Red Blood Cell Survival Following Transfusion in Infants
试验速览
- 阶段
- 2 期
- 状态
- 已完成
- 发起方
- 入组人数
- 140
- 试验地点
- 4
- 主要终点
- Number of Discrete Biotinylated RBC Densities (up to 5 Discrete Densities) That Can be Accurately Measured by Flow Cytometry, i.e., Without Overlap.
研究概览
简要总结
OUR OVERALL HYPOTHESIS is that post-transfusion survival of allogeneic and autologous RBCs can be accurately quantified in anemic human infants using biotin-labeled RBCs combined with mathematical modeling that adjusts for confounding factors commonly encountered in neonates. These confounding factors include 1) dilution of labeled RBC as a result of growth stimulated erythropoiesis, anemia stimulated erythropoiesis, and blood transfusion; 2) loss of labeled RBC due to laboratory phlebotomy; and 3) variable RBC life spans resulting from RBCs having been produced at different developmental periods and under varying rates of erythropoiesis. In contrast to infants, adjustment for these factors is not necessary in healthy adults under conditions of steady state erythropoiesis. Instead in adults, RBC survival is typified by a linear decline in concentration of labeled RBCs over time. When this line is extrapolated to zero concentration, the intercept with the time axis represents the mean potential lifespan (MPL) of RBCs. (<7 d) and stored (>21 d) allogeneic adult RBCs transfused in the same infant.
详细描述
Phase I: Includes only Aim #1 from Thrasher Foundation Grant in which adult subjects will be studied.
SPECIFIC AIM #1 (Thrasher Foundation Grant): To develop in vitro and validate in vivo in adult humans and anemic infants the capability of biotinylating RBCs at up to 5 discrete densities for simultaneously determining RBC kinetics of multiple, distinct RBC populations. This requires expansion of the RBC biotin labeling technology we have previously developed. After refinement, the method will be applied in the subsequent aims conducted in anemic infants receiving clinically ordered RBC transfusions.
As suggested by our previous RBC survival studies, we anticipate that the heaviest biotin labeling will alter the intrinsic RBC structural properties of RBCs, shortening their long term survival. The in vitro and in vivo validation studies we propose in adults are necessary because the conditions for reproducibly obtaining discrete RBC biotin densities at appropriate, closely spaced intervals have not been conclusively worked out, nor have we determined empirically which of the five densities will not artifactually shorten long-term RBC survival. We can use the lighter densities for RBC survival measurements and the heavier densities for the simultaneous RBC volume measurements needed to account for RBC volume increases caused by growth. It is important to perform these feasibility studies in both adults and infants because of the vastly different physiologic states, ie, normal, healthy adults are in steady state erythropoiesis while critically ill, anemic infants experience multiple clinical circumstances which perturb RBC survival, eg, growth, phlebotomy, intervening transfusion, etc.
In addition to the biotin labeling of RBC method, the "differential agglutination, antigenic method" using flow cytometry will be applied for infants receiving allogeneic RBC transfusions. The results of the two methods will be compared with one another. The differential agglutination method utilizes differences in the RBC surface antigens between the donor and the recipient for determining short- and long-term RBC survival. Genotyping results of adult donor and the infant recipient RBC antigens (performed at the Mississippi Valley Regional Blood Center) permits identification of minor blood group differences between donor and recipient RBCs so that appropriately labeled minor RBC antibodies (available commercially and used by blood banks for minor blood group RBC typing) can be used in flow cytometric determination of RBC survival. RBC survival determined for each of the biotin labels and for the RBC antigenic differences will all be compared among one other. The differential agglutination/antigen method will considered the "gold standard" as the RBCs are labeled ex-vivo, AFTER the RBC transfusion, thus without modifying the RBC membrane surface proteins as biotinylation does. Our hypothesis is that the addition of too much biotin can lead to artifactually shortened in vivo RBC survival, but that lower doses of biotin to not. By also including the differential agglutination/antigen method RBC survival results, we will be able to better validate our multi-density biotin hypothesis.
Our overall objective in this research is to improve red blood cell (RBC) transfusion practices for anemic, critically ill infants. This project has received support from two granting agencies: 1) The Thrasher Foundation, entitled, "Red Blood Cell Recovery and Survival Following Transfusion in Infants;" and 2) NIH PPG Grant P01 HL046925, Project 1 entitled, "Red Blood Cell Survival Following Transfusion In Infants." Abstracts for both are included below. This project will be completed in two phases:
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 1 Hour 至 6 Months（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Males or post-menopausal females
- •18-65 years of age.
