anti-B Antibody Titer Research Articles

Relative Quantification for Obtaining the IgG Blood Group Antibodies in Plasma by the Absorption and Elution Test

To establish the absorption and elution test for relatively quantitive obtaining anti-A and anti-B blood group IgG antibodies in the plasma of O-type RhD-positive pregnant women. 95 cases of the O-type RhD-positive pregnant women plasma samples were randomly selected for obtaining the IgG antibodies of anti-A and anti-B blood group, with absorption test under 37 ℃ and elution test under 56 ℃, and the IgG anti-A and anti-B antibody titers of plasma and elution were determined by the microcolumn gel anti-human globulin test. The differences and correlation between the titers of IgG antibodies in the eluent and plasma were compared and analyzed. After a logarithmic transformation (Log2), there was no statistically difference between IgG antibody anti-A difference value and anti-B difference value in the eluent and plasma (P >0.05). The titer of IgG antibody in the eluent was positively correlated with the titer of IgG antibody in the plasma (r =0.914). The linear equation for IgG antibody titers fitted by a scatter plot between the eluent and plasma was Y=-3.55+0.96X. The absorption and elution test can be used to obtain the anti-A and anti-B IgG antibodies in the plasma of O-type RhD-positive pregnant women, whose plasma origin IgG titer is greater than 8. Meanwhile, the acquisition of anti-A antibodies was as effective as anti-B antibodies at the same time, and the antibodies obtained are positive proportional to their respective concentrations in the plasma.

Feasibility Analysis of Establishing Combat Readiness Blood Bank Based on Low Titer Group O Whole Blood and Group A Plasma

To explore the feasibility of establishing combat readiness blood bank with low titer group O whole blood and group A plasma. The Galileo automatic blood analyzer was used to detect the titers of IgM anti-A and anti-B antibodies in the samples of group O blood donors and IgM anti-B titer in the samples of group A blood donors. Group O blood donors with antibody titers below 128 were selected and included in the mobile blood bank for combat readiness, group A plasma with anti-B titer lower than 128 and group O whole blood with antibody titers below 128 were included in the combat readiness entity blood bank. A total of 1 452 group O blood donors were selected, and the anti-A/B antibody titers were detected. Both antibody titers were distributed below 512, and both peak values of sample distribution were at titer 4. The proportion of samples with titers>128 for both antibodies was relatively low. There was a significant positive correlation between the titers of the two antibodies (r =0.383), and the proportion of samples with IgM anti-A titer higher than IgM anti-B titer was relatively high. 1 335(91.94%) group O blood donors with IgM anti-A and anti-B antibody titers <128 could be included in the mobile blood bank. The anti-B titer of group A blood was detected in 512 cases and the results showed that as the antibody titer increased, the proportion of blood donors gradually decreased. 99.8% of group A blood donors had anti-B antibody titer less than 128, and only one case did not meet the inclusion criteria. The proportion of group O blood donors whose whole blood meet the low antibody titer standard is high, and almost all plasma of group A blood donors meet the low titer standard, which improves the blood supply rate in emergencies.

Comparative Analysis of AB vs. ABO-specific Plasma for Desensitization in Blood Group O Recipients: An In Vitro Study.

Neutralizing capacity measurement (NCM) of soluble ABH substances (SAS) in plasma was assessed to guide the selection of the appropriate ABO group of fresh-frozen plasma (FFP) for plasma exchange (PE) in blood group O recipients with ABO-incompatible transplantations. Neutralizing capacity was assessed by measuring anti-A and/or anti-B titers in samples comprising one unit of O FFP and 10 O EDTA plasma samples and subtracting the binary logarithm of the titer in each group with a saline dilution. Ten EDTA plasma samples with Lewis b (Leb) antigen positivity and 10 sets of pooled FFP from each blood group were used as diluents. In O FFP, the NCM values (mean±SD) were 3.4±0.52 (2.6±0.52) and 2.6±0.52 (1.5±0.3) in B and AB for IgM (total antibody) anti-B (both P<0.001), and in the 10 O EDTA plasma samples, they were 3.9±0.88 (3.1±0.88) and 3.2±0.79 (2.4±0.97) for IgM (P=0.0013) and total anti-B (P=0.025), respectively. In vitro analysis revealed that B FFP is more effective than AB FFP in reducing IgM and total anti-B antibody titers in O recipients, regardless of Leb antigen positivity.

