Are serum C3 levels or kidney C3 deposits useful markers for predicting outcomes in patients with ANCA-associated vasculitis?

Introduction: Complement activation emerged as a key actor of anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV). Whether serum levels of C3 (sC3) or C3 kidney deposition may help to refine the prognosis of AAV remains elusive. Methods: Retrospective multicentric study that included 154 patients with a first flare of AAV and sC3 (n = 143) or C3 kidney staining (n = 95) available at diagnosis. Clinical presentations, kidney pathology, and survival of patients with normal or low sC3 were compared using univariate analyses, Kaplan-Maier curves with log-rank comparison, or multivariate Cox' model, as appropriate. Results: 20 patients (14 %) had low sC3. sC3 (as bivariate low/normal or as a continuous variable) was associated with 5-year mortality but not with kidney survival. C3 kidney deposition (C3+) was identified in 23 patients who were characterized by more frequent chronic hypertension and lower eGFR at presentation (p = 0.04). C3+ correlated with IgG, IgM, C1q deposition (p = 0.07, p < 0.0001 and p = 0.003, respectively). Chronicity and activity scores were similar in C3+ and C3- patients. Among C3+ patients, those with C3 deposition ≥2+ had lower eGFR at presentation (p = 0.006) and were more frequently classified as sclerotic using the Berden classification (p = 0.04) and as 'high risk' using the Brix score (p = 0.03). However, eGFR improvement following induction regimen was similar between C3+ and C3- patients, and kidney survival at 5 years was similar. Conclusions: Correlation of sC3 with mortality confirms mechanistic links between complement pathways and AAV, but the lack of clear predictive sC3 cut-off and the similar kidney outcome irrespective of C3 deposition precludes their use as biomarkers of AAV outcomes and response to treatment.

Accuracy of Serological Screening for the Diagnosis of Celiac Disease in Type 1 Diabetes Children.

Background and Objectives: Patients with type 1 diabetes (T1D) are considered at high-risk for developing celiac disease (CD). The purpose of our study was to determine the prevalence of CD among children who were followed in our unit for T1D using the latest ESPGHAN guidelines, and avoiding intestinal biopsies in some of the children. Materials and Methods: We performed a prospective monocentric study, which included 663 T1D children between June 2014 and June 2016. We considered CD according to serological (tissue transglutaminase (TGAs) and endomysium antibodies) results. Children were included either at the time of T1D diagnosis or during their follow up. We looked for clinical and biochemical signs of CD, and for T1D characteristics. Results: The children's ages ranged from 11 months to 18 years. CD was confirmed in 32 out of 663 patients with T1D, with a prevalence of 4.8%. CD was excluded in 619 children and remained uncertain for 12 children, who had positive TGAs without the required criteria. We found that 95% of T1D children express HLA-DQ2 and/or -DQ8, which was 2.4 times higher than in the general population. Conclusions: An intestinal biopsy could be avoided to confirm CD in the majority of T1D children. Silent forms of CD are frequent and screening is recommended for all patients. Importantly, repeated TGA assessment is required in HLA genetically predisposed T1D patients, while it is unnecessary in the 5% who are HLA-DQ2 and -DQ8 negative.

Cerebrospinal fluid YKL-40 level evolution is associated with autoimmune encephalitis remission.

Objective: Because of its heterogeneity in clinical presentation and course, predicting autoimmune encephalitis (AIE) evolution remains challenging. Hence, our aim was to explore the correlation of several biomarkers with the clinical course of disease. Methods: Thirty-seven cases of AIE were selected retrospectively and divided into active (N = 9), improved (N = 12) and remission (N = 16) AIE according to their disease evolution. Nine proteins were tested in both serum and cerebrospinal fluid (CSF) at diagnosis (T0) and during the follow-up (T1), in particular activated MMP-9 (MMP-9A) and YKL-40 (or chitinase 3-like 1). Results: From diagnosis to revaluation, AIE remission was associated with decreased YKL-40 and MMP-9A levels in the CSF, and with decreased NfL and NfH levels in the serum. The changes in YKL-40 concentrations in the CSF were associated with (1) still active AIE when increasing >10% (P-value = 0.0093); (2) partial improvement or remission when the changes were between +9% and -20% (P-value = 0.0173); and remission with a reduction > -20% (P-value = 0.0072; overall difference between the three groups: P-value = 0.0088). At T1, the CSF YKL-40 levels were significantly decreased between active and improved as well as improved and remission AIE groups but with no calculable threshold because of patient heterogeneity. Conclusion: The concentration of YKL-40, a cytokine-like proinflammatory protein produced by glial cells, is correlated in the CSF with the clinical course of AIE. Its introduction as a biomarker may assist in following disease activity and in evaluating therapeutic response.

