Evaluation of a walking-donor blood transfusion program in an intensive care nursery

Transfusion-Related Alloimmunization to Red Blood Cell Antigens in Japanese Pediatric Recipients

Red blood cell (RBC) transfusion to neonates is thought to rarely provoke an immune response. Neonatal testing guidelines suggest that antibody screening is not necessary when the mother has no antibodies. Alternatively, maternal blood samples can be used for antibody screening and cross-matching. However, the guidelines are based on small-scale studies of white-dominant populations. Furthermore, transfusion-related alloimmunization is less well established among children and adolescents as a whole among Japanese and East Asians. To elucidate the incidence of transfusion-related alloimmunization among neonates, children, and adolescents, and whether current guidelines are applicable to Japanese populations, a nationwide retrospective multicenter cohort survey was conducted in 50 tertiary-care hospitals in Japan. Between 2001 and 2015 inclusive, recipients of at least 1 allogeneic RBC transfusion were categorized into groups A-F according to their age at the time of transfusion: (A) neonates <1 month; (B) infants 1 to <12 months; (C) children 1 to <5 years; (D) prepubescents 5 to <10 years; (E) young pubescents 10 to <15 years; and (F) adolescents/young adults 15 to <20 years. Excluding maternally derived antibodies and naturally occurring, cold-reactive, and/or nonspecific antibodies, 69 (0.61%) of 11350 RBC recipients <20 years old formed at least 1 clinically significant alloantibody. The alloimmunization rate differed significantly (P < .0001) by age: none (0%) of 3407 in group A; 11 (0.46%) of 2410 in group B; 18 (0.76%) of 2361 in group C; 9 (0.80%) of 1119 in group D; 12 (1.15%) of 1043 in group E; and 19 (1.88%) of 1010 in group F. Clearly different incidences of alloimmunization emerged in group A compared to B, C, D, E, or F, as confirmed by logistic regression analysis adjusted by numbers of donor exposure. Alloimmunization did not occur from RBC transfusions within the first month of life and rarely occurred (0.46%-0.80%) after transfusion within the first decade of life. Alloimmunization occurred in 1.15%-1.88% of young pubescents and adolescents/young adults. These findings support the use of guidelines developed in Europe and the United States for East Asian pediatric recipients.

Effect of Blood Donor Characteristics on Transfusion Outcomes: A Systematic Review and Meta-Analysis

Optimal selection of blood donors is critical for ensuring the safety of blood products. The current selection process is concerned principally with the safety of the blood donor at the time of donation and of the recipient at the time of transfusion. Recent evidence suggests that the characteristics of the donor may affect short- and long-term transfusion outcomes for the transfused recipient. We conducted a systematic review with the primary objective of assessing the association between blood donor characteristics and red blood cell (RBC) transfusion outcomes. We searched MEDLINE, EMBASE, and Cochrane Central databases and performed manual searches of top transfusion journals for all available prospective and retrospective studies. We described study characteristics, methodological quality, and risk of bias and provided study-level effect estimates and, when appropriate, pooled estimates with 95% confidence intervals using the Mantel-Haenszel or inverse variance approach. The overall quality of the evidence was graded using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. From 6121 citations identified by our literature search, 59 studies met our eligibility criteria (50 observational, 9 interventional). We identified the evaluation of association of 17 donor characteristics on RBC transfusion outcome. The risk of bias and confounding of the included studies was high. The quality of evidence was graded as very low to low for all 17 donor characteristics. Potential associations were observed for donor sex with reduced survival at 90 days and 6 months in male recipients that receive donated blood from females (hazard ratio 2.60 [1.09, 6.20] and hazard ratio 2.40 [1.10, 5.24], respectively; n = 1), Human Leukocyte Antigen - antigen D Related (HLA-DR) selected transfusions (odds ratio [OR] 0.39 [0.15, 0.99] for the risk of transplant alloimmunization, n = 9), presence of antileukocyte antibodies (OR 5.84 [1.66, 20.59] for risk of transfusion-related acute lung injury, n = 4), and donor RBC antigens selection (OR 0.20 [0.08, 0.52] for risk of alloimmunization, n = 4). Based on poor quality evidence, positive antileukocyte antibodies, female donor to male recipients, HLA-DR selected RBC transfusion, or donor RBC antigen selection may affect RBC transfusion outcome. Our findings that donor characteristics may be associated with transfusion outcomes warrant establishing vein-to-vein data infrastructure to allow for large robust evaluations. PROSPERO registration number: CRD42013006726.

