Timing of RhD-positive red blood cell administration is associated with D-alloimmunization in injured patients

Background

The D-alloimmunization rate in trauma patients does not appear to depend on the number of RhD-positive units transfused. The effect of the timing and pattern of RhD-positive transfusions has not been evaluated.

Methods

RhD-negative trauma patients who were transfused with RhD-positive red blood cells (RBC) or low titer group O whole blood (collectively called RBCs) on at least two separate calendar days and who had antibody detection tests performed at least 14 days after the second RhD-positive RBC transfusion without receiving RhIg were included in the analysis. Patients whose anti-D was detected within 14 days of the index RhD-positive RBC transfusion were excluded. Patient demographics and the dates of RhD-positive RBC transfusions and results of antibody detection tests performed after the index transfusion were collected on eligible patients.

Results

There were 44/61 (72.1%) patients in whom anti-D was not detected (non-alloimmunized) and 17/61 (27.9%) in whom anti-D was detected (alloimmunized). The patients had similar demographics with trends towards higher median admission heart rates and lower median admission Glasgow Coma Scale values in the alloimmunized group. Both groups received statistically identical median quantities of RhD-positive RBCs (non-alloimmunized 5 vs. alloimmunized 4 units, p = .53), however, the alloimmunized group received all their RhD-positive RBCs over a significantly shorter period of time compared to the non-alloimmunized (median 4 vs. 15 days, respectively, p = .01).

Conclusion

Receipt of all RhD-positive RBCs over a shorter period of time was associated with higher D-alloimmunization rates. These results need to be confirmed in larger studies.     

Transfusion of ABO-group identical red blood cells following uncrossmatched transfusion does not lead to higher mortality in civilian trauma patients

Background

Questions persist about the safety of switching non-group O recipients of group O uncrossmatched red blood cells (RBC) or low titer group O whole blood (LTOWB) to ABO-identical RBCs during their resuscitation.

Methods

The database of an earlier nine-center study of transfusing incompatible plasma to trauma patients was reanalyzed. The patients were divided into three groups based on 24-h RBC transfusion: (1) group O patients who received group O RBC/LTOWB units (control group, n = 1203), (2) non-group O recipients who received only group O units (n = 646), (3) non-group O recipients who received at least one unit of group O and non-group O units (n = 562). Fixed marginal effect of receipt of non-O RBC units on 6- and 24-h and 30-day mortality was calculated.

Results

The non-O patients who received only group O RBCs received fewer RBC/LTOWB units and had slightly but significantly lower injury severity score compared to control group; non-group O patients who received both group O and non-O units received significantly more RBC/LTOWB units and had a slightly but significantly higher injury severity score compared to control group. In the multivariate analysis, the non-O patients who received only group O RBCs had significantly higher mortality at 6-h compared to the controls; the non-group O recipients of O and non-O RBCs did not demonstrate higher mortality. At 24-h and 30-days, there were no differences in survival between the groups.

Conclusion

Providing non-group O RBCs to non-group O trauma patients who also received group O RBC units is not associated with higher mortality.     

高效价冷凝集素对ABO血型正反定型和电子交叉配血试验的影响

目的探讨高效价冷凝集素对ABO血型正反定型和电子交叉配血试验的影响。方法选择2015年11月至2016年10月该院因紧急情况输血的500例患者作为研究对象,观察电子交叉与血清交叉主次侧配型结果,不同温度下ABO血型正反定型与电子交叉配血试验的结果,冷凝集素试验红细胞凝集情况及交叉配血结果。结果电子交叉配血与血清学交叉配血相比,主侧结果差异无统计学意义(P0.05),次侧结果差异有统计学意义(P0.05)。电子交叉配血时,20℃时有18例出现凝集,明显多于37℃时(P0.05)。患者血型在正定型A型,反定型B型,O型均有凝集出现,且在20℃时O型与自身对照也有凝集出现。冷凝集素试验结果,当温度低于31℃时会出现红细胞凝集,当低于4℃时,可见明显凝集,但当温度回升到37℃时,凝集消失。结论高效价冷凝集素在低温条件下会促进红细胞凝集,干扰ABO血型正反定型和电子交叉配血试验的结果,从而影响临床输血治疗。     

Receipt of low titer group O whole blood does not lead to hemolysis in children weighing less than 20 kilograms

Objective

The safety of Low Titer Group O Whole Blood (LTOWB) transfusion has not been well-studied in small children.

Methods

This is a single-center retrospective cohort study of pediatric recipients of RhD-LTOWB (June 2016–October 2022) who weigh less than 20 kilograms. Biochemical markers of hemolysis (lactate dehydrogenase, total bilirubin, haptoglobin, and reticulocyte count) and renal function (creatinine and potassium) were recorded on the day of LTOWB transfusion and post-transfusion days 1 and 2. Group O and non-Group O recipients were compared.

