Monoclonal anti‐D specificity and Rh D structure: criteria for selection of monoclonal anti‐D reagents for routine typing of patients and donors

Abstract

The Rh blood group system is the next most important to the ABO system in terms of its clinical significance in blood transfusion. It is vital to the safe, efficient practice of transfusion medicine that Rh D phenotyping tests are selected, executed and interpreted correctly. However, the Rh D blood group antigen has been shown to be subject to many phenotypic variations, and different reagents and typing techniques vary in their ability to detect these variants. The range of D-positive phenotypes are reviewed in terms of their reactivity with monoclonal antibody reagents and their clinical significance. In view of the available evidence, it is suggested that patient typing can be safely achieved by the duplicate use of one high-avidity or two very similar IgM monoclonal anti-D reagents that detect most variants except category DVI in simple tube or microplate saline tests. Antiglobulin testing for weak D should not be carried out on patient samples. Donor typing can be safely achieved by the use of the same monoclonal, used in parallel with a polyclonal anti-D reagent that detects DVI on sensitive automated equipment.

Molecular basis of the D variant phenotypes DNU and DII allows localization of critical amino acids required for expression of Rh D epitopes epD3, 4 and 9 to the sixth external domain of the Rh D protein

“…Serological analysis of DNU and D II phenotype erythrocytes with monoclonal anti-Ds of antiepD3, 4 and 9 specificity (nine-epitope model) reveal subtle differences in the expression of these epitopes (Table I). Our findings subsplit these epitopes (EpD3a/b, EpD4a/b, epD9a/ b), and are novel reaction profiles to those described by Jones et al (1995) (Table I). We have shown that the DNU phenotype arises by a single point mutation in the RHD gene, altering amino acid 353 (Gly → Arg).…”

“…This observation, although localizing these residues to the predicted sixth external domain of the protein, is surprising inasmuch as almost all anti-epD3, 4 and 9 antibodies react strongly with bromelain treated D-positive erythrocytes ( Jones et al, 1995). It would appear that, following protease treatment of erythrocytes, the overall integrity of the sixth loop structure is maintained allowing recognition by antibodies.…”

“…Erythrocytes of the DNU (donor 1) and D II (donor 2) phenotype (samples obtained from Department of Transfusion Medicine, Ulm, Germany, and from the Blood Transfusion Service, Royal Infirmary, Edinburgh, respectively) were investigated using a panel of monoclonal anti-D with defined specificity to the Rh D antigen using either the nine epitope model (Lomas et al, 1989(Lomas et al, , 1993 or the 30-epitope model ( Jones et al, 1995). BRAD-2, BRAD-3, BRAD-5, BRAD-8, AB5, FEF-7 and 2B6 were provided by Dr Kumpel, IBGRL, U.K.; HAM-A, MAD-2 and RUM-1 by BPL, U.K.; BS221 and BS226 by Dr Sonneborn, Biotest AG, Germany; P3X249, P3X21211F1, P3X21223B10, HM16, P3X61, HM10 and P3X35 by Diagast Laboratories, France; BIRMA-D6 by the National Blood Service, Birmingham; ESD-1 by the Scottish National Blood Transfusion Service, Edinburgh; REG-A and FOM-1 by N. Hughes-Jones, Cambridge, U.K.; UCHD4 by Dorothy Crawford, UCH, London; MCAD-1 by CSL Australia; MS26 by K. Thompson, IGRL, Norway; 8D8 by CLB Netherlands; HD7 by MRC, Cambridge, U.K. LOS-1, F-64, MCAD-6, LORI 1/2, 21 G6, OSK3-1, DBF-11, OSK3, FLOS3, D7 F2 F4, LDM-1 and LDM-2 were obtained from the ISBT/ICSH working party on blood grouping reagents.…”

“…By comparison of the reactivity of these anti-D with the red cells of other D-positive individuals with anti-D in their sera it was possible to categorize these individuals into distinct D variants (Tippett & Sanger, 1962 (Lomas et al, 1993). Analysis of further D variant erythrocytes with extended panels of monoclonal antibodies has indicated that there are in excess of 30 D epitopes recognized by monoclonal antibodies ( Jones et al, 1995).…”

Clinical Evaluation of Triple and Quadruple Helicobacter Pylori Eradication Therapy in Peptic Ulcer Patients With Different Abo Blood Group Phenotypes

“…ABO phenotypes and Rh factor evaluations were carried out by standard hemagglutination assays [36]. H. pylori positivity was assessed through H. pylori antigen rapid test device (feces) [37] or UBT [38].…”