Case Report: Presence of Anti-MAG in the CSF Can Be Associated With a Neurodegenerative Process With Frontal Involvement.

Background: Autoimmune encephalitis (AIE) is an increasingly broad nosological framework that may clinically mimic neurodegenerative diseases (NDDs). Cases Reported: We describe here the clinical, radiological, electrophysiological, and biological evolution of three patients. Two women aged 73 and 72 years and a 69-year-old man presented with complex cognitive and focal neurological symptoms and each had a predominant frontal dysexecutive involvement and an unexpectedly high titer of anti-MAG antibodies in the serum and cerebrospinal fluid (CSF). The question of an autoimmune cause was raised. After 2 years of follow-up and, for two of them, without improvement despite immunosuppressive treatments, diagnoses of NDD were eventually retained: post-radiation encephalopathy, progressive supranuclear palsy (PSP), and Alzheimer's disease. Conclusion: The presence of a high titer of anti-MAG antibodies may be found in NDD. It could reflect cerebral tissue damages, particularly in the case of significant frontal involvement. Atypical presentations may lead to a search for a paraneoplastic neurologic syndrome or AIE. However, the indirect immunofluorescence staining positivity on a monkey cerebellum section linked with anti-MAG antibodies should not lead to those diagnoses being retained.

Post-CMV Guillain-Barré Syndrome with Anti-GM2 Antibodies: Two Cases and a Review of the Literature.

INTRODUCTION: Guillain-Barré syndrome (GBS) is an acute post-infectious inflammatory polyneuropathy of ubiquitous distribution. Cytomegalovirus (CMV) is the virus that is most frequently involved. All ages are affected but rare pediatric cases seem to show some distinctive features in terms of specificity and severity. Specific antibodies that target the peripheral nervous system have been identified in several forms of GBS in adults, such as anti-GM2 ganglioside antibodies in post-CMV GBS, which in most instances present as demyelinating polyneuropathies, with a more favorable progression and fewer complications. MATERIALS AND METHODS: This is a retrospective report on two cases of post-CMV GBS with a demyelinating disorder and positive for anti-GM2 IgM. The review of the literature examines five other cases of children with post-CMV GBS with anti-GM2 IgM. RESULTS: In terms of progression, our two cases of post-CMV GBS with a demyelinating disorder and anti-GM2 IgM are similar to the five other cases described in the literature. The CMV infection was asymptomatic or paucisymptomatic and involved girls (6/7), often presenting severe motor forms with frequent loss of the ability to walk (4/6), facial involvement (⅗), little respiratory involvement (⅙), and favorable progression with adapted treatment. CONCLUSION: Post-CMV GBS with anti-GM2 IgM is a specific clinical spectrum that seems to affect children as it affects adults with a predominance among females, demyelination, and severe motor involvement, but a good prognosis. On the other hand, unlike adults, the use of assisted ventilation does not seem to be more frequent.

Lupus band test can be used in combination with anti-chromatin antibodies and complement analysis to predict transition from cutaneous to systemic lupus.

The lupus band test (LBT) is frequently performed for patients with lupus erythematosus (LE) but its capacity to discriminate cutaneous (C)LE from systemic (S)LE is debated, as well as its association with serum antinuclear antibodies (ANA) and complement reduction. Among 158 patients, 56 received retrospectively a diagnosis of CLE, 37 have SLE and 65 other skin disorders. Considering 29 clinical, histopathologic, LBT, and serological parameters: 5 parameters were effective in distinguishing LE from other skin disorders (e.g. skin photosensitivity, LBT positivity, basal vacuolar changes, thickening of the basement membrane, and anti-SSA-60 kDa); and 8 parameters were able to separate SLE from CLE (e.g. arthritis, lupus nephritis, hematological manifestations, Raynaud/sicca manifestations, anti-chromatin, anti-dsDNA, and low levels of C3/4). A positive LBT was further determined to be associated with systemic manifestations when associated with anti-chromatin response and complement reduction in the profile of patients evolving to a systemic form of lupus.

Combining multi-antigenic immunodot with indirect immunofluorescence on HEp-2 cells improves the diagnosis of systemic sclerosis.

