Higher rate of progression in HIV- than in HIV+ patients after rituximab for HHV8+ multicentric Castleman disease

Rituximab has revolutionized the treatment of Kaposi sarcoma-associated herpesvirus/human herpesvirus 8-associated multicentric Castleman disease (HHV8+ MCD), converting a rapidly fatal illness into a relapsing disease. HHV8+ MCD mainly affects patients with HIV infection but can also be observed in patients without HIV infection. We retrospectively analyzed a cohort of 99 patients (73 who tested HIV+ and 26 who tested HIV-), with HHV8+ MCD treated with rituximab-based therapy. Baseline characteristics were similar in patients who had HIV- and HIV+ results, although those who tested HIV- were older (65 vs 42 years) and presented less frequently with Kaposi sarcoma (15% vs 40%). Ninety-five patients (70 HIV+ and 25 HIV-) achieved complete remission (CR) after rituximab-based therapy. After a median follow-up of 51 months, 36 patients (12 HIV- and 24 HIV+) experienced disease progression. The 5-year progression-free survival (PFS) was 54%. The 5-year PFS was lower in HIV- patients than in HIV+ patients : 26% and 62%, respectively (P = .02). A multivariate prognostic factors analysis including time-dependent covariates revealed that HIV- status, reoccurrence of HHV8 DNA >3 log copies per mL, and serum C-reactive protein (CRP) >20 mg/mL were independently associated with an increased risk of progression after rituximab-induced CR (P = .001; P = .01; and P = .01, respectively). The lower rate of progression observed in the population with HIV+ results despite a longer follow-up period might have resulted from the possible immune restoration upon antiretroviral therapy. HHV8 viral load and serum CRP monitoring after rituximab therapy provide information on the progression risk and may help in the decision to resume specific therapy.

Intestinal Candida albicans overgrowth in IgA deficiency

BACKGROUND

Secretory IgA interacts with commensal bacteria, but its impact on human mycobiota ecology has not been widely explored. In particular, whether human IgA-deficiency is associated with gut fungal dysbiosis remains unknown.

OBJECTIVES

Our goal was to study the impact of IgA on gut mycobiota ecology.

METHODS

The Fungi-Flow method was used to characterize fecal, systemic, and maternal IgA, IgM, and IgG responses against 14 representative fungal strains (yeast/spores or hyphae forms) in healthy donors (HDs) (n = 34, 31, and 20, respectively) and to also compare gut mycobiota opsonization by secretory antibodies in HDs (n = 28) and patients with selective IgA deficiency (SIgAd) (n = 12). Stool mycobiota composition was determined by internal transcribed spacer gene sequencing in HDs (n = 23) and patients with SIgAd (n = 17). Circulating CD4+ T-cell cytokine secretion profiles were determined by intracellular staining. The impact of secretory IgA, purified from breast milk (n = 9), on Candidaalbicans growth and intestinal Caco-2 cell invasion was tested in vitro.

RESULTS

Homeostatic IgA binds commensal fungi with a body fluid-selective pattern of recognition. In patients with SIgAd, fungal gut ecology is preserved by compensatory IgM binding to commensal fungi. Gut Calbicans overgrowth nevertheless occurs in this condition but only in clinically symptomatic patients with decreased TH17/TH22 T-cell responses. Indeed, secretory IgA can reduce in vitro budding and invasion of intestinal cells by Calbicans and therefore exert control on this pathobiont.

CONCLUSION

IgA has a selective impact on Calbicans ecology to preserve fungal-host mutualism.

Real-life use of mTOR inhibitor-based therapy in adults with autoimmune cytopenia highlights strong efficacy in relapsing/refractory multi-lineage autoimmune cytopenia

Data on mTOR inhibitors (mTORi) in autoimmune cytopenia (AIC), in adults are scarce. We retrospectively analysed 30 cases of refractory or relapsing AIC treated with an mTORi-based therapy. Eleven warm autoimmune hemolytic anaemia, 10 autoimmune thrombocytopenia, 6 acquired pure red cell aplasia, 3 autoimmune neutropenia were included. Twenty were multilineage AIC (67%) and 21 were secondary AIC (70%). mTORi were associated with other therapies in 23 AIC (77%). Twenty-two AIC (73%) responded to mTORi-based therapy: 5 reached a partial response (17%) and 17 a complete response (57%). Survival without unfavourable outcome (failure, requirement of a new therapy, or death) was longer in multilineage AIC compared to single-lineage AIC (p = 0.049) with a median event-free survival of 48 versus 12 months. Median event-free survival was 48 months in secondary AIC and 33 months in primary AIC (p = 0.79). mTORi were discontinued in 4 patients (15%) for safety reasons and in 3 patients for patient's choice (12%). In conclusion, mTORi could be considered as an alternative or an add-on therapy in refractory or relapsing AIC in adult patients, especially in multilineage AIC.

