Autoantibodies against P29ING4 are associated with complex regional pain syndrome.

INTRODUCTION: Complex regional pain syndrome (CRPS) is a complication following trauma or surgery and may be difficult to diagnose since biomarkers are lacking. Using protein array technology, we found antibodies binding to p29ING4, which we further characterized using ELISA. METHODS: Thirty-six sera of early-stage type 1 CRPS, 66 sera of rheumatoid arthritis (RA), 53 sera of axial spondyloarthritis (axSpA), 29 sera of psoriatic arthritis (PsA), 22 sera of patients after radial fractures (trauma control), and 100 sera of blood donors (BD) were analyzed for anti-p29ING4. We established ELISAs with 7 different antigens and using different secondary antibodies binding to IgG, IgG1, IgG2, IgG3, IgG4, IgA, and IgM, and 2 different tests to detect immune complexes (IC) of p29ING4 and IgG or IgG1. RESULTS: The highest likelihood ratios versus CRPS and trauma control were observed considering the A1-23 (sensitivity 19%, specificity 100%, LR > 19) using IgG as a secondary antibody, the A120-165 (sensitivity 17%, specificity 100%, LR = 17) using IgG as a secondary antibody and the A120-165 (sensitivity 31%, specificity 95%, LR = 6.2) using IgA as a secondary antibody. IC of p29ING4 and IgG were present in 11/36 (31%) CRPS sera, 17/64 (27%) RA sera, 13/53 (25%) SpA sera, 5/29 (17%) PsA sera, 1/22 (5%) trauma control sera, and 4/100 (4%) sera of BD. IC of p29ING4 and IgG1 were present in 14/36 (39%) CRPS sera, 19/64 (30%) RA sera, 13/53 (25%) SpA, 1/29 (3%) PsA, 2/22 (9%) trauma control, and 4/100 (4%) of the BD sera. CONCLUSION: Due to the lack of other biomarkers of type 1 CRPS, P29ING4 autoantibodies could be helpful in its diagnostic work-up.

Autoantibodies binding to ubiquitin-fold modifier-conjugating enzyme 1 (Ufc1) and pleckstrin homology domain containing, family G (with RhoGef domain) member 2 (Plekhg2) are associated with mycobacterial infections.

OBJECTIVES: The diagnosis of extrapulmonary tuberculous infections and nontuberculous mycobacterial (NTM) infections is difficult because the symptoms are nonspecific and suitable specimens for bacterial culture are often not available. Recent publications reported the existence of autoantibodies in tuberculous infections. We screened for specific autoantibodies in mycobacterial infections. METHODS: We screened four in 29 patients with active mycobacterial infections and different controls using protein array technology. We could identify autoantibodies against ubiquitin-fold modifier-conjugating enzyme 1 (Ufc1) and pleckstrin homology domain containing, family G (with RhoGef domain) member 2 (Plekhg2) in all four patients. Subsequently, we designed enzyme-linked immunosorbent assays (ELISAs) for the detection of autoantibodies binding to Ufc1 and Plekhg2. RESULTS: Autoantibodies binding to Ufc1 and Plekhg2 were found in 19 of 29 patients (66%) with active mycobacterial infections. In comparison, we found these autoantibodies in one of 31 patients (3%) with successfully treated mycobacterial infections, in three of 40 (8%) HIV-infected patients not receiving combination antiretorviral therapy (cART) and in six of 134 (5%) blood donors. Interestingly, six of eight (75%) patients with HIV-associated B-cell non-Hodgkin lymphoma (B-NHL) at the onset of disease had autoantibodies against Ufc1 and Plekhg2, but none of nine (0%) patients after treatment of HIV-associated B-NHL, none of seven patients with non-HIV-associated B-NHL and 11 of 115 (10%) patients with other malignant diseases had autoantibodies against both proteins. CONCLUSIONS: In view of the high frequency of these autoantibodies, we postulate that they might be of potential use for additional diagnostics for mycobacterial infections, and further studies may shed light on the pathomechanisms of these two autoantibodies.

Increased T-cell turnover is associated with spondyloarthritis in virally suppressed patients with HIV-1 infection.

OBJECTIVES: Spondyloarthritis (SpA) is one of the most frequently observed inflammatory joint diseases in HIV-1-seropositive patients. T-cells were described frequently as one of the major driving forces in SpA, therefore we tried to look for T-cell aberrancies in our HIV-positive patients with SpA. METHODS: A total of 1098 files for HIV-positive patients who attended the HIV out-patient clinic of the Department of Clinical Immunology and Rheumatology at the Medical University Hanover for at least one visit between January 2004 and December 2010 were screened for the presence of a diagnosis of SpA. A cross-sectional study was conducted to investigate aberrancies in T-cell homeostasis induced by HIV-1 in these subjects. RESULTS: The prevalence of SpA in the HIV-positive patients was 1.6% (18 of 1098). Interestingly, the percentage of patients with SpA who were human leucocyte antigen (HLA)-B27 negative in our HIV-positive cohort was 80%. Despite combination antiretroviral therapy (cART) and viral suppression, an incomplete immune recovery of T-cell naïve/memory distribution and turnover, as identified by intracellular Ki-67 expression, was observed in HIV-positive patients with SpA. CONCLUSIONS: Independent of HLA-B27 status and despite cART, HIV-positive patients can develop SpA and exhibit an increased T-cell turnover rate.

