Humoral and cellular immunogenicity two months after SARS-CoV-2 messenger RNA vaccines in patients with cancer.

Little is known on the long-lasting humoral response and the T cell activation induced by SARS-CoV-2 mRNA vaccines in patients with cancer. The study assessed the efficacy of the SARS-CoV-2 mRNA vaccines through measuring the seroconversion rate at pre-specified time points and the effect on the T cell immunity in patients with cancers. The study included 131 adult patients with solid or hematological cancer, who received SARS-CoV-2 mRNA vaccines. 96.2% of them exhibited adequate antibody response to the SARS-CoV-2 mRNA vaccines 2 months after the booster dose. SARS-CoV-2 mRNA vaccines could induce T cell activation; however, this is more likely in patients who have a positive seroconversion (94%) compared with the patients who did not (50%). Further research into the clinical relevance of low antibodies titers and lack of T cell activity is required to set up an effective vaccination strategy within this group of patients.

Interleukin 8, a Biomarker to Differentiate Guillain-Barré Syndrome From CIDP.

OBJECTIVE: To determine whether CSF interleukin 8 (IL-8) concentration can help to distinguish Guillain-Barré syndrome (GBS) from chronic inflammatory demyelinating polyneuropathy (CIDP) at the initial stage of the disease. METHODS: We performed retrospective immunoassay of IL-8 in CSF, collected at the University Hospitals of Geneva between 2010 and 2018, from patients diagnosed with GBS (n = 45) and with CIDP (n = 30) according to the Brighton and European Federation of Neurological Societies/Peripheral Nerve Society criteria by a physician blinded to biological results. RESULTS: CSF IL-8 was higher in GBS (median: 83.9 pg/mL) than in CIDP (41.0 pg/mL) (p < 0.001). Receiver operating characteristic analyses indicated that the optimal IL-8 cutoff was 70 pg/mL. Above this value, patients were more likely to present GBS than CIDP (specificity 96.7%, sensitivity 64.4%, positive predictive value [PPV] 96.7%, and negative predictive value [NPV] 64.4%). Among GBS subcategories, IL-8 was higher in acute inflammatory demyelinating polyneuropathy (AIDP, median: 101.8 pg/mL) than in other GBS variants (median: 53.7 pg/mL). In addition, with CSF IL-8 above 70 pg/mL, patients were more likely to present AIDP than acute-onset CIDP (p < 0.001; specificity 100%, sensitivity 78.8%, PPV 100%, and NPV 46.2%) or other CIDP with nonacute presentation (p < 0.0001; specificity 95.8%, sensitivity 78.8%, PPV 96.3%, and NPV 76.7%). CONCLUSION: CSF IL-8 levels can help to differentiate AIDP variant of GBS from CIDP, including acute-onset CIDP, with high specificity and PPV. This may improve early and appropriate treatment. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that CSF IL-8 levels accurately distinguish patients with GBS from those with CIDP.

Head-to-Head Evaluation of Five Automated SARS-CoV-2 Serology Immunoassays in Various Prevalence Settings.

PURPOSE: To assess the diagnostic performances of five automated anti-SARS-CoV-2 immunoassays, Epitope (N), Diasorin (S1/S2), Euroimmun (S1), Roche N (N), and Roche S (S-RBD), and to provide a testing strategy based on pre-test probability. METHODS: We assessed the receiver operating characteristic (ROC) areas under the curve (AUC) values, along with the sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs), of each assay using a validation sample set of 172 COVID-19 sera and 185 negative controls against a validated S1-immunofluorescence as a reference method. The three assays displaying the highest AUCs were selected for further serodetection of 2033 sera of a large population-based cohort. RESULTS: In the validation analysis (pre-test probability: 48.1%), Roche N, Roche S and Euroimmun showed the highest discriminant accuracy (AUCs: 0.99, 0.98, and 0.98) with PPVs and NPVs above 96% and 94%, respectively. In the population-based cohort (pre-test probability: 6.2%) these three assays displayed AUCs above 0.97 and PPVs and NPVs above 90.5% and 99.4%, respectively. A sequential strategy using an anti-S assay as screening test and an anti-N as confirmatory assays resulted in a 96.7% PPV and 99.5% NPV, respectively. CONCLUSIONS: Euroimmun and both Roche assays performed equally well in high pre-test probability settings. At a lower prevalence, sequentially combining anti-S and anti-N assays resulted in the optimal trade-off between diagnostic performances and operational considerations.