Platelet transfusion in an infant leading to formation of anti-D: implications for immunoprophylaxis

BACKGROUND

The immature infant immune system rarely makes RBC alloantibodies; however, most studies confirming the absence of alloantibodies in infants have involved transfusions that were matched for one of the most immunogenic antigens, rhesus D. The potential for D- infants to develop anti-D is unknown. Specifically, this issue has not been analyzed for infants receiving whole-blood-derived PLTs from D+ donors. The importance of understanding such risk is underscored by the fact that anti-D formation can be prevented by the administration of Rh immunoglobulin.

CASE REPORT

A D- infant with congenital heart disease received two D-mismatched whole-blood-derived PLT units at 17 weeks of age. He did not receive Rh immunoglobulin prophylaxis. Upon a subsequent admission 13 months later, anti-D was identified in his plasma sample.

CONCLUSION

The case presented here demonstrates that a young infant can respond to less than 0.6 mL of D+ RBCs and documents the youngest patient to have developed a RBC alloantibody from a PLT transfusion. To prevent anti-D formation, we recommend administering Rh immunoglobulin to all D- pediatric patients that receive PLT transfusions from D+ donors [correction].

Low frequency of observed anti-HLA among transfused preterm infants

BACKGROUND

Although low-birth-weight infants (LBWI) often receive multiple transfusions, there is controversial information on their development of antibodies against WBCs or platelets.

STUDY DESIGN AND METHODS

A total of 52 LBWI with birth weights less than 1500 g were randomly assigned to receive either RBCs that had been WBC- reduced (n = 25) or nonfiltered blood (n = 27). Serum samples collected from 37 infants at 3 months of age and from 30 children when they were 5 to 11 years old were tested. Anti-HLA was assayed with an anti-human globulin-augmented lymphocytotoxicity test against a panel consisting of 13 lymphocytes and against parental cells.

RESULTS

None of 52 transfused LBWI of either group developed anti-HLA (95% CI, 0%-6.8% for overall, 0%-13.7% for the WBC-reduced group, and 0%-12.7% for the nonfiltered group).

CONCLUSION

Multiply transfused LBWI rarely produced antibodies to HLA of blood donors and to noninherited maternal antigens. The benefits of WBC reduction to prevent HLA alloimmunization during infancy were not supported by this study and need further investigation.

Alloimmunization in preterm infants after repeated transfusions of WBC-reduced RBCs from the same donor

BACKGROUND

Preterm infants are among the most heavily transfused of patient groups, yet multiply transfused infants only rarely produce alloantibodies against RBC or WBC antigens. It is not known whether rates of alloimmunization might be increased by repeated exposure to RBCs and WBCs from the same donor, as in limited-donor-exposure programs, or whether infants might benefit from WBC-reduced RBC components as a means of diminishing the risk of possible alloimmunization.

STUDY DESIGN AND METHODS

Preterm infants (birth weight 0.6-1.3 kg) received prestorage WBC-reduced RBCs from dedicated donors, collected in AS-3 as a means of limiting donor exposures. Blood samples were collected serially from infants shortly after birth until either discharge or age 6 months and were studied for RBC and WBC antibodies-the latter with reactivity against either HLA class I or neutrophil-specific antigens.

RESULTS

Thirty preterm infants received 139 transfusions (mean, 4.6; median, 4 transfusions per infant), with 81 percent of transfusions obtained from one donor per infant. Eighty-four blood samples (mean, 2.7/infant) were studied, and no infant produced RBC antibodies. Twenty-seven percent of infants exhibited WBC antibodies, but only 13 percent actually produced WBC antibodies (passive maternal antibody excluded). Of the WBC antibodies produced by infants, three were against HLA class I and one was against neutrophil-specific antigens; none were linked to adverse effects.

CONCLUSIONS

Because infants only rarely produce RBC antibodies, no changes in blood banking practices are necessary for limited-donor-exposure programs. Although the production of WBC antibodies by infants occurs, it seems to be uncommon; thus, the possible benefits, if any, of WBC reduction are uncertain, and further study is required before changes in practice can be justified.

Comparing alloimmunization in preterm infants after transfusion of fresh unmodified versus stored leukocyte-reduced red blood cells

PURPOSE

To compare the occurrence of red blood cell (RBC), platelet (PLT), and white blood cell (WBC) antibodies in preterm infants after transfusions.

METHODS

A randomized, blinded trial was conducted in which preterm infants were transfused either with stored RBCs, prepared by prestorage leukocyte reduction and transfused throughout 42 days of storage to limit donor exposure (n = 18), or with fresh RBCs prepared without leukocyte reduction and transfused within 7 days after collection from as many donors as needed to guarantee freshness (n = 17). Nontransfused preterm infants of comparable birth weight were control subjects (n = 11).

