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

Background: 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 (D ), RH30 (Go ), KEL6 (Js ), and MNS6 (He).

Family study of a Swiss patient uncovered a novel genetic basis for the S-s-U+(var) phenotype.

Background: The rare S-s- phenotype is typically found in persons of African origin. Three genetic bases underlying this phenotype have been identified so far: a large deletion including the GYPB gene, which encodes the S and s antigens, and two mutations affecting GYPB splicing (commonly called "P2" and "NY"). The discovery of the S-s- phenotype in a Swiss patient prompted this study.

Molecular analysis of patients with weak D and serologic analysis of those with anti-D (excluding type 1 and type 2).

Whether or not patients whose red blood cells (RBCs) carry certain weak D types produce anti-D, and if they do whether it is allo- or auto anti-D, remains controversial. The aim of this study was to determine the serologic features of anti-D in individuals expressing a weak D other than type 1 or type 2 and to assess whether the anti-D was an allo- or autoantibody. Serologic D typing and molecular analyses were performed on 748 individuals.

Identification of novel silent KEL alleles causing KEL:-5 (Ko) phenotype or discordance between KEL:1,-2 phenotype/KEL*01/02 genotype.

Background: The Kell system, encoded by the KEL gene, is one of the most clinically important blood group systems. Molecular defects may lead to the absence of Kell antigen expression. The very rare KEL:5 results from silent KEL genes, also called KELnull alleles.

Molecular background of novel silent RHCE alleles.

Background: The absence of expression of C/c and E/e antigens has been associated with rare variant RHCE alleles, referred to as silent RHCE alleles, classically identified among individuals with a rare D- - or Rhnull phenotype. This work reports on different molecular mechanisms identified in three novel silent RHCE alleles.

Study Design And Methods: Samples from D- - or Rhnull individuals and their family members, from families for whom Rh phenotype and/or serologic data were unexplained by inheritance of conventional RH alleles, were analyzed.

Antibodies to co-trimoxazole (trimethoprim and/or sulfamethoxazole) related to the presence of the drug in a commercial low-ionic-strength solution.

Background: Drug-dependent antibodies have been associated with approximately 10% of acquired immune hemolytic anemia cases. These antibodies are a rare cause of interference in pretransfusion red blood cell (RBC) serologic testing. The aim of this work was to report three cases of subjects developing antibodies against co-trimoxazole, a combination of trimethoprim (TMP) and sulfamethoxazole (SMX).

Anti-D investigations in individuals expressing weak D Type 1 or weak D Type 2: allo- or autoantibodies?

Background: Whether anti-D produced by individuals with a weak D phenotype are allo- or autoantibodies remains a matter of debate even though blood transfusion practice is impacted. The aim of our study was to determine the serologic features of anti-D in individuals expressing the most frequent weak D type in Caucasians that are weak D Type 1 or weak D Type 2, to assess whether anti-D were allo- or autoantibodies.

Study Design And Methods: Serologic D typing and molecular analysis enabled the including of 121 weak D Type 1 individuals and 99 weak D Type 2 individuals in our study.

Analysis of RhCE variants among 806 individuals in France: considerations for transfusion safety, with emphasis on patients with sickle cell disease.

Background: DNA testing has enabled the documenting of numerous variants of RHCE alleles, especially in individuals of African origin. The risk for production of clinically significant alloantibodies to Rh antigens of patients carrying variant RHCE alleles has led us to analyze the different RhCE variants investigated by molecular biology. Alloimmunization was analyzed regarding the RHCE genetic profile.

Heterogeneous molecular background of the weak C, VS+, hr B-, Hr B- phenotype in black persons.

Background: The rare Hr(B)- phenotype is encoded by the (C)ce(s) haplotype when present at the homozygous state. This haplotype contains two altered genes: a hybrid RHD-CE-D(s) gene segregated with a ce(s) allele of RHCE (733C>G and 1006G>T substitutions in Exon 5 and Exon 7 respectively). The aim of this study was to further investigate the molecular background of the (C)ce(s) haplotype.