[Anti-DFS70: significance and clinical utility of a new anti-nuclear antibody]. / Anti-DFS70 : signification et utilité clinique d'un nouvel anticorps antinucléaire.

When screening anti-nuclear antibodies (ANAs) by immunofluorescence, a positive result is often found in subjects without proven autoimmune pathologies. The observed pattern is then very frequently « dense fine speckled ¼ (DFS). The ANAs responsible for this aspect are directed against the DFS70/LEDGF protein and are present in 2-22% of healthy subjects while they are very rarely found in patients suffering from systemic autoimmune rheumatic diseases (SARD). When isolated, with no other detectable specific anti-nuclear antibodies, anti-DFS70 is even considered a negative predictor for the development of a SARD. It is therefore interesting to identify and then confirm the presence of these autoantibodies when investigating the significance of ANAs.

Lors de la recherche des anticorps antinucléaires (AAN) par immunofluorescence, un résultat positif est souvent trouvé chez des sujets sans pathologies auto-immunes avérées. L'aspect observé est alors très fréquemment dense et finement moucheté, en anglais, Dense Fine Speckled (DFS). Les AAN responsables de cet aspect sont dirigés contre la protéine DFS70/LEDGF et sont présents chez 2 à 22 % des sujets sains alors qu'ils sont très rarement retrouvés chez les patients souffrant de maladies auto-immunes systémiques rhumatismales (MASR). Lorsqu'ils sont isolés, sans autres anticorps antinucléaires spécifiques décelables, les anti-DFS70 sont même considérés comme un élément prédictif négatif pour le développement d'une MASR. Il est donc intéressant d'identifier puis de confirmer la présence de ces auto-anticorps lors de la positivité des AAN.

Predictive value of anti-CarP and anti-PAD3 antibodies alone or in combination with RF and ACPA for the severity of rheumatoid arthritis.

OBJECTIVES: The objective of this study was to analyse the predictive value of anti-carbamylated protein (anti-CarP) and anti-peptidyl-arginine deiminase type-3 (anti-PAD3) antibodies, alone or in combination with RF and ACPA, to identify patients at high risk of developing severe RA outcomes. METHODS: Patients within the Swiss Clinical Quality Management registry with a biobank sample were tested for RF, ACPA, anti-CarP, and anti-PAD3 antibodies. We examined the association of each autoantibody with DAS28, HAQ and radiographic damage (Ratingen) at baseline and longitudinally. RESULTS: Analyses included 851 established RA patients and 516 disease controls [axial spondyloarthritis (axSpA = 320) and PsA (196)]. Anti-CarP and anti-PAD3 antibodies were, respectively, present in 22.4% and 10.7% of the whole RA population, and in 13.2% and 3.8% of the RF and ACPA double seronegative patients. At baseline, RA patients with anti-PAD3 had higher DAS28 (4.2 vs 3.7; P= 0.005) and significantly more radiographic damage (14.9 vs 8.8; P= 0.02) than anti-PAD3-negative patients. In the ACPA-negative subgroup, baseline Ratingen scores were significantly higher in anti-PAD3-positive patients (P= 0.01). The combination of anti-PAD3, RF IgM, and ACPA was associated with significantly higher baseline radiographic scores than the double seropositive group (P= 0.04). The presence of any two of the previous autoantibodies was associated with significantly greater radiographic progression over 10 years than if all were absent (P= 0.02). There were no differences in RA outcome measures with regards to anti-CarP. CONCLUSIONS: Anti-PAD3 antibodies are associated with higher disease activity and joint damage scores in RA patients.

Immunological Assessment of Pediatric Multisystem Inflammatory Syndrome Related to Coronavirus Disease 2019.