A neomorphic mutation in the interferon activation domain of IRF4 causes a dominant primary immunodeficiency

Here, we report on a heterozygous interferon regulatory factor 4 (IRF4) missense variant identified in three patients from a multigeneration family with hypogammaglobulinemia. Patients' low blood plasmablast/plasma cell and naïve CD4 and CD8 T cell counts contrasted with high terminal effector CD4 and CD8 T cell counts. Expression of the mutant IRF4 protein in control lymphoblastoid B cell lines reduced the expression of BLIMP-1 and XBP1 (key transcription factors in plasma cell differentiation). In B cell lines, the mutant IRF4 protein as wildtype was found to bind to known IRF4 binding motifs. The mutant IRF4 failed to efficiently regulate the transcriptional activity of interferon-stimulated response elements (ISREs). Rapid immunoprecipitation mass spectrometry of endogenous proteins indicated that the mutant and wildtype IRF4 proteins differed with regard to their respective sets of binding partners. Our findings highlight a novel mechanism for autosomal-dominant primary immunodeficiency through altered protein binding by mutant IRF4 at ISRE, leading to defective plasma cell differentiation.

Post-traumatic stress disorder and quality of life alterations in survivors of immune-mediated thrombotic thrombocytopenic purpura and atypical hemolytic and uremic syndrome

Thrombotic thrombocytopenic purpura (iTTP) and atypical hemolytic-uremic syndrome (aHUS), once in remission, may cause long-term symptoms, among which mental-health impairments may be difficult to detect. We conducted telephone interviews 72 [48-84] months after ICU discharge to assess symptoms of anxiety, depression, and posttraumatic stress disorder (PTSD) and the 36-item Short Form questionnaire (SF-36). Of 103 included patients, 52 had iTTP and 51 aHUS; 74% were female, median age was 39 y (31-54), and 39 (38%) patients were still taking treatment. Symptoms of anxiety, PTSD and depression were present in 50%, 27% and 14% of patients, respectively, with no significant difference between the iTTP and aHUS groups. Patients with PTSD symptoms had significantly greater weight gain and significantly worse perceived physical and/or emotional wellbeing, anxiety symptoms, and depression symptoms. The SF-36 physical and mental components indicated significantly greater quality-of-life impairments in patients with vs. without PTSD symptoms and in those with aHUS and PTSD vs. iTTP with or without PTSD. In the aHUS group, quality of life was significantly better in patients with vs. without eculizumab treatment. Factors independently associated with PTSD symptoms were male sex (odds ratio [OR], 0.11; 95%CI, 0.02-0.53), platelet count ≤20 G/L at acute-episode presentation (OR, 2.68; 1.01-7.38), and current treatment (OR, 2.69; 95%CI, 1.01-7.36). Mental-health screening should be routine in patients with iTTP and aHUS to ensure appropriate care.

Etoposide treatment in secondary hemophagocytic syndrome: impact on healthcare-associated infections and survival

Background

Etoposide remains the cornerstone of symptomatic management of critically ill patients with secondary hemophagocytic syndrome (sHS). Risk of healthcare-associated infections (HAIs) in this setting with etoposide has never been assessed. We sought to evaluate the association between etoposide administration, HAIs occurrence and survival in critically ill adult patients with sHS. In this retrospective single-center study conducted in a university hospital ICU between January 2007 and March 2020, all consecutive patients with sHS were included. HAIs were defined as any microbiologically documented infection throughout ICU stay. Competing risk survival analysis was performed to determine factors associated with HAIs. Propensity score-based overlap weighting was performed to adjust for factors associated with etoposide use.

Results

168 patients with a median age of 49 [38, 59] were included. Forty-three (25.6%) patients presented with at least 1 microbiologically documented HAI throughout ICU stay. After adjustment, cumulative incidence of HAI was higher in patients receiving etoposide (p = 0.007), while survival was unaffected by etoposide status (p = 0.824). By multivariable analysis, etoposide treatment was associated with a higher incidence of HAIs (sHR 3.75 [1.05, 6.67]), whereas no association with survival (sHR 0.53 [0.20, 1.98]) was found. Other factors associated with increased mortality after adjustment included age, immunodepression, male sex, SOFA score > 13, and occurrence of HAI.

Conclusions

In patients with sHS, etoposide treatment is independently associated with increased occurrence of HAIs, whereas no association with survival was found. Intensivists should be aware of increased infectious risk, to promptly detect and treat infections in this specific setting. Studies to assess benefits from prophylactic anti-infectious agents in this setting are warranted and the lack of benefit of etoposide on survival needs to be interpreted cautiously.

A Comprehensive Clinicopathologic and Molecular Study of 19 Primary Effusion Lymphomas in HIV-infected Patients

