Ensuring HLA-matched platelet support requires an ethnic diverse donor population

BACKGROUND

Patients refractory for platelet transfusions benefit from human leukocyte antigen (HLA)‐matched platelet transfusions. Differences in ethnic background of patients and donors could hamper the availability of sufficient numbers of HLA‐matched donors for all patients. We evaluated our HLA‐matched donor program and explored the role of ethnic background of patients related to the number of available donors.

METHODS

We performed a cohort study among consecutive patients who received HLA‐matched platelet concentrates in the Netherlands between 1994 and 2017. The number of available matched donors was determined per patient. Haplotypes were constructed from genotypes with computer software (PyPop). Based on haplotypes, HaploStats, an algorithm from the National Marrow Donor Program, was used to assess the most likely ethnic background for patients with 5 or fewer and 30 or more donors.

RESULTS

HLA typing was available for 19,478 donors in September 2017. A total of 1206 patients received 12,350 HLA‐matched transfusions. A median of 83 (interquartile range, 18‐266) donors were available per patient. For 95 (10.3%) patients, 5 or fewer donors were available. These patients were more likely to have an African American background, whereas patients with 30 or more donors were more often from Caucasian origin, compared with Caucasian origin for patients with 30 donors.

CONCLUSION

Adequate transfusion support could be guaranteed for most but not all refractory patients. More non‐Caucasian donors are required to ensure the availability of HLA‐matched donors for all patients in the Netherlands.

[Blood safety in the Netherlands: prevention of blood-transmitted infections]

Amongst the various blood-safety measures to prevent blood-transmitted infections in transfusion recipients, the most important are the selection of blood donors and the testing for infections of the donations. A look-back procedure aims to inform hospitals about potentially infected blood products and to trace the relevant recipients. The opposite, reverse look-back, can also occur: following a report that a patient has an infection of which blood transfusion may be the possible source, all possibly implicated donors will be screened for the particular agent. Over the period 2007-2017, 84 look-backs were carried out by the Dutch blood product organisation Sanquin. Transmission via blood products of the human immunodeficiency virus, hepatitis C virus, human T-cell Lymphotropic virus or Treponema pallidum were not found. Look-back identified four recipients with hepatitis-B virus infection. These recipients had received a blood product from donors with an occult chronic hepatitis-B virus infection. In the Netherlands, the risks associated with transmission of infection through blood products are minimal; however, transmission may still occur, despite extensive blood-safety measures.

A Conceptual Framework for Optimizing Blood Matching Strategies: Balancing Patient Complications Against Total Costs Incurred

Alloimmunization is currently the most frequent adverse blood transfusion event. Whilst completely matched donor blood would nullify the alloimmunization risk, this is practically infeasible. Current matching strategies therefore aim at matching a limited number of blood groups only, and have evolved over time by systematically including matching strategies for those blood groups for which (serious) alloimmunization complications most frequently occurred. An optimal matching strategy for controlling the risk of alloimmunization however, would balance alloimmunization complications and costs within the entire blood supply chain, whilst fulfilling all practical requirements and limitations. In this article the outline of an integrated blood management model is described and various potential challenges and prospects foreseen with the development of such a model are discussed.

Utility of zinc protoporphyrin in management of whole blood donors

BACKGROUND

Deferral for low hemoglobin (Hb) increases the likelihood that donors do not return for future donations. Zinc protoporphyrin (ZPP) has been described as a sensitive marker of iron-deficient erythropoiesis, before Hb decreases. It is a relatively cheap, rapid, and easy-to-perform measurement in a drop of whole blood. To assess the utility of ZPP measurement in donor management we examined whether ZPP and Hb levels among first-time donors differ from repeat donors. We further explored whether ZPP increases over subsequent donations at a donor population level and whether increasing ZPP levels coincide with decreasing Hb levels and donor deferral.