Estimation of ABO Anti-A and Anti-B Agglutinin Titers among Blood Donors at a Tertiary Care Referral Teaching Hospital Blood Centre in Southern India: A Cross-sectional Study

Introduction: Transfusion of blood Group O and its components with high ABO antibody titers to non O recipients has been shown to cause acute transfusion reactions, especially in platelet transfusions, as platelets contain significant amounts of ABO antigen on their surface as well as Anti-ABO alloisogglutinins in plasma. Aim: To estimate the ABO Anti-A and Anti-B agglutinin titers among blood donors at a tertiary care referral teaching hospital blood centre. Materials and Methods: This cross-sectional observational study was conducted at the Immunohaematology laboratory of the Department of Transfusion Medicine, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India, from March 2021 to June 2022. All blood donors presenting to the blood centre were screened for eligibility for blood donation. Donors who fulfilled the eligibility criteria as per the Drugs and Cosmetics Act, 1940, and Rules, 1945 were included. Anti-A and Anti-B titers were determined by the conventional tube method with dilutions of 1 in 2, 1 in 4, 1 in 8, 1 in 16, 1 in 32, 1 in 64, 1 in 128, 1 in 256, 1 in 512, and 1 in 1024. A titer of &lt;64 was considered as a low titer, while a titer of &gt;64 was considered as a high titer. Results: A total of 399 donors were included in the study, with 393 (98.5%) being males and 6 (1.5%) being females. The mean age of the study population was 28.49 years. Among blood group A, the percentage of individuals with an IgM anti-B titer of &lt;64 was 85.44% (88) and &gt;64 was 14.56% (15), whereas in blood group B, IgM anti-A titers of &lt;64 were 65.5% (93) and &gt;64 were 34.5% (49). In blood group O, the percentage of individuals with &lt;64 and &gt;64 titers of IgM anti-A were 52.60% (81) and 47.40% (73), respectively, whereas for anti-B, &lt;64 and &gt;64 titers were 77.92% (120) and 22.08% (34), respectively. Conclusion: It is recommended that a database be maintained in all institutes by estimating antibody titers for every A, B, O blood group donors. Whole blood or platelets from group O donors with IgM Anti-A and Anti-B antibody titers &lt;64 can only be transfused across the ABO barrier. As the majority of group A donors had titers &lt;64, group A platelets may be transfused across the ABO barrier in emergency situations.

Decreased rate of blood donors with high ABO antibody titers in Japan and the underlying factors: Comparisons between 2010 and 2021

Background and ObjectivesPreviously (2007), it was reported that ABO antibody titers in Japanese blood donors had decreased significantly compared to 20 years before. Here we evaluated whether further decrease of antibody titers had occurred in recent years, and the potential factors associated with changes in antibody titers. Materials and MethodsSerum/plasma from random blood donors in 2010 and 2021 (2010: 3369, 2021: 5796 donors) was classified into low, middle, and high ABO antibody titers according to the reactivity of diluted serum/plasma (2.5-fold and 20-fold) by an automated microplate system. The rates of low/high titer in the two periods were compared. Logistic regression and age-gender-BMI subgroup analyses were conducted to identify the factors that contributed to changes in antibody titers. ResultsCompared to 2010, the rate of donors with high ABO antibody titers was decreased in 2021 for both anti-A and anti-B (anti-A, 2010: 23.8%, 2021: 19.3%; anti-B, 2010: 23.8%, 2021: 16.4%). In logistic regression analysis, age was found to significantly affect both anti-A and anti-B antibody titers (anti-A, adjusted odds ratio 0.36, 95% CI 0.31–0.41; anti-B, 0.42, 0.37–0.47), and BMI (0.82, 0.73–0.92) and other time-related factors (0.79, 0.71–0.88) significantly affect anti-B antibody titers. Subgroup analysis revealed decreased rate of high anti-B titers in the higher age group in 2021. ConclusionThe rate of high ABO antibody titers, especially high anti-B titers, was significantly decreased in 2021, and our results suggested an association with aging and obesity of blood donors as well as other time-related factors.

