There is no specific treatment for COVID-19 (Corona Virus Disease 2019, COVID-19).From the perspective of immunology, since COVID-19 patients produce anti-novel coronavirus antibodies during infection, the recovered plasma can be used for passive immunotherapy. The specific antibodies in the recovered patient's plasma can neutralize the virus in the patient, thereby reducing the viral load in the patient, and ultimately reducing or improving the clinical symptoms caused by the virus. The recovered plasma is mainly used in the treatment of COVID-19 patients with rapid disease progression, severe disease and critical disease. At present, in the absence of specific drugs and vaccines, the plasma treatment of recovered patients is one of the effective means to rescue critically ill COVID-19 patients. However, the plasma collection of recovered covid-19 patients is different from that of ordinary unpaid blood donation in the collection method and collection process. In addition to meeting the standard of normal unpaid blood donors, recovered patients are also involved in a series of problems, including clinical evaluation, psychology of recovered patients, cognition, understanding and support of recovered patients' families and the public. This paper discusses how to strengthen the care and privacy protection of plasma donors in COVID-19 rehabilitation period, so as to provide Suggestions and references for blood banks to recruit plasma donors in COVID-19 rehabilitation period and improve the collection success rate.

Objective To analyze the immunological changes of severe COVID-19 patients after infusion of convalescent plasma. Methods Eight severe COVID-19 patients in our hospital were infused with COVID-19 convalescent plasma. The changes of IL-6, COVID-19 virus specific IgM and IgG antibodies, lymphocyte percentage and COVID-19 virus nucleic acid detection were compared before and after treatment. Adverse reactions of transfusion occurred during and after transfusion were recorded. Results On the first day after infusion, the percentage of lymphocytes in the patient decreased by 2.5%（P<0.01）. On the second day after infusion, the level of COVID-19 virus specific IgG increased by 6.04 AU/mL （P<0.05）. There was no significant change in specific IgM and lymphocyte percentage. One week after infusion, 62.5% of COVID-19 patients turned a negative nucleic acid test result. There was no significant change in IL-6 level before and after infusion. There were no blood transfusion adverse reactions. Conclusion Convalescent plasma may play a certain role in the treatment of patients with severe COVID-19.

Objective Inactivation refers to the method of destroying microorganisms by physical or chemical means to lose their biological activity, but without damaging their important antigens. Blood group test requires blood sample from patient with coronavirus disease（COVID-19）to be inactivated at 56℃ in a water bath for 30 minutes prior to pre-transfusion testing.This study aims to discover the effect of the inactivation process on the detection of erythrocyte blood group antigens. Methods The titrated blood grouping reagents were used to detect blood group antigens in five blood samples before and after 56℃ inactivation. Results Using the titrated antibodies to detect A, B, RhD and Fy^a antigens by gel method, we found that there were no statistically significant difference in each dilution between A and B antigens. While, RhD antigen showed statistical differences in each dilution test（diluted 1∶8：P<0.05;diluted 1∶16 ~ 1∶256：P<0.01）, and Fy^a antigen also showed statistical differences in each dilution test （P<0.01）. Conclusion The 56℃ inactivation process could weaken erythrocyte blood group antigens and it exerts greater effects on blood group antigens detection.

Objective To study the effect on the quality of cryoprecipitation from fresh frozen plasma which was centrifugated with high speed once or twice. We detected the content of free hemoglobin, factor Ⅷ and fibrinogen in cryoprecipitate. Methods 40 units whole blood（200 mL per-unit）were divided into two groups. The fresh frozen plasma in control group was centrifugated for once, and that in experimental group was centrifugated twice. Then the following separations were in accordance with national standards. We got the cryoprecipitate of two groups 14 days later, then detected the content of free hemoglobin, factor Ⅷ and fibrinogen in cryoprecipitate. Results Free hemoglobin in the experimental group (17.64±5.60) mg/L is lower than that in the control group (25.75±9.78) mg/L, (P<0.05); and in the experimental group, the content of factor Ⅷ is (53.26±6.08) IU/unit, which is higher than that in the control group （47.34±9.14）IU/ unit（P<0.05）; and the content of fibrinogen is（162±29.01）mg/ unit, which is higher than that in the control group (147.28±43.39) mg/ unit, （P>0.05）. Conclusion By additional high speed centrifugation, more residual red blood cells can be removed from fresh frozen plasma, which may improve the quality of the cryoprecipitation, and increase the content of factor Ⅷ and fibrinogen.