Primary effusion lymphoma (PEL) is associated with human herpesvirus 8 and frequently with Epstein-Barr virus (EBV). We report here a single-center series of 19 human immunodeficiency virus-associated PELs, including 14 EBV+ and 5 EBV- PELs. The objectives were to describe the clinicopathologic features of PELs, with a focus on programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, to search for genetic alterations by targeted deep sequencing analysis, and to compare the features between EBV+ and EBV- cases. All the patients were male, and the median age at diagnosis was 47 years old (interquartile range: 40 to 56 y). Reflecting the terminal B-cell differentiation, immunophenotypic profiles showed low expression levels of B-cell markers, including CD19 (0/19), CD20 (1/19), CD79a (0/19), PAX5 (1/19), BOB1 (3/19), and OCT2 (4/19), contrasting with a common expression of CD38 (10/19), CD138 (7/19), and IRF4/MUM1 (18/19). We observed a frequent aberrant expression of T-cell markers, especially CD3 (10/19), and less frequently CD2 (2/19), CD4 (3/19), CD5 (1/19), and CD8 (0/19). Only 2 cases were PD-L1 positive on tumor cells and none PD-1 positive. With respect to immune cells, 3 samples tested positive for PD-L1 and 5 for PD-1. Our 36-gene lymphopanel revealed 7 distinct variants in 5/10 PELs, with either a single or 2 mutations per sample: B2M (n=2), CD58 (n=1), EP300 (n=1), TNFAIP3 (n=1), ARID1A (n=1), and TP53 (n=1). Finally, we did not observe any major clinical, pathologic, or immunohistochemical differences between EBV+ and EBV- PELs and the outcome was similar (2-y overall survival probability of 61.9% [95% confidence interval, 31.2-82.1] vs. 60.0% [95% confidence interval, 12.6-88.2], respectively, P=0.62).

Pre-COVID-19 Immunity to Common Cold Human Coronaviruses Induces a Recall-Type IgG Response to SARS-CoV-2 Antigens Without Cross-Neutralisation

The capacity of pre-existing immunity to human common coronaviruses (HCoV) to cross-protect against de novo COVID-19is yet unknown. In this work, we studied the sera of 175 COVID-19 patients, 76 healthy donors and 3 intravenous immunoglobulins (IVIG) batches. We found that most COVID-19 patients developed anti-SARS-CoV-2 IgG antibodies before IgM. Moreover, the capacity of their IgGs to react to beta-HCoV, was present in the early sera of most patients before the appearance of anti-SARS-CoV-2 IgG. This implied that a recall-type antibody response was generated. In comparison, the patients that mounted an anti-SARS-COV2 IgM response, prior to IgG responses had lower titres of anti-beta-HCoV IgG antibodies. This indicated that pre-existing immunity to beta-HCoV was conducive to the generation of memory type responses to SARS-COV-2. Finally, we also found that pre-COVID-19-era sera and IVIG cross-reacted with SARS-CoV-2 antigens without neutralising SARS-CoV-2 infectivity in vitro. Put together, these results indicate that whilst pre-existing immunity to HCoV is responsible for recall-type IgG responses to SARS-CoV-2, it does not lead to cross-protection against COVID-19.

Leg‐type form of idiopathic multicentric Castleman disease associated with severe lower extremity chronic venous/lymphatic disease

Idiopathic multicentric Castleman disease (iMCD) is a lymphoproliferative disease of unknown etiology. Deciphering mechanisms involved in CD pathogenesis may help improving patients’ care. Six cases of stereotyped sub‐diaphragmatic iMCD affecting lower limb‐draining areas and associated with severe and often ulcerative lower extremity chronic dermatological condition were identified in our cohort. Pathological examination revealed mixed or plasma‐cell type MCD. In three patients, shotgun metagenomics failed to identify any pathogen in involved lymph nodes. Antibiotics had a suspensive effect while rituximab and tocilizumab failed to improve the condition. This novel entity requires a specific approach and exclusion of potentially harmful immunomodulation.

Characteristics of thrombocytopenia, anasarca, fever, reticulin fibrosis and organomegaly syndrome: a retrospective study from a large Western cohort

Idiopathic multicentric Castleman disease (iMCD) is a non-clonal inflammatory lymphoproliferative disorder of unknown origin. Recently, TAFRO syndrome (thrombocytopenia, anasarca, fever, reticulin fibrosis and organomegaly) emerged as a singular variant of iMCD in Asia and was associated with a severe course and a poor outcome. The present study describes the first large Western cohort of TAFRO syndrome patients (n = 25) meeting the All Japan TAFRO Syndrome Research Group diagnostic criteria. Characteristics of TAFRO patients were compared to iMCD-not otherwise specified (iMCD-NOS) patients used as a control group (n = 43). Our results show that despite baseline characteristics in accordance with previously reported series, Western TAFRO syndrome patients do not appear to present with a worse outcome than iMCD-NOS patients. There were no significant differences between the two groups regarding treatment choice, response to rituximab (71% vs. 67%) or tocilizumab (69% vs. 91%) in TAFRO and iMCD-NOS, respectively. The two-year overall survival was above 95% in both groups. Limits of inclusion and exclusion criteria for TAFRO definition are also discussed. Our findings raise the question of the singularity of the TAFRO entity in Western countries. The data should promote further research using unsupervised models to identify markers of disease severity in Western cohorts of iMCD patients.

Coagulation disorders in patients with severe hemophagocytic lymphohistiocytosis

Background

Coagulation disorders are common in patients with hemophagocytic lymphohistiocytosis (HLH), associated with an increased risk of bleeding and death. We aim to investigate coagulation disorders and their outcome implications in critically ill patients with HLH.

Methods

We prospectively evaluated 47 critically ill patients with HLH (median age of 54 years [42–67]) between April 2015 and December 2018. Coagulation assessments were performed at day 1. Abnormal standard coagulation was defined as prothrombin time (PT) <50% and/or fibrinogen <2g/L. HLH aetiology was mostly ascribed to haematological malignancies (74% of patients).