Platelet Additive Solutions as an Alternative Storage Medium of Apheresis Platelets to Reduce ABO Antibody Titer for ABO-Incompatibility Platelet Transfusion.

Introduction Platelet additive solutions (PASs) are nutrient media commonly used to replace and reduce the need for storage plasma. They are an alternative medium to maintain high-quality platelets lasting longer on the shelf for about seven days. Platelets with high titer of ABO antibody can pose a hemolytic transfusion reaction (HTR) risk if units are given across the ABO barrier. The risk of complication is greater when group O platelet is released to non-group O patients. The PAS has been known as a safe medium, where the titer of ABO antibodies is expected to be diluted. In this study, we compared the anti-A and anti-B antibody titers of apheresis platelets in PAS and non-PAS (plasma) as the suspending media. Methods A total of 20apheresis platelet donors were selected, with seven from blood group A, eight from blood group B, and five from blood group O. The platelets were collectedusing an Amicus cell separator. They were suspended in PAS and plasma before being stored at a temperature range of 22-24ºC. Anti-A (blood group B and O)and Anti-B(blood group A and O) antibody titers were measured and compared between the two suspending media. Wilcoxon signed-rank test is used for statistical analysis, and a p-value <0.05 is considered significant. Results The median titer of the anti-A antibody of apheresis platelets showed a significant difference between suspended in PAS (2.50) and plasma (4.00), p=0.002. Similar findings were also seen with the median titer of the anti-B antibody of apheresis platelet, in which it showed a significant difference between suspended in PAS (2.00) and plasma (4.00), p=0.004. It was observed that there was a significant reduction in both anti-A and anti-B antibody titers in the PAS as compared to the plasma group. Conclusion The decrease in ABO antibody titer in apheresis platelets stored with PAS can be beneficial for patients. This reduces the risk of HTRs if ABO-incompatible platelet units need to be issued. Thus, using PAS as a storage medium significantly improves platelet inventory management without compromising patient safety.

An assessment of the safety, hemostatic efficacy, and clinical impact of low-titer group O whole blood in children and adolescents.

Low-titer group O whole blood (LTOWB) use has been associated with improved survival and less blood transfusions in adult trauma patients. Its use in pediatric trauma has been shown to be safe when using leukoreduced, LTOWB with anti-A, anti-B antibody titers of <1:50. We set out to evaluate the safety, hemostatic potential, and impact on pediatric outcomes at a center using non-leukoreduced, LTOWB with anti-A, anti-B antibody titers of <1:200. Patients younger than 18 years, who received emergency-release, uncrossed matched blood, and presented to our trauma center from November 2017 to April 2021 were included. Patients were divided into those receiving any LTOWB and those receiving only RBC and or plasma (COMP). Primary outcome was 30-day survival. One hundred sixty-four patients received emergency release blood products. Of these, 73 received at least one unit of LTOWB. The LTOWB group were younger (14 years vs. 13 years), more likely to be male (87% vs. 49%), and to have sustained penetrating trauma (44% vs. 23%); all p < 0.05. Low-titer group O whole blood patients received more blood than their COMP counterparts prior to arrival. Serial hemolysis panels (K+, bilirubin, LDH, haptoglobin) obtained at 24 hours, 48 hours, and 72 hours were similar between groups; all p > 0.05. There was no difference in survival by univariate analysis but after adjusting for inverse probability of treatment weights there was an observed association between WB administration and improved survival, with an odds ratio of 2.48 (1.15-5.47). Non-leukoreduced, LTOWB in anti-A/anti-B antibody titers of <1:200 appear safe in children and adolescents. While patients receiving LTOWB had more evidence of shock, higher torso injury severity, and received more prehospital blood products, there may be a mortality benefit with whole blood. Larger, multicenter studies are needed. Therapeutic/Care Management; Level IV.

