RHD genotype and zygosity analysis in the Chinese Southern Han D+, D- and D variant donors using the multiplex ligation-dependent probe amplification assay.

BACKGROUND AND OBJECTIVES: Several comprehensive genotyping platforms for determining red blood cell (RBC) antigens have been established and validated for use in the Caucasian and Black populations, but not for the Chinese. The multiplex ligation-dependent probe amplification (MLPA) assay was validated for RHD genotyping in the Chinese. MATERIALS AND METHODS: The blood samples of 200 D+, 200 D- and 62 D variant Chinese donors were collected. RhD antigen was routinely typed by serological method. D variant phenotype was determined by an anti-D panel (D-Screen), when RBCs were available. The RHD genotype and its zygosity were analysed with the RH-MLPA technique. When the MLPA was unable to identify a RHD variant, direct sequencing of all exons of the RHD gene was performed. RESULTS: In 200 D+ donors, DD (168/200, 84%), D (12/200, 6%), DDD genotype (1/200) and D variant allele carriers (19/200, 9·5%) were found. In 200 D- donors, six reported RHD alleles, RHD*01EL.01, RHD*01N.03, RHD*01N.05, RHD*01N.16, RHD*DFR2 and RHD*weak partial 15 and one novel RHD*1154T allele were identified in 36·5% (73/200) of them. In 62 D variant donors, three novel RHD alleles, RHD*79_81delCTC, RHD*710T and RHD*689A, and twelve reported alleles, RHD*DVI.3, RHD*weak partial 15, RHD*DVI.4, RHD*01EL.01, RHD*01N.03, RHD*DLO, RHD*DV.5, RHD*D-CE(2-10), RHD*730C, RHD*weak D type 25, 33 and 72, were identified, either alone or in combination. CONCLUSION: The RH-MLPA assay correctly identified the common RHD variant alleles in the Chinese population. However, DNA sequencing was required to identify certain alleles; probes to detect these alleles should be added into the assay.

The distribution of MNS hybrid glycophorins with Mur antigen expression in Chinese donors including identification of a novel GYP.Bun allele.

BACKGROUND AND OBJECTIVES: MNS hybrid glycophorins are identified by characteristic antigen profiles. One of these is the Mur antigen, which is expressed on red cell hybrid glycophorins of several phenotypes of the 'Miltenberger' series found predominantly in East Asian population. The aim of this study was to investigate the distribution of Mur-positive hybrid glycophorins and clarify the genetic basis in the donors from southern China. MATERIALS AND METHODS: Blood samples from 528 donors were collected for Mur antigen serological typing. Sequencing of GYPB pseudoexon 3 and MNS phenotyping were conducted in Mur-positive samples. The multiplex ligation-dependent probe amplification (MLPA) was used to confirm the zygosity of the GYP.Mur allele and determine the MNSs genotype. The expression of Mur antigen was evaluated by flow cytometry. RESULTS: Fifty-one Mur-positive samples were identified by serological testing. Sequencing analysis showed 50 donors (50/528, 9.5%) with the GYP.Mur allele (48 heterozygotes and two homozygotes), which were confirmed by the MLPA genotyping analysis, and one donor (1/528, 0.19%) with a novel GYP.Bun allele. Flow cytometry analysis revealed higher Mur antigen expression on GP.Mur (Mi.III) homozygotes than heterozygotes. For the GYP.Mur homozygotes, an incorrect 'N' positive typing with anti-N lectin was obtained. CONCLUSION: GP.Mur (Mi.III) is the main Mur-positive hybrid glycophorin in Guangzhou donors. The dosage effect of Mur antigen observed provides a basis for selecting the homozygous GP.Mur RBCs as the reagent cells to avoid neglecting weak antibodies. A separate GYP.Bun lineage found in the southern China provides evidence for further complexity in the MNS system.

Establishment of platelet donor registry improves the treatment of platelet transfusion refractoriness in Guangzhou region of China.

Platelet transfusion refractoriness (PTR) is the major complication of long-term platelet supportive care. To improve the effectiveness of platelet transfusion therapy in PTR patients, we aimed to establish a platelet donor registry in our region (Guangzhou, China) by typing the human leukocyte antigen (HLA) and human platelet antigen (HPA). Blood donors (n = 864) from our population were genotyped for HLA-A, HLA-B and HPA systems by polymerase chain reaction amplification with sequence-specific primer(PCR-SSP) techniques. Using this cohort, we compared the results of platelet transfusions (matched vs. random) in 23 patients with PTR. Matched platelets were selected either by HLA antigen matching or by HLA antibody matching, as predicted by antibody specificity prediction (ASP) analysis. Significantly higher platelet recovery (PPR) values were obtained with HLA-matched platelets in comparison with random platelets. No significant difference in PPR was observed between HLA matching and ASP methods. In two patients, platelet-specific alloantibodies (alloabs) (anti-HPA-3b and anti-HPA-5b) were detected besides HLA class I alloabs. Transfusion with HLA- and HPA-compatible platelets in both the patients resulted in significantly higher PPR when compared with HLA-compatible platelet transfusion alone. In this study, we demonstrated that the establishment of an HLA- and HPA-typed platelet aphaeresis donor registry is useful to improve the treatment outcome of PTR patients and to maintain a long-term platelet transfusion strategy.

A methodology of characterizing status and trend of land changes in oases: a case study of Sangong River watershed, Xinjiang, China.

Land change is often studied with Markov models to develop a probability transition matrix. The existing methods dependent on such matrixes cannot effectively characterize some important aspects associated with land change such as status, direction, trend and regional variations. This study presents mathematical models to quantify these elements, defining unbalanced, quasi-balanced and balanced status, one- and two-way transitions and the rising or falling trends. Using these models and remote-sensing imageries, the landscape was studied for a case area, the oasis of Sangong River in Xinjiang, Northwest China where typical arid conditions prevail. Land expansion and contraction among various land types and for the entire oasis were analyzed for the periods of 1978-1987, 1978-1998 and 1987-1998. The changes were closely related to a strong economic growth after the land-reform campaign and adoption of the market economy in China in the 1980s to early 1990s, a process not strictly Markovian that requires stationarity and randomness. Information on land-change status and trend is important for a better understanding of the underlying driving processes but also for land-use planning and decision-making.

Multi-wavelength mid-infrared micro-spectral imaging using semiconductor lasers.

Infrared (IR, 3-12-microm) microscopic spectral imaging is an important analytical technique. Many current instruments employ thermal IR light sources, which suffer the problem of low brightness and high noise. This paper evaluates the system engineering merit in using semiconductor lasers, which offer orders-of-magnitude-higher power, brightness, and lower noise. A microscopic spectral imaging system using semiconductor lasers (quantum cascade) as illuminators, and focal plane array detectors demonstrated a high signal-to-noise ratio (> 20 dB) at video frame rate for a large illuminated area. The comparative advantages of laser vs. thermal light source are analyzed and demonstrated. Microscopic spectral imaging with fixed-wavelength and tunable lasers of 4.6-, 5.1-, 6-, and 9.3-microm wavelength was applied to a number of representative samples that consist of biological tissues (plant and animal), solid material (a stack of laminated polymers), and liquid chemical (benzene). Transmission spectral images with approximately 30-dB dynamic range were obtained with clear evidence of spectral features for different samples. The potential of more advanced systems with a wide coverage of spectral bands is discussed.