Results

Coagulation disorders and severe bleeding events were frequent, occurring in 30 (64%) and 11 (23%) patients respectively. At day 1, median fibrinogen level was 2∙65g/L [1.61–5.66]. Fibrinolytic activity was high as suggested by increased median levels of D-dimers, fibrin monomers, PAI-1 (plasminogen activator inhibitor) and tPA (tissue plasminogen activator). Forty-one (91%) patients had a decreased ADAMTS13 activity (A Disintegrin-like And Metalloproteinase with ThromboSpondin type 1 repeats, member 13). By multivariable analysis, the occurrence of a severe bleeding (OR 3.215 [1.194–8.653], p = 0∙021) and SOFA score (Sepsis-Related Organ Failure Assessment) at day 1 (OR 1.305 per point [1.146–1.485], p<0∙001) were independently associated with hospital mortality. No early biological marker was associated with severe bleeding.

Conclusions

Hyperfibrinolysis may be the primary mechanism responsible for hypofibrinogenemia and may also participate in ADAMTS13 degradation. Targeting the plasmin system appears as a promising approach in severe HLH-related coagulation disorders.

Rituximab-resistant splenic memory B cells and newly engaged naive B cells fuel relapses in patients with immune thrombocytopenia

Rituximab (RTX), an antibody targeting CD20, is widely used as a first-line therapeutic strategy in B cell-mediated autoimmune diseases. However, a large proportion of patients either do not respond to the treatment or relapse during B cell reconstitution. Here, we characterize the cellular basis responsible for disease relapse in secondary lymphoid organs in humans, taking advantage of the opportunity offered by therapeutic splenectomy in patients with relapsing immune thrombocytopenia. By analyzing the B and plasma cell immunoglobulin gene repertoire at bulk and antigen-specific single-cell level, we demonstrate that relapses are associated with two responses coexisting in germinal centers and involving preexisting mutated memory B cells that survived RTX treatment and naive B cells generated upon reconstitution of the B cell compartment. To identify distinctive characteristics of the memory B cells that escaped RTX-mediated depletion, we analyzed RTX refractory patients who did not respond to treatment at the time of B cell depletion. We identified, by single-cell RNA sequencing (scRNA-seq) analysis, a population of quiescent splenic memory B cells that present a unique, yet reversible, RTX-shaped phenotype characterized by down-modulation of B cell-specific factors and expression of prosurvival genes. Our results clearly demonstrate that these RTX-resistant autoreactive memory B cells reactivate as RTX is cleared and give rise to plasma cells and further germinal center reactions. Their continued surface expression of CD19 makes them efficient targets for current anti-CD19 therapies. This study thus identifies a pathogenic contributor to autoimmune diseases that can be targeted by available therapeutic agents.

Perturbed Microbiota/Immune Homeostasis in Multiple Sclerosis

Objective

Based on animal models and human studies, there is now strong suspicion that host/microbiota mutualism in the context of gut microbial dysbiosis could influence immunity and multiple sclerosis (MS) evolution. Our goal was to seek evidence of deregulated microbiota-induced systemic immune responses in patients with MS.

Methods

We investigated gut and systemic commensal-specific antibody responses in healthy controls (n = 32), patients with relapsing-remitting MS (n = 30), and individuals with clinically isolated syndromes (CISs) (n = 15). Gut microbiota composition and diversity were compared between controls and patients by analysis of 16S ribosomal ribonucleic acid (rRNA) sequencing. Autologous microbiota and cultivable bacterial strains were used in bacterial flow cytometry assays to quantify autologous serum IgG and secretory IgA responses to microbiota. IgG-bound bacteria were sorted by flow cytometry and identified using 16S rRNA sequencing.

Results

We show that commensal-specific gut IgA responses are drastically reduced in patients with severe MS, disease severity being correlated with the IgA-coated fecal microbiota fraction (r = −0.647, p < 0.0001). At the same time, IgA-unbound bacteria elicit qualitatively broad and quantitatively increased serum IgG responses in patients with MS and CIS compared with controls (4.1% and 2.5% vs 1.9%, respectively, p < 0.001).

Conclusions

Gut and systemic microbiota/immune homeostasis are perturbed in MS. Our results argue that defective IgA responses in MS are linked to a breakdown of systemic tolerance to gut microbiota leading to an enhanced triggering of systemic IgG immunity against gut commensals occurring early in MS.

Prévalence de la dénutrition et évaluation de l’efficacité d’une prise en charge nutritionnelle précoce chez les patients hospitalisés atteints du COVID-19

Introduction et but de l’étude

L’infection par le SARS-Cov2 (COVID-19) s’associe à un risque majeur de dénutrition. Cependant, les données nutritionnelles chez les patients atteints de COVID-19 sont limitées. Nos objectifs étaient :

– d’évaluer la prévalence de la dénutrition chez les patients hospitalisés pour COVID-19 à j0 puis à j30 post-hospitalisation ;

– d’étudier les liens entre dénutrition et gravité de la maladie à l’admission ;

– d’étudier l’impact de la dénutrition sur une évolution défavorable de la maladie (transfert vers une unité de soins intensifs (USI) ou décès) ;

– d’évaluer l’impact d’une prise en charge nutritionnelle précoce.