Analisis Titer dan Subtipe Antibodi pada Inkompatibilitas ABO yang Menyebabkan Hemolytic Disease of Fetus and Newborn

Background: Hemolytic disease of the fetus and newborn (HDFN) is a type of anemia in the fetus or newborn. Clinical features of HDFN such as hepatosplenomegaly, liver failure, ascites, at birth die from heart failure to brain damage. One of the most common causes is incompatibility of blood groups such as ABO. Differences in clinical manifestations that occur in HDFN are caused by differences in antibody titers and IgG subtypes.Objective: The aim of this study was to determine the anti-A and anti-B antibody titers and the types of immunoglobulins that affect HDFN due to ABO incompatibility.Methods: The sample used in this study was blood and umbilical cord blood from 30 pairs of mother-babies who had different blood groups. Titration examination by tube method and IgG subtype by ELISA method were performed on maternal samples.Results: The correlation of total bilirubin levels with maternal Anti-A and Anti-B titers are p= 0.023 and p= 0.001, in addition there are significant increase in OD of Anti-A IgG1 and Anti-B IgG1 againts elevated infant bilirubin levels.Conclusion: IgG titers &gt;8 causing hyperbilirubinemia, but no jaundice and IgG titers &gt;16 causing hyperbilirubinemia to jaundice. The IgG subtype that plays a more role in causing clinical problems is IgG1.

Logistics of managing a trauma whole blood inventory in a civilian level 1 trauma center.

Institutional data on initiating and maintaining a low-titer O positive whole blood (LTOWB) inventory for the civilian trauma sector may help other institutions start a LTOWB program. This study from a level 1 trauma center with a hospital-based donor center highlights challenges faced during the collection, maintenance, and utilization of LTOWB. Male O positive donors with low (≤1:100) anti-A and anti-B antibody titers were recruited for LTOWB collection. The daily inventory goal of 4 LTOWB units was kept in the emergency department refrigerator and transfused to adult male trauma patients. Unused units older than 10 days were reprocessed into packed red blood cells. Of 900 donors screened, 61% qualified and 52% of eligible donors provided a collective total of 505 LTOWB units over 2.5 years. The number of collected units directly correlated with the availability of inventory; 42% of the units were transfused, 54% were reprocessed, and 4% were discarded. The inventory goal was maintained for 56% of the year 2018 and 83% of the year 2019. Over these 2 years, 52% of patients had their transfusion needs fully met, 41% had their needs partially met, and 6.5% did not have their needs met. Initial challenges to LTOWB implementation were inventory shortages, low utilization rates, and failure to meet clinical demand. Proposed solutions include allowing for a higher yet safe titer, extending shelf life, expanding the donor pool, identifying barriers to utilization, and permitting use in female trauma patients beyond childbearing age.

ABO-Incompatible Kidney Transplantation After Bone Marrow Transplantation: A Case Report

Many studies have been made on ABO-compatible kidney transplants following hematopoietic stem cell transplantation. However, there have been few reports on ABO-incompatible kidney transplantation following hematopoietic stem cell transplantation (HSCT). We report on the case of a successful ABO-incompatible kidney transplantation with high titers after bone marrow transplantation experienced no infectious episodes. The patient was a 38-year-old man with end-stage kidney disease resulting from interstitial nephritis induced by drug toxicity or graft-vs-host disease (GVHD). He had received allogeneic bone marrow transplantation from a human leukocyte antigen-identical unrelated donor to treat chronic myelogenous leukemia. The patient with high anti-B antibody titers (IgM 1:1024 IgG 1:256) received a desensitization protocol consisting of 2 doses of rituximab and 5 courses of plasmapheresis. The patient had prolonged depletion of circulating B cells 2 years after the transplant and was infected with cytomegalovirus viremia, pneumocystis jiroveci pneumonia, and adenovirus urinary tract infection at 2, 3, and 17 months post-transplant, respectively. Currently, at 6 years after his transplant, the patient has had no rejection and is in good clinical condition with only mild renal insufficiency. Our results suggest that ABO-incompatible kidney transplantation may be an effective renal replacement therapy for patients with end-stage kidney disease after HSCT, but desensitization in combination with immunosuppressants could lead to a state of over-immunosuppression, causing various infections.

