Role of some rhizospheric Pseudomonas on the growth and physiology of broad bean (Vicia faba) under salt stress conditions

Salt stress affects the development and growth of plants in various ways as a result of its effect on water relationships, photosynthesis, and nutrient absorption by physiological and biochemical processes. Consequently, several researchers have increasingly studied the effect of plant growth promoting bacteria (PGPR) as promoters and enhancers under saline environment. The main goals of this study were to examine the manifested response of the broad bean plant under saline conditions and to evaluate the role of some Pseudomonas isolates in improving plant tolerance to salt stress. Three Pseudomonas strains were isolated (P1 and P7 from a saline soil and P15 from a vineyard soil). These isolates were screened by salinity and used as inoculums in Vicia faba plants (OTONO variety) irrigated with two saline solutions (NaCl; 100 and 150 mM L−1) and one without salinity. The results show that salinity decreased the fresh weight, total chlorophyll content, and the Na+/K+ ratio, but it increased proline accumulation in inoculated and noninoculated plants. The inoculation of V. faba plants with P1, P7, and P15 strains significantly increased the production of fresh biomass in the presence and absence of salt stress, and positively affected the accumulation of proline and the Na+/K+ ratio. The inoculation with bacterial strains increased the total chlorophyll content in plants at all salt treatment levels, especially the P1 strain that showed a significant effect

International forum. an investigation of iron status in blood donors

No abstract availabl

Anti-CD20 Antibody Prevents Red Blood Cell Alloimmunization in a Mouse Model

International audienceAlloimmunization against RBCs can cause life-threatening delayed hemolytic transfusion reactions. Anti-CD20 Ab has recently been used to prevent alloimmunization. However, its effects remain unclear, particularly in lymphoid organs. We investigated the impact of murine anti-CD20 Ab in the blood and spleen. We assessed protocols for preventing primary alloimmunization and for abolishing established alloimmunization. Prophylactic protocols prevented alloimmunization. However, anti-CD20 treatment could only limit the further amplification of established alloimmunization. Residual B cell subtype distribution was disrupted in the spleen, but adoptive transfer studies indicated that these cells were neither plasma nor memory cells. Anti-CD20 Ab had a major effect on alloreactive CD4+ T cells, increasing the expansion of this population and its CD40 expression, while lowering its CD134 expression, thereby confirming its role in alloimmunization. In conclusion, this study shows that anti-CD20 immunotherapy can prevent RBC Ab development. However, this immunotherapy is limited by the increase in alloreactive CD4+ T lymphocytes. Nevertheless, treatment with anti-CD20 Abs should be considered for patients requiring transfusion with a very high risk of alloimmunization and life-threatening complications

Comparison of hepatitis E virus nucleic acid test screening platforms and RNA prevalence in French blood donors

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High immunogenicity of red blood cell antigens restricted to the population of African descent in a cohort of sickle cell disease patients

International audienceBACKGROUND : Sickle cell disease (SCD) patients undergo multiple red blood cell (RBC) transfusions and are regularly exposed to low‐prevalence (LP) antigens specific to individuals of African descent. This study evaluated the prevalence of antibodies against LP antigens in SCD patients and the need to identify these antibodies in everyday practice.STUDY DESIGN AND METHODS : Plasma from 211 SCD patients was tested with RBCs expressing the following LP antigens: RH10 (V), RH20 (VS), RH23 (DW), RH30 (Goa), KEL6 (Jsa), and MNS6 (He).RESULTS : Nine LP antibodies were found in eight patients (3.8%): five anti‐RH23, two anti‐RH30, and two anti‐MNS6. The exposure risk, calculated for each LP antigen, was below 3% per RBC unit, for all antigens tested. Thus, in this cohort of transfused SCD patients, the prevalence of LP antibodies was similar to that of antibodies against antigens of the FY, JK, and MNS blood group systems. These findings also reveal the occurrence of anti‐RH23 in SCD patients. No anti‐RH20 or anti‐KEL6 were found, despite the high frequency of mismatch situations.CONCLUSION : These results highlight the immunogenicity of these LP antigens, and the evanescence of antibodies against LP antigens. They also highlight the importance of appropriate pretransfusion testing for patients frequently transfused, who are likely to be exposed to multiple types of blood group antigens

Clinical severity in adult warm autoimmune hemolytic anemia and its relationship to antibody specificity

International audienceNo abstract availabl

Prospective detection of chikungunya virus in blood donors, Caribbean 2014.