BACKGROUND: Recently, cases of multisystem inflammatory syndrome in children (MIS-C) associated with coronavirus disease 2019 (COVID-19) have been reported worldwide. Negative polymerase chain reaction (RT-PCR) testing associated with positive serology in most of the cases suggests a postinfectious syndrome. Because the pathophysiology of this syndrome is still poorly understood, extensive virological and immunological investigations are needed. METHODS: We report a series of 4 pediatric patients admitted to Geneva University Hospitals with persistent fever and laboratory evidence of inflammation meeting the published definition of MIS-C related to COVID-19, to whom an extensive virological and immunological workup was performed. RESULTS: RT-PCRs on multiple anatomical compartments were negative, whereas anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin A (IgA) and immunoglobulin G (IgG) were strongly positive by enzyme-linked immunosorbent assay and immunofluorescence. Both pseudoneutralization and full virus neutralization assays showed the presence of neutralizing antibodies in all children, confirming a recent infection with SARS-CoV-2. The analyses of cytokine profiles revealed an elevation in all cytokines, as reported in adults with severe COVID-19. Although differing in clinical presentation, some features of MIS-C show phenotypic overlap with hemophagocytic lymphohistiocytosis (HLH). In contrast to patients with primary HLH, our patients showed normal perforin expression and natural killer (NK) cell degranulation. The levels of soluble interleukin (IL)-2 receptor (sIL-2R) correlated with the severity of disease, reflecting recent T-cell activation. CONCLUSION: Our findings suggest that MIS-C related to COVID-19 is caused by a postinfectious inflammatory syndrome associated with an elevation in all cytokines, and markers of recent T-cell activation (sIL-2R) occurring despite a strong and specific humoral response to SARS-CoV-2. Further functional and genetic analyses are essential to better understand the mechanisms of host-pathogen interactions.

Head-to-Head Accuracy Comparison of Three Commercial COVID-19 IgM/IgG Serology Rapid Tests.

BACKGROUND: Comparative data of SARS-CoV-2 IgM/IgG serology rapid diagnostic tests (RDTs) is scarce. We thus performed a head-to-head comparison of three RDTs. METHODS: In this unmatched case-control study, blood samples from 41 RT-PCR-confirmed COVID-19 cases and 50 negative controls were studied. The diagnostic accuracy of three commercially available COVID-19 RDTs: NTBIO (RDT-A), Orient-Gene (RDT-B), and MEDsan (RDT-C), against both a recombinant spike-expressing immunofluorescence assay (rIFA) and Euroimmun IgG ELISA, was assessed. RDT results concordant with the reference methods, and between whole blood and plasma, were established by the Kendall coefficient. RESULTS: COVID-19 cases' median time from RT-PCR to serology was 22 days (interquartile range (IQR) 13-31 days). Whole-blood IgG detection with RDT-A, -B, and -C showed 0.93, 0.83, and 0.98 concordance with rIFA. Against rIFA, RDT-A sensitivity (SN) was 92% (95% CI: 78-98) and specificity (SP) 100% (95% CI: 91-100), RDT-B showed 87% SN (95% CI: 72-95) and 98% SP (95% CI: 88-100), and RDT-C 100% SN (95% CI: 88-100) and 98% SP (95% CI: 88-100). Against ELISA, SN and SP were above 90% for all three RDTs. CONCLUSIONS: RDT-A and RDT-C displayed IgG detection SN and SP above 90% in whole blood. These RDTs could be considered in the absence of routine diagnostic serology facilities.

Diagnostic accuracy of Augurix COVID-19 IgG serology rapid test.

AIMS: To validate the diagnostic accuracy of the Augurix SARS-CoV-2 IgM/IgG rapid immunoassay diagnostic test (RDT) for COVID-19. METHODS: In this unmatched 1:1 case-control study, blood samples from 46 real-time RT-PCR-confirmed SARS-CoV-2 hospitalized cases and 45 healthy donors (negative controls) were studied. Diagnostic accuracy of the IgG RDT was assessed against both an in-house recombinant spike-expressing immunofluorescence assay (rIFA), as an established reference method (primary endpoint), and the Euroimmun SARS-CoV-2 IgG enzyme-linked immunosorbent assays (ELISA) (secondary endpoint). RESULTS: COVID-19 patients were more likely to be male (61% vs 20%; P = .0001) and older (median 66 vs 47 years old; P < .001) than controls. Whole blood IgG-RDT results showed 86% and 93% overall Kendall concordance with rIFA and IgG ELISA, respectively. IgG RDT performances were similar between plasma and whole blood. Overall, RDT sensitivity was 88% (95% confidence interval [95%CI]: 70-96), specificity 98% (95%CI: 90-100), PPV 97% (95%CI: 80-100) and NPV 94% (95%CI: 84-98). The IgG-RDT carried out from 0 to 6 days, 7 to 14 days and > 14 days after the SARS-CoV-2 RT-PCR test displayed 30%, 73% and 100% positivity rates in the COVID-19 group, respectively. When considering samples taken >14 days after RT-PCR diagnosis, NPV was 100% (95%CI:90-100), and PPV was 100% (95%CI:72-100). CONCLUSIONS: The Augurix IgG-RDT done in whole blood displays a high diagnostic accuracy for SARS-CoV-2 IgG in high COVID-19 prevalence settings, where its use could be considered in the absence of routine diagnostic serology facilities.