Matériel et méthodes

Tous les patients hospitalisés pour COVID-19 dans le service de médecine interne du CHU Pitié-Salpêtrière ont été inclus du 21 mars au 24 avril 2020 (n = 114, 60,5 % d’hommes, âge : 59,9 ± 15,9 ans). L’état nutritionnel de ces patients a été défini en utilisant les critères de la Haute Autorité de santé (HAS) 2019. Les caractéristiques cliniques, radiologiques et biologiques des patients atteints de COVID-19 ont été comparées en fonction de leur statut nutritionnel. Une régression logistique a été utilisée pour évaluer les associations entre les paramètres nutritionnels et l’évolution défavorable de la maladie. Une prise en charge nutritionnelle précoce selon la perte de poids et d’appétit des patients (consistant à une alimentation enrichie, une prévention du syndrome de renutrition inappropriée, des compléments nutritionnels oraux CNO et/ou une nutrition entérale NE), a été mise en place dès l’admission. À j30 post-hospitalisation, les données nutritionnelles cliniques, biologiques, anthropométriques, ont été collectées afin d’étudier l’évolution de l’état nutritionnel.

Résultats et analyse statistique

La prévalence globale de la dénutrition à j0 était de 44,6 % (14,2 % de dénutrition modérée, 30,4 % de dénutrition sévère). Celle-ci atteignait 66,7 % chez les patients provenant d’un service de réanimation. Une hypoalbuminémie initiale était associée à un risque plus élevé de transfert en unité de soins intensifs (pour 10 g/L d’albumine, OR [IC95 %] : 0,31 [0,1 ; 0,7] ; p < 0,01) et ce, indépendamment de l’âge et de la CRP. Après prise en charge nutritionnelle (69 % de CNO et 2,6 % de NE), la prévalence de la dénutrition à j30 post-hospitalisation était de 20,6 % (15,2 % de dénutrition modérée et 5,4 % de dénutrition sévère). À j30, on observait une masse musculaire basse selon impédancemétrie et une fonction musculaire altérée selon Handgrip chez 29,3 % des patients par rapport aux normes HAS.

Conclusion

La COVID-19 en service de médecine est associée à une forte prévalence de la dénutrition, encore plus marquée chez les patients provenant d’une USI. L’hypoalbuminémie à l’admission est associée à une évolution défavorable de la maladie, et ce indépendamment de la CRP et de l’âge. Un dépistage et une prise en charge nutritionnelle globale est possible (malgré les difficultés de recueil de données anthropométriques et de mise en place de la stratégie nutritionnelle liées aux mesures barrière), nécessaire et efficace chez ces patients, de manière précoce, ainsi que dans le suivi.

Performance of Diagnostic Scores in Thrombotic Microangiopathy Patients in the Intensive Care Unit: A Monocentric Study

Early thrombotic thrombocytopenic purpura (TTP) recognition is critical as this disease is almost always lethal if not treated promptly with therapeutic plasma exchanges. Currently, as ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity is not widely available in emergency, scores have been developed to help differentiating TTP from other thrombotic microangiopathies (TMAs). The aim of this work was to study the accuracy of these diagnostic scores in the intensive care unit (ICU) setting. Performance of both Coppo and PLASMIC scores was studied in a cohort of adult TMA patients requiring admission to one university hospital ICU from 2006 to 2017. Receiver operating characteristic (ROC) curves were established, and confidence intervals of the area under the curve (AUC) were determined. Multivariate logistic regression analysis was performed to identify parameters specifically associated with TTP, to compare diagnostic scores and to elaborate more accurate diagnostic models. During the study period, 154 TMA patients required ICU admission, including 99 (64.2%) TTP and 55 (35.7%) non-TTP patients. AUC under the ROC curve in predicting TTP was 0.86 (95% confidence interval [CI]: 0.81-0.92) for the Coppo score, 0.67 (95% CI: 0.58-0.76) for the PLASMIC score, and 0.86 (95% CI: 0.81-0.92) for platelet count alone. Platelet count ≤20 G/L, determined as the best cut-off rate for thrombocytopenia, performed similarly to the Coppo score and better than the PLASMIC score to differentiate TTP from non-TTP patients, both using AUC ROC curve and logistic regression. In a monocentric cohort of TMA patients requiring ICU admission, the PLASMIC score had limited performance for the diagnosis of TTP. The performance of the Coppo score was good but similar to a single highly discriminant item: platelet count ≤20 G/L at admission.

IgA dominates the early neutralizing antibody response to SARS-CoV-2

Humoral immune responses are typically characterized by primary IgM antibody responses followed by secondary antibody responses associated with immune memory and composed of IgG, IgA, and IgE. Here, we measured acute humoral responses to SARS-CoV-2, including the frequency of antibody-secreting cells and the presence of SARS-CoV-2-specific neutralizing antibodies in the serum, saliva, and bronchoalveolar fluid of 159 patients with COVID-19. Early SARS-CoV-2-specific humoral responses were dominated by IgA antibodies. Peripheral expansion of IgA plasmablasts with mucosal homing potential was detected shortly after the onset of symptoms and peaked during the third week of the disease. The virus-specific antibody responses included IgG, IgM, and IgA, but IgA contributed to virus neutralization to a greater extent compared with IgG. Specific IgA serum concentrations decreased notably 1 month after the onset of symptoms, but neutralizing IgA remained detectable in saliva for a longer time (days 49 to 73 post-symptoms). These results represent a critical observation given the emerging information as to the types of antibodies associated with optimal protection against reinfection and whether vaccine regimens should consider targeting a potent but potentially short-lived IgA response.