Impact of Positive Donor-Specific HLA Antibodies Crossmatch on Graft Survival in ABO-Incompatible Liver-Kidney Transplantation: A Case Report

We present a patient with positive donor-specific antibodies (DSA) and crossmatch of ABO-incompatible (ABOi) combined liver and kidney transplantation (CLKT). Antibody-mediated rejection did not occur and the graft had survived for over one year at the time of writing without infectious complications. A 56-year-old man with positive DSA and positive crossmatch underwent living donor CLKT. The preoperative protocol for ABOi consisted of a single dose of rituximab and total plasma exchange (TPE). The result of anti-B antibody titer for IgG was 1:32. The evaluations of complement-dependent cytotoxicity and flow cytometry cross-match revealed a change from T+/B+ to T-/B+. The patient required adult living donor CLKT. Acute rejection episodes were treated using antithymocyte globulin, and the kidney required 7 days' treatment to recover. No further rejection and infectious episodes have been observed in past 13 months since the transplant. DSA and crossmatches are important for antibody detection and analysis. In the rituximab era, TPE can be used to achieve a successful decrease in antibody titer. In countries with a severe shortage of cadaveric organ donors, it may be possible to select ABOi candidate donors with positive DSA and crossmatch.

STUDY ON MIXING ANTI-A MONOCLONAL ANTIBODY AND ANTI-B MONOCLONAL ANTIBODY TO MAKE ANTI-AB SAVE AS ABO BLOOD GROUPING REAGENT

So, it needs to balance the ratio of anti-A monoclonal antibody and anti-B monoclonal antibody in the mixing so that the possibility of agglutination is the best. In this paper, anti-A monoclonal antibody (titer is 1/256) and anti-B monoclonal antibody (titer is 1/256) was used. The best results were obtained at one volume anti A monoclonal antibody is mixed one volume anti-B monoclonal antibody. The anti-A,B antibody titer was 1/128 for red blood group A and it was 1/128 for red blood group B. The intensity of agglutination reached 3+ for both red blood group A and B.

Establishment of a procedure for producing the anti-b monoclonal antibody from B4C10D9 hybridoma cell line

