[Identification of alloantibodies and their associations: Balance sheet of 3 years at the Regional Center of Blood Transfusion in Rabat/Morocco and difficult in transfusion management]. / Identification des allo-anticorps seuls et associés : bilan de trois années au centre régional de transfusion sanguine de Rabat/Maroc et difficultés de prise en charge transfusionnelle.

Red blood cell immunization can lead to delays or even an impasse in a transfusion. OBJECTIVES: Determine the specificities of the most common of alloantibodies and their associations to correct management of red blood cell transfused. METHODS AND MATERIALS: A retrospective study between 2013 and 2015 in immunohematology laboratories at the Blood Transfusion Center of Rabat in Morocco. The following data were studied: frequency, specificities of alloantibodies, blood group involved in alloimmunization and difficult of management of transfusion in case with association of alloantibodies. RESULTS: Five hundred of alloantibodies were identified in 425 people (372 patients/pregnant women and 53 blood donors). The alloantibodies were directed against the following antigen: RH1 (50.8 %), RH3 (11.4 %), KEL 1 (8.2 %), RH2 (7.6 %), RH4 (4.6 %), MNS1 (4 %), MNS3 (2.6 %), Jka (2.4 %) and Fya (2.2 %). Only one alloantibody was identified in 85 % of cases. In 15 %, at least, two alloantibodies were found. The most common associations were directed against: anti-(D+C) (25), anti-(E+K) (4), anti-(E+c) (3) and anti-(D+C+E) (3). The rhesus system is the most involved in alloimmunization. Frequency of specific associations of alloantibodies was identified: Fya-/Jkb- (18.23 %), Fyb-/Jkb- (11.7 %), Jka-/S- (8.70 %), Jka-/Fyb- (5.20 %), Fyb-/s- (3.40 %) and Fyb-/Jkb-/s- (0.85 %). CONCLUSIONS: Red blood cell immunization is a serious problem in transfused patients. This study proves the data of literature, the interest of using RH-Kel1 red cell units compatibles among women in age to procreate and for the transfused patients to reduce the rate of immunization. Associations of antibodies with low frequency suggest a promotion of donation.

[A quantitative determination of IgG anti-D subclasses by Elisa in hemolytic disease of the newborn]. / Etude quantitative des sous-classes d'IgG anti-D par Elisa au cours de la maladie hémolytique néonatale.

The quantification of IgG anti-D subclasses is one of the most important parameters considered in the assessment of the severity of hemolytic disease of the newborn. Traditionally IgG subclassing is performed using qualitative haemagglutination methods, difficult to interpret. A quantitative enzyme-linked immunosorbent assay (Elisa) was implemented for measuring IgG anti-D subclasses in 20 sera collected from 14 RhD-immunized pregnant women. All 4 IgG subclasses were detected in the 20 sera tested. The mean proportion of IgG1 was 52.8%. The mean proportion of IgG3 was 30.7%. The mean proportions of IgG2 and IgG4 were 14.5 and 1.9% respectively. A good correlation between the sum of IgG subclasses and the severity of HDN was found. Severe HDN occurred when both IgG1 and IgG3 were present. IgG1 anti-D was the predominant subclass in 4 of the 8 severe cases.

[Fetal RHD genotyping by PCR using plasma from D negative pregnant women]. / Génotypage RHD fœtal par PCR dans le plasma de femmes enceintes D négatif.

AIM OF THE STUDY: Free fetal DNA in maternal blood offers a non invasive method for prenatal diagnosis. The aim of this study is to perform fetal RHD genotyping by conventional PCR in D negative pregnant women of Moroccan origin. PATIENTS AND METHODS: Plasma sample from 120 D negative pregnant women from 10 to 40 gestational weeks were tested by conventional PCR for the presence of exons 7 and 10 of RHD gene. The results were compared with the RhD phenotype of the newborns. RESULTS: In this study, the positive and the negative predictive value of the fetal RhD status were 98.7 and 96.7%, respectively. CONCLUSION: These results demonstrate de feasibility of fetal RHD genotyping by conventional PCR in D negative pregnant women of Moroccan origin.