Based on the high level of human granulocyte—macrophage colony—stimulating factor(HGM—CSF)re-ceptor of HL60 cell line upon induction by DMSO,we developed a hioassay method for HGM—CSF with ahigher specificity and sensitivity.The sensitivity of this assay reached to 0.3ng/ml by selecting the optimalHL60 cell—induced time,cell density and GM—CSF—stimulated time.With this assay,we are able to quantifythe level of rHuGM—CSF as well as conditioned media from human bladder carcinoma cell line U5637 screatinga high level of GM—CSF.

Objective To investigate the distribution,phenotype and genotype of D-elute type(Del)in blood donors with RhD negative blood in Guangzhou,so as to understand the molecular biological background of DEL blood group in this area.Methods During the period from November 1,2021 to June 30,2022,the RhD-negative blood initially screened by saline method was confirmed by indirect anti-human globulin test(IAT)serology,and RhCE phenotype was determined by RhCE typing card.A total of 1 146 RhD-negative samples,including all RhD-negative samples with RhCE C+(n=459)and a randomly selected subset of RhCE C-(n=175),were subjected to adsorption-elution(Del)screening(a total of 634 sam-ples).DNA from Del-positive samples was extracted for real-time fluorescent PCR detection of the RHD gene c.1227 locus using high-resolution melting curve analysis(HRM).For samples without mutations detected at the RHD?1227 locus by HRM,restriction fragment length polymorphism polymerase chain reaction(PCR-RFLP)was performed to amplify the prod-uct which was subsequently digested with Pst I enzyme and analyzed by electrophoresis to determine RHD gene haplotypes.Sanger sequencing was performed for exon sequencing(exon 1-10)of the RHD gene,and gene mutations were analyzed u-sing SeqMan software.Suspected Del-positive samples were subjected to RHD whole gene analysis using third-generation sin-gle-molecule sequencing technology.Results Among the 634 confirmed RhD-negative samples,229(36.1%)displayed Del phenotype,accounting for20%(229/1 146)of the total confirmed RhD-negative samples.The RhCE phenotypes of the 229 DEL cases were as follows:Ccee in 181 cases,CCee in 40 cases,CcEe in 7 cases,and ccEe in 1 case.HRM combined with RHD haplotype analysis showed that there were 170 cases with RHD gene as RHD?1227A/01N.01,32 cases with RHD gene as RHD?1227A/1227G,26 cases with RHD gene as RHD?1227A/1227A,and 6 cases with RHD gene as RHD?1227G/1227G(sequencing results included 1 case of weak D type 12,4 cases of D-,and 1 case of RHD?01EL.02).Con-clusion The individual genotype of DEL blood donors in Guangzhou area is mainly characterized by RHD?1227A/01N.01,and their RhCE phenotypes are all C+.HRM can be used as a molecular biology method for routine screening of Asian-type DEL blood type genes.

【Objective】 To investigate the distribution of ABO and RhD blood groups among voluntary blood donors in Guangzhou, in order to ensure clinical blood safety and better serve blood donors. 【Methods】 Routine ABO and RhD blood group screening tests were carried out among voluntary blood donors from January 2021 to December 2022. The composition ratio of ABO blood group was statistically analyzed. The samples with discrepancy between forward and reverse blood grouping and negative RhD blood group samples were further verified by serological test to analyze the ABO subtypes and the reasons for missed detection. 【Results】 A total of 749 123 blood samples were screened from January 2021 to December 2022, and 513 291 samples were collected after excluding repeat blood donors, with the ABO blood groups as 208 126(40.55%) of O type, 138 859(27.05%) of A type, 130 987(25.52%) of B type and 35 319(6.88%) of AB type. The screening results showed discrepancy between forward and reverse blood grouping in 506 samples, of which 58 were with weak/non-erythrocyte reaction, 16 with erythrocyte reaction, 215 with weak/non-serum reaction, and 217 with serum reaction. Further serological test indicated that 44 samples were ABO subtypes, among which 13 were subtype A, 26 subtype B, 5 subtype AB and 3 B (A) and 14 Bombay-like blood group. The blood group with the highest missed detection rate in repeat blood donors were A3/B3 subtype (68.42%). A total of 128 unexpected antibody positive samples were detected among 513 291 samples A total of 2 277 samples were screened negative for RhD blood type, of which 2 188 were confirmed to be Rh negative (2 188/513 291, 0.43%), 89 were D variants (89/513 291, 0.02%, ) and 30 were detected with unexpected antibodies (30/2 188, 1.37%). 【Conclusion】 The ABO blood group distribution of blood donors in Guangzhou is O>A>B>AB, and the proportion of RhD negative population is 0.43%, slightly highter than 0.3%-0.4% of Han population nationwide. The ABO blood group subtype is dominated by B subtype. The detection rate and missed detection rate of A3/B3 subtypes in routine blood group tests are the highest.