Human IgA binds a diverse array of commensal bacteria

In humans, several grams of IgA are secreted every day in the intestinal lumen. While only one IgA isotype exists in mice, humans secrete IgA1 and IgA2, whose respective relations with the microbiota remain elusive. We compared the binding patterns of both polyclonal IgA subclasses to commensals and glycan arrays and determined the reactivity profile of native human monoclonal IgA antibodies. While most commensals are dually targeted by IgA1 and IgA2 in the small intestine, IgA1⁺IgA2⁺ and IgA1⁻IgA2⁺ bacteria coexist in the colon lumen, where Bacteroidetes is preferentially targeted by IgA2. We also observed that galactose-α terminated glycans are almost exclusively recognized by IgA2. Although bearing signs of affinity maturation, gut-derived IgA monoclonal antibodies are cross-reactive in the sense that they bind to multiple bacterial targets. Private anticarbohydrate-binding patterns, observed at clonal level as well, could explain these apparently opposing features of IgA, being at the same time cross-reactive and selective in its interactions with the microbiota.

From Dysgammaglobulinemia to Autosomal-Dominant Activation-Induced Cytidine Deaminase Deficiency: Unraveling an Inherited Immunodeficiency after 50 Years

The genetic investigation of a family presenting with a dominant form of hyper IgM syndrome published in 1963 and 1975 revealed a R190X nonsense mutation in activation-induced cytidine deaminase. This report illustrates the progress made over 6 decades in the characterization of primary immunodeficiencies, from immunochemistry to whole-exome sequencing.

FRI0157 EPSTEIN BARR VIRUS BLOOD REPLICATION INCREASES DURING ACTIVE SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

A role for Epstein Barr Virus (EBV) infection in Systemic Lupus Erythematosus (SLE) pathogenesis is highly suspected. The frequency of EBV seroprevalence and DNA detection in peripheral blood mononuclear cells are increased in SLE patients compared to healthy controls.

Objectives:

To analyse the relationship between EBV blood replication and SLE disease activity.

Methods:

Monocentric, observational and retrospective study of SLE patients (ACR or SLICC criteria) who have had a blood EBV DNA assessment using Polymerase Chain Reaction (artus® EBV Virus QS-RGQ assay) between 2012 and 2018. Exclusion criteria were: organ or bone marrow transplant, absence of EBV seroconversion and insufficient data. SLE clinical features, the Safety of Estrogens in Lupus Erythematosus National Assessment–Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) flare index (SFI) and therapeutic regimen on the day of EBV DNA load assessment were recorded. A SELENA-SLEDAI score > 4 defined an active SLE. A blood EBV DNA load ≥125 IU/mL was defined as elevated.

Results:

A total of 105 patients (98 women and 7 men) were included in the study. At inclusion, median (quartiles) age and SLE duration were 34 (23.5-43) and 7 (2-14) years old, respectively. Treatment were hydroxychloroquine (HCQ) (n = 67; 64%), prednisone (n = 66; 63%) with an average (±Standard Deviation) dose of 11.3 (±16) mg/day and an immunosuppressant (n = 42; 40%). According to SFI, 57 SLE patients were experiencing a flare at the time of EBV assessment; flares were classified as severe and mild/moderate in 38 (36%) and 19 (18%) SLE patients, respectively. According to the SELENA-SLEDAI score, 60 patients (57%) were deemed active and 45 (43%) inactive. Main clinical manifestations were arthritis in 32 (30%) patients, constitutional symptoms (fever, weight loss, anorexia or lymphadenopathy) in 31 (30%), cutaneous involvement in 23 (22%), glomerulonephritis in 19 (18%), cytopenia in 14 (13%), neuropsychiatric involvement in 13 (12%) and serositis in 10 (16%). Blood EBV DNA was elevated in 54 (90%) of the 60 patients with active lupus versus 6 (13%) of the 45 patients with inactive SLE (p <10-4). It was increased in 34 (89%) of the 38 patients with severe flare, in 17 (89%) of the 19 patients with a mild/moderate flare (p = 1) and in 8 (17%) of the 48 patients without flare (p <10-4vs severe flare and p <10-4vs mild/moderate flare). EBV DNA load correlated with SELENA-SLEDAI score (r=0.58; p<0.0001). Elevated blood EBV DNA was not associated with HCQ, prednisone or immunosuppressant intakes. Eighteen patients with active SLE had a second assessment of blood EBV DNA load. For these patients, the median [range] of viral load was significantly higher during periods of active SLE (236 [0-2680] IU/mL) compared with periods with lower SELENA-SLEDAI score (0 [0-1537] IU/mL, p<10-4in paired analysis).