Association of ferritin antibodies with Takayasu arteritis.

Takayasu arteritis (TA) is difficult to diagnose because diagnostic biomarkers have not yet been established. In a previous study, we detected autoantibodies against the human ferritin heavy chain protein (HFC) in the sera of patients with giant cell arteritis (GCA) and/or polymyalgia rheumatica (PMR). The aim of this study is to evaluate the frequency of autoantibodies against HFC in TA. We established seven ELISA assays for the detection of autoantibodies against HFC. We used the full-length recombinant HFC expressed in Escherichia coli or one of six different HFC peptides as autoantigens: 1-18Aa (98.8 % purity), 19-45Aa (98.8 % purity), 52-78Aa (98.3 % purity), 79-104Aa (98.8 % purity), 105-143Aa (98.4 % purity) and 145-183Aa (98.5 % purity). We collected sera from 48 patients with TA, 36 patients with systemic lupus erythematosus (SLE), 35 patients with arteriosclerosis, 133 patients with febrile diseases, which are known to generate unspecific autoantibodies, and 50 blood donors, which served as controls. The best results were obtained using the ferritin peptides as antigens. By combining the results from the different ELISAs that detect autoantibodies against the HFC peptides 19-44A, 79-104A and 105-144A, we were able to detect ferritin peptide antibodies in 30/48 (62 %) of the TA patients. The frequency was lower than in early GCA and PMR (previous study showed up to 92 %). Positive results were observed in 0/50 (0 %) of the control blood donors, 10/36 (28 %) of the SLE patients, 4/35 (11 %) of the arteriosclerosis patients and 27/133 (20 %) of the fever patients. Considering the lack of biomarkers for TA, autoantibodies against HFC peptides could act as useful markers for TA.

Large vessel vasculitis and spondyloarthritis: coincidence or associated diseases?

INTRODUCTION: Although cardiac complications have been reported in established spondyloarthritis (SpA), little is known about peripheral axial SpA in large vessel vasculitis (LVV). The aim of this study was to assess the prevalence of SpA in patients with newly diagnosed LVV. METHOD: Retrospective single-centre analysis of all newly diagnosed LVV patients was performed between January 2011 and December 2012. Vasculitides were confirmed on thoracic magnetic resonance imaging (MRI) or 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). Patients completed a standardized questionnaire incorporating the Berlin criteria to assess inflammatory back pain. Existing scans were reassessed for sacroiliitis and ferritin antibodies measured in all patients. RESULTS: Fifteen patients exhibiting new LVV were identified. Diagnosis was confirmed using MRI in nine patients and FDG-PET/CT in six. Six patients (40%) fulfilled American College of Rheumatology (ACR) criteria for giant cell arteritis (GCA) and polymyalgia rheumatica (PMR), and nine PMR only. Four patients fulfilled the Berlin criteria for inflammatory back pain, with three demonstrating sacroiliitis on imaging. All remaining patients demonstrated no sacroiliitis. One further patient with LVV lacking features of inflammatory back pain had known psoriatic arthritis (PsA). Patients with coexisting SpA were younger (mean age 57 years vs. 66 years) and had higher C-reactive protein (CRP) levels (200 mg/L vs. 85 mg/L) at presentation. Four SpA patients and seven out of nine patients with isolated LVV had ferritin antibodies. CONCLUSIONS: We have demonstrated a higher than anticipated prevalence of SpA in LVV, given the reported 0.5-1% prevalence in the general population. Coexisting SpA should be considered in LVV patients exhibiting inflammatory back pain despite steroid initiation. Ferritin antibodies demonstrated a similarly high prevalence in aortitis and SpA as reported previously in untreated GCA and PMR.

Autoantibodies against CD74 in spondyloarthritis.

BACKGROUND: Spondyloarthritis (SpA) is a common debilitating inflammatory disorder. Establishing the diagnosis is often difficult, since abnormalities in conventional X-ray develop with a latency of several years and only HLA-B27 is used as a laboratory marker. The goal of our study was to identify new autoantibodies as diagnostic markers of SpA. METHODS: Protein array technology was used to screen for new autoantigens in ankylosing spondylitis. Then, the results were confirmed by ELISA using Class II-associated invariant chain peptide domain of CD74 as antigen. Sera for the ELISA were obtained from 216 patients with axial (n=156) and peripheral (n=60) SpA. Sera of patients with psoriatic arthritis without axial involvement as another subtype of peripheral SpA, rheumatoid arthritis, systemic lupus erythematosus, HIV infection and blood donors served as controls. All donors provided informed consent for the study which was approved by the local ethics committee (project number 4928). RESULTS: Using protein arrays, we detected IgG antibodies against CD74 in SpA sera. Using ELISA technology on sera that had previously been frozen for several years, IgG autoantibodies against CD74 were found in 67% of the SpA patients and were even more frequent in patients with a short disease duration. In the controls, the prevalence of the new autoantibodies was 18/40 (45%) in psoriatic arthritis without axial involvement, 9/80 (11%) in rheumatoid arthritis, 6/40 (15%) in systemic lupus erythematosus, 1/40 (2.5%) in HIV and 1/125 (0.8%) in blood donors. CONCLUSIONS: Antibodies against CD74 could provide an important additional tool for diagnosis of SpA.