There are two the most important blood group system in blood transfusion, that is the ABO system and the Rh system. The anti-A or anti-B antibodies in the blood of recipient cause strongly agglutination the red blood cells of donor bearing A or B antigens on their surface respectively. So, all donated blood and received blood must be typed group for the ABO system to be safe in blood transfusion. To blood grouping, used of know antisera reacts with the whole blood samples to determine antigen on the surface of red blood cell or use of know red blood cells reacts with the individual's serum to determine antibody. The serology method is widely used, antisera are usually monoclonal antibodies secreted by hybridoma cells. Our previous studies showed that the B4C10D9 hybridoma cell line generated anti-B monoclonal antibody was produced by hybridoma technology. This antibody causes specificity agglutination the red blood cells caring B antigen on their surface. It is classed as IgM antibody with it heavy chains are µ and κ light chains. The aim of the study was to produce the anti-B monoclonal antibody form B4C10D9 hybridoma cells line serve as a part of ABO blood grouping reagent. Based on results of experiments, procedure for producing the anti-B monoclonal antibody from B4C10D9 hybridoma cell line has also been established with following steps. At first, refresh the frozen B4C10D9 hybridoma cells and the density of B4C10D9 hybridoma cells is 4.0 x 104 cells/ml at 24 hours post-inoculation. Then the B4C10D9 hybridoma cells are splitted 1:5 every 48 hours for 2 times to obtain the cell biomass. In the next step, the hybridoma cells are splitted into 125 cm2 flasks with the initial cell density of 105 cells/ml. The B4C10D9 hybridoma cells density reach 9.9 x 106 cells/ml at 48 hours post-inoculation. After 144 hours of post-inoculation, collect culture medium and concentrate the anti-B monoclonal antibody by precipitation with saturated ammonium sulfate at a final concentration of 50%. If resuspending volume equals initial volume, then the anti-B monoclonal antibody titer reaches 1/256 and the antibody reaction intensity will be 3+. And if the obtained antibody solution volume equals one fifth of the original volume, then the anti-B monoclonal antibody titer reaches 1/1024, and the antibody reaction intensity will be 4+. Citation: Establishment of a procedure for producing the anti-b monoclonal antibody from B4C10D9 hybridoma cell line. Tap chi Sinh hoc, 39(3): 342-348. DOI: 10.15625/0866-7160/v39n3.10765. *Corresponding author: tnhai@ibt.ac.vn Received 20 August 2017, accepted 20 September 2017

An evaluation of the effects of influenza vaccination on HIV/AIDS-stricken patients in Kermanshah Province, Western Iran

Background: Influenza is a contagious disease that runs a deteriorating and lethal course among high-risk groups such as HIV/AIDS patients. Influenza vaccination is significant among the high-risk groups, but there is inadequate information about vaccination among HIV/AIDS- patients. Objective: The aim of the study was investigating the effects of influenza vaccination on HIV/AIDS-stricken patients residing in Kermanshah Province, Western Iran. Materials and Methods: The present work was classified as a clinical trial. To perform the study, 134 HIV/AIDS-stricken patients were selected at the Counseling Center for Behavioral Disorders based in Kermanshah in 2014. The inclusion criteria were patients under antiretroviral treatment for at least 12 months' duration and availability of the participants in the study. 0.5 millimeters of influenza vaccine were injected into the deltoid muscles of the participants. One month before and after the injection, their blood samples were taken and stored at a temperature of –20 °C. The antibody titer tests were performed at the National Influenza Centre (NIC) based in Tehran, Iran, through the cold chain. After data collection, the SPSS Statistics 21 Software was utilized for data analysis. Results: In total 63.4% of the subjects were men and the rest (36.6) were women. The average age of the patients was 37.5 ± 8.5 years (men = 39.9±7.7 and women = 34±1.2). The results showed that the serum level of the anti-A (H1N1) antibody increased from 71.6% to 91.8% and that of the anti-B antibody went up from 70.1% to 92.5%. In addition, the results of t-test demonstrated that there was a significant difference between the levels of anti-B antibody titer and anti-A (H1N1) antibody titer before and after the influenza vaccination (P ≤ 0.05). Also, the means of CD4 and CI95% were significantly different before and after the injection (P ≤ 0.05). In this research, the CD4 count over 500 cells/mm3 rose from 22.2% to 32.8% before and after the vaccination, indicating a significant increase according to the t-test (P ≤ 0.05). Conclusion: From the presented, it can be concluded the CD4 count over 500 cells/mm3 increased after vaccination among HIV/AIDS-stricken patients. Therefore, the annual vaccination of HIV/AIDS-stricken patients against influenza can lessen the severity of pathogenicity, length of hospital stays, and mortality through stimulating the immune system and increasing the anti-Band anti-A (H1N1) antibody titers and CD4 cell counts.