Objective To analyze the screening results and risk factors of irregular antibodies in patients receiving blood transfusions, and provide theoretical evidence for promoting safe clinical transfusion. Methods We retrospectively analyzed the detection rate, distribution characteristics and risk factors of irregular antibodies in 8 775 patients who were planned to be transfused from June 2012 to October 2018 in our hospital. Results The positive rate of irregular antibodies in this study was 0.91% (80/8 775), and 77 cases were further identified. Except for 1 case of pseudoagglutination, Rh antibodies most frequently detected was 28.95% (22/76), of which anti-E accounted for 59.09% (13/22). Followed by MNS antibodies 19.74% (15/76), of which anti-M accounted for 66.67% (10/15). Others were Lewis antibodies 6.58% (5/76), Duffy antibodies 1.32% (1/76), multiple antibodies 15.79% (12/76), autoantibodies 17.11% (13/76), cold antibodies and antibodies of undetermined specificity 10.53% (8/76). Univariate analysis showed that there were significant differences in age, history of blood transfusion, and disease types between patients with positive antibody screen and negative group (P<0.05). Binary logistic regression analysis revealed history of blood transfusion, digestive system disease, chronic kidney disease, solid tumor and hematological diseases, severe internal disease were independent risk factors for the detection of irregular antibodies (P<0.05). Conclusion We recommend adding RhCcEe (at least RhE) typing Rh-matched transfusions as well as the standard ABO/RhD match for patient who has a history of blood transfusion or requires long-term support with frequent transfusions, and providing matched antigen-negative blood products for transfusion based on positive for other irregular antibodies in patient. This will effectively prevent patients from producing irregular antibodies and promote blood transfusion safety.

Objective Analyze the distribution characteristics of weak positive results of irregular antibody screening tests to explore the significance in clinical transfusion practice. Methods 32 684 patients requiring transfusion in our hospital between July 2017 and June 2019 were selected and samples were screened for irregular antibodies using antiglobulin test. The positive samples were further tested for antibody identification using saline test and antiglobulin test tube method. The distribution characteristics and possible reasons of agglutination reaction≤1+ results were analyzed. Results Of the 71 cases with weak positive antibody screening results, 31 were male and 40 were female,but there was no statistically significant difference（P>0.05）. The weak positive rate of irregular antibodies was not related to age（P>0.05）. 43 cases had a blood transfusion, and 28 cases had no history of blood transfusion; 52 cases were specific alloantibodies; 10 cases could not determine antibody specificity; 9 cases were negative for panelcell-16 antibody identification. Conclusion More attention should be paid to weak positive irregular antibody screening results, and provide compatible blood products to avoid blood transfusion ineffectiveness and adverse events of hemolytic transfusion reactions.

Objective To observe the effect of intraoperative cell salvage (ICS) on allogeneic blood transfusion and economic benefits of cesarean women. Methods A total of 369 cesarean women admitted to the obstetrics department of a top three hospital from January 2016 to September 2018 were retrospectively collected, including 252 cases in the ICS group and 120 cases in the control group (allogeneic blood transfusion). According to the amount of bleeding during the operation, the two groups of cesarean women were divided into subgroups. The maternal allogeneic blood transfusion (red blood cells, plasma, platelets, and cryoprecipitation) and economic benefits (time spent in hospital, blood transfusion costs, and pre-transfusion examinations) were compared in each subgroup. Results There was no significant difference in the general data between two groups (both P>0.05). Compared with the control group, the amount of allogeneic red blood cells was significantly reduced in the subgroups of the ICS group. Allogeneic red blood cells and allogeneic plasma usage are significantly reduced in the blood loss less than 1600 mL subgroups of the ICS group (all P<0.05). Compared with the control group, the blood transfusion cost of each subgroup in the ICS group with blood loss ≥800 mL was significantly reduced (all P<0.05). There were no significant differences in the length of hospital stay and the cost of pre-transfusion examinations in each subgroup between the two groups (all P>0.05). Conclusion ICS can save the use of allogeneic red blood cells and allogeneic plasma in cesarean section, reduces the cost of blood transfusion, and has good economic benefits.