- •Weight >110 lbs.
- •Healthy- the subject feels well and can perform normal activities.
- •Hemoglobin at or above 12.5 g/dL or hematocrit at or above 38%.
- •Note: Members of the research team that are not supervised or under the employee of the PI may participate in the study.
排除标准
- •Presence of chronic illness unless the subject is being treated and the condition is under control.
- •Consumption of biotin supplements or raw eggs.
- •Premenopausal women.
- •Blood donation in the previous 8 weeks (single donation) or 16 weeks (double red cell donation).
- •Blood loss in the previous 8 weeks due to epistaxis, gastrointestinal blood loss, trauma, significant diagnostic phlebotomy loss (i.e., > 30 mL total), or other significant bleeding
- •Treatment with antibiotics within the last 7 days. Antibiotics for prevention of an infection or treatment of acne are not exclusion criteria.
- •Note: If study subjects experience any of these conditions associated with blood loss or donate any blood products, they will not be included in the primary analysis but will be replaced.
- •Infant Study:
- •MOTHERS FOR PLACENTAL BLOOD COLLECTION AND MOTHERS OF INFANT STUDY SUBJECTS
- •Inclusion Criteria:
- •>/= 24 weeks gestation
- •mothers who deliver through the birth canal or by c-section can be included in the study.
- •Exclusion Criteria:
- •Pregnant with fetus with major congenital anomaly.
- •Clinically suspected or documented maternal chorioamnionitis (This only applies to infant study subjects receiving autologous RBCs from the placenta).
- •Viral or bacterial infection (e.g. HIV, Hepatitis B, Hepatitis C, Primary Herpes, Tuberculosis) based on clinically available prenatal or postnatal test results in the mother's medical record. (This only applies to infant study subjects receiving autologous RBCs from the placenta.)
- •minor mothers (<18 years old) are excluded from the study.
- •INFANT STUDY SUBJECTS
- •Inclusion Criteria:
- •Newborns >/=24 weeks gestation who are patients in the Neonatal Intensive Care Unit (NICU) at UIHC that:
- •Are being treated with the expectation of survival.
- •Exclusion Criteria:
- •Difference of more than 5% in the percentage of HbF cells (measured by flow cytometry in the Widness lab) between blood harvested from the placenta and that from discarded neonatal blood in the first day of life and before the first neonatal blood transfusion. This is done to exclude the rare possibility of transfusing newborns with blood that is contaminated with a significant proportion of their mother's blood if a maternal-to-placenta bleed occurs after umbilical cord clamping is done. (This only applies to infant study subjects receiving autologous RBCs from the placenta.)
- •Need of emergent blood transfusion as determined by the subject's medical care team.
- •Hematological diseases (except for anemia associated with phlebotomy loss and prematurity)
- •Alloimmune hemolytic anemia, diffuse intravascular coagulation, and thrombosis.
- •Major congenital anomaly.
- •Sepsis with positive blood or spinal fluid culture.
- •Receiving treatment with erythropoietin (r-HuEPO) or cardiorespiratory bypass support (ECMO).
- •Overt clinical bleeding.
结局指标
主要结局
Number of Discrete Biotinylated RBC Densities (up to 5 Discrete Densities) That Can be Accurately Measured by Flow Cytometry, i.e., Without Overlap.
时间窗: from day of blood draw this can be accomplished in 4 hours
The biotin-labeled RBCs that were studied were: 2, 6, 18, 54, and 162 µg NHS-biotinylating reagent per mL of packed RBCs. Here we report the number of discrete biotin densities without overlap as determined in vitro.
RBC Survival (Life Span) in Days of Multiple, Distinct BioRBC Density Populations of Transfused Autologous RBCs in Adults and Premature Infants.
时间窗: for up to 5 months
Using flow cytometry was measured for each RBC biotin density in days as determined when RBC measurement was no longer detectable.
RBC Survival (Life Span) in Days of Multiple, Distinct BioRBC Density Populations of Transfused Allogeneic RBCs in Premature Infants.
时间窗: for up to 4 months
Using flow cytometry was measured for each RBC biotin density in days as determined when RBC measurement was no longer detectable.
次要结局
- Survival of Allogeneic RBCs in Days as Measured by the Antigenic Method Using Flow Cytometry for Comparison With BioRBC in Premature Infants(4 months)
- Number of Participants With Positive Antibody Screen in Response to Biotin-labeled RBCs.(4 to 5 mo post transfusion of biotin RBCs)
研究者
John A Widness
Professor
University of Iowa