[Acute chest syndrome in sickle cell disease]. / Syndrome thoracique aigu : une complication grave de la drépanocytose.

The acute chest syndrome is a frequent complication in patients with sickle cell disease. It results from the occlusion of pulmonary capillaries and complex pathophysiological mechanisms. The diagnosis of an acute chest syndrome includes bilateral infiltrates on x-ray, along with fever or respiratory symptoms. The appropriate medical treatment includes hydration, analgesics, oxygen, broad-spectrum antibiotics that cover atypical bacteria and transfusions or exchange transfusion.

Le syndrome thoracique aigu est une complication grave et la première cause de mortalité de la drépanocytose. Elle résulte d'une occlusion des capillaires pulmonaires, suivie de phénomènes physiopathologiques complexes. Le diagnostic est posé en présence d'un infiltrat pulmonaire bilatéral radiologique, accompagné de symptômes cliniques tels qu'un état fébrile ou des symptômes respiratoires. Les traitements comprennent une hydratation, une oxygénothérapie, une antalgie, une antibiothérapie à large spectre incluant une couverture des germes atypiques et des thérapies transfusionnelles en cas d'évolution non favorable (transfusions ou échanges transfusionnels).

[Threshold for allogeneic red cell transfusions in adult patients]. / Stratégie transfusionnelle pour les concentrés erythrocytaires chez l'adulte.

Red cell concentrate is a life-saving but expensive and sometimes limited resource. Its use is associated with a wide range of rare but potentially severe complications. Adequate red cell transfusion is critical in terms of costs, resource utilization and safety. Transfusion thresholds have been widely debated and recent evidence suggest that a restrictive transfusion strategy may allow safely reducing the use of red cell concentrates and even improving clinical outcomes in some situations. The aim of this article is to review the physiologic adaptive responses to anemia and to discuss the clinical evidence about erythrocyte transfusion strategies in adult patients in order to provide evidence-based transfusion recommendations.

Defibrotide Shows Efficacy in the Prevention of Sinusoidal Obstruction Syndrome After Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Study.

Sinusoidal obstruction syndrome (SOS), also known as hepatic veno-occlusive disease (VOD), is a well-known complication of allogeneic hematopoietic stem cell transplantation (HSCT) associated with a mortality rate of up to 85%.  Defibrotide has shown efficacy in treatment of SOS/VOD. Moreover, evidence exists supporting the efficacy of defibrotide as SOS/VOD prophylaxis. We have previously reported our single center experience on 52 HSCT recipients receiving defibrotide as SOS/VOD prophylaxis, which has shown that the patients did not develop any SOS/VOD under this prophylaxis. The aim of the present study was to see if we can confirm the previous results, mainly on the decrease incidence of SOS/VOD, as well as improve event-free survival (EFS) on a larger study population. We extended our previous study in a single-center retrospective analysis to include 237 consecutive patients (248 transplantations) who underwent transplantation between 1999 and 2009 for hematological diseases and receiving intravenous defibrotide as prophylaxis. This cohort was compared to 241 patients (248 transplantations) treated before 1999 or after 2009 when defibrotide prophylaxis was not routinely used in our center. Median follow-up for the study group was 10 (range 2-16) years and for the control group 2.7 (range 1-18) years. None of the 237 patients in the defibrotide group developed SOS/VOD. The cumulative incidence (CI) of SOS/VOD was 0% in the defibrotide group as compared to 4.8% (95% confidence interval [CI], 2.6-8%; P= .00046) in the control group. There was also a better 1-year EFS with 38% (95% CI, 32%-44%) in the defibrotide group versus 28% (95% CI, 22%-34%) (P= .00969) and decreased cumulative incidence of acute graft-versus-host disease (GvHD) in the defibrotide group 31% (95% CI, 25%-37%) versus 42% (95% CI, 36%-48%) (P= .026). The 1-year overall survival, relapse incidence, and non-relapse mortality were not statistically different. Multivariable analysis, performed taking into account clinical factors known to influence the risk of SOS/VOD, confirmed the favorable impact of defibrotide on SOS/VOD (HR 1.38e-08 [95% CI, 3.28e-09-5.80e-08]; P< .00001). Conversely, multivariable analysis failed to confirm the impact of defibrotide on 1-year EFS or acute GvHD. This large retrospective study on SOS/VOD-prophylaxis with defibrotide suggests that this approach may be of benefit. These results need to be confirmed in a prospective randomized trial.

Neutralization capacity of antibodies elicited through homologous or heterologous infection or vaccination against SARS-CoV-2 VOCs.

Emerging SARS-CoV-2 variants raise questions about escape from previous immunity. As the population immunity to SARS-CoV-2 has become more complex due to prior infections with different variants, vaccinations or the combination of both, understanding the antigenic relationship between variants is needed. Here, we have assessed neutralizing capacity of 120 blood specimens from convalescent individuals infected with ancestral SARS-CoV-2, Alpha, Beta, Gamma or Delta, double vaccinated individuals and patients after breakthrough infections with Delta or Omicron-BA.1. Neutralization against seven authentic SARS-CoV-2 isolates (B.1, Alpha, Beta, Gamma, Delta, Zeta and Omicron-BA.1) determined by plaque-reduction neutralization assay allowed us to map the antigenic relationship of SARS-CoV-2 variants. Highest neutralization titers were observed against the homologous variant. Antigenic cartography identified Zeta and Omicron-BA.1 as separate antigenic clusters. Substantial immune escape in vaccinated individuals was detected for Omicron-BA.1 but not Zeta. Combined infection/vaccination derived immunity results in less Omicron-BA.1 immune escape. Last, breakthrough infections with Omicron-BA.1 lead to broadly neutralizing sera.

