Immunohematology最新文献

Since publication of the original Immunohematology review of the Kidd blood group system in 2015 (Hamilton JR. Kidd blood group system: a review. Immunohematology 2015;31:29-34), knowledge has mushroomed pertaining to gene structure, alleles causing variant and null phenotypes, clinical significance in renal transplant and hemolytic disease of the fetus and newborn, and physiologic functions of urea transporters in non-renal tissues. This review will detail much of this new information.

This extraordinary case showcases the identification of a rare anti-En^a specificity that was assisted by DNA-based red blood cell antigen typing and collaboration between the hospital blood bank in the United States, the home blood center in Qatar, the blood center Immunohematology Reference Laboratory, as well as the American Rare Donor Program (ARDP) and the International Society for Blood Transfusion (ISBT) International Rare Donor Panel. En^a is a high-prevalence antigen, and blood samples from over 200 individuals of the extended family in Qatar were crossmatched against the patient's plasma with one compatible En(a-) individual identified. The ISBT International Rare Donor Panel identified an additional donor in Canada, resulting in a total of two En(a-) individuals available to donate blood for the patient.

It has been reported that anti-A and anti-B (ABO antibody) titers decrease with age, but little is known about the association between ABO antibody titers and physiologic/biochemical parameters such as body mass index (BMI), gamma-glutamyl transpeptidase (GGT), and total cholesterol (T-Cho). We investigated the present situation of ABO antibody titers among healthy blood donors in Japan and the physiologic/biochemical factors that may be associated with changes in ABO antibody titers. Plasma from 7450 Japanese blood donors was tested for ABO antibody titers using ABO reverse typing reagents by an automated microplate system; donor samples were classified into low, middle, and high titers according to the agglutination results obtained with diluted plasma samples. Multivariate regression analysis was performed to analyze the association between ABO antibody titers and age, gender, biochemical parameters (alanine transaminase [ALT], GGT, globulin, T-Cho, and glycosylated albumin [GA]), and BMI according to the ABO blood groups. A significant correlation between ABO antibody titers and age/gender, except for gender in anti-A of blood group B donors, was observed. BMI showed significant but negative correlations with anti-A and anti-B (β = -0.085 and -0.062, respectively; p < 0.01) in blood group O donors. In addition, significant but negative correlations between GGT and T-Cho with anti-B of blood group A donors (β = -0.055 and -0.047, respectively; p < 0.05) were observed. Although differences existed among the ABO blood groups, ABO antibody titers seem to be associated with physiologic and biochemical parameters of healthy individuals.

Screening for clinically significant antibodies is crucial in transfusion medicine and is a routine part of pre-transfusion testing. The indirect antiglobulin test (IAT) is the most reliable and effective test for detecting clinically significant alloantibodies reacting at the antihuman globulin phase. Two of the main methods used for antibody detection and identification are solid-phase red cell adherence (SPRCA) and microcolumn agglutination technology (CAT), with or without enzyme-treated red blood cells (RBCs). This study was undertaken to detect and identify alloantibodies by performing antibody screen (ABS) and antibody identification (ABID) testing using SPRCA and CAT, with and without ficin-treated RBCs. Residual patient samples collected between 1 December 2020 and 19 May 2021 were saved, de-identified, and frozen at ≤-30°C before testing for alloantibodies. Seventy antibodies were detected in 53 samples among the 203 samples that underwent an ABS. Of those samples, 150 (73.0%) were nonreactive, 47 (23.1%) yielded positive results with both CAT and SPRCA, and six (3.0%) yielded positive ABS results with SPRCA only. Fifty-three samples that underwent ABID by both methods yielded eight samples with antibodies identified by SPRCA only. Additional enhancement of the CAT method by the use of ficin-treated RBCs was required to detect seven of the eight SPRCA-only antibodies; one sample remained nonreactive regardless. SPRCA testing detected clinically significant antibodies without the addition of enzyme-treated RBCs that was necessary in the CAT testing.

In sub-Saharan Africa, antibody detection tests remain inaccessible because of the high cost and limited shelf life of red blood cell (RBC) reagents. This study aimed at investigating the feasibility and performance of locally prepared RBC reagents for antibody detection in Burkina Faso. We conducted an experimental study comparing commercial RBC panels and a local panel prepared from phenotyped blood donors in Ouagadougou, Burkina Faso. Antibody detection testing was performed by the indirect antiglobulin test using a gel card filtration column in a low-ionic-strength solution. Judgment criteria were the concordance rate and the kappa agreement coefficient of results generated by the two panels. A total of 302 blood donors were phenotyped for the major antigens of the RH, KEL, MNS, FY, JK, LE, and P1PK blood group systems. From this pool of donors, we designed an RBC detection panel that was used to screen for unexpected antibodies in 1096 plasma samples from 832 patients with a history of transfusion and 264 recently delivered or pregnant women with no history of blood transfusion. A positive antibody detection test was observed in 8.1 percent of the samples using the local panel versus 6.4 percent with the commercial panels. A total of 23 samples were negative with the commercial panels and positive with the local panel, while the findings were reversed for four samples. The concordance rate was 97.5 percent, and the kappa agreement coefficient was 0.815. Our results suggest that the development of local RBC panels can be an alternative to commercial panels in countries with limited resources. It could also be a cost-effective intervention, mainly for children under 5 years of age, women of childbearing age, and pregnant women, all of whom are most at risk for malaria and sickle cell disease complications. Blood services could develop and implement appropriate strategies to make phenotyped donor pools available for the design of suitable RBC panels.

Solid-phase red cell adherence (SPRCA) is a sensitive platform for antibody detection, but nonspecific reactions may occur. One pattern of apparent nonspecific reactivity is a panagglutinin with a negative direct antiglobulin test (DAT). The purpose of this study was to define the clinical characteristics of patients with these nonspecific reactions and their associated serologic findings. Twenty patients with panreactive SPRCA testing results were identified between November 2022 and May 2023. In addition to panagglutinins, these patients had (1) a negative polyethylene glycol (PEG) antibody detection test, (2) a negative PEG autocontrol, and (3) a negative DAT. The strength of SPRCA panreactivity and the results of eluate testing (by tube and SPRCA) were studied. Clinical characteristics of patients included age, sex, and primary diagnosis. Each patient was also assessed for evidence of hemolysis. Fourteen female and six male patients were evaluated (average age 44 years). Primary diagnoses included pregnancy (n = 10), acute bleeding (n = 4), orthopedic (n = 3), and other (n = 3). There was no clinical or laboratory evidence of hemolysis. The predominant strength of SPRCA panreactivity was evenly distributed across reaction grades (1+ to 3+). Fifty-five percent of the eluates tested in PEG showed panreactivity, consistent with warm-reactive autoantibodies, while 85 percent of eluates tested by SPRCA were panreactive. Six discrepant cases, in which PEG eluate testing was negative and solid-phase eluate testing showed panreactivity, were associated with weak solid-phase plasma panreactivity (1+). In addition, the reactivity strengths of the eluates tested by SPRCA were invariably more strongly reactive than those eluates tested in PEG. Panagglutination is a distinct SPRCA-only plasma reactivity pattern. Despite a negative PEG tube and DAT, most panagglutinins are warm-reactive autoantibodies. Fortunately, these "interfering" panagglutinins do not appear to be clinically significant and are easily managed by an alternative testing method such as PEG.