STUDY DESIGN AND METHODS

We included first-time (n = 4983) and repeat (n = 3533) whole blood donors from the ZPP and Iron in the Netherlands Cohort (ZINC) study. ZPP and Hb were measured at each subsequent donation during a 4-year period after inclusion in the study.

RESULTS

Median ZPP levels were higher in repeat than in first-time donors. In first-time donors, especially women, ZPP levels were increased with a corresponding decline in Hb levels over subsequent donations. ZPP levels were increased among first-time donors deferred for low Hb.

CONCLUSION

Our results suggest that adding ZPP to Hb measurements in the daily blood collection setting, especially for first-time donors and first-time female donors may add to the identification of a donor subpopulation with low functional iron stores.

The effect of World Blood Donor Day on digital information seeking and donor recruitment

BACKGROUND

The purpose of World Blood Donor Day (WBDD) is to raise awareness for the importance of blood donation. The aim of this study was to quantify the impact of WBDD on digital information seeking and donor recruitment.

STUDY DESIGN AND METHODS

Google Trends data were used to quantify seeking behavior on "blood donation" and "blood donor." Differences in relative search volume (RSV) between the 3 weeks surrounding WBDD and the rest of the year were calculated. Second, mean differences in RSV were compared to assess the additional effect of hosting using translated search terms. Third, we compared the period around WBDD with the control period regarding page views of the Sanquin website and Facebook likes and number of newly registered donors in 2016.

RESULTS

The mean RSV for "blood donation" in the period of interest was 78.6, compared to 72.1 in the control period (difference, 6.5; 95% confidence interval [95% CI], 1.2-11.8). For "blood donor" this was 78.9 compared to 65.9 (difference, 12.9; 95% CI, 8.1-17.8). We found no additional effect of hosting. In the period of interest, the website of Sanquin was visited 6862 times a day and 4293 times in the control period (difference, 2569; 95% CI, 1687-3451). In June 2016, 54.6% (95% CI, 53.0-56.2) more new donors were registered compared to the control period.

CONCLUSION

An international campaign like WBDD raises the awareness of blood donation and is effective in convincing people to register as blood donors.

Impact of red blood cell transfusion strategies in haemato-oncological patients: a systematic review and meta-analysis

Haemato-oncological patients receive many red blood cell (RBC) transfusions, however evidence-based guidelines are lacking. Our aim is to quantify the effect of restrictive and liberal RBC transfusion strategies on clinical outcomes and blood use in haemato-oncological patients. A literature search, last updated on 11 August 2016, was performed in PubMed, EMBASE (Excerpta Medica Database), Web of Science, Cochrane, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Academic Search Premier without restrictions on language and year of publication. Randomized controlled trials and observational studies that compared different RBC transfusion strategies in haemato-oncological patients were eligible for inclusion. Risk of bias assessment according to the Cochrane collaboration's tool and Newcastle-Ottawa scale was performed. After removing duplicates, 1142 publications were identified. Eventually, 15 studies were included, reporting on 2636 patients. The pooled relative risk for mortality was 0·68 [95% confidence interval (CI) 0·46-1·01] in favour of the restrictive strategy. The mean RBC use was reduced with 1·40 units (95% CI 0·70-2·09) per transfused patient per therapy cycle in the restrictive strategy group. There were no differences in safety outcomes. All currently available evidence suggests that restrictive strategies do not have a negative impact regarding clinical outcomes in haemato-oncological patients, while it reduces RBC use and associated costs.

How we manage patients with hereditary haemochromatosis

A number of disorders cause iron overload: some are of genetic origin, such as hereditary haemochromatosis, while others are acquired, for instance due to repeated transfusions. This article reviews the treatment options for hereditary haemochromatosis, with special attention to the use of erythrocytapheresis. In general, therapy is based on the removal of excess body iron, for which ferritin levels are used to monitor the effectiveness of treatment. For many decades phlebotomy has been widely accepted as the standard treatment. Recent publications suggest that erythrocytapheresis, as a more individualized treatment, can provide a good balance between effectiveness, tolerability and costs. Other treatments like oral chelators and proton pomp inhibitors, which are used in selected patients, create the possibility to further individualize treatment of hereditary haemochromatosis. In the future, hepcidin-targeted therapy could provide a more fundamental approach to treatment.

