Detection of weak D antigen by flow cytometry / 中国实验血液学杂志

Flow cytometry was previously applied for analysis of Rh(D) antigen density, therefore it was suggested that the flow cytometry may be used for routine detection of weak D positive phenotypes. This study was purposed to evaluate its practicability. Six weak D positive and 7 DEL individuals were detected by using saline, IAT and absorption/elution test from 2010 to 2011 years. By RHD genotyping, zygosity analysis and sequencing, 3 cases of weak D type 15, 3 cases of partial D type DVI-III and 7 cases of DEL carrying RHD1227A alleles were identified. Taking 2 normal Rh(D)-positive and 2 D-negative samples as controls, all the samples were tested by using flow cytometry, and the median fluorescence intensities were observed as well. The results indicated that all weak D type 15 and partial D type DVI samples were detected to be positive by flow cytometry, as compared with 2 Rh(D)-negative samples (P < 0.05). Seven 7 DEL samples were tested to be negative (P > 0.05), although one of 7 DEL was tested as "±" in IAT and strong positive in absorption/elution. The RHD zygosity analysis showed this DEL individual as RHD(+)/RHD(+) homozygote. It is concluded that the sensitivity of detecting D antigen by flow cytometry is similar to that of IAT, but lower than absorption/elution test. As for detecting weak D or partial D antigens, IAT is easier than flow cytometry; as for identifying DEL, the flow cytometry is not sensitive enough.

An analysis of RHD zygosity of Rh(D)-positive Chinese Han population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the RHD zygosity of Rh(D)-positive Chinese Hans in order to study the mother-fetus Rh isoimmunization prophylaxis.</p><p><b>METHODS</b>Rh(D) blood group of 31 115 donors were serotyped, and the RHD zygosities were analyzed, or determined through a PCR method for 3628 donors of Rh(D)-positive individuals.</p><p><b>RESULTS</b>Among the 31 115 donors, 99 were tested Rh(D)-negative by indirect antiglobulin test (IAT) (0.318%). The d frequency was 0.056 41, D was 0.943 59, and Dd heterozygosity was 0.106 45 (10.6%). However the rate was 0.090 32 (about 9.0%) after excluding DEL (IAT-negative). For the 3628 PCR tested donors, 3383 were DD (93.2%), 245 were Dd (6.8%). After excluding nonfunctional RHD alleles, 7.4% of the donors were carrying one functional RHD. It showed that an Rh(D)-negative Chinese Han woman gives an Rh(D)-negative child at a rate of 3.7%-4.5% when her husband is Rh(D)-positive.</p><p><b>CONCLUSION</b>Fetus Rh(D) genotyping may be unnecessary for Chinese Hans if invasive operation was needed for prenatal diagnosis. The Rh prophylaxis could be chosen assuming an Rh(D)-positive fetus.</p>