Results

Twenty-one children were included. Their median (interquartile range [IQR]) weight was 12 kg (12–18) with minimum 2.8 kg, and median (IQR) age was 3 years (1.75–5.00) with minimum 0.08 years (29 days old). The most common indication for transfusion was trauma (17/21; 81%). The median (IQR) volume of LTOWB transfused was 30 mL/kg (20–42). There were 9 non-group O and 12 group O recipients. There were no statistically significant differences in the median concentrations of any of the biochemical markers of hemolysis or the renal function markers between the non-group O and the group O recipients at any of the three time points (p > 0.05 for all comparisons). There were also no statistically significant differences in demographic parameters or clinical outcomes including 28-day mortality, length of stay, ventilator days, and venous thromboembolism between the groups. No transfusion reactions were reported in either group.

Conclusion

These data suggest LTOWB use is safe in children weighing less than 20 kg. Further multi-center studies and larger cohorts are needed to confirm these results.     

3种常用溶液配制ABO反定型红细胞的探讨

目的对3种常用溶液配制ABO反定型红细胞悬液进行比较。方法利用生理盐水、低离子溶液、Sysmex血液分析仪用稀释液3种溶液制备2%的红细胞悬液,(4±2)℃冰箱保存,每天对红细胞的凝集强度、红细胞数量和质量、上清液游离血红蛋白进行观察,每3天监测一次细菌生长情况等。观察用3种溶液制备的反定型红细胞的有效期限。结果用Sysmex血液分析仪专用稀释液配制的反定型红细胞有效期仅6 d,用生理盐水配制的反定型红细胞有效期不到24 h,低离子溶液配制的反定型红细胞当天溶血。结论用Sysmex血液分析仪专用稀释液可制备简便的ABO反定型红细胞,有效期6 d;低离子溶液不适用于配制的反定型红细胞;生理盐水配备的反定型红细胞应每天配制。     

Rh phenotype prediction by DNA typing and its application to practice

The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies.     

输血相容性检测室内质控品制备技术优化与性能评价

目的优化自制输血相容性检测室内全血质控品制备技术,检测其保存过程中综合性能指标的变化,确定合理的处理流程、保存期限并评价其应用价值。方法选择多人份采集时间≤10 d的B型RhD阴性健康献血者标本,将其混合后离心留取上清血浆,再将混合浓缩红细胞分成2组,MAP组:使用MAP红细胞保养液洗涤2次;Saline组:使用生理盐水洗涤2次。将2组洗涤后的红细胞分别与MAP红细胞保存液、对应混合血浆按照1∶2∶3的体积比混合。选择商品化IgG抗-D试剂做抗-D效价测定,确定出现最后1个2+凝集强度的稀释倍数,并按照此稀释倍数分别在2组质控品中填加相应体积的IgG抗-D。将2组混合悬液分装在硬质塑料试管中盖帽4℃保存,每天在室温放置1 h,分别在保存的0、35、42、49 d检测质控品标本红细胞与标准抗-B的凝集强度、IgM抗-A与反定A细胞的凝集强度、IgG抗-D与RhD阳性O型红细胞的凝集强度、上清液中Na+、K+、LDH、乳酸、FHb浓度、红细胞形态变化以及质控品中细菌繁殖情况。结果保存过程中2组质控品红细胞B抗原、IgG抗D抗体反应活性均无明显变化(P>0.05),IgM抗A抗体反应活性虽出现波动(P<0.01),但凝集强度变化均在1+范围内;2组质控品K+、乳酸浓度均随保存时间延长明显增高(P<0.01),但保存35、42d时2组各指标之间无明显差异(P>0.05);2组质控品FHb浓度均随保存时间延长而增高,但相同保存时间2组之间比较无明显差异(P<0.01)。保存49 d时MAP组和Saline组FHb浓度分别为(857.1±301.5)mg/L和(595.3±334.9)mg/L,与保存0d相比均明显升高(P<0.01),MAP组部分质控品FHb浓度已经超过中度溶血标准(1 000 mg/L);2组质控品保存末期(≤42 d)红细胞都会出现一定程度的皱缩并形成棘突,但2组之间无明显差异;2组质控品保存过程中都未见细菌生长。结论本室采用2种方法自制的全血质控品质量无明显差异,保存期都能达到42 d,且管间差异小、抗原抗体反应活性稳定,能够满足输血相容性检测室内质控的相关要求,适合在输血相容性检测实验室推广。