direct role of anti-Ribos.P in the development of glomerulonephritis in-vitro and in animal models. STUDY DESIGN NZBxW/F1 lupus prone mice were immunized with recombinant Ribos.P0 (rRibos.P). Evaluation of renal disease included mice evaluation for proteinuria and histologic analysis of the kidneys. Anti-Ribos.P monoclonal Ab was prepared from the rRibos.P immunized NZBxW/F1 mice by hybridoma technology. MAPKs expression was analyzed by MAPKs protein array and confirmed by real-time PCR and western blot. To elucidate whether anti-Ribos.P induce glomerulonephritis, naïve C3H mice were immunized with recombinant rRibos.P and the glomerulonephritis was followed up as described above. RESULTS The immunized NZBxW/F1 lupus prone mice developed anti-Ribos.P which was cross reactive with Sm and not dsDNA. The mice developed accelerated glomerulonephritis manifested by early proteinuria and immunoglobulin deposites in the mesangium of the kidneys. Anti-Ribos.P deposited in the glomerular mesangium were eluted from the kidney. The Ribos.P immunized naïve C3H/Hen mice developed glomerulonephritis manifested by circulating autoantibodies directed to Ribos.P, dsDNA and Sm. The anti Ribos.P were cross reactive with Sm but not with dsDNA, and were deposited in the glomeruli. Interestingly these mice developed alopecia. In vitro. Primary mesangial cells exposed to mouse anti-Ribos.P mAb originated from the immunized lupus mice and to human anti-Ribos.P Abs, induced activation of mesangial cells via p38α, JNK, AKT and HSP27 MAPKs expression pathway. CONCLUSIONS Our data show for the first time that anti-Ribos.P are nephritogenic autoantibodies, as illustrated by in-vitro and in-vivo experiments: a) They accelerate the development of glomerulonephritis in lupus prone mice; b) They induce nephritis in naïve mice. c) Anti-Ribos.P Abs trigger MAPKs expression in primary mesangial cells. These data contribute a direct mechanistic link between anti-Ribos.P and nephritis in lupus mice.

Immunoglobulin-like Transcripts as Risk Genes for Autoimmunity

Abstract:  Risk genes for multiple sclerosis (MS) are localized in the gene regions 6p21‐11 and 19q13, the latter harboring the genes of the immunoglobulin‐like transcripts (ILTs). ILTs are a family of activating and inhibitory receptors expressed on antigen‐presenting cells (APCs) as well as on natural killer (NK) and T cells. Because of the inhibitory function of ILT2 and ILT4 and their binding to human leukocyte antigen (HLA)‐G, they play a role in immune tolerance and may be important in pathogenesis of autoimmunity. ILT6 shows presence–absence variability and is produced by macrophages in a soluble form. ILT6 deletion is associated with MS. Furthermore, ILT6 activates T cell proliferation and is therefore a candidate gene for autoimmune disorders.