Rimeporide as a first- in-class NHE-1 inhibitor: Results of a phase Ib trial in young patients with Duchenne Muscular Dystrophy.

Rimeporide, a first-in-class sodium/proton exchanger Type 1 inhibitor (NHE-1 inhibitor) is repositioned by EspeRare for patients with Duchenne Muscular Dystrophy (DMD). Historically, NHE-1 inhibitors were developed for cardiac therapeutic interventions. There is considerable overlap in the pathophysiological mechanisms in Congestive Heart Failure (CHF) and in cardiomyopathy in DMD, therefore NHE-1 inhibition could be a promising pharmacological approach to the cardiac dysfunctions observed in DMD. Extensive preclinical data was collected in various animal models including dystrophin-deficient (mdx) mice to characterise Rimeporide's anti-fibrotic and anti-inflammatory properties and there is evidence that NHE-1 inhibitors could play a significant role in modifying DMD cardiac and also skeletal pathologies, as the NHE-1 isoform is ubiquitous. We report here the first study with Rimeporide in DMD patients. This 4-week treatment, open label phase Ib, multiple oral ascending dose study, enrolled 20 ambulant boys with DMD (6-11 years), with outcomes including safety, pharmacokinetic (PK) and pharmacodynamic (PD) biomarkers. Rimeporide was safe and well-tolerated at all doses. PK evaluations showed that Rimeporide was well absorbed orally reaching pharmacological concentrations from the lowest dose, with exposure increasing linearly with dose and with no evidence of accumulation upon repeated dosing. Exploratory PD biomarkers showed positive effect upon a 4-week treatment, supporting its therapeutic potential in patients with DMD, primarily as a cardioprotective treatment, and provide rationale for further efficacy studies.

Antinuclear Antibodies With a Homogeneous and Speckled Immunofluorescence Pattern Are Associated With Lack of Cancer While Those With a Nucleolar Pattern With the Presence of Cancer.

Background: Different antinuclear antibody (ANA) patterns have been associated with the presence of cancer, while other are typically seen in autoimmune diseases. This study aims to investigate the association between ANA and cancer, focusing on patients with ANA with a nucleolar indirect immunofluorescence (IIF) pattern. Materials and Methods: ANA patterns and positivity of antibodies against nuclear antigens (NA), in particular those responsible for a nucleolar ANA pattern and/or associated with systemic sclerosis (CENP-A/B, fibrillarin, Ku, NOR-90, PM/Scl-100, PM/Scl-75, RNAP-III, Scl-70, Ro52/TRIM21, and Th/To) were analyzed and correlated to an internal database of patients with cancer. Results: The study included 15,728 patients who had an ANA analysis, 386 patients who had immunodot analysis for antibody/ies against/to specific NA and 15,701 patients diagnosed with cancer. The presence of ANA with a nucleolar pattern showed an increased relative risk (RR 1.5, 95%CI 1.03-2.3) for an associated cancer. Anti-Scl70 and anti-RNAP-III were associated with cancer in 15 and 14%, respectively. The presence of ANA with a homogeneous & speckled (HS) pattern was significantly associated with the absence of cancer (p < 0.01). Patients with a HS pattern were found to have a lower relative risk (RR 0.7, 95%CI 0.5-0.9) of having cancer compared to those with other patterns. Conclusions: Larger studies are needed to investigate which particular antibody/ies against/to specific NA is responsible for the association between nucleolar ANA and cancer, but anti-Scl70 and anti-RNAP-III, which is frequently associated with the presence of anti-RNAP-I, are good candidates to explain this association. Patients with a nucleolar pattern might be considered for cancer screening, in particular if they have anti-Scl70 and anti-RNAP-III antibodies.