Baseline anti-blood group antibody titers and their response to desensitization and kidney transplantation

In recent years, immunological barriers historically considered as absolute contraindications to transplantation are being reevaluated. One such barrier is the ABO blood group incompatibility. With better understanding of immunological mechanisms and effective various regimens for controlling it, ABO-incompatible (ABO-I) kidney transplantation is now being performed with increasing frequency. For good outcome, most important is to achieve and maintain low anti-blood group antibody titers (ABGATs). Twenty-two patients with ABO-I donors have been studied. The anti-A and anti-B antibody titers (IgG and IgM) were estimated by column agglutination technology using Automated Ortho BioVue System. For desensitization, pretransplant plasmapheresis and/or immunoadsorption and rituximab were used. ABGAT was determined before transplant and periodically after transplant. It was observed that one-third of the patients have low baseline ABGAT. In these cases with low ABGAT, transplant can be performed without any desensitization. In those with titers <1:256, rituximab (two doses of 200 mg weekly) and 3–6 sessions of plasmapheresis can bring down titers to <1:32. In those with titers >1:256, immunoadsorption may be used from the beginning to reduce ABGAT. After transplant, the titers drop to <1:8 in majority. Rise in titers to >1:64 require close observation and biopsy. If there is evidence of antibody-mediated rejection, treatment should be promptly started. Rise in titers 4–6 weeks after transplant is not associated with any graft dysfunction, and hence not of any clinical significance.

Antibody titers in Group O platelet donors.

BACKGROUND AND OBJECTIVES:The occurrence of hemolysis due to transfusion of ABO plasma-incompatible platelets (PLTs) is challenging. There has been no consensus for critical antibody titers in the transfusion community. This study was conducted to understand the trends of anti-A and anti-B antibody titer levels in O group donors and to identify any specific patterns of distribution in relation to age and gender.MATERIALS AND METHODS:A total of 1635 Group O PLT donors were randomly selected for this prospective study. Serial 2-fold doubling dilutions were prepared for each sample to calculate the titer of anti-A and anti-B in a standard 96 well micro-plate. Tube technique was used for comparison with the microplate method for 100 samples.RESULTS:Out of 1635 donors, 1430 (87.46%) were males and 205 (12.54%) were females. The median titer for anti-A and anti-B was 128 with range from 4 to 2048. Spearman's correlation coefficient for microplate versus tube technique was estimated to be 0.803 (P < 0.01, two-tailed). 57.12% and 51.19% of all donors had titers ≥128 for anti-A and anti-B, respectively. The geometric mean of anti-A and anti-B was 155.7 and 137.28, respectively. The titers were significantly higher (P < 0.001) in female donors. An inverse relation between titer levels and age was seen.CONCLUSION:Microplate can be used to perform titers in resource-constrained settings. Screening for critical titers in O group donors is essential as they are more implicated in hemolytic transfusion reactions. In the absence of a global consensus on this topic, institutes may need to formulate their own guidelines on handling ABO plasma-incompatible PLT transfusions.

Acquired Downregulation of Donor-Specific Antibody Production After ABO-Incompatible Kidney Transplantation.

The mechanism of long-term B cell immunity against donor blood group antigens in recipients who undergo ABO-incompatible (ABOi) living-donor kidney transplantation (LKTx) is unknown. To address this question, we evaluated serial anti-A and anti-B antibody titers in 50 adult recipients. Donor-specific antibody titers remained low (≤1:4) in 42 recipients (84%). However, antibodies against nondonor blood group antigens were continuously produced in recipients with blood type O. We stimulated recipients' peripheral blood mononuclear cells invitro to investigate whether B cells produced antibodies against donor blood group antigens in the absence of graft adsorption invivo. Antibodies in cell culture supernatant were measured using specific enzyme-linked immunosorbent assays (ELISAs). Thirty-five healthy volunteers and 57 recipients who underwent ABO-compatible LKTx served as controls. Antibody production invitro against donor blood group antigens by cells from ABOi LKTx patients was lower than in the control groups. Immunoglobulin deposits were undetectable in biopsies of grafts of eight recipients with low antibody titers (≤1:4) after ABOi LKTx. One patient with blood type A1 who received a second ABOi LKTx from a type B donor did not produce B-specific antibodies. These findings suggest diminished donor-specific antibody production function in the setting of adult ABOi LKTx.