Systemic sclerosis (SSc) is associated, in nearly all patients, with autoantibodies (Ab). Accordingly, and in order to identify major (anti-CEN A/B and anti-Topo I) but also minor Abs, the usefulness of combining indirect immunofluorescence (IIF) on HEp-2 cells with an 11 multi-antigenic SSc immunodot was explored. 1689 samples tested at the request of clinicians, were evaluated retrospectively. The positivity rate was 28.8% and the diagnosis of SSc was supported for 232 samples. Two groups of Abs were considered: group 1, Abs (anti-CENP A/B, anti-Topo I) present at elevated levels in SSc patients; group 2, Abs for which the Ab specificity (odds ratio and/or positive predictive value) was improved by using IIF on HEp-2 cells (RNA-Polymerase III, fibrillarin, Th/T0, PM-Scl). Altogether, this study highlights the utility of combining IIF on HEp-2 cells with the SSc immunodot as the first line of an SSc Abs detection/SSc diagnostic strategy.

A microplate assay to measure classical and alternative complement activity.

BACKGROUND: We developed and validated a kinetic microplate hemolytic assay (HA) to quantify classical and alternative complement activity in a single dilution of human plasma or serum. METHODS: The assay is based on monitoring hemolysis of sensitized sheep (or uncoated rabbit) red blood cells by means of a 96-well microplate reader. The activity of the calibrator was evaluated by reference to 200 healthy adults. The conversion of 50% hemolysis time into a percentage of activity was obtained using a calibration curve plotted daily. RESULTS: The linearity of the assay as well as interference (by hemolysis, bilrubinemia and lipemia) was assessed for classical pathway (CP). The within-day and the between-day precision was satisfactory regarding the performance of commercially available liposome immunoassay (LIA) and ELISA. Patients with hereditary or acquired complement deficiencies were detected (activity was measured <30%). We also provided a reference range obtained from 200 blood donors. The agreement of CP evaluated on samples from 48 patients was 94% with LIA and 87.5% with ELISA. The sensitivity of our assay was better than that of LIA, and the cost was lower than either LIA or ELISA. In addition, this assay was less time consuming than previously reported HAs. CONCLUSIONS: This assay allows the simultaneous measurement of 36 samples in duplicate per run of a 96-well plate. The use of a daily calibration curve allows standardization of the method and leads to good reproducibility. The same technique was also adapted for the quantification of alternative pathway (AP) activity.

Clinical association of mixed connective tissue disease and granulomatosis with polyangiitis: a case report and systematic screening of anti-U1RNP and anti-PR3 auto-antibody double positivity in ten European hospitals.

We report here the case of a 50-years-old man treated for mixed connective tissue disease (MCTD) positive for anti-U1 ribonucleoprotein (U1RNP) antibodies who secondarily developed a granulomatosis with polyangiitis (GPA) associated with anti-proteinase 3 anti-neutrophil cytoplasmic antibodies (PR3-ANCA). We then evaluated the frequency of the association between anti-U1RNP and anti-PR3-ANCA antibodies by a systematic retrospective study in ten European hospitals. Overall, out of 11,921 samples analyzed for both auto-antibodies, 18 cases of anti-U1RNP and anti-PR3-ANCA double positivity were found and only one patient presented with both MCTD and GPA symptoms. Our retrospective analysis indicates that anti-U1RNP and anti-PR3-ANCA antibodies double positivity is infrequent and very rarely associated with both MTCD and GPA. Our observation describes for the first time the coexistence of MTCD and severe GPA in a Caucasian patient. Association of anti-U1RNP and ANCA antibodies was rarely reported in the literature. Eleven cases of MCTD and ANCA vasculitis have been reported to date, with only two cases with anti-PR3-ANCA association, and only one vasculitis. The seven other cases reported in the literature presented with an association of MCTD and microscopic polyangiitis which appears to be a more frequent presentation than MTCD associated with GPA.

Heterogeneous clinical spectrum of anti-SRP myositis and importance of the methods of detection of anti-SRP autoantibodies: a multicentric study.