Epitope mapping of antibodies against ferritin heavy chain in giant cell arteritis and polymyalgia rheumatica.

OBJECTIVES: In a previous study we found an association between antibodies against the human ferritin heavy chain (HFC) protein and giant cell arteritis (GCA) and/or polymyalgia rheumatica (PMR), especially in GCA/PMR patients prior to glucocorticoid treatment. Antibodies against the N-terminal part of ferritin were present in 92% of untreated patients, 69% of patients with disease flare, and 13% of patients in remission. These antibodies appeared to be markers for the early detection of a disease complex usually diagnosed with considerable delay. Our aim in this study was to optimize the diagnostic test by epitope mapping of antibodies against HFC using peptide antigens in enzyme-linked immunosorbent assays (ELISAs). METHOD: We evaluated serum samples from a selected group of GCA/PMR patients in whom the sensitivity of antibodies against the N-terminal ferritin peptide was only 35%. Patients with late-onset rheumatoid arthritis (LORA), patients with fever, patients with granulomatosis with polyangiitis (GPA), patients without any autoimmune disease at age > 65 years, and blood donors served as controls. RESULTS: By combining different ELISAs we were able to increase the frequency of human ferritin peptide antibodies in GCA/PMR (p < 0.0001) without significantly altering the false-positive rate (FPR) of the diagnostic test. The frequency of antibodies against human ferritin peptide increased from 53% to 74% in GCA/PMR patients with disease flare, from 29% to 40% in GCA/PMR patients in partial remission, and from 8% to 45% in GCA/PMR patients in complete remission. CONCLUSIONS: The potential diagnostic test for GCA/PMR can be improved by combining three human ferritin peptide antibodies.

[Adult onset Still's disease, fever, diagnosis and therapy]. / Adulter Morbus Still, Fieber, Diagnose und Therapie.

Adult onset Still's disease (AOSD) with an incidence of 1-3 cases per 1 million belongs to the most difficult diagnosis of febrile diseases. The lack of biomarkers and its similarity to infectious and malignant and rheumatic diseases lead to a prolongation of its diagnosis. The following report focuses on providing an overview of the current knowledge of relevant symptoms and laboratory parameters for the diagnosis of AOSD and new treatment possibilities.

Association of ferritin autoantibodies with giant cell arteritis/polymyalgia rheumatica.

OBJECTIVES: Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are relatively common inflammatory disorders. Establishing the diagnosis however may be difficult, since so far no specific biomarkers of the disorders are available. METHODS: As a screening procedure, the authors used protein arrays for the detection of new autoantigens in GCA and PMR. The results of the protein array were confirmed by different ELISAs detecting IgG antibodies against the human ferritin heavy chain, N-terminal 27 amino acids of the human ferritin heavy chain or the homologous peptide of Staphylococcus epidermidis. Sera of patients with only GCA (n=64), only PMR (n=47) and both PMR and GCA (n=31) were used. RESULTS: In the ELISA using the human ferritin peptide, the sensitivity of IgG antibodies against ferritin was 92% in 36 GCA and/or PMR patients before initiation of treatment, 22/32 (69%) in patients with disease flares and 64/117 (55%) in the total cohort including treated and inactive patients. In controls, the false positive rate was 11/38 (29%) in systemic lupus erythematosus, 1/36 (3%) in rheumatoid arthritis, 0/31 (0%) in late onset rheumatoid arthritis, 3/46 (6.5%) in B-non-Hodgkin's lymphoma and 1/100 (1%) in blood donors. In the ELISA using the ferritin peptide of S epidermidis, 89% of 27 patients with untreated GCA and PMR were positive. CONCLUSION: Antibodies against the ferritin peptide were present in up to 92% of untreated, active GCA and PMR patients. They can be useful as a diagnostic marker of PMR and GCA.

[Eosinophilic fasciitis and asplenia]. / Eosinophile Fasziitis und Asplenie.

Eosinophilic fasciitis (Shulman syndrome) is a chronic inflammation primarily of the septums and fascia, and is characterized by the infiltration of eosinophils with additional similarities to systemic sclerosis. Several diseases have been described in association with eosinophilic fasciitis. Among these are aplastic anaemia, haemolytic anaemia, thrombocytopenia, lymphoproliferative disorders, thyroiditis, pulmonary fibrosis, Sjögren's syndrome, Raynaud's phenomenon, myositis, medium vessel vasculitis, pericarditis, colitis and glomerulonephritis. To date, no association with congenital asplenia has been described. We report the case of a woman with eosinophilic fasciitis and congenital asplenia and discuss the possible causes and potential consequences.