Objective To investigate the diagnostic effect of platelet function analyzer（PFA）-200P2Y and Light transmittance aggregometry（LTA）on clopidogrel resistance（CR）and analyze the relevant factors for CR. Methods Ninety-five patients with acute cerebral infarction were selected from Nanjing Drum Tower Hospital from January 2018 to December 2018. All patients were treated with clopidogrel 75 mg/d for more than 3 days, platelet function was measured by PFA-200P2Y and LTA methods. The incidence of CR detected by the two methods was calculated and the correlation between the results of the two methods was analyzed. The patients were divided into CR group and N-CR（non-clopidogrel resistance）group according to the test results. The differences of clinical factors between the two groups were compared, and the related factors that may influence the occurrence of CR were analyzed by Logistic regression. Results 22（23.2%）CR patients were detected by PFA-200P2Y and 53（55.8%）CR patients were founded by LTA. There was significant difference between the two methods（χ²= 21.170,P<0.001）. Univariate analysis showed that there were significant differences in blood homocysteine （χ²=8.589, P=0.004）and white blood cell count（χ²=5.537,P=0.021）between the CR and N-CR groups according to LTA grouping. Logistic regression analysis showed that white blood cell count（OR=1.551,P=0.010）was an independent risk factor for CR, and homocysteine（OR=0.916,P=0.037）was an independent protective factor for CR. Conclusion The consistency between the results of PFA-200P2Y and LTA methods in detecting clopidogrel resistance in patients with acute cerebral infarction is poor. Homocysteine was an independent protective factor and increased leukocyte count was an independent risk factor for CR.

Objective To investigate the transfusion status of pediatric orthopaedic operation, so as to provide basis evidence for clinical blood protection in pediatric orthopaedic surgery. Methods A total of 7 217 children undergoing orthopedic surgery in our hospital from October 2015 to September 2018 were enrolled. The age, the number of blood transfusion cases, the infusion volume of blood components were collected and statistically analyzed. Results The rate of perioperative transfusion was higher in 2-4-year-old preschool children (P<0.05), and the transfusion proportion was higher in fracture and congenital malformation groups （P<0.05）. Except for developmental hip dysplasia （DDH）, there were significant differences in the number of surgical cases and transfusion rate among different age groups, and there was a certain correlation with age. There were significant differences in the total number of transfusions and the per capita transfusion volume of red blood cells and plasma among different diseases （P<0.05）. Conclusion The analysis of perioperative transfusion for pediatric orthopaedic diseases is helpful to improve transfusion technology in our hospital.

Objective To explore the accurate identification method of ABO subtypes, we analysed the serological and molecular biological features of three samples with B subtpye of the ABO blood group. Methods ABO phenotype of three samples were detected using traditional serological methods. The genotypes of Three samples were confirmed by DNA sequencing for exon 6, exon 7 and intron 3 at ABO locus . Results The serological phenotype of three samples were identified as B3,B3 and Bel. The genotype of sample 1 was identified as B303/O02 which with 5G>A mutation in intron 3. The genotypes of sample 2 and sample 3 were identified as Bx03/O01 which with 541 C>T mutation in exon 7 and Bel03/O02 which with 502 C>T mutation in exon 7, respectively. Conclusion ABO subtype can be accurately identified by combining serological and molecular biological method,and molecular biological methods are helpful to explore the mechanism of how ABO subtpyes generate.