Anti-signal recognition particle (SRP) antibodies are important serological markers for the diagnosis and the prognosis of idiopathic inflammatory myopathy (IIM), especially to distinguish immune-mediated necrotizing myopathy (IMNM). This study was set up to investigate the phenotype associated with anti-SRP antibodies and to evaluate the methods for detecting these antibodies. Clinical and biological data were retrospectively obtained from 60 adult patients with anti-SRP antibodies detected by a dot immunoassay from 12 centers. Thirty-six (60 %) out of these 60 patients suffered from an IIM, and among them, 21 patients were diagnosed as IMNM. Among patients with a definite IIM, proximal weakness and myalgia were prominent symptoms at the time of diagnosis. Only few patients displayed severe extra-muscular symptoms such as cardiac involvement or severe myositis. Mean creatine kinase levels were high for all patients except for two of them. When testing by indirect immunofluorescence (IIF) on HEp2 cells, the fraction of patients displaying the typical anti-SRP fine speckled staining of the cytoplasm was higher in patients with IIM (30/36) (83 %) than in patients with non-IIM (3/24) (12.5 %) (p < 0.0001). Thirty (91 %) out of 33 patients with a positive immunodot and a characteristic IIF cytoplasmic staining suffered from a clinical definite myositis, whereas only 6 (22 %) out of 27 patients with a positive immunodot but a negative cytoplasmic pattern suffered from a myositis (p < 0.00001). This series highlights the strong heterogeneity of anti-SRP positivity that encompassed IMNM and non-IMNM and supports the necessity of considering both IIF and dot immunoassay to confirm the diagnosis of anti-SRP-associated myositis.

Are immunoglobulin A anti-gliadin antibodies helpful in diagnosing coeliac disease in children younger than 2 years?

The usefulness of immumoglobulin (Ig) A antibodies to gliadin (AGA-IgA) in addition to IgA anti-endomysium and tissue transglutaminase antibodies was evaluated in 4122 children younger than 2 years with a suspicion of coeliac disease (CD). Eight percent (312/4122) displayed IgA anti-endomysium and/or IgA anti-tissue transglutaminase, whereas 2.1% (85/4122) displayed only AGA-IgA. Clinical data were obtained for 62 of 85 children with isolated AGA-IgA, and 33 children underwent a duodenal biopsy. Histologically proven CD was established for 5 patients, whereas 57 children were diagnosed to experience other diseases. The systematic detection of AGA-IgA using native gliadin conferred no additional diagnostic benefit for the diagnosis of CD in children younger than 2 years of age, except for rare cases.

IgA-mediated anti-glomerular basement membrane disease: an uncommon mechanism of Goodpasture's syndrome.

Goodpasture's (GP) disease is usually mediated by IgG autoantibodies. We describe a case of IgA-mediated GP, in a patient presenting with isolated rapidly progressive glomerulonephritis. The diagnosis was established on kidney biopsy, since routine enzyme-linked immunosorbent assay (ELISA) targeted at IgG circulating autoantibodies failed to detect the nephritogenic antibodies. Immunofluorescence microscopy showed intense linear deposition of IgA along the glomerular capillary walls. An elevated titre (1:80) of circulating IgA anti-glomerular basement membrane (GBM) antibodies was retrospectively demonstrated by indirect fluorescence. Despite immunosuppressive regimen, the disease progressed to end-stage renal failure (ESRF). Transplantation was not associated with recurrence in the kidney graft. We reviewed the 11 previously reported cases of IgA-mediated GP.

Prevalence of autoantibodies to cyclic citrullinated peptide in patients with rheumatic diseases other than rheumatoid arthritis: a French multicenter study.

Our objective was to evaluate the prevalence of autoantibodies to cyclic citrullinated peptides (anti-CCP aAbs) in a cohort of patients with a variety of inflammatory or non-inflammatory rheumatic diseases other than rheumatoid arthritis (RA). Six hundred and nine serum samples were tested for anti-CCP aAbs and for rheumatoid factor (RF) using enzyme-linked immunosorbent assays and immunonephelometry. The prevalence of anti-CCP aAbs and RF reached 10% and 25%, respectively, using the positive cutoff value suggested by the manufacturers. Using a higher cutoff value (50 U/ml) for both aAbs, the prevalence was lower with 6% and 16%, respectively. The specificity of both markers for RA thus reached 94% and 84%, respectively. Anti-CCP aAbs were found to be elevated in inflammatory and also in non-inflammatory rheumatic diseases in the same proportion. Clinical data obtained for 36 positive patients showed that 17% developed RA within 5 years. In conclusion, anti-CCP aAbs are clearly more specific than RF for RA. Follow-up of anti-CCP aAbs-positive patients with inflammatory or non-inflammatory rheumatic diseases other than RA could be important considering the predictive value of these aAbs for the development of RA.