【Objective】 To explore the characteristics of the D antigen epitope of individuals with RhD variants and the genetic molecular mechanism of gene mutations in Guangzhou. 【Methods】 A total of 59 samples of RhD variants were collected from blood donors and hospitals in Guangzhou from January to August 2019. Serological characteristics of D epitopes were further analyzed using two kinds of monoclonal anti-D reagents and D epitope detection kits, and RHCE phenotypic typing was performed. QuickGene DNA extraction kit was used to extract the genomic DNA of the samples, and PCR-RFLP method was used to analyze the RHD gene zygote type. The RHD gene sequence was detected by multiple ligation-dependent probe amplification(MLPA) genotyping, and the RHD exon(1~10) Sanger sequencing was performed on the samples still in doubt after the above detection. DNAStar/SeqMan analysis software was used for comprehensive analysis. 【Results】 In this group of individuals with RhD variants in Guangzhou, 27.12%(16/59) were detected from blood donors [accounting for 0.007%(16/232 793) of blood donors in Guangzhou during the same period], and difficult samples of patients sent by hospitals for determination accounted for 72.88%(43/59). RHD genotype detection: 40.68%(24/59) were RHD^*weak partial 15, 25.42%(15/59) were RHD^* DⅥ.3 and 33.90%(20/59) were rare RHD variants [76.92%(10/13) were RhD variants with 2 different alleles]. Serological D-screen revealed a relatively fixed pattern of RHD^*DⅥ.3 in anti-D antibody(clone: P3^*212 23B10), while the others was negative. The phenotypic distribution of RhD variant CE was Ccee 38.98%(23/59), ccEe 35.59%(21/59), CcEe 25.42%(15/59). 【Conclusion】 Weak partial D15 and DⅥ.3 were the most common RhD variants in Guangzhou Han population, and DⅥ can be preliminarily identified by serological methods such as D-Screen anti-D reagent, while the remaining RhD variants can only be identified by molecular biological methods, and >95% of the RhD variants were C+ or E+ phenotypes.

【Objective】 To assess the trend of hepatitis B virus (HBV) prevalence and associated risk factors among voluntary blood donors in Guangzhou area from 2011 to 2020, and to explore the impact of hepatitis B vaccination in neonates on the risk of HBV infection. 【Methods】 Blood samples of 2 624 434 voluntary blood donors from 2011 to 2020 in Guangzhou were tested by HBV surface antigen (HBsAg) enzyme-linked immunosorbent assay (ELISA) reagents twice and nucleic acid test (NAT) reagent once. Samples reactive to ELISA twice, or ELISA once + NAT were considered as HBV infection. The gender, age, ethnicity and region of HBV infected blood donors were collected, and the incidence of HBV infection in blood donors born before and after 1992 (when HBV vaccination was conducted in neonates) was compared. The trend and risk factors of HBV infection in blood donors in Guangzhou from 2011 to 2020 were analyzed. 【Results】 An overall HBV prevalence of 0.75% was found in voluntary blood donors in Guangzhou area from 2010 to 2020, showing an overall downward trend(P<0.05). HBV prevalence was lower in blood donors born after 1992 (0.49 %, 4 825/98 5362) than prior to 1992 (P<0.05). HBV prevalence in male blood donors (0.89%, 15 049/1 695 062) was significantly higher than that in female blood donors (P<0.05). HBV prevalence in blood donors aged 18~25(0.52%, 6 337/1 219 282)was lower than that in other age groups (P<0.05). HBV prevalence was similar in donors resident in Guangdong and other provinces(P>0.05), but both were significantly higher than that in Hong Kong, Macao, Taiwan and foreign countries (P<0.05). HBV prevalence in Han nationality donors was significantly higher than the ethnic minority donors (P<0.05). Gender, age, ethnicity and birth vaccination are the main risk factors for HBV infection among blood donors. 【Conclusion】 The overall HBV prevalence among voluntary blood donors in Guangzhou area from 2011 to 2020 has shown a decreasing trend, and differences have been found in gender, age, region, ethnicity and birth vaccination, which is helpful to formulate targeted recruitment strategies, thus reducing the risk of transfusion transmitted HBV.