Successful ABO-Incompatible Living-Related Intestinal Transplantation: A 2-Year Follow-up

ABO-incompatible intestinal transplantation has rarely been performed due to poor patient outcomes. Herein we present a case of successful ABO-incompatible intestinal transplantation with a 2-year follow-up. A 16-year-old female with a history of extensive bowel resection received an ABO-incompatible living donor bowel graft from her father (blood type AB graft into a type A recipient). Posttransplant immunosuppression consisted of an initial anti-CD20, plasmapheresis/intravenous immunoglobulin before transplantation, followed by an anti-thymocyte globulin (ATG) induction and splenectomy, and maintenance with tacrolimus and prednisone. Her postoperative course was remarkable for a single episode of rejection on day 14 which responded promptly to treatment with methyprednisolone and ATG. Three months after transplantation, the patient developed an abdominal abscess requiring open surgical drainage. No viral infections were encountered. Posttransplant anti-B antibody titers and anti-B7 donor-specific antibody levels remained low. At a 2-year follow-up, the patient showed a progressive weight gain of 5.0 kg. This case illustrates that ABO-incompatible living-related bowel transplantation is immunologically feasible and is associated with good outcomes for the recipient. The management of blood type antibodies and the use of adequate immunosuppression in the early period of the procedure may be the keys to the success of future cases.

Plasmapheresis as preconditioning protocol in an extremely high titer ABO incompatible renal transplant (ABOiRTx) case: A new prospect for chronic kidney disease patients in India

The biggest hurdle in renal transplantation is the ABO blood group system. But recently ABO incompatible renal transplants have been performed using plasmapheresis (PP) as a part of the preconditioning protocol. In the present study, the objective of PP along with immunosuppression was to bring down the antibody titer of the patient to ⩽16 during the transplant and keep it low, around 32, until post-operative 4–14weeks. The patient (O Negative) had his mother (B Positive) as the ABO non-identical donor. The PP was performed with an apheresis equipment Com.Tec (Fresenius Kabi, Germany) to lower the anti-B antibody titer in the recipient. An Antihuman globulin (AHG) titer was performed for anti-B antibody following the departmental standard operating procedure. A total of 11 plasmapheresis procedures was performed preoperatively and four procedures were performed post-operatively to maintain the titer of the anti-B antibody at or below the desired level. The baseline anti-B antibody titer in the recipient was 512. The baseline titer came down to 8 after the end of the 11th procedure. Post-operatively we performed four plasmapheresis procedures to keep the titer at 32. During the post-operative follow up the titer has been maintained at 32 and the serum creatinine level has been maintained at approximately 1.0mg/dl and other parameters relevant to graft function were within normal limits. Our case could be the first reported case from India in which we used a plasmapheresis procedure as a part of preconditioning protocol instead of using an immunoadsorption column. Furthermore, it could be one of the few ABOiRTx cases, which has been performed at an isoagglutinin titer of 512 using plasma exchange as part of a preconditioning regime.

Renal transplantation across ABO barrier

In India, patients without a compatible blood group donor are usually excluded from renal transplantation. For young patients, it is a difficult therapeutic choice to stay on long-term dialysis. We describe the case of a 19-year-old male patient who had blood group O +ve and had no compatible donor in the family. His mother was B +ve and was willing to donate. The patient had an initial anti-B antibody titer of 1:512 and underwent antibody depletion with plasmapheresis (11 sessions) and intravenous immunoglobulin (IVIG) 100 mg/kg after every plasmapheresis. He also received rituximab 500 mg for 3 days prior to transplant and was induced with basiliximab. At the time of transplant, his anti-B titers were <1:8. Post-operatively, he required four sessions of plasmapheresis and IVIG as his titers rebounded to 1:64. The titers then spontaneously subsided to <1:16 and have stayed at the same level for 6 months post-transplant. The patient continues to have normal renal function with a creatinine of 1.4 mg/dl% and has had no episodes of rejection.