Lookback procedures after postdonation notifications during a Q fever outbreak in the Netherlands

BACKGROUND

Since 2007, large outbreaks of Q fever occurred in the Netherlands. The unprecedented number of Q fever infections resulted in the need for the Dutch blood transfusion service to evaluate the risk of transmission of Coxiella burnetii via blood.

STUDY DESIGN AND METHODS

A lookback procedure (recipient tracing) was performed for transfused blood products of whole blood donors with confirmed C. burnetii infection within 3 weeks before to 3 weeks after blood donation. Repository samples of index donations were tested with real-time polymerase chain reaction (PCR) for C. burnetii DNA. Hospitals were asked to review the medical records of recipients and-if considered necessary-to test the recipients for infection with C. burnetii.

RESULTS

From 2007 through 2011, a total of 33 blood donors notified the blood bank of infection with C. burnetii. Thirteen donations fulfilled the criteria for a lookback procedure (18 blood products). C. burnetii PCR was positive in 1 of 13 repository samples of index donations. Blood products were transfused to 18 recipients. Information was retrieved from 12 of them; seven were tested for C. burnetii. Two recipients showed positive serology. However, transmission of C. burnetii via transfusion was unlikely, especially since most recipients lived in the same Q fever-affected area as the donors.

CONCLUSION

Blood donors who have clinical Q fever around the time of blood donation are unlikely to test positive for C. burnetii by PCR in repository samples. Transmission of C. burnetii via transfusion of blood products could not be demonstrated in a lookback exercise.

[Erythrocytapheresis for hereditary haemochromatosis]

With a prevalence of 0.4%, hereditary haemochromatosis is the most common autosomal-recessive genetic disease in Northern Europe. Hereditary haemochromatosis is characterized by an increase in the absorption of iron. This consequently leads to the excessive deposition of iron in tissues and organs with resultant functional impairment. Early-stage treatment can prevent complications resulting from the accumulation of iron. The standard treatment for hereditary haemochromatosis is phlebotomy, whereby 500 ml of whole blood is removed once a week until serum ferritin levels of 50-100 μg/l are achieved. After this, the patient must undergo lifelong maintenance treatment consisting of 3-6 phlebotomies per year on average. An alternative treatment is erythrocytapheresis, the selective removal of erythrocytes by way of apheresis. This procedure makes it is possible to collect more erythrocytes than during phlebotomy, resulting in significantly fewer treatment sessions being needed for the initial removal of overabundant iron.

Thirteen novel mutations in the factor VIII gene in the Nijmegen haemophilia A patient population

The development of neutralising antibodies to factor VIII (FVIII) is a major complication of haemophilia A (HA) therapy. We aimed to construct an individual risk profile for the development of inhibitors in HA and started by screening for the causative mutation in our HA patient population. A total of 109 patients and 28 carriers were screened. The analysis revealed 38 different mutations in the FVIII gene, of which 13 have not been described on the Haemophilia A Mutation, Search, Test and Resource Site (HAMSTeRS). Twenty-five mutations have been reported previously and all except two had a similar phenotype to what has been described. Three novel mutations were associated with severe HA: one non-missense mutation, a small insertion in the A2 domain, and two missense mutations, a H256R mutation in the A1 domain and a L2025P substitution in the C1 domain. One novel mutation, Y156C, was associated with moderate HA. Nine novel mutations caused mild HA. The P130R, D167E and V278M mutations are located in the A1 domain. R439C, Y511H, A544G and Q645H in the A2 domain, L1758F in the A3 domain and a S2157R mutation in the C1 domain. In conclusion, the genotypic profile of our HA population was not different from others described and is suitable to study inhibitor formation.