Evaluation of Disease Risk Comorbidity Index after Allogeneic Stem Cell Transplantation in a Cohort with Patients Undergoing Transplantation with In Vitro Partially T Cell Depleted Grafts.

Outcomes of hematopoietic stem cell transplantation (HSCT) are influenced by comorbidities, disease type, and status at transplantation. Several prognostic scores can be used, such as the disease risk index (DRI) or the hematopoietic cell transplantation-specific comorbidity index (HCT-CI). Recently, a new prognostic tool, the disease risk comorbidity index (DRCI), combining the DRI and the HCT-CI, was published. The DRCI determines 6 patient groups (very low risk [VLR], low risk [LR], intermediate risk 1 [IR-1], intermediate risk 2 [IR-2], high risk [HiR], and very high risk [VHR]) with a significant predictive value for overall survival (OS), disease-free survival (DFS), relapse incidence (RI), and graft-versus-host disease-free/relapse-free survival (GRFS). However, the DRCI has not been evaluated for patients allografted with partially in vitro T cell depleted (pTDEP) grafts. In our center, we offer pTDEP to reduce graft-versus-host disease for patients in complete remission at transplant time. In this retrospective study, we investigated the DRCI in 404 adult patients (including 37.6% pTDEP) undergoing a first HSCT for hematological malignancies from 2008 to 2018. Because of the small number of patients in LR, VLR and LR were combined for analysis. In the entire cohort, 2-year OS was 84.4% (95% CI, 71.6% to 97.2%) for LR, 61.6% (54.8% to 68.4%) for IR-1, 45.7% (33.3% to 58.1%) for IR-2, 31% (19.4% to 42.6%) for HiR, and 30.9% (14.5% to 47.3%) for VHR (P < .001). In addition, the DRCI was predictive of DFS, RI, and GRFS but not of nonrelapsed mortality and graft-versus-host disease. Our study confirms similar results with the original publication but gives less accurate prognosis information than the DRI and HCT-CI when used separately. In conclusion, the DRCI does not seem to offer more relevant information than the DRI and HCT-CI to help physicians and patients for the HSCT decision.

Case Report: Severe Complement-Mediated Thrombotic Microangiopathy in IgG4-Related Disease Secondary to Anti-Factor H IgG4 Autoantibodies.

Objective: To first describe and estimate the potential pathogenic role of Ig4 autoantibodies in complement-mediated thrombotic microangiopathy (TMA) in a patient with IgG4-related disease (IgG4-RD). Methods: This study is a case report presenting a retrospective review of the patient's medical chart. Plasma complement C3 and C4 levels, immunoglobulin isotypes and subclasses were determined by nephelometry, the complement pathways' activity (CH50, AP50, MBL) using WIESLAB® Complement System assays. Human complement factor H levels, anti-complement factor H auto-antibodies were analyzed by ELISA, using HRP-labeled secondary antibodies specific for human IgG, IgG4, and IgA, respectively. Genetic analyses were performed by exome sequencing of 14 gens implicated in complement disorders, as well as multiplex ligation-dependent probe amplification looking specifically for CFH, CFHR1-2-3, and 5. Results: Our brief report presents the first case of IgG4-RD with complement-mediated TMA originating from both pathogenic CFHR 1 and CFHR 4 genes deletions, and inhibitory anti-complement factor H autoantibodies of the IgG4 subclass. Remission was achieved with plasmaphereses, corticosteroids, and cyclophosphamide. Following remission, the patient was diagnosed with lymphocytic meningitis and SARS-CoV-2 pneumonia with an uneventful recovery. Conclusion: IgG4-RD can be associated with pathogenic IgG4 autoantibodies. Genetic predisposition such as CFHR1 and CFHR4 gene deletions enhance the susceptibility to the formation of inhibitory anti-Factor H IgG4 antibodies.

Partial T-cell depletion improves the composite endpoint graft-versus-host disease-free, relapse-free survival after allogeneic hematopoietic stem cell transplantation.

Graft-versus-host disease (GvHD)-free, relapse-free survival (GRFS) is a recently reported composite endpoint that allows to simultaneously estimate risk of death, relapse and GvHD after allogeneic hematopoietic stem cell transplantation (HSCT). In this retrospective study comprising 333 patients transplanted for hematologic malignancies, we compared GRFS in patients receiving partial T-cell-depleted (pTCD) grafts with patients receiving T-cell-replete grafts (No-TCD). pTCD was associated with a significantly improved GRFS. The beneficial effect of pTCD on GRFS remained highly significant in multivariable analysis taking into account clinical factors differing between patient groups. We observed no effect of pTCD on overall survival, progression-free survival, and relapse cumulative incidence, while non-relapse mortality cumulative incidence was significantly lower in patients receiving pTCD. The results of our retrospective analysis suggest that pTCD could improve GRFS in allogeneic HSCT recipients without significantly affecting OS and PFS, thus improving patients' quality of life without impairing the curative potential of allogeneic HSCT.