Conclusion:

Blood EBV viral load is dramatically increased in active phase of SLE, independently of the treatment. We were unable to demonstrate whether the replication of EBV was the cause or the consequence or just an epiphenomenon of the disease activity. Further studies are needed to study whether EBV viral load is linked with Interferons secretion or B lymphocyte activation.

Disclosure of Interests:

None declared

Thrombocytopenia, Anasarca, Fever, Reticulin Fibrosis/Renal Failure, and Organomegaly (TAFRO) Syndrome with Bilateral Adrenal Hemorrhage in Two Caucasian Patients

Case series

Patients: Male, 19-year-old • Female, 31-year-old

Final Diagnosis: TAFRO syndrome

Symptoms: Fever • splenomegaly • lymphadenopathies

Medication: —

Clinical Procedure: —

Specialty: Hematology

The antibody/microbiota interface in health and disease

The human intestine is densely colonized with commensal microbes that stimulate the immune system. While secretory Immunoglobulin (Ig) A is known to play a crucial role in gut microbiota compartmentalization, secretory IgM, and systemic IgG have recently been highlighted in host-microbiota interactions as well. In this review, we discuss important aspects of secretory IgA biology, but rather than focusing on mechanistic aspects of IgA impact on microbiota, we stress the current knowledge of systemic antibody responses to whole gut microbiota, in particular their generation, specificities, and function. We also provide a comprehensive picture of secretory IgM biology. Finally, therapeutic and diagnostic implications of these novel findings for the treatment of various diseases are outlined.

Microbial ecology perturbation in human IgA deficiency

Paradoxically, loss of immunoglobulin A (IgA), one of the most abundant antibodies, does not irrevocably lead to severe infections in humans but rather is associated with relatively mild respiratory infections, atopy, and autoimmunity. IgA might therefore also play covert roles, not uniquely associated with control of pathogens. We show that human IgA deficiency is not associated with massive quantitative perturbations of gut microbial ecology. Metagenomic analysis highlights an expected pathobiont expansion but a less expected depletion in some typically beneficial symbionts. Gut colonization by species usually present in the oropharynx is also reminiscent of spatial microbiota disorganization. IgM only partially rescues IgA deficiency because not all typical IgA targets are efficiently bound by IgM in the intestinal lumen. Together, IgA appears to play a nonredundant role at the forefront of the immune/microbial interface, away from the intestinal barrier, ranging from pathobiont control and regulation of systemic inflammation to preservation of commensal diversity and community networks.

Synergistic convergence of microbiota-specific systemic IgG and secretory IgA

BACKGROUND

Commensals induce local IgA responses essential to the induction of tolerance to gut microbiota, but it remains unclear whether antimicrobiota responses remain confined to the gut.

OBJECTIVE

The aim of this study was to investigate systemic and intestinal responses against the whole microbiota under homeostatic conditions and in the absence of IgA.

METHODS

We analyzed blood and feces from healthy donors, patients with selective IgA deficiency (SIgAd), and patients with common variable immunodeficiency (CVID). Immunoglobulin-coated bacterial repertoires were analyzed by using combined bacterial fluorescence-activated cell sorting and 16S rRNA sequencing. Bacterial lysates were probed by using Western blot analysis with healthy donor sera.

RESULTS

Although absent from the healthy gut, serum antimicrobiota IgG are present in healthy subjects and increased in patients with SIgAd. IgG converges with nonoverlapping secretory IgA specificities to target the same bacteria. Each individual subject targets a diverse microbiota repertoire with a proportion that correlates inversely with systemic inflammation. Finally, intravenous immunoglobulin preparations target CVID gut microbiota much less efficiently than healthy microbiota.

CONCLUSION

Secretory IgA and systemic IgG converge to target gut microbiota at the cellular level. SIgAd-associated inflammation is inversely correlated with systemic anticommensal IgG responses, which might serve as a second line of defense. We speculate that patients with SIgAd could benefit from oral IgA supplementation. Our data also suggest that intravenous immunoglobulin preparations can be supplemented with IgG from IgA-deficient patient pools to offer better protection against gut bacterial translocations in patients with CVID.

Immune/microbial interface perturbation in human IgA deficiency

In a recently published article we report the metagenomic analysis of human gut microbiomes evolved in the absence of immunoglobulin A (IgA). We show that human IgA deficiency is not associated with massive quantitative perturbations of gut microbial ecology. While our study underlines a rather expected pathobiont expansion, we at the same time highlight a less expected depletion in some typically beneficial symbionts. We also show that IgM partially supply IgA deficiency, explaining the relatively mild clinical phenotype associated with the early steps of this condition. Microbiome studies in patients should consider potential issues such as cohort size, human genetic polymorphism and treatments. In this commentary, we discuss how such issues were taken into account in our own study.

Comment on "Diversification of the antigen-specific T cell receptor repertoire after varicella zoster vaccination"

Analysis of antigen-specific T cells can be confounded by T cell activation in vitro.

Regulatory T Cell Responses to High-Dose Methylprednisolone in Active Systemic Lupus Erythematosus

BACKGROUND/PURPOSE

A slight increase in the proportion of circulating regulatory T (Treg) cells has been reported in systemic lupus erythematosus (SLE) patients taking oral prednisone. The effects of intravenous (IV) high dose methylprednisolone (MP) on Tregs have not yet been described, especially in active SLE.