Frequent detection of respiratory viruses in adult recipients of stem cell transplants with the use of real-time polymerase chain reaction, compared with viral culture

Background. Respiratory virus infections have been recognized as important causes of severe pneumonia in patients who have undergone stem cell transplantation (SCT). Reported incidences of respiratory virus infection in adult SCT recipients vary in the literature from 3.5% to 36% when determined by viral culture. However, a more sensitive method to assess the presence of respiratory viruses in the lower airways may be important for delineation of the true incidence of respiratory virus—associated pneumonia and may be essential for guidance on implementation of antiviral therapy and prevention or limitation of nosocomial spread of infection with respiratory viruses.

Methods. To determine the incidence and severity of respiratory tract illness (RTI) and to assess the diagnostic value of real-time reverse-transcriptase polymerase chain reaction (RT-PCR) versus viral culture, 72 SCT recipients were monitored during a 6-month period.

Results. A respiratory virus was detected in 21% of episodes of RTI by viral culture and in 63% of RTI episodes by real-time RT-PCR (P < .0001). In lower respiratory tract illness, real-time RT-PCR was much more sensitive than viral culture for detection of respiratory virus (73% vs. 9%; P = .008). The mortality rate for patients with respiratory virus—associated lower respiratory tract illness (25%) was similar to rates reported elsewhere. Respiratory viruses (predominantly rhinovirus) were detected by real-time RT-PCR in 9% of samples obtained from symptom-free SCT recipients at predetermined times by real-time RT-PCR and by viral culture in 1% (P < .0001), indicating that asymptomatic shedding of respiratory viruses also occurs.

Conclusion. We conclude that, although asymptomatic shedding of respiratory virus occurs, respiratory viruses are frequent causes of RTI in SCT recipients.

Frequent detection of human coronaviruses in clinical specimens from patients with respiratory tract infection by use of a novel real-time reverse-transcriptase polymerase chain reaction

During the past years, human coronaviruses (HCoVs) have been increasingly identified as pathogens associated with more-severe respiratory tract infection (RTI). Diagnostic tests for HCoVs are not frequently used in the routine setting. It is likely that, as a result, the precise role that HCoVs play in RTIs is greatly underestimated. We describe a rapid, sensitive, and highly specific quantitative real-time reverse-transcriptase polymerase chain reaction (RT-PCR) for the detection of HCoV that can easily be implemented in the routine diagnostic setting. HCoV was detected in 28 (11%) of the 261 clinical specimens obtained from patients presenting with symptoms of RTI ranging from common cold to severe pneumonia. Only 1 (0.4%) of the 243 control specimens obtained from patients without symptoms of RTI showed the presence of HCoV. We conclude that HCoVs can be frequently detected in patients presenting with RTI. Real-time RT-PCR provides a tool for large-scale epidemiological studies to further clarify the role that coronavirus infection plays in RTI in humans.

Polymerase chain reaction is more sensitive than viral culture and antigen testing for the detection of respiratory viruses in adults with hematological cancer and pneumonia

We retrospectively analyzed the value of polymerase chain reaction (PCR) for the detection of respiratory viral infections in 43 patients with hematological cancer whose bronchoalveolar lavage (BAL) samples had been stored. In addition, 17 nose-throat (NT) swabs and 29 blood samples had been obtained. PCR was performed to detect parainfluenza viruses 1-3, respiratory syncytial virus, rhinovirus, influenza viruses A and B, enteroviruses, and coronaviruses. Viral cultures or antigen testing of BAL samples revealed 9 respiratory viruses in 8 patients. By use of PCR, 8 more respiratory viruses were detected in another 7 patients, increasing the rate of identification from 19% to 35% (P<.0005). Available NT swabs yielded the same results with PCR as did BAL samples. We conclude that PCR is more sensitive than viral culture or antigen or serologic testing for detection of respiratory viruses in patients with hematological malignancies, and that it offers the possibility for early, more rapid diagnosis.