【Objective】 To retrospectively analyze the reasons of insufficient blood collected, to provide evidences for further taking targeted measures, to reduce the discard of insufficient whole blood and prevent the loss of blood donors. 【Methods】 Calculate the total number of whole blood donors and the number of whole blood donors donating insufficient blood during 2018~2020 annually in Guangzhou Blood Center Information System, and the data was analyzed in SPSS (22.0) software for χ²test and linear trend test. 【Results】 During 2018~2020, the incidence of insufficient blood collected was 0.066 4%(531/799 439), and the incidence of insufficient blood collected because of poor blood flow, needle-sickness and other reasons were 0.048 7%(389/799 439), 0.010 6%(85/799 439) and 0.007 1%(57/799 439). Furthermore, the incidence of insufficient blood collected of the three above reasons had statistically significant difference between the years respectively (P<0.05), meanwhile the incidence of insufficient blood collected because of poor blood flow was in a general rising trend significantly (0.036 3%<0.038 2%<0.072 7%, P<0.05). 【Conclusion】 The incidence of insufficient blood collected because of poor blood flow was in the rising trend and further precautions should be considered. Under the normalization of the novel corona-virus pneumonia (COVID-19), the professional knowledge of epidemic prevention and control should be learned and trained, in addition the puncture technique, the ability of offering psychological care and dealing with adverse events during blood collection should be also improved among nurses continually, so as to provide high quality services for blood donors.

【Objective】 To investigate the condition of confidential unit exclusion(CUE) in Guangzhou, so as to ensure blood safety. 【Methods】 The number of CUE donors, demographic characteristics of CUE donors, reasons for CUE, and response time of CUE after blood donation in Guangzhou from 2009 to 2022 were statistically analyzed. 【Results】 From 2009 to 2022, the response ratios of CUE was 0.006 2% (260/4 170 984) and the ratios had statistically significant difference between different years(P<0.05). For the response ratios of CUE, no statistically significant difference was noticed in gender and occupation (P>0.05), but statistically significant differences were found in age, number of blood donations, education background, and marital status (P<0.05). Blood donors aged 18~30 (0.007 3%, P<0.05) and first-time blood donors (0.010 8%, P<0.05) were the main groups of CUE. High risk sexual behavior (28.46%, 74/260) was the primary reason for CUE. The CUE response peak was within 72 hours after blood donation, and the response ratios within 24-72 hours after blood donation was the highest (68.46%, 178/260). 【Conclusion】 CUE is a crucial measure to ensure blood safety. Detailed pre-donation health consultations are suggested for blood donors aged 18-30 and first-time blood donors so as to better excluding high-risk blood donors. Strengthening the publicity of CUE response and process, registering and classifying the reasons for CUE are also important.

【Objective】 To explore the correlation between serological screening of human T-lymphotropic virus antibodies (anti HTLV) and Western blot(WB) confirmatory tests among blood donors, so as to explore the infection status of HTLV Ⅰ/Ⅱ in Guangzhou. 【Methods】 The anti HTLV Ⅰ/Ⅱ enzyme-linked immunosorbent assay(ELISA) kit was used to screen voluntary blood donors from Guangzhou Blood Center from July 2016 to August 2022. WB was used to confirm 395 reactive blood samples by ELISA. The correlation between the S/CO values of anti HTLV Ⅰ/Ⅱ ELISA reagents and the confirmatory test was analyzed using ROC curves. 【Results】 The results showed that 25 out of 395 initially screened reactive blood donor samples were confirmed as HTLV positive by WB, while 16 were uncertain. ROC curve analysis showed a correlation between the S/CO values by ELISA and the confirmatory test results: the S/CO value at the highest Youden index was 3.789, which was the optimal threshold. The S/CO value had a certain correlation with the predicted positive rate of confirmatory results (P<0.05): the larger the S/CO value, the higher the predicted positive value. The overall prevalence of HTLV in Guangzhou is relatively low. 【Conclusion】 The prevalence of HTLV among blood donors in Guangzhou is low.Since the false positive rate of HTLV Ⅰ/Ⅱ antibody by ELISA serological screening is high, the confirmatory testing is particularly important.

[Objective] To analyze the influence of the cycle length of hepatitis B surface antigen (HBsAg) double reagent positive samples collected from voluntary blood donors in Guangzhou on the detection results. [Methods] A total of 127 044 blood samples from voluntary blood donors at Guangzhou Blood Center from August 10 to December 9, 2023 were selected. Two ELISA reagents were used for HBsAg detection, and samples with HBsAg double reagent positive and S/CO values<10 were tested continuously for 7 days to observe the changes in their S/CO values. [Results] A total of 505 HBsAg double reagent positive samples were detected, of which 52 had S/CO values less than 10. After 7 consecutive days of uninterrupted testing, the S/CO values of Wantai (median 5 decreased to 3) and Xinchuang (median 5 decreased to 3) showed an overall downward trend, and the HBsAg missed detection rate showed an upward trend (from 0 on the first day to 1/10 000 on the seventh day). A total of 13 cases had negative double reagent test results within the 7-day testing cycle. [Conclusion] With the extension of the detection cycle, the S/CO value of HBsAg detection shows a downward trend, and the missed detection rate of HBsAg shows an upward trend. Samples used for HBsAg detection should be tested promptly after sampling to improve the quality of blood testing.