How to avoid the problem of erythrocyte alloimmunization in sickle cell disease

Erythrocyte alloimmunization is a major barrier to transfusion in sickle cell disease (SCD) because it can lead to transfusion deadlock and the development of life-threatening hemolytic transfusion reactions (HTRs). Several risk factors have been identified, such as blood group polymorphism in these patients of African ancestry frequently exposed to antigens they do not carry and an inflammatory clinical state of the disease. The most important preventive measure is prophylactic red blood cell antigen matching, and there is a consensus that matching for Rh (D, C, E, c, e) and K antigens should be performed for all SCD patients. However, some patients are high responders and more at risk of developing antibodies and HTRs. For these patients, the extension of matching to other blood groups, including variant antigens of the RH blood group, the use of genotyping rather than serology to characterize significant blood groups, and the prophylactic administration of immunosuppressive treatments remain a matter of debate due to low levels of certainty concerning their effects and the difficulty of determining which patients, other than those already immunized, are at high risk. These issues were recently addressed by a panel of experts established by the American Society of Hematology. Here, we review and stratify the various interventions for preventing alloimmunization, based on the literature and our experience and taking into account the obstacles to their implementation and any future developments required.

When O Bites Back: Unrecognized Acute Hemolytic Reaction from Out-of-Group HLA-Compatible Platelet Transfusion

Managing a platelet blood product inventory in a hospital-based transfusion service (TS) is challenging. Thus, to optimize platelet inventory availability and to prevent excess outdating, most tertiary care center-based TSs do not require ABO-identical platelet (PLT) transfusions. To mitigate the risk of hemolysis associated with the transfusion of high titer ABO antibody-containing PLT, our institutional policy allows the transfusion of PLT containing ABO-incompatible plasma only if PLT is re-suspended in platelet additive solution (PAS). Despite the steps taken to reduce the risk of hemolytic transfusion reactions to PLT transfusions at our institution, our center has observed hemolytic reactions to PLT in PAS. The current case study highlights the importance of recognizing a hemolytic reaction (HTR) from ABO-incompatible PLT transfusions and discusses the current strategies and recommendations to mitigate this risk.

Hemolysis inhibits humoral B-cell responses and modulates alloimmunization risk in patients with sickle cell disease

Red blood cell alloimmunization remains a barrier for safe and effective transfusions in sickle cell disease (SCD), but the associated risk factors remain largely unknown. Intravascular hemolysis, a hallmark of SCD, results in the release of heme with potent immunomodulatory activity, although its effect on SCD humoral response, specifically alloimmunization, remains unclear. Here, we found that cell-free heme suppresses human B-cell plasmablast and plasma cell differentiation by inhibiting the DOCK8/STAT3 signaling pathway, which is critical for B-cell activation, as well as by upregulating heme oxygenase 1 (HO-1) through its enzymatic byproducts, carbon monoxide and biliverdin. Whereas nonalloimmunized SCD B cells were inhibited by exogenous heme, B cells from the alloimmunized group were nonresponsive to heme inhibition and readily differentiated into plasma cells. Consistent with a differential B-cell response to hemolysis, we found elevated B-cell basal levels of DOCK8 and higher HO-1-mediated inhibition of activated B cells in nonalloimmunized compared with alloimmunized SCD patients. To overcome the alloimmunized B-cell heme insensitivity, we screened several heme-binding molecules and identified quinine as a potent inhibitor of B-cell activity, reversing the resistance to heme suppression in alloimmunized patients. B-cell inhibition by quinine occurred only in the presence of heme and through HO-1 induction. Altogether, these data suggest that hemolysis can dampen the humoral B-cell response and that B-cell heme responsiveness maybe a determinant of alloimmunization risk in SCD. By restoring B-cell heme sensitivity, quinine may have therapeutic potential to prevent and inhibit alloimmunization in SCD patients.

Does ABO and RhD matching matter for platelet transfusion?