Objective To understand the genetic polymorphism of HLA-A,B alleles and HPA1-17 in platelet donors in Zibo area, and establish a database of platelet donors with HLA and HPA locus. Methods Polymerase chain reaction-sequencing based typing (PCR-SBT) and Polymerase chain reaction-sequence specific primer (PCR-SSP) methods were applied in genotyping for HLA-A,B and HPA1-17, respectively.Total of 200 blood samples were collected from unrelated platelet donors．The gene frequencies of HLA-A、B and HPA1-17 were calculated using direct counting method. Results The numbers of low-resolution alleles identified were 15 for HLA-A and 29 for HLA-B,respectively. The most frequent alleles at HLA-A locus were A^*02、A^*24、A^*11、A^*30、A^*33,with a gene frequency in 0.260 0、0.172 5、0.137 5、0.135 0、0.070 0,respectively．For HLA-B locus,the common alleles were B^*13、B^*15、B^*40、B^*44、B^*51,with a gene frequency of 0.160 0、0.132 5、0.130 0、0.067 5、0.062 5,respectively.Within HPA4a, 7a-14a, 16a and 17a systems, only HPA-aa genotype were found. Findings of HPA-15 showed the greatest heterozygosity with a genotype frequency of 0.275 0、0.530 0 and 0.195 0 for HPA15a/15a,HPA15a/15b,and HPA15b /15b,respectively. Conclusion The distribution of HLA-A,B and HPA1-17 in platelet donors in Zibo area have been explored. This research can contribute to establish a regional bank of platelet donors in Shandong province.

Objective The feasibility of returning to the team was discussed through two follow-up and analysis of single nucleic acid testing（NAT）positive blood donors. Methods The single NAT positive blood donors contacted by telephone were followed up for two consecutive times after informed consent. The samples were followed up for routine detection of 3 items of ELISA,3 items of NAT（detected by 2~3 nucleic acid systems at the same time）and 5 items of HBV by chemiluminescence. The results were analyzed statistically. Results 28 donors were followed twice. 21 NAT tested positive at least once（75%）; 27 HBcAb tested positive（96.43%）; 16 HBsAb tested positive （76.19%）. Conclusion The single NAT positive blood donors are mainly infected by HBV occult infection, and the risk of returning to blood donation is large, so it is necessary to establish the returning route carefully.

Objective Conducting a Brucella screening test on some unpaid blood donors in the Zhangjiakou area,statistical analysis of test data, confirmatory testing of suspected cases and follow-up visits, to study the risk of suspected Brucella infected individuals participating in blood donation for blood safety and improve blood safety. Methods For the part of the agricultural and pastoral counties in the Zhangjiakou area and non-agricultural and pastoral areas, the Rose Bengal Plate Test was used for the initial screening of Brucella; The positive screening samples are confirmed by tube agglutination test and sent to the local infectious disease hospital laboratory for review; A PCR confirmation test was performed on a specimen of a patient who had been infected with previous disease. Research and analysis were conduct based on all test data and follow-up visit records. Results The survey screened 3 134 blood donors in farming and pastoral areas, and compared with 2 667 blood donors in non-agricultural and pastoral areas, the positive screening rate of agricultural and pastoral areas was 0.35%, and the positive rate was 0.06%, the positive screening rate of non-agricultural and pastoral areas was 0.11%, and the positive rate was 0.04%. A PCR-fluorescent probe test was performed on blood samples from a patient with previous disease who participated in blood donation to confirm positive. Infectious factors were analyzed from data including occupational, exposure and contact history and follow-up treatment of Brucella positive blood donors. Conclusion Brucella-positive people were found in unpaid blood donors in Zhangjiakou area, and there was no statistically significant difference in Brucella infection between unpaid blood donors in pastoral and non-pastoral areas. It is suggested that Brucella infection is no longer unique to pastoral areas but gradually invades the lives of urban residents, and the blood donated by those donors has safety risk. It is important to increase the Brucella consultation and preliminary screening test in the unpaid blood donors in the high-risk area of brucellosis.