RESULTS

No RBC antibodies were detected in serial blood samples taken during the first 6 months of life. Similarly, no definite WBC antibodies were found, although weak reactivity was detected transiently in sera from two infants. Accordingly, RBC and WBC antibody production did not differ among groups. In all, 11% of the transfused the infants exhibited platelet antibodies: 14% of the infants given stored leukocyte-reduced RBCs and 7% of the infants given fresh nonleukocyte-reduced RBCs (difference not statistically significant).

CONCLUSIONS

Preterm infants rarely produce antibodies to blood cell antigens after RBC transfusions, regardless of whether the exposure is to fresh unmodified RBCs from several donors or to stored leukocyte-reduced RBCs from a limited number of donors. Therefore, efforts to limit donor exposures or to remove WBCs from blood components cannot be justified simply for purposes of preventing alloimmunization in neonates.

Transfusion-transmitted cytomegalovirus: the part-time pathogen

Viral infection is a well-known risk of blood product transfusion and much work has been devoted to the detection of such well-known pathogens as human immunodeficiency virus and hepatitis viruses in blood donors. Cytomegalovirus (CMV) is found in a much larger percentage of donor units than these other viruses but will cause disease in only a minority of recipients. Many pediatric patients (especially premature infants) are at risk for transfusion-transmitted CMV. This review describes work delineating the populations of patients most at risk for transfusion-transmitted CMV, describes methods for detecting CMV in blood donors, evaluates current methods for leuko-depletion of blood products, and provides recommendations for patients most likely to benefit from blood products with low risk of CMV transmission.

Neonatal cytomegalovirus infections due to blood

Infants with very low birthweights (less than 1250g) are immunocompromised and have immature hematopoietic systems. They require frequent blood transfusions and have an increased susceptibility to infection. These very low birthweight infants who lack passively acquired antibody against CMV, acquire transfusion-associated CMV infections with a frequency of approximately 30%. These infections are associated with significant morbidity and mortality. The source of these postnatally acquired CMV infections are seropositive blood donors. These infections can be prevented by appropriate donor selection and/or blood processing. Recent but limited data suggests that all infants (regardless of birthweight or the presence of antibody against CMV) should receive CMV seronegative blood products if they are likely to receive multiple transfusions from multiple donors.

Prevention of transfusion-acquired cytomegalovirus infections in newborn infants

Transfusion-acquired cytomegalovirus infections occurred in 13.5% of 74 infants of seronegative mothers who were exposed to one or more blood donors who had a CMV indirect hemagglutination titer of 1:8 or higher. None of 90 infants of seronegative mothers exposed only to donors with CMV IHA titers of less than 1:8 became infected. Ten of 41 (24%) infants of seronegative mothers who received more than 50 ml of packed red blood cells and who were exposed to at least one seropositive donor became infected. None of 23 infants of seronegative mothers who received this amount of blood but who were exposed only to seronegative donors became infected. Fatal or serious symptoms developed in 50% of the infected infants of seronegative mothers and in none of the 32 infected infants of seropositive mothers. Acquired CMV infections occurred in 15% of infants of seropositive mothers who were exposed to the red blood cells of seropositive donors and in 17.6% of infants of seropositive mothers exposed only to seronegative donors. Use of seronegative donors reduced the prevalence of excretion of CMV among hospitalized infants who were 4 weeks of age or older from 12.5 to 1.8% and eliminated acquired CMV infections in infants of seronegative mothers.

New transfusion program for an intensive care nursery

We have established a new transfusion program for an intensive care nursery which is based on crossmatching several infants to the same unit of type O Rh0(D) negative packed red blood cells, dividing the unit into quadpacks, and allowing multiple entry into each quadpack over a 24-hour period in the nursery. With this procedure, each donor unit can be used to provide multiple transfusions to four infants over a four-day period. Follow-up of transfusion recipients revealed that 20% had evidence of previous or ongoing CMB infection at 10 months of age, a prevalence comparable to that for transfused infants in other studies. We found no evidence for transmission of HB infection and a low risk of allosensitization to red cell and lymphocyte antigens.

Collection and use of autologous fetal blood

A prospective study was completed to evaluate the feasibility of autologous fetal blood collection. Following puncture on the umbilical vein, fetal blood was drawn into sterile heparinized plastic syringes and aliquots were subjected to coagulation and culture studies. None of the blood samples exhibited significant growth of bacterial pathogens and all patients had normal coagulation studies at 24 hours of age. These data demonstrate that fetal blood can be safely collected and given to infants subjected to shock or iatrogenic blood loss.

Cytomegalovirus and blood transfusion in neonates

A fatal case of neonatal cytomegalovirus (CMV) infection attributed to exchange transfusion is described. The incidence of CMV transmission by exchange and other neonatal transfusion was studied, and the use of CMV antibody-free blood for these procedures was shown to be effective in preventing CMV infection in neonates.