Platelets express ABO antigens and are collected in plasma, which contains ABO antibodies as would be consistent with the donor ABO group. Platelet ABO antigens that are incompatible with recipient ABO antibodies may have accelerated clearance from circulation and result in lower count increments. ABO antibodies that are passively transferred from donor plasma may result in hemolysis of recipient red blood cells. Although platelets do not express Rh antigens, they contain small numbers of intact red blood cells or fragments, which can lead to alloimmunization in the recipient. Alloimmunization to the RhD antigen may occur when platelets obtained from RhD-positive donors are transfused to RhD-negative recipients. All of these compatibility considerations must be balanced against the available supply, which may be limited due to the 5- to 7-day shelf life of platelets. This articles describes considerations for platelet ABO and RhD selection for platelet transfusions, including the impact of major ABO incompatibility on count increments, the risks of hemolysis associated with minor ABO incompatibility, and the risk of RhD alloimmunization when RhD-negative patients receive platelets obtained from RhD-positive donors.

Seroprevalence and Seroconversion of Cytomegalovirus in a Large Group of Healthy, German Blood Donors: Potential Contribution to Transfusion Transmitted Infections

BACKGROUND

Immunocompromised patients are at increased risk of morbidity and mortality due to transfusion transmitted cytomegalovirus (CMV) infections. To avoid or minimize such risk, clinicians working in the field continually monitor the changing epidemiology of CMV infections.

MATERIALS AND METHODS

A total of 234,192 blood donations obtained from 44,779 donors were tested. CMV seroprevalence and antibody conversion rates were determined over a 3-year period.

RESULTS

A significant percentage (37.5%) of all male and female blood donors tested seropositive. Both age and gender were risk factors for CMV infection. A total of 177 seroconversions (0.4% of donors) were identified. The highest antibody conversion rate occurred among men between 30 and 39 years of age; women did not experience a similar peak in antibody conversion rate. Approximately 10% of infected blood donors were identified by CMV DNA testing prior to seroconversion.

CONCLUSIONS

The high rates of seroprevalence and seroconversion and the identification of a significant number of CMV DNA-positive (infected) blood donors prior to seroconversion indicate that the routine testing of blood samples for CMV DNA could reduce the potential risk of CMV transmission to high-risk patients.

Examining the Role of Complement in Predicting, Preventing, and Treating Hemolytic Transfusion Reactions

Red blood cell (RBC) transfusion is a critical component of optimal management for a broad range of conditions. Regardless of the indication, pretransfusion testing is required to appropriately match RBC donors and recipients to provide immunologically compatible blood. Although this approach is effective in the vast majority of situations, occasionally, patients will inadvertently receive an incompatible RBC transfusion, which can result in a hemolytic transfusion reaction (HTR). In addition, patients with life-threatening anemia and a complex alloantibody profile, which precludes rapid procurement of compatible RBCs, may also receive incompatible RBCs, placing them at risk for an HTR. Despite the rarity of these clinical situations, when incompatible blood transfusion results in an HTR, the consequences can be devastating. In this review, we will explore the challenges associated with actively preventing and treating acute HTRs following incompatible RBC transfusion. In doing so, we will focus primarily on the role of complement, not only as a key player in HTRs, but also as a potential target for the prevention and treatment of HTRs.

Acute Hemolytic Transfusion Reaction Due to the "Anti-E" Rhesus Antibody in a Patient with Crohn's Disease

BACKGROUND

The rhesus (Rh) system is the second most important blood group system after ABO, with highly immunogenic antigens. Although the anti-E Rh antibody has been reported to cause hemolytic disease of the newborn and delayed hemolytic transfusion reactions, acute hemolytic transfusion reactions (AHTR) have been rarely reported.

METHODS

Peripheral blood (PB) samples were screened for irregular antibodies using a commercial ID-Diacell I - II antibody screening Panel (Bio-Rad Laboratories, Glattbrugg, Switzerland) and ID-cards "LISS/Coombs" (Bio-Rad, Switzerland). The antibody was confirmed using ID DiaPanel, an antibody identification panel (Bio-Rad, Switzerland). Rh phenotyping was performed for RhC/c and RhE/e antigens using an immediate-spin tube test with monoclonal anti-C, -c, -E, and -e (OrthoClinical Diagnostics, High Wycombe, UK) in saline-filled test-tubes.

RESULTS

The patient was negative for antibody screening test before transfusion. After receiving a total of 6 units of cross-matching negative RBC transfusion, the antibody screening test result increased to 2+ after showing traces and the antibody was confirmed as anti-E Rh antibody. The Rh phenotype of the patient was C (+), c (+), E (-), and e (+). In addition, we verified that all the six units of RBCs transfused were E (+) except for the two units transfused before surgery.