Objective To detect the polymorphism of platelet specific antigen (HPA) -1-6/17 gene in patients with thrombocytopenia (ITP) in Qingdao, and to analyze its relationship with genetic susceptibility to ITP disease. Methods 126 ITP patients diagnosed and treated in the Affiliated Hospital of Qingdao University from 2013 to 2016 were selected as the research objects, and 120 healthy people in the hospital during the same period were selected as the control group. Genomic DNA was extracted by QIAamp DNA Blood Mini Kit , and HPA-1-6/17 was genotyped by PCR-SSP. Results The HPA gene polymorphism of ITP patients and normal population in Qingdao conformed to Hardy-Weinberg law（P>0.05）. There was no significant difference in genotype frequencies and alleles of HPA1-2, HPA4-6 and HPA17 between ITP group and normal people（P>0.05）. There were significant differences in HPA-3 genotype and allele frequency between the two groups（P<0.05）. Compared with the control group, the frequency of HPA-3 aa genotype in ITP group was significantly lower（P<0.05）, and the frequency of HPA-3 bb genotype was significantly higher（P<0.05）. The frequency of HPA-3a gene in ITP patients was significantly lower than that in control group（P<0.05）, and the frequency of HPA-3b gene was significantly higher than that in control group（P<0.05）. Logistic regression analysis showed that the increase of frequency of HPA-3b gene was associated with ITP genetic susceptibility（P<0.05）. Conclusion sHPA-3 system is related to the occurrence of ITP. The frequency of HPA-3b gene in ITP patients is significantly higher than that in control group, which may be a susceptible factor for ITP.

Objective To isolate CD4⁺CD25⁺ regulatory T cells (Tregs) from human umbilical cord blood (UCB), and to amplify and culture in vitro CD4⁺CD25⁺ Tregs by immunomagnetic beads and report these function. Methods CD4⁺CD25⁺ Tregs were isolated from human UCB by immunomagnetic separation beads. The isolated CD4⁺CD25⁺ Tregs were co-cultured with expanded immunomagnetic beads. The content of lymphocyte in UBC was observed by lymphocyte analysis experiment, Tregs by magnetic beads sorting, and selected cell viability by PI staining. The proliferation ability of immunomagnetic beads to Tregs was observed under different culture conditions (immunomagnetic beads group, control group). Results CD4⁺CD25⁺Tregs and CD4⁺CD25^-cells in CD4⁺ UCB were about 4.5% and 95.5%, respectively. Tregs were effectively enriched by magnetic beads sorting and cells stained with PI showed no loss of cell viability, and the content was about 81%. After co-culture with human T cell amplified magnetic beads, Tregs could effectively amplify. Conclusion Immunomagnetic beads can effectively enrich Tregs in umbilical cord blood mononuclear cells without obvious damage. Experiments show that immunomagnetic beads can effectively amplify Tregs in vitro, while evaluation of cells biological function needs further research.

Objective To explore the value of serum amyloid A (SAA), creatine kinase (CK) and endothelin (ET) levels for assessing the severity of acute infective diarrhea in children. Methods From February 2017 to November 2018, 173 children with acute infectious diarrhea were set up as observation group. The serum SAA, CK and ET levels were compared in observation group. Results Before treatment, SAA, CK, ET levels in children with different illness severity were significantly different, severe group>medium group>light group（P<0.05）. SAA, CK and ET levels were positively associated with the severity of acute infectious diarrhea in children（r=5.320,P=0.007;r=4.419,P=0.034;r=5.852,P=0.016). After treatment, the levels of markers were lower than those before treatment in observation group（P<0.05）. Conclusion Serum SAA, CK and ET levels are of great significance in evaluation of the severity of acute infectious diarrhea in children, and can be used as markers to assist in assessing the severity of acute infectious diarrhea in children.

