Swati Kulkarni1, Garima Mishra1, Harita Maru1, Disha Parchure1, Debasish Gupta2, Anantpreet Kaur Bajaj3, Sangeeta Pahuja Sindhwani4, Anand Chaphekar5, Ripal Shah6, Claude Férec7,8, Manisha Madkaikar1, Yann Fichou7,9. 1. Department of Transfusion Medicine, ICMR-National Institute of Immunohaematology, Mumbai, India. 2. Department of Transfusion Medicine, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India. 3. Department of Immunhaematology and Blood Transfusion, Armed Forces Medical College, Pune, India. 4. Department of Immunhaematology and Blood Transfusion, Lady Hardinge Medical College, New Delhi, India. 5. KEM Hospital Blood Bank, Pune, India. 6. Prathama Blood Centre, Ahmedabad, India. 7. "Génétique, Génomique Fonctionnelle et Biotechnologies", INSERM, EFS, Université de Brest, UMR1078, IBSAM, Brest, France. 8. Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France. 9. Laboratory of Excellence (LabEx) GR-Ex, Paris, France.
Abstract
BACKGROUND: Rh antigens are critical in haemolytic disease of the foetus and newborn (HDFN). The D-- phenotype is a rare blood group characterised by the lack of expression of C, c, E and e antigens at the surface of red blood cells because of mutations in both RHCE alleles inactivating the expression of a "normal" protein. The aim of the study was to determine the molecular basis of D-- individuals of Indian origin. MATERIALS AND METHODS: Ten Rh D-positive postnatal women who had produced antibodies against all Rh antigens, except D, leading to HDFN and foetal loss, were investigated. Extensive serological and molecular (polymerase chain reaction [PCR] using sequence-specific primers), quantitative multiplex PCR of short fluorescent fragments (QMPSF), and Sanger sequencing analyses were carried out. RESULTS: Serological testing with anti-C, anti-c, anti-E, and anti-e reagents showed absence of the four antigens in all ten index cases, as well as in three siblings. Flow cytometry indicated absence of these antigens with a typical exalted expression of the D antigen, thus confirming the rare D-- phenotype. Molecular analysis by QMPSF suggested homozygous CE-D hybrid alleles causing the D-- phenotype: RHCE-D(3-9)-CE (n = 11), RHCE-D(3-8)-CE (n=1), and RHCE-D(2-6)-CE (n=1). DISCUSSION: For the first time, we report the molecular basis of the D-- phenotype in the Indian population. Identification and characterisation of RHCE-null variants by molecular methods can help resolve transfusion-related problems in these individuals. Family studies of index cases helped to identify rare blood donors and offer counselling to females of child-bearing age on the complications involved in such pregnancies.
BACKGROUND: Rh antigens are critical in haemolytic disease of the foetus and newborn (HDFN). The D-- phenotype is a rare blood group characterised by the lack of expression of C, c, E and e antigens at the surface of red blood cells because of mutations in both RHCE alleles inactivating the expression of a "normal" protein. The aim of the study was to determine the molecular basis of D-- individuals of Indian origin. MATERIALS AND METHODS: Ten Rh D-positive postnatal women who had produced antibodies against all Rh antigens, except D, leading to HDFN and foetal loss, were investigated. Extensive serological and molecular (polymerase chain reaction [PCR] using sequence-specific primers), quantitative multiplex PCR of short fluorescent fragments (QMPSF), and Sanger sequencing analyses were carried out. RESULTS: Serological testing with anti-C, anti-c, anti-E, and anti-e reagents showed absence of the four antigens in all ten index cases, as well as in three siblings. Flow cytometry indicated absence of these antigens with a typical exalted expression of the D antigen, thus confirming the rare D-- phenotype. Molecular analysis by QMPSF suggested homozygous CE-D hybrid alleles causing the D-- phenotype: RHCE-D(3-9)-CE (n = 11), RHCE-D(3-8)-CE (n=1), and RHCE-D(2-6)-CE (n=1). DISCUSSION: For the first time, we report the molecular basis of the D-- phenotype in the Indian population. Identification and characterisation of RHCE-null variants by molecular methods can help resolve transfusion-related problems in these individuals. Family studies of index cases helped to identify rare blood donors and offer counselling to females of child-bearing age on the complications involved in such pregnancies.
Authors: David N Hackney; Eric J Knudtson; Karen Q Rossi; Dave Krugh; Richard W O'Shaughnessy Journal: Obstet Gynecol Date: 2004-01 Impact factor: 7.661