CONCLUSIONS

Here is an unusual case of an AHTR due to the anti-E Rh antibody after E-positive RBC transfusion in a patient with Crohn's disease. Because anemia is common in patients with Crohn's disease, it is important to determine the cause of the anemia and necessary to examine the Rh phenotype before transfusions because of the high need for transfusion due to any cause. Awareness of this possibility will ensure safe blood transfusion with special care to screen for antibodies and perform Rh phenotyping, thereby minimizing morbidity and preventing potential mortality.

Long-lasting discussion: Adverse effects of intraoperative blood loss and allogeneic transfusion on prognosis of patients with gastric cancer

Gastrectomy with radical lymph node dissection is the most promising treatment avenue for patients with gastric cancer. However, this procedure sometimes induces excessive intraoperative blood loss and requires perioperative allogeneic blood transfusion. There are lasting discussions and controversies about whether intraoperative blood loss or perioperative blood transfusion has adverse effects on the prognosis in patients with gastric cancer. We reviewed laboratory and clinical evidence of these associations in patients with gastric cancer. A large amount of clinical evidence supports the correlation between excessive intraoperative blood loss and adverse effects on the prognosis. The laboratory evidence revealed three possible causes of such adverse effects: anti-tumor immunosuppression, unfavorable postoperative conditions, and peritoneal recurrence by spillage of cancer cells into the pelvis. Several systematic reviews and meta-analyses have suggested the adverse effects of perioperative blood transfusions on prognostic parameters such as all-cause mortality, recurrence, and postoperative complications. There are two possible causes of adverse effects of blood transfusions on the prognosis: Anti-tumor immunosuppression and patient-related confounding factors (e.g., preoperative anemia). These factors are associated with a worse prognosis and higher requirement for perioperative blood transfusions. Surgeons should make efforts to minimize intraoperative blood loss and transfusions during gastric cancer surgery to improve patients’ prognosis.

Clinical presentation of delayed hemolytic transfusion reactions and hyperhemolysis in sickle cell disease

Red blood cell (RBC) transfusion therapy is a key component in the comprehensive management of patients with sickle cell disease (SCD). Consequently, most adult SCD patients will receive at least one, and many will receive more than a hundred RBC transfusions in their lifetime. SCD patients develop RBC alloantibodies much more frequently than non-SCD transfused patients, which often make the selection of compatible RBCs extremely difficult, in addition to placing patients at significantly higher risk of suffering from delayed hemolytic transfusion reactions (DHTRs). Similar to alloimunization, DHTRs are much more common in patients with SCD compared to other heavily transfused populations, and are particularly consequential due to their propensity to cause hyperhemolysis, a life-threatening phenomenon in which both transfused RBCs in addition to the patient's own sickle-erythrocytes are destroyed. In this review, we highlight the incidence and pathophysiology of DHTRs; illustrate common presentations, appropriate evaluations and outcomes of DHTRs in patients with SCD; and discuss strategies for preventing or reducing the likelihood of DHTRs from occurring.

Red Blood Cell Alloimmunization in Multitransfused Pediatric Population in a Tertiary Care Hospital

OBJECTIVES

To estimate the prevalence and specificity pattern of red blood cell (RBC) alloimmunization among pediatric multitransfused patients, and to identify the factors associated with alloimmunization.

METHODS

This was a descriptive cross-sectional study conducted among mutitransfused pediatric patients over a period of two years. The relevant clinical details of patients were collected, and RBC antibody screening was done. Samples with positive antibody screen were subjected to antibody identification. Patient factors were analysed to find any significant relation to the development of RBC alloimmunization.

RESULTS

Alloantibodies were obtained in 4 (6.35%) of the total 63 patients, and autoantibody in 1 (1.59%). The specificities of alloantibodies identified were all against Rh antigens-one each of anti E, anti c, anti Cw and anti D + anti C. A significant association was seen between development of alloimmunization and first transfusion at more than 2 y of age.

CONCLUSIONS

RBC alloimmunization against Rhesus (Rh) antigens is a significant problem for multitransfused children in our population. Extended RBC phenotyping at least for antigens of the Rh system and provision of antigen matched RBCs may be an option for such children, where ongoing transfusion requirement is anticipated.

