Novel intronic RHD variants identified in serologically D-negative blood donors.

BACKGROUND: Blood group genotyping is used to predict RhD phenotype in transfusion and obstetric medicine. Prediction of antigen D is based on molecular techniques which targets most common RHD-specific polymorphism. However, inactive RHD variants can suggest false-positive RhD phenotype. Their types and frequencies vary among ethnicities. Our study aimed to identify RHD variants among Moroccan blood donors who are serologically D negative. STUDY DESIGN AND METHODS: DNA from 53 blood donors who are serologically D negative RhC and/or RhE positive were screened for RHD exon 10 by PCR-SSP. RHD-positive samples were further tested by multiplex PCR covering exons 3, 4, 5, 6, 7 and 9 and then sequenced by targeted next-generation sequencing method. Mutations' impact on mRNA splicing was predicted using alamut software version 2·0. RESULTS: PCR-SSP revealed 9 of 53 (16·9%) RHD-positive samples. Five of nine samples were positive for all tested exons, two of nine were positive for exon 9, and two of nine were undetermined. Sequencing revealed four novel RHD variants based on six mutations in introns 1, 3, 5 and 6. In silico analysis revealed aberrant splicing of three mutations (RHD c.487-1024delG, RHD c.487-256T>G and RHD c.940-187_940-188del), while three other mutations (RHD c.149-682C>A, RHD c.802-37delA and RHD c.939 + 1151dup) had no effect on splicing compared to wild type. CONCLUSIONS: All identified RHD variants contain at least one mutation that probably affects splicing to generate D-negative phenotype. Hence, ethnic RhD antigen background must be considered when developing transfusion and obstetric strategies.

[Stem cell transplantation in Morocco: report of 87 cases]. / Greffe de cellules souches hématopoïétiques au Maroc : à propos de 87 cas.

PURPOSE: The autologous peripheral blood stem cells (CSP) are used as a support to the restoration of the hematopoiesis in oncohematology. The objective of this work, carried out in the laboratory of cryobiology at the Center Regional of Blood Transfusion, Casablanca, is to assess the short- and long-term results of this type of autograft. PATIENTS AND METHODS: This retrospective study focused on 87 patients treated for hematological malignancies in services of oncohaematology over a period from June 2004 to March 2009. One hundred and twenty-seven cytapheresis were conducted to collect the CSP. The rate of CD34+ cells ranged from two to 50x10(6) per kilogram. The removal, treatment with 10% DMSO, the characterization, cryopreservation, thawing and washing of grafts on Cobe 2991 were made before the autograft. RESULTS: Forty-nine patients were transplanted for multiple myeloma, 24 for Hodgkin's disease, 13 for a non-Hodgkin lymphoma and one for rabdomyosarcome. The mean age of patients was 35 years. The mean length of hospitalization was 27 days. The average time of release for aplasia is 7 to 49 days, with a mean of 16 days. A blood transfusion was necessary during the aplasia: two to 41 red blood cells per patient and six to 298 platelet units per patient. The short-term complications after autologous transplantation are primarily infectious. Seven times the progressive hematologic malignancies and seven deaths are regrettable. CONCLUSION: The autologous CSP is simple, effective and well tolerated, which should be developed in our context.

[ABO polymorphism in blood donors in Morocco]. / Polymorphisme ABO chez les donneurs de sang au Maroc.

Blood grouping were improved since the advent of monoclonal antibodies and the automation of the tests. No comparative study has been done before in Morocco concerning ABO regional genetic frequencies. Hence, the aim of this work is to actualize and to precise them. The ABO blood grouping has been carried out on 344 954 blood donors by micro method in several regional blood transfusion centers. Genetic frequencies were calculated according to the Bernstein's method. The national mean values are A: 0.2141, B: 0.105, O: 0.6777. The regional frequencies show gradients between the north and the south of Morocco.