Identification of highly active systemic lupus erythematosus by combined type I interferon and neutrophil gene scores vs classical serologic markers.

OBJECTIVES: In SLE, heterogeneous clinical expression and activity may reflect diverse pathogenic and/or effector mechanisms. We investigated SLE heterogeneity by assessing the expression of three gene sets representative of type I IFN (IFN-I), polymorphonuclear neutrophil (PMN) and plasmablast (PB) signatures in a well-characterized, multidisciplinary cohort of SLE patients. We further assessed whether individual gene products could be representative of these three signatures. METHODS: Whole blood, serum and clinical data were obtained from 140 SLE individuals. Gene expression was assessed by NanoString technology, using a panel of 37 probes to compute six IFN-I, one PMN and one PB scores. Protein levels were measured by ELISA. RESULTS: Depending on the score, 45-50% of SLE individuals showed high IFN-I gene expression. All six IFN-I scores were significantly associated with active skin involvement, and two of six were associated with arthritis. IFN-induced Mx1 protein (MX1) level was correlated with IFN-I score (P < 0.0001) and associated with a similar clinical phenotype. In all, 25% of SLE individuals showed high PMN gene expression, associated with SLE fever, serositis, leukopoenia and glucocorticoid use. PB gene expression was highly affected by immunosuppressant agents, with no association with SLE features. Combined IFN-I and PMN gene scores were significantly associated with high disease activity and outperformed anti-dsDNA and anti-C1q autoantibody and complement levels for predicting SLE activity. CONCLUSION: IFN-I and PMN gene scores segregate with distinct SLE clinical features, and their combination may identify high disease activity. MX1 protein level performed similar to IFN-I gene expression.

[How to manage giant cell arteritis]. / Allergologie-immunologie - Prise en charge de l'artérite gigantocellulaire en 2019.

Giant cell arteritis (GCA) is the most common vasculitis in adults over 50 years, which requires an urgent treatment with corticosteroids to reduce ischemic complications. Because of their side-effects, a valid diagnosis is necessary. Histological confirmation remains the gold-standard but non-invasive imaging along specific clinical criteria can nowadays diagnose GCA, particularly temporal artery ultrasound. Alternatives to corticosteroids are being studied and recently, the addition of tocilizumab to corticosteroids has been validated by international institutions and is approved by Swissmedic. Similarly to tocilizumab, methotrexate has been shown to decrease the total dose of corticosteroids and the number of relapses. We will also discuss newer potential therapies (abatacept and ustekinumab).

L'artérite à cellules géantes est une vasculite des gros vaisseaux fréquentes après 50 ans, nécessitant un traitement par corticostéroïdes dès le diagnostic pour diminuer les complications ischémiques. En raison des effets secondaires du traitement, une certitude diagnostique est importante. Bien que la confirmation histologique reste le gold standard, l'imagerie permet désormais de poser un diagnostic non invasif en présence de critères bien définis. Des alternatives aux stéroïdes sont étudiées et récemment, l'adjonction de tocilizumab a été validée par Swissmedic, entre autres dans le but de diminuer la dose totale de stéroïdes et le nombre de rechutes. Le méthotrexate, alternative au tocilizumab, existe et est toujours d'actualité. Nous discuterons également de l'abatacept et de l'ustékinumab, molécules prometteuses en cours d'évaluation.

Management of allergy transfer upon solid organ transplantation.

Allergy transfer upon solid organ transplantation has been reported in the literature, although only few data are available as to the frequency, significance, and management of these cases. Based on a review of 577 consecutive deceased donors from the Swisstransplant Donor-Registry, 3 cases (0.5%) of fatal anaphylaxis were identified, 2 because of peanut and 1 of wasp allergy. The sera of all 3 donors and their 10 paired recipients, prospectively collected before and after transplantation for the Swiss Transplant Cohort Study, were retrospectively processed using a commercial protein microarray fluorescent test. As early as 5 days posttransplantation, newly acquired peanut-specific IgE were transiently detected from 1 donor to 3 recipients, of whom 1 liver and lung recipients developed grade III anaphylaxis. Yet, to define how allergy testing should be performed in transplant recipients and to better understand the impact of immunosuppressive therapy on IgE sensitization, we prospectively studied 5 atopic living-donor kidney recipients. All pollen-specific IgE and >90% of skin prick tests remained positive 7 days and 3 months after transplantation, indicating that early diagnosis of donor-derived IgE sensitization is possible. Importantly, we propose recommendations with respect to safety for recipients undergoing solid-organ transplantation from donors with a history of fatal anaphylaxis.

