ABO-incompatible allogeneic hematopoietic stem cell transplantation (HSCT) can be complicated by poor red cell engraftment and hemolysis, both mediated by isoagglutinins. Anecdotally, isoagglutinins indicates an activation of donor’s immunity or even relapse. Consequently, the routine monitoring of isoagglutinins could help physicians to predict the risk of complications. The purpose of this study is to investigate the time to disappearance and appearance of isoagglutinins after ABO-incompatible allogeneic HSCT. In a one-year follow-up, data of 136 ABO-incompatible hematopoietic stem cell (HSC) allogeneic transplanted patients were studied, of which 60 had major, 61 minor and 15 bidirectional incompatibility. Survival analyses were conducted and association with hematological diseases, HLA-compatibility and transplantation strategy was investigated. We observed a disappearance of isoagglutinin A in 82.0% of cases at one year with a median and 75th percentile of 38.4 and 138.6 days, respectively. For isoagglutinin B, these same values were 96.4%, 15.9 and 29.1 days, respectively. The appearance of isoagglutinin A occurred in 10.7% of cases. Disappearance of isoagglutinin A was significantly slower in patients with myeloid diseases compared to other diseases. The results of this study provide useful values to detect early risks of preventable immunohematological complications and possibly, in exceptional cases, relapse.

Objectives. To determine the ferritin inter-assay differences between three “Conformité Européenne” (CE) marked tests, the impact on reference intervals (RI), and the proportion of individuals with iron deficiency (ID), we used plasma and serum from healthy blood donors (HBD) recruited in three different Switzerland regions. Design and Methods. Heparinized plasma and serum from HBD were obtained from three different transfusion centers in Switzerland (Fribourg, Geneva, and Neuchatel). One hundred forty samples were recruited per center and per matrix, with a gender ratio of 50%, for a total of 420 HBD samples available per matrix. On both matrices, ferritin concentrations were quantified by three different laboratories using electrochemiluminescence (ECL), latex immunoturbidimetric assay (LIA), and luminescent oxygen channeling immunoassay (LOCI) assays, respectively. The degree of agreement between matrices and between the three sites/methods was assessed by Passing–Bablok and we evaluated the proportion of individuals deemed to have ID per method. Results. Overall, no difference between serum and heparinized plasma ferritin values was observed according to Passing–Bablok analyses (proportional bias range: 1.0–3.0%; maximum constant bias: 1.84 µg/L). Significant median ferritin differences (p < 0.001 according to Kruskal–Wallis test) were observed between the three methods (i.e., 83.6 µg/L, 103.5 µg/L, and 62.1 µg/L for ECL, LIA, and LOCI in heparinized plasma, respectively), with proportional bias varying significantly between ±16% and ±32% on serum and from ±14% to ±35% on plasma with no sign of gender-related differences. Affecting the lower end of RI, the proportion of ID per method substantially varied between 4.76% (20/420) for ECL, 2.86% (12/420) for LIA, and 9.05% (38/420) for LOCI. Conclusions. Serum and heparinized plasma are exchangeable for ferritin assessment. However, the order of magnitude of ferritin differences across methods and HBD recruitment sites could lead to diagnostic errors if uniform RI were considered. Challenging the recently proposed use of uniform ferritin thresholds, our results highlight the importance of method- and region-specific RI for ferritin due to insufficient inter-assay harmonization. Failing to do so significantly impacts ID diagnosis.

La transfusion de concentrés érythrocytaires (CE) en milieu préhospitalier est déjà réalisée dans de nombreux pays tant dans un contexte militaire que c...

Asaia spp. are an environmental Gram-negative bacterial species rarely implicated in human infections. Only a handful of cases have been reported, primarily involving catheter-associated bloodstream infections or infections related to intravenous drug abuse. We present here a case of bacteremia caused by Asaia lannensis in an immunocompromised patient with hairy cell leukemia. An 84-year-old man with a history of hairy cell leukemia presented with relapse and was treated with cladribine via a subclavian central venous catheter. The patient developed a febrile episode three weeks after the start of chemotherapy, without hemodynamic instability but with elevated inflammatory markers and a mild erythema at the catheter site. Blood cultures drawn both by venipuncture and from the catheter grew a slow-growing, thin Gram-negative bacillus after prolonged incubation. Conventional identification methods based on biochemical profiling misidentified the bacterium as Serratia fonticola, and MALDI-TOF MS analysis was inconclusive. After initial genus-level identification through 16 S rDNA gene sequencing, whole genome sequencing demonstrated the classification to Asaia lannensis. The same organism was cultured directly from the catheter, confirming the source of infection. Antimicrobial susceptibility testing revealed elevated MICs to most commonly-used antibiotics, including beta-lactams, macrolides, quinolones, and last-resort agents such as colistin and cefiderocol. However, lower minimal inhibitory concentrations were observed for aminoglycosides and tetracyclines, suggesting potential in vitro activity. The patient showed rapid clinical improvement after catheter removal and a short antibiotics course, with no recurrence of fever or hemodynamic deterioration. This clinical observation is singular in that Asaia lannensis was recovered both from blood cultures and directly from the catheter, confirming the device as the source of infection. This case illustrates the potential of Asaia lannensis to cause clinically-significant infections in immunocompromised patients, particularly those with central venous catheters. It highlights the limitations of conventional microbiological identification techniques when dealing with uncommon environmental pathogens. Catheter removal was crucial to resolution, underscoring the importance of device management in the treatment of catheter-associated bloodstream infections. Clinicians and microbiologists should remain alert to rare opportunistic organisms in patients with indwelling medical devices and consider advanced molecular diagnostics when standard methods fail.