Jean-Louis Kerkhoffs

The clinical impact of platelet refractoriness : correlation with bleeding and survival

BACKGROUND: Despite supportive care with platelet (PLT) transfusions, bleeding complications occur in a substantial number of patients with thrombocytopenia due to cytotoxic therapy. Moreover, refractoriness to PLT transfusions remains a frequently encountered problem. The clinical impact of PLT transfusion failure was investigated in 117 patients, part of a randomized PLT transfusion trial, which excluded patients with HLA and/or HPA alloantibodies.

A brief review on newborn screening methods for hemoglobinopathies and preliminary results selecting beta thalassemia carriers at birth by quantitative estimation of the HbA fraction

OBJECTIVES We present in a brief summary the basic aspects of the most rational technologies used for new born screening (NBS) of the hemoglobinopathies and we report the preliminary results for the identification of beta-thalassemia carriers at birth by measuring the expression of the HbA fraction. DESIGN AND METHODS Separation and measurement of the Hb fractions in 1.500 cord blood samples collected among the multi-ethnic Dutch population using different methods. RESULTS By using a cut of <15% HbA we have found 4 carriers of point mutations defects 3 of which among a group of 34 newborns of ethnic origin and one among 120 north Europeans. DISCUSSION All methods for NBS summarized in this paper provide identification at practically 100% sensitivity and high specificity. However, all methods should be followed by routine parents analysis to confirm the provisional results. Taking into consideration the gestation age and the HbA expression, we believe that carriers of beta-thalassemia can be preselected at birth with a reasonable degree of sensitivity and be confirmed by parent analysis.

Early occurrence of red blood cell alloimmunization in patients with sickle cell disease

Red blood cell (RBC) alloimmunization is a major complication of transfusion therapy in sickle cell disease (SCD). Identification of high‐risk patients is hampered by lack of studies that take the cumulative transfusion exposure into account. In this retrospective cohort study among previously non‐transfused SCD patients in the Netherlands, we aimed to elucidate the association between the cumulative transfusion exposure, first alloimmunization and independent risk factors. A total of 245 patients received 11 952 RBC units. Alloimmunization occurred in 43 patients (18%), half of them formed their first alloantibody before the 8th unit. In patients with exposure to non‐extended matched transfusions (ABO and RhD) the cumulative alloimmunization risk increased up to 35% after 60 transfused units. This was significantly higher compared to a general transfused population (HR 6.6, CI 4.2–10.6). Receiving the first transfusion after the age of 5 was an independent risk factor for alloimmunization (HR 2.3, CI 1.0–5.1). Incidental, episodic transfusions in comparison to chronic scheme transfusions (HR 2.3, CI 0.9–6.0), and exposure to non‐extended matched units in comparison to extended matching (HR 2.0, CI 0.9–4.6) seemed to confer a higher alloimmunization risk. The majority of first alloantibodies are formed after minor transfusion exposure, substantiating suggestions of a responder phenotype in SCD and stressing the need for risk factor identification. In this study, older age at first transfusion, episodic transfusions and non‐extended matched transfusions appeared to be risk factors for alloimmunization. Am. J. Hematol. 91:763–769, 2016.

Hb Lepore-Leiden: A New δ/β Rearrangement Associated with a β-Thalassemia Minor Phenotype

The Lepore hemoglobins (Hbs) are a group of structural defects resulting from different recombination events between the δ- and β-globin genes. They may come with different β-thalassemia (β-thal) minor-like phenotypes in the carrier and with variably severe phenotypes in the rare homozygote, and in the common compound heterozygote with β-thal. The most seriously affected patients are those of Yugoslavian origin presenting with severe transfusion-dependent hemolytic anemia, dyserythropoiesis, hepatosplenomegaly and skeletal malformations. Because of genetic risk, couples where both partners are carriers of these combinations may require prognosis and prenatal diagnosis. In these cases, recognition of the defect must be done with particular care. We report a case of Hb Lepore induced by a yet unknown crossover event found in a 24-year-old Turkish male and compare the novel mutation with those previously reported.

A study protocol for a randomised controlled trial evaluating clinical effects of platelet transfusion products: the Pathogen Reduction Evaluation and Predictive Analytical Rating Score (PREPAReS) trial

Introduction Patients with chemotherapy-induced thrombocytopaenia frequently experience minor and sometimes severe bleeding complications. Unrestrictive availability of safe and effective blood products is presumed by treating physicians as well as patients. Pathogen reduction technology potentially offers the opportunity to enhance safety by reducing bacterial and viral contamination of platelet products along with a potential reduction of alloimmunisation in patients receiving multiple platelet transfusions. Methods and analysis To test efficacy, a randomised, single-blinded, multicentre controlled trial was designed to evaluate clinical non-inferiority of pathogen-reduced platelet concentrates treated by the Mirasol system, compared with standard plasma-stored platelet concentrates using the percentage of patients with WHO grade ≥2 bleeding complications as the primary endpoint. The upper limit of the 95% CI of the non-inferiority margin was chosen to be a ≤12.5% increase in this percentage. Bleeding symptoms are actively monitored on a daily basis. The adjudication of the bleeding grade is performed by 3 adjudicators, blinded to the platelet product randomisation as well as by an automated computer algorithm. Interim analyses evaluating bleeding complications as well as serious adverse events are performed after each batch of 60 patients. The study started in 2010 and patients will be enrolled up to a maximum of 618 patients, depending on the results of consecutive interim analyses. A flexible stopping rule was designed allowing stopping for non-inferiority or futility. Besides analysing effects of pathogen reduction on clinical efficacy, the Pathogen Reduction Evaluation and Predictive Analytical Rating Score (PREPAReS) is designed to answer several other pending questions and translational issues related to bleeding and alloimmunisation, formulated as secondary and tertiary endpoints. Ethics and dissemination Ethics approval was obtained in all 3 participating countries. Results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal. Trial registration number NTR2106; Pre-results.

