[Transfusion protocols in hematopoietic stem cell allogeneic transplantation]. / Consignes transfusionnelles en cas d'allogreffe de cellules souches hématopoïétiques.

Hematopoietic stem cell (HSC) allogeneic transplantation is now commonly used as a therapeutic tool in patients with certain types of hematologic malignancies. Such patients, on account of severe pre-graft conditioning regimens, present with severe marrow aplasia justifying specific transfusion care. Given a complex immunological situation (immediately after transplantation, co-existence of two cell populations with different immunohematological characteristics), transfusion protocols must rest on clear and well-defined recommendations. Recent transfusion recommendations in settings of HSC allogeneic transplantation have defined criteria for the choice of blood products (red blood cell concentrates, plasma and platelet concentrates) depending on recipient and graft immunohematological characteristics (minor/major/mixed ABO compatibility/incompatibility and time of transplantation). Transfusion instructions are summarized in a synthesis document entitled : "Instructions for transfusion following HSC allogeneic transplantation". This document specifies the immunohematological characteristics of blood products and various transfusion protocols (systematic irradiation, negative CMV, etc.). This document is used by the teams who distribute blood products, for selection purposes, as well as by the medical transfusion team when they perform ultimate pre-transfusion control steps.

Two new alleles of the RHCE gene in Black individuals: the RHce allele ceMO and the RHcE allele cEMI.

Six unrelated individuals of Afro-Caribbean origin, whose red cells have a marked reduction of the Rhe antigen expression, have been identified. All exhibited the same serological profile with anti-e monoclonal antibodies and lacked expression of the high frequency e-related antigen hrS. Transcripts and genomic analysis showed that these phenotypes resulted from the presence of two new RHCE alleles, ceMO and cEMI. The ceMO allele corresponded to a RHce gene carrying a G667T mutation (exon 5) and was detected at the homozygous state in sample 1 and at the heterozygous state in samples 2-6. The G667T mutation resulted in a Val223Phe substitution on the Rhce polypeptide, in close proximity to Ala226 (e-antigen polymorphism), which might account for the altered expression of e. The ceMO allele is also associated with the lack of expression of the hrS antigen. The absence of the hrS antigen expression may have implications in transfusion as hrS-negative individuals may develop clinically significant antibodies. The cEMI allele corresponded to a silent RHE allele carrying a nine nucleotide deletion within exon 3 and was detected at the heterozygous state in sample 2. This deletion resulted in a shortened polypeptide of 414 residues (instead of 417) that was absent (or severely reduced) at the red cell surface, as the E antigen was undetectable using serology and Western blot analysis with anti-E reagents. In DNA-based polymerase chain reaction genotyping for RHE determination, the cEMI allele provided a false positive result as the cells carrying this allele are serologically phenotyped as E-negative. The incidence of this allele in the Black population is unknown but, as shown already for D genotyping, one must exercise caution when genotyping is performed to detect the e/E polymorphism.

Arg89Cys substitution results in very low membrane expression of the Duffy antigen/receptor for chemokines in Fy(x) individuals.

The Duffy (FY) blood group antigens are carried by the DARC glycoprotein, a widely expressed chemokine receptor. The molecular basis of the Fya/Fyb and Fy(a-b-) polymorphisms has been clarified, but little is known about the Fyx antigen and the FY*X allele associated with weak expression of Fyb, Fy3, Fy5, and Fy6 antigens. We analyzed here the structure and expression of the FY gene in 4 Fy(a-bweak) individuals. As compared with Fy(a-b+) controls, the Fy(a-bweak) red blood cell membranes contained residual amount of DARC polypeptide and these cells were poorly bound by anti-Fy antibodies and chemokines. The FY gene from Fy(a-b+) and Fy(a-bweak) individuals differed by one substitution, C286T. The resulting Arg89Cys amino acid change reduced the binding of anti-Fy antibodies and chemokines to DARC transfectants. We concluded that the Fybweak donors carried the FY*X allele at the FY locus and that the Fyx antigen corresponds to highly reduced expression of a grossly normal Fyb polypeptide caused by the Arg89Cys substitution. Because FY is a single copy gene, this defect should also affect DARC expression in nonerythroid cells. Because the Fyx phenotype is not associated with apparent clinical consequences, we discussed these findings in the light of the putative roles of DARC in various tissues. Finally, we developed a Fyx DNA typing assay that should be useful for genetic studies and clinical transfusion medicine.

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases]. / Les accidents immuno-hémolytiques transfusionnels. III. Etude de 61 cas.

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

[Neonatal hypoglycemia due to hyperinsulinism secondary to Langerhans' polyadenomatosis. Recovery after pancreatectomy]. / Hypoglycemie neonatale par hyperinsulinisme secondaire a une polyadenomatose Langheransienne. Pancreatectomie suivie de guerison

Report of a case of a neonatal hypoglycemia detected at the 11th hour of life, secondary to a Langherans polyadenomatosis in a girl with an hemihypertrophy. Pre- and post-operative tests are reported. In case of neonatal hypoglycemia, the criteria leading to the diagnosis of hyperinsulinism, i.e. the only neonatal hypoglycemia with surgical treatment are reviewed. Except in the case of adenoma, the pancreatectomy should be performed subtotally. The best time for surgery is as soon as the 3rd week, in order to preserve the cerebral development.