Credidio Débora Castilho, Pellegrino Jordão, Castilho Lilian
Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro, UNICAMP, Rua Carlos Chagas, 480, Caixa Postal 6198, CEP 13081-970 Barão Geraldo, Campinas, SP, Brazil.
Immunohematology. 2011;27(1):6-11.
Rh discrepancies are a problem during routine testing because of partial D or weak D phenotypes. Panels of monoclonal antibodies (MoAb) are being developed to identify D variants such as partial D and weak D when there are anomalous D typing results; however, molecular characterization offers a more specific classification of weak and partial D. The weak D and partial D phenotypes are caused by many different RHD alleles encoding aberrant D proteins, resulting in distinct serologic phenotypes and the possibility of anti-D immunization. We evaluated currently used serologic methods and reagents to detect and identify D variants and correlated the results with molecular analyses. A total of 306 blood samples from Brazilian blood donors and patients with discrepant results in routine D typing were analyzed. In total, 166 (54.2%) weak D, 136 (44.4%) partial D, 3 (1%) DEL, and 1 (0.3%) DHAR variants were identified. Among weak D samples, 76 weak D type 1 (45.8%), 75 weak D type 2 (45.2%), 13 weak D type 3 (7.8%), and 2 weak D type 5 (1.2%) alleles were found. Among the partial D samples, 49 type 4.0 weak partial D (36%), 9 DAR (6.6%), 24 DFR (17.6%), 6 DBT (4.4%), 1 DHMi (0.73%), 26 DVI (19%), 14 DVa (10.3%), 5 DIVb (3.7%), and 2 DVII (1.5%) were observed. Two samples identified as DEL by adsorption-elution were characterized by molecular analyses as RHD(IVS5–38DEL4) and one sample was characterized as RHD(K409K). One sample was characterized as DHAR, a CE variant positive with some monoclonal anti-D. Our results showed that the use of different methods and anti-D reagents in the serologic routine analysis revealed D variants that can be further investigated. Molecular methods can help to differentiate between partial D and weak D and to characterize the weak D types, providing additional information of value in the determination of D phenotypes. This distinction is important for optimized management of D– RBC units and for the prevention of anti-D–related hemolytic disease of the fetus and newborn.
由于部分D或弱D表型，Rh血型不符在常规检测中是个问题。正在研发单克隆抗体（MoAb）组合，以在D血型分型结果异常时识别D变异体，如部分D和弱D；然而，分子特征分析可为弱D和部分D提供更具体的分类。弱D和部分D表型由许多不同的RHD等位基因引起，这些等位基因编码异常的D蛋白，导致不同的血清学表型以及产生抗-D免疫的可能性。我们评估了当前用于检测和识别D变异体的血清学方法和试剂，并将结果与分子分析进行了关联。对来自巴西献血者和常规D血型分型结果不一致的患者的306份血样进行了分析。总共鉴定出166例（54.2%）弱D、136例（44.4%）部分D、3例（1%）DEL和1例（0.3%）DHAR变异体。在弱D样本中，发现76例弱D 1型（45.8%）、75例弱D 2型（45.2%）、13例弱D 3型（7.8%）和2例弱D 5型（1.2%）等位基因。在部分D样本中，观察到49例4.0型弱部分D（36%）、9例DAR（6.6%）、24例DFR（17.6%）、6例DBT（4.4%）、1例DHMi（0.73%）、26例DVI（19%）、14例DVa（10.3%）、5例DIVb（3.7%）和2例DVII（1.5%）。通过吸附-洗脱鉴定为DEL的两个样本经分子分析表征为RHD(IVS5–38DEL4)，一个样本表征为RHD(K409K)。一个样本表征为DHAR，是一种对某些单克隆抗-D呈阳性的CE变异体。我们的结果表明，在血清学常规分析中使用不同的方法和抗-D试剂可揭示可进一步研究的D变异体。分子方法有助于区分部分D和弱D，并对弱D类型进行表征，为确定D表型提供有价值的额外信息。这种区分对于优化D阴性红细胞单位的管理以及预防胎儿和新生儿与抗-D相关的溶血病很重要。