Anti-apolipoprotein A-1 autoantibodies correlate with disease activity in systemic lupus erythematosus.

OBJECTIVES: Apolipoprotein A-1 (ApoA-1) is a protein fraction of the high-density lipoproteins with anti-inflammatory and antioxidant properties that play a major role in reverse cholesterol transport. The presence of anti-ApoA-1 IgG has been reported in SLE to be variably associated with disease activity or cardiovascular events (CVEs). We assessed the clinical performance of anti-ApoA-1 IgG and of antibodies directed against its immunodominant F3L1 peptide (F3L1 IgG) in a well-characterized Swiss SLE cohort study. METHODS: A total of 354 biological samples and interviews from 176 individuals were studied. SLEDAI, clinical characteristics, anamnestic CVEs and therapy details were recorded. Sera were tested for the presence of anti-ApoA-1 IgG, anti-F3L1 IgG, anti-dsDNA IgG and aPL. RESULTS: Anti-ApoA-1 and anti-F3L1 IgG positivity was associated with higher SLEDAI, mostly due to concomitant positivity of dsDNA IgG and low complement. Variations in time of anti-ApoA-1 IgG correlated positively with variations of anti-dsDNA IgG and inversely to variations of C3 levels. No cross-reactivity was found between anti-ApoA-1 and anti-dsDNA IgG. Positivity for anti-Apo-A1 IgG was more frequent in individuals receiving 10 mg/day or more of prednisone. We did not find any significant association between anti-ApoA-1 IgG positivity and CVEs. CONCLUSION: Anti-ApoA-1 and anti-F3L1 IgG in SLE correlate strongly with laboratory markers of activity, particularly with the presence and titre of dsDNA IgG. These results confirm and extend previous findings and support the use of anti-ApoA1 IgG in the clinical setting. Their role in CVEs deserves further investigation.

Anti-C1q Antibodies as Occurring in Systemic Lupus Erythematosus Could Be Induced by an Epstein-Barr Virus-Derived Antigenic Site.

Previous infection with Epstein-Barr virus (EBV) is believed to trigger autoimmunity and to drive autoantibody generation as occurring in patients with systemic lupus erythematosus (SLE). Complement C1q and autoantibodies targeting it (anti-C1q) are also considered to be involved in the pathogenesis of SLE, independently of the impact of environmental insults. Still, the circumstances under which these autoantibodies arise remain elusive. By studying a major antigenic site of C1q targeted by anti-C1q (A08), we aimed to determine environmental factors and possible mechanisms leading to the development of anti-C1q. First, we determined antigenic residues of A08 that were critical for the binding of anti-C1q; importantly, we found the binding to depend on amino-acid-identity. Anti-C1q of SLE patients targeting these critical antigenic residues specifically cross-reacted with the EBV-related EBNA-1 (Epstein-Barr virus nuclear antigen 1)-derived peptide EBNA348. In a cohort of 180 SLE patients we confirmed that patients that were seropositive for EBV and recognized the EBNA348 peptide had increased levels of anti-A08 and anti-C1q, respectively. The correlation of anti-EBNA348 with anti-A08 levels was stronger in SLE patients than in matched healthy controls. Finally, EBNA348 peptide-immunization of C1q-/- mice induced the generation of cross-reactive antibodies which recognized both the A08 epitope of C1q and intact C1q. These findings suggest that anti-C1q in SLE patients could be induced by an EBV-derived epitope through molecular mimicry, thereby further supporting the pathogenic role of EBV in the development of SLE. Considering the role of C1q and anti-C1q, modifying the anti-EBV response might be a promising strategy to improve the course of the disease.

[Screening for latent tuberculosis infection in immunosuppressed patients not infected with HIV]. / Dépistage de l'infection tuberculeuse latente chez les patients immuno­supprimés non infectés par le VIH.