Acute Hemolytic Transfusion Reaction Due to Anti-Kpa Antibody

BACKGROUND

Kpa (KEL3, Penney) is a red blood cell antigen within the Kell system, first described in 1957, that occurs in less than 2 percent of the population. Although anti-Kpa antibodies were identified in 2-5 percent of those with alloantibodies among patients requiring chronic transfusion, only five previously published case reports of anti-Kpa reactions were identified.

CASE REPORT

Reported here is a case of an elderly female who experienced an acute hemolytic transfusion reaction due to this antigen. Following initiation of blood transfusion, she experienced a sudden onset of rigorous chills, accompanied by elevated temperature, tachycardia, and hypertension. Laboratory studies showed uremia, elevated creatinine, positive direct Coomb's, and low haptoglobin. Serology revealed anti-Kpa antibody.

CONCLUSION

This report is only the sixth, to our knowledge, of a significant reaction attributable to anti-Kpa and only the second of an acute hemolytic reaction associated with it. It serves as a reminder of the potential of low incidence antigens causing severe reactions; this potential should be considered when evaluating acute hemolytic reaction.

An acute transfusion reaction

We present the case of a 67-year-old man who suffered an acute anaphylactic reaction during red cell transfusion due to the presence of anti-IgA antibodies. The incidence and clinical relevance of anti-IgA antibodies in IgA deficiency is reviewed, and the wider investigation and management of acute transfusion reactions is also discussed. This case highlights the need to consider the potential risks of blood component transfusion against the purported benefit.

Silent killers: Transfusion Transmissible Infections-TTI, among asymptomatic population of Pakistan

OBJECTIVE

To analyse transfusion transmissible infections in asymptomatic population.

METHODS

This study was conducted at the Allama Iqbal Medical College and Jinnah Hospital, Lahore, Pakistan, from December 2014 to November 2015, and comprised healthy asymptomatic blood donors.Every sample was screened for the presence of antibodies/antigens of hepatitis C virus, human immunodeficiency virus, treponemapallidum, hepatitis B virus and malaria parasite through rapid immunochromatographic technique.

RESULTS

Of the 18,274 blood donors, 17,276(94.53%) were found healthy and 998(5.46%) were infected. Besides, 71(0.38%) had multiple infections. The overall frequency of anti-hepatitis C virus, treponemapallidum (syphilis), hepatitis B surface antigen, malaria parasite and anti-human immunodeficiency virus was 480(2.62%), 284(1.55%), 210(1.10%), 20(0.10%) and 4(0.02%), respectively.

CONCLUSIONS

Blood transfusion was found to be a significant but preventable mode of spread of transfusion transmissible infections.

The Prevalence of Red Blood Cell Alloantibodies in Lower Northern Thailand

BACKGROUND

Hemolytic transfusion reactions due to the presence of pre-existing alloantibodies are among the most common immunologic adverse effects in transfusion medicine. In addition to determining the presence and characteristics of the specific alloantibodies, one of the major obstacles is the selection of compatible blood units that lack the corresponding antigens to avoid such transfusion reactions. A delay in this process can lead to various detrimental complications.

OBJECTIVE

To characterize the prevalence and specificity of alloantibodies in patients from lower northern Thailand who required a blood transfusion.

MATERIAL AND METHOD

A retrospective review of the Blood Bank database of Naresuan University, Thailand, was conducted. Thirty one thousand four hundred patients who had been screened for the presence of alloantibodies between January 2007 and April 2014 were reviewed. The standard test tube method was used in all patients to identify the specificity of alloantibodies against red blood cell surface antigens.

RESULTS

Among the 31,400 patients, 169 patients (0.54%) were found to have pre-existing red blood cell alloantibodies. Anti-Mi (anti-Miltenberger blood group) was the most common alloantibody identified (43.79%). Other common alloantibodies were anti-E (18.34%), anti-P1 (17.75%), anti-Lea (17.16%), and anti-Leb (9.47%).

CONCLUSION

To minimize hemolytic transfusion reactions, we recommend greater availability and issuing of Mi, E, P1, Lea, and Leb-matched blood units for patients with known alloantibodies against these antigens, or for patients who require multiple transfusions. This is in addition to the standard pre-transfusion screening and cross-matching processes.