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Red blood cells for transfusion in patients with sepsis: respective roles of unit age and exposure to recipient plasma

International audienceBackground: Red blood cell (RBC) storage in blood banks is not exempt from cellular injury. Alterations not observed on RBCs freshly isolated from units can rapidly appear in circulation. The transfusion of old blood units, even if this is a controversial issue, could therefore have adverse effects on the recipient. We wanted to determine the respective effects of storage duration and recipient plasma on RBCs for transfusion into patients with severe sepsis.Study design and methods: Eleven stored RBC units were sampled at various time points, approximately Days 3 to 8 (referred to as fresh RBCs) and Days 38 to 42 (old RBCs) and tested in coincubation experiments with plasma obtained from 13 patients with severe sepsis and 17 healthy donors as controls. RBCs were tested after 24 or 48 hours at 37°C for the detection of senescence markers (phosphatidylserine exposure, calcium influx, and reactive oxygen species detection and decrease in size) with or without exposure to plasma.Results: We confirmed that a 42-day refrigerated storage of RBCs alone (without any incubation in plasma) had no significant effect on RBCs and no senescence marker detected. By contrast, ex vivo exposure to plasma samples altered both fresh and old RBCs, with a much larger effect for old RBCs, regardless of the plasma used (sepsis vs. control).Conclusion: We show that the main factor affecting the senescence of RBCs for transfusion into patients with severe sepsis is the age of the stored units rather than the clinical status of the recipient

Epidemiology of Chikungunya Virus Outbreaks in Guadeloupe and Martinique, 2014: An Observational Study in Volunteer Blood Donors

International audienceBackground: During Dec-2013, a chikungunya virus (CHIKV) outbreak was first detected in the French-West Indies. Subsequently, the virus dispersed to other Caribbean islands, continental America and many islands in the Pacific Ocean. Previous estimates of the attack rate were based on declaration of clinically suspected cases.Methods/Principal findings: Individual testing for CHIKV RNA of all (n = 16,386) blood donations between Feb-24th 2014 and Jan-31st 2015 identified 0·36% and 0·42% of positives in Guadeloupe and Martinique, respectively. The incidence curves faithfully correlated with those of suspected clinical cases in the general population of Guadeloupe (abrupt epidemic peak), but not in Martinique (flatter epidemic growth). No significant relationship was identified between CHIKV RNA detection and age-classes or blood groups. Prospective (Feb-2014 to Jan-2015; n = 9,506) and retrospective (Aug-2013 to Feb-2014; n = 6,559) seroepidemiological surveys in blood donors identified a final seroprevalence of 48·1% in Guadeloupe and 41·9% in Martinique. Retrospective survey also suggested the absence or limited "silent" CHIKV circulation before the outbreak. Parameters associated with increased seroprevalence were: Gender (M>F), KEL-1, [RH+1/KEL-1], [A/RH+1] and [A/RH+1/KEL-1] blood groups in Martiniquan donors. A simulation model based on observed incidence and actual seroprevalence values predicted 2·5 and 2·3 days of asymptomatic viraemia in Martiniquan and Guadeloupian blood donors respectively.Conclusions/Significance: This study, implemented promptly with relatively limited logistical requirements during CHIKV emergence in the Caribbean, provided unique information regarding retrospective and prospective epidemiology, infection risk factors and natural history of the disease. In the stressful context of emerging infectious disease outbreaks, blood donor-based studies can serve as robust and cost-effective first-line tools for public health surveys

Incidence and predictive score for delayed hemolytic transfusion reaction in adult patients with sickle cell disease

International audienceDelayed hemolytic transfusion reaction (DHTR) is a life-threatening complication of transfusion in sickle cell disease (SCD). The frequency of DHTR is underestimated because its symptoms mimic those of vaso-occlusive crisis and antibodies (Abs) are often not detectable. No predictive factors for identifying patients likely to develop DHTR have yet been defined. We conducted a prospective single-center observational study over 30 months in adult sickle cell patients. We included 694 transfusion episodes (TEs) in 311 patients, divided into occasional TEs (OTEs: 360) and chronic transfusion program (CTEs: 334). During follow-up, 15 cases of DHTR were recorded, exclusively after OTEs. DHTR incidence was 4.2% per OTE (95% CI [2.6; 6.9]) and 6.8% per patient during the 30 months of the study (95% CI [4.2; 11.3]). We studied 11 additional DHTR cases, to construct a predictive score for DHTR. The DHTR mortality is high, 3 (11.5%) of the 26 DHTR patients died. The variables retained in the multivariate model were history of DHTR, number of units previously transfused and immunization status before transfusion. The resulting DHTR-predictive score had an area under the ROC curve of 0.850 [95% CI: 0.780-0.930], a negative-predictive value of 98.4% and a positive-predictive value of 50%. We report in our study population, for the first time, the incidence of DHTR, and, its occurrence exclusively in occasionally transfused patients. We also describe a simple score for predicting DHTR in patients undergoing occasional transfusion, to facilitate the management of blood transfusion in SCD patients