Screening for latent tuberculosis infection (LTI) is recommended in immunosuppressed patients due to an increased risk of progression from LTI to active tuberculosis. Screening involves indirect immunological tests such as the tuberculin skin test (TST) and the interferon-y release assays (IGRAs). IGRAs seem to show superior performance compared to TST in screening for LTI. However, their use and interpretation in immunosuppressed patients is questionable, particularly because of an increased number of false negative or indeterminate results and a low agreement between tests. Presently, there are no swiss national recommendations for their use in immunosuppressed -patients, except for candidates to anti-TNF treatment.

Le dépistage d'une infection tuberculeuse latente (ITL) est ­recommandé chez les patients immunosupprimés en raison du risque accru de la progression de l'ITL vers la tuberculose active. Son dépistage se fait notamment à l'aide de tests immunologiques indirects que sont le test de sensibilité à la tuberculine (TST) et les tests de détection de production de l'interféron-gamma (IGRA). Les IGRA semblent montrer une performance ­supérieure par rapport au TST dans le dépistage d'une ITL. Mais leur utilisation et leur interprétation chez les immunosupprimés sont sujettes à caution notamment à cause d'un nombre accru de résultats faussement négatifs ou indéterminés et d'une mauvaise concordance entre tests. À l'heure actuelle, il n'existe pas de ­recommandations nationales suisses sur leur utilisation chez les immunosupprimés mis à part pour les candidats au traitement anti-TNF (tumor necrosis factor).

[Evaluation of the new algorithm in ANCA testing]. / Présentation des nouveaux algorithmes de dosage d'ANCA.

Testing for ANCA is useful for the diagnosis and monitoring of disease activity in ANCA associated vasculitis. ANCA testing is also sometimes requested for other indications. The relevance of indirect immunofluorescence in ANCA testing is controversial and has recently been the object of new international recommendations. The new approach certainly improves the performance of this test, particularly in Switzerland where, due to the large number of requests, the pre-test probability of ANCA associated vasculitis is relatively low. However, in this article we discuss the possible flaws of the new algorithm based on two recent cases, and highlight the importance of a good communication with the laboratory in order to improve the interpretation of the results.

La recherche des ANCA est utilisée pour le diagnostic et le suivi de l'activité des vasculites associées aux ANCA, mais aussi parfois pour d'autres indications plus controversées. La place de l'immunofluorescence indirecte dans l'algorithme de dépistage et de suivi des vasculites à ANCA est contestée depuis plusieurs années et a récemment fait l'objet de nouvelles recommandations internationales. Cette nouvelle approche améliore certainement le rendement de ce test, en particulier en Suisse où, en raison du grand nombre d'analyses demandé, la probabilité prétest d'une vasculite à ANCA est relativement faible. Cependant, nous discutons dans cet article les possibles failles de la nouvelle approche en nous basant sur deux cas récents au laboratoire et rendons les prescripteurs attentifs sur l'importance de la communication avec le laboratoire afin d'améliorer l'interprétation des résultats.

Identifying True Celiac Disease and Wheat Allergy in the Era of Fashion Driven Gluten-Free Diets.

BACKGROUND: Diagnosing both celiac disease (CD) and wheat allergy (WA) might be challenging due to the increasingly popular gluten-free diets. OBJECTIVES: This study investigates the value of anti-tissue transglutaminase IgA (tTGIgA) and wheat-specific IgE (WIgE), and identifies clinical and serological features associated with CD and WA. METHOD: Serological markers of autoimmunity and allergy along with medical charts of patients assessed for tTGIgA and WIgE between 2010 and 2016 were evaluated. RESULTS: During the last years, an increasing number of patients have been tested for tTGIgA, while the number of positive results decreased linearly. Among the 2,965 patients included, 128 patients showed at least once a positive tTGIgA. All patients with tTGIgA levels higher than the 12-fold upper normal limit had CD. The ratio of tTGIgA/total IgA did not perform better as a diagnostic test for CD compared to tTGIgA. tTGIgA and anti-nuclear antibodies were significantly associated. WA was only rarely investigated, particularly in adults. However, positive WIgE were found in nearly 50% of the cases. WIgE and tTGIgA values were negatively correlated. CONCLUSIONS: tTGIgA were increasingly tested, while the rate of positive results decreased in recent years, possibly reflecting the impact of current alimentary trends on clinical practice. Associated autoimmune disease was frequently found in CD. High levels of tTGIgA accurately predicted CD diagnosis. WA was rarely investigated and deserves more attention, in particular in children with atopic background. WA does not seem to be associated with CD.