Molecular determination of RhD phenotype by DNA typing: clinical applications

COTORRUELO C; BIONDI C; GARCÍA BORRÁS S; GALIZZI S; DI MÓNACO R; RACCA A

ANNALS OF CLINICAL BIOCHEMISTRY

Royal Society of Medicine Press

Lugar: Guildford; Año: 2000 vol. 37 p. 781 - 789

0004-5632

The Rh system is of clinical importance because it is involved in immunohematologic disorders. RhD typing is performed by agglutination methods. In clinical situations where these techniques cannot be performed, RhD-DNA typing is an alternative approach. The Rh antigens are encoded by the RHD and RHCE genes. In RhD negative individuals the RHD gene is absent or grossly deleted, but variation in the arrangement of the RH locus in different populations is emerging. The aim of this study was to analyse the gross organization of the RH genes in our population using a previously described multiplex PCR method with some modifications. We studied 253 DNA samples from Argentinean blood donors, 15 samples with a reduced expression of the D antigen and 1 Dc- phenotype. We evaluated the clinical utility of this method to ascertain the RhD antigen in 10 patients with warm type autoimmune haemolytic anaemia (AIHA) and 14 samples of amniotic fluids. All Rh phenotypes were properly characterized and no discrepancies with serological typing were found. Analyses performed in the Dc- phenotype suggest the presence of a hybrid RHCE-RHD gene. DNA typing confirmed the RhD negative type of 1 AIHA sample in which serological tests were inconclusive. Fetal DNA typing correctly indicated the RhD in every fetus. VNTR and STR analysis detected maternal contamination in 2 amniocentesis samples and confirmed the fetal origin of 12. This multiplex PCR strategy is suitable for RhD determination in clinical situations in which serological typing cannot be accomplished with its usual ease.