METHODS

We prospectively analyzed the proportion of circulating CD4+ Treg cell subsets defined as follows: (1) naïve Treg (nTreg) FoxP3lowCD45RA+ cells; (2) effector Treg (eTreg) FoxP3highCD45RA- cells; and (3) non-suppressive FoxP3lowCD45RA- cells (non-regulatory Foxp3low T cells). Peripheral blood mononuclear cells of patients with active SLE were analyzed before the first infusion of IV high dose MP (day 0) and the following days (day 1, day 2, ±day 3 and ±day 8). The activity of SLE was assessed by the SLEDAI score.

RESULTS

Seventeen patients were included. Following MP infusions, the median (range) percentage of eTregs significantly increased from 1.62% (0.53-8.43) at day 0 to 2.80% (0.83-14.60) at day 1 (p = 0.003 versus day 0), 4.64% (0.50-12.40) at day 2 (p = 0.06 versus day 1) and 7.50% (1.02-20.70) at day 3 (p = 0.008 versus day 2), and declined to baseline values at day 8. Expanding eTreg cells were actively proliferating, as they expressed Ki-67. The frequency of non-regulatory FoxP3low T cells decreased from 6.39% (3.20-17.70) at day 0 to 4.74% (1.03-9.72) at day 2 (p = 0.005); nTreg frequency did not change. All patients clinically improved immediately after MP pulses. The absence of flare after one year of follow up was associated with a higher frequency of eTregs at day 2.

CONCLUSION

IV high dose MP induces a rapid, dramatic and transient increase in circulating regulatory T cells. This increase may participate in the preventive effect of MP on subsequent flares in SLE.

Quality control of microbiota metagenomics by k-mer analysis

Background

The biological and clinical consequences of the tight interactions between host and microbiota are rapidly being unraveled by next generation sequencing technologies and sophisticated bioinformatics, also referred to as microbiota metagenomics. The recent success of metagenomics has created a demand to rapidly apply the technology to large case–control cohort studies and to studies of microbiota from various habitats, including habitats relatively poor in microbes. It is therefore of foremost importance to enable a robust and rapid quality assessment of metagenomic data from samples that challenge present technological limits (sample numbers and size). Here we demonstrate that the distribution of overlapping k-mers of metagenome sequence data predicts sequence quality as defined by gene distribution and efficiency of sequence mapping to a reference gene catalogue.

Results

We used serial dilutions of gut microbiota metagenomic datasets to generate well-defined high to low quality metagenomes. We also analyzed a collection of 52 microbiota-derived metagenomes. We demonstrate that k-mer distributions of metagenomic sequence data identify sequence contaminations, such as sequences derived from “empty” ligation products. Of note, k-mer distributions were also able to predict the frequency of sequences mapping to a reference gene catalogue not only for the well-defined serial dilution datasets, but also for 52 human gut microbiota derived metagenomic datasets.

Conclusions

We propose that k-mer analysis of raw metagenome sequence reads should be implemented as a first quality assessment prior to more extensive bioinformatics analysis, such as sequence filtering and gene mapping. With the rising demand for metagenomic analysis of microbiota it is crucial to provide tools for rapid and efficient decision making. This will eventually lead to a faster turn-around time, improved analytical quality including sample quality metrics and a significant cost reduction. Finally, improved quality assessment will have a major impact on the robustness of biological and clinical conclusions drawn from metagenomic studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1406-7) contains supplementary material, which is available to authorized users.

Outcome of acute promyelocytic leukemia (APL) in children and adolescents: an analysis in two consecutive trials of the European APL Group

PURPOSE

Acute promyelocytic leukemia (APL) is rare in children. All-trans-retinoic acid (ATRA) combined with chemotherapy, the reference treatment of APL, is generally considered to produce similar results in children and adults. However, previously published childhood APL studies have generally analyzed all patients age < 18 years as a group, without further dividing according to age.

PATIENTS AND METHODS

We compared disease characteristics and outcomes of children (age ≤ 12 years), adolescents (13 to 18 years), and adults (> 18 years) included in two multicenter APL clinical trials (APL 93 and 2000 trials).

RESULTS

Of the 833 patients age ≤ 60 years included in the two trials, 26 (3%), 58 (7%), and 749 (90%) were children, adolescents, and adults, respectively. Children had significantly higher baseline WBC counts (P < .001). The complete remission (CR) rate (92%, 100%, and 94.5%, respectively) and 5-year cumulative incidence of relapse (CIR; 28%, 20%, and 23%, respectively) did not differ between children, adolescents, and adults, whereas adolescents had significantly better overall survival (OS; 5-year OS, 93.6% v 80.4% in adults and 80.4% in children; P = .03). However, in children age ≤ 4 years, the 5-year CIR was 52%, compared with 17.6% in children age 5 to 12 years (P = .006), although most of the younger children who relapsed experienced durable salvage with autologous or allogeneic stem-cell transplantation.

CONCLUSION

Adolescents and children age > 4 years with APL treated with ATRA and chemotherapy have outcomes at least as favorable as those of adults. Younger children seem to experience more relapses and may require reinforcement of first-line treatment.