Nonclassical FCGR2C haplotype is associated with protection from red blood cell alloimmunization in sickle cell disease

Red blood cell (RBC) transfusions are of vital importance in patients with sickle cell disease (SCD). However, a major complication of transfusion therapy is alloimmunization. The low-affinity Fcγ receptors, expressed on immune cells, are important regulators of antibody responses. Genetic variation in FCGR genes has been associated with various auto- and alloimmune diseases. The aim of this study was to evaluate the association between genetic variation of FCGR and RBC alloimmunization in SCD. In this case-control study, DNA samples from 2 cohorts of transfused SCD patients were combined (France and The Netherlands). Cases had a positive history of alloimmunization, having received ≥1 RBC unit. Controls had a negative history of alloimmunization, having received ≥20 RBC units. Single nucleotide polymorphisms and copy number variation of the FCGR2/3 gene cluster were studied in a FCGR-specific multiplex ligation-dependent probe amplification assay. Frequencies were compared using logistic regression. Two hundred seventy-two patients were included (130 controls, 142 cases). The nonclassical open reading frame in the FCGR2C gene (FCGR2C.nc-ORF) was strongly associated with a decreased alloimmunization risk (odds ratio [OR] 0.26, 95% confidence [CI] 0.11-0.64). This association persisted when only including controls with exposure to ≥100 units (OR 0.30, CI 0.11-0.85) and appeared even stronger when excluding cases with Rh or K antibodies only (OR 0.19, CI 0.06-0.59). In conclusion, SCD patients with the FCGR2Cnc-ORF polymorphism have over a 3-fold lower risk for RBC alloimmunization in comparison with patients without this mutation. This protective effect was strongest for exposure to antigens other than the immunogenic Rh or K antigens.

The observation of bleeding complications in haemato-oncological patients: stringent watching, relevant reporting

The reported percentage of haemato‐oncological patients experiencing bleeding complications is highly variable, ranging from 5 to 70%, posing a major problem for comparison of clinical platelet transfusion trials using bleeding complications as a primary endpoint. In a pilot study we assessed the impact of the design of scoring of bleeding on the percentage of patients with WHO grade 2 or higher bleeding grades.

Feasibility of nonselective testing for hemoglobinopathies in early pregnancy in The Netherlands

To examine the feasibility of standardized hemoglobinopathy (HBP) carrier testing for pregnant women in The Netherlands in addition to the standard anemia screening.

Evaluation of platelet transfusion clinical trials – response to Corash & Sherman

posttransfusion platelet increments, platelet refractoriness, and platelet transfusion intervals in thrombocytopenic patients. Blood, 105, 4106– 4114. Slichter, S.J., Kaufman, R.M., Assman, S.F., McCullough, J., Triulzi, D.J., Strauss, R.G., Gernsheimer, T.B., Ness, P.M., Brecher, M.E., Josephson, C.D., Konkle, B.A., Woodson, R.D., Ortel, T.L., Hillyer, C.D., Skerrett, D.L., McCrae, K.R., Sloan, S.R., Uhl, L., George, J.N., Aquino, V.M., Manno, C.S., McFarland, J.G., Hess, J.R., Leissinger, C. & Granger, S. (2010) Dose of prophylactic platelet transfusios and prevention of hemorrhage. New England Journal of Medicine, 362, 600–613. Snyder, E., McCullough, J., Slichter, S.J., Strauss, R.G., Lopez-Plaza, I., Lin, J.S., Corash, L. & Conlan, M.G. (2005) Clinical safety of platelets photochemically treated with amotoslaen HCl and ultraviolet A light for pathogen inactivation: the SPRINT trial. Transfusion, 45, 1864–1875.

Hemostatic efficacy of pathogen-inactivated- versus untreated- platelets: a randomized controlled trial

Pathogen inactivation of platelet concentrates reduces the risk for blood-borne infections. However, its effect on platelet function and hemostatic efficacy of transfusion is unclear. We conducted a randomized noninferiority trial comparing the efficacy of pathogen-inactivated platelets using riboflavin and UV B illumination technology (intervention) compared with standard plasma-stored platelets (control) for the prevention of bleeding in patients with hematologic malignancies and thrombocytopenia. The primary outcome parameter was the proportion of transfusion-treatment periods in which the patient had grade 2 or higher bleeding, as defined by World Health Organization criteria. Between November 2010 and April 2016, 469 unique patients were randomized to 567 transfusion-treatment periods (283 in the control arm, 284 in the intervention arm). There was a 3% absolute difference in grade 2 or higher bleeding in the intention-