Objective To explore the significance of serum bilirubin in the evaluation of disease activity in patients with lupus nephritis (LN). Methods From May 2016 to September 2018, a total of one hundred systemic lupus erythematosus (SLE) patients as well as fifty healthy volunteer were enrolled in this study. SLE patients were divided into SLE group（n=50）and LN group（n=50）with or without renal damage. Variance analysis was used to analyze the differences of serum total bilirubin（TBIL）, direct bilirubin（DBIL）and indirect bilirubin（IBIL）levels. Pearson correlation analysis was employed to further identify the correlation of these factorsand SLE disease activity index（SLEDAI）score, cystatin C（CysC）and C-reactive protein（CRP）. Multivariate logistic regression analysis further analyzed the correlation between serum bilirubin and LN. ROC curve evaluated the sensitivity and specificity of TBIL, IBIL and DBIL in the diagnosis of LN. Results The levels of TBIL and IBIL were significantly lower in SLE group and LN group than HC group（P<0.05）, and the levels of TBIL, IBIL and DBIL also significantly lower in LN group than SLE group（P<0.05）.In LN group, TBIL, IBIL and DBIL level was respectively negatively correlated with SLEDAI score, CysC level and CRP concentration[（r=-0.489,P<0.05;r=-0.427,P<0.05;r=-0.381,P<0.05）,（r=-0.512,P<0.05;r=-0.423,P<0.05;r=-0.375,P<0.05）,（r=-0.398,P<0.05;r=-0.324,P<0.05;r=-0.318,P<0.05）].TBIL、IBIL、DBIL were protective factors for the pathogenesis of LN;The sensitivity of TBIL, IBIL and DBIL for the diagnosis of LN was 80.00%, 78.00% and 50.00%, and the specificity was 78.00%, 76.00% and 80.00%, respectively. Conclusion Bilirubin level can be used as a new biomarker to evaluate the degree of LN disease activity and renal function injury.

Objective To investigate JAK2, CALR and MPL gene mutations in patients with classical BCR-ABL1-negative myeloproliferative neoplasms (MPNs) and to analysis their clinical features. Methods This retrospective study analyzed clinical and laboratory data from 126 patients with classical BCR-ABL1-negative MPNs diagnosed from July 2017 to July 2019 for two consecutive years at a single center. Results ①JAK2 V617F mutation is the highest frequency in MPNs patients, accounting for 77.78%, and in PV patients, accounting for 95.24%. Among the ET patients,JAK2 V617F mutation-positive patients had significantly higher hemoglobin levels than triple-negative patients, and were older than CALR mutation-positive patients（P<0.05）; Among the PMF patients, JAK2 V617F mutation-positive patients had significantly higher white blood cell counts than triple-negative patients （P<0.05）. ②The incidence of thrombotic events in patients aged ≥60 years was significantly higher than that in patients aged <60 years（P=0.015）. WBC, PLT and fibrinogen（Fb）in the thrombus group were significantly higher than those in the non-thrombosis group（P<0.05）. Conclusion Patients with classic BCR-ABL1-negative MPNs have a high level of JAK2 V617F mutation. JAK2 V617F positive patients, old age（≥60 years）, patients with high WBC counts, high PLT counts and high Fb levels are associated with higher risk of thrombotic events.

Objective To find out the molecular basis and genetic rule of ABO subtypeby genotyping and pedigree analysis of a sample suspected to be cisAB by serological examination. Methods ABO blood group was identified by blood group serology in all samples. Exons 6 and 7 of ABO gene were amplified by polymerase chain reaction (PCR) and sequenced. Results The results showed that thegenotype of the sample was ABO*cisAB.01/O.01.02. In the family investigation, it was found thatserological results of the other fourmembers were found to be inconsistent with positive and negative reactions, but the blood type characteristics were different. The sequencing results showed that all of them carried the ABO*cisAB.01 gene. Conclusion ABO* cisAB.01 gene can lead to weak expression of A/B antigen and stable inheritance. ABO blood groups can be identified by molecular biological methods in the detection of serological specimens with different positive and negative blood types. The samples with incompatible serological typing can be detected by molecular biology method to assist in the identification of ABO blood group.

With the development of blood transfusion medicine, more and more attention has been paid to the health of donors. In order to monitor the adverse reactions of blood donors, many countries and regions have formulated the vigilance standards for the adverse reactions of blood donation. They have carried out the vigilance of the adverse reactions of blood donation systematically, and studied the incidence rate and occurrence mechanism for the prevention and disposal of the adverse reactions of blood donation. In our review, we summarized vigilance standards, data access, incidence of adverse reactions, the related factors and the influence of blood donation adverse reaction and analyzed the measures of prevention and treatment of adverse reactions. It provides scientific basis for the blood collecting and supplying institutions and related departments to understand the adverse reactions of blood donation and carry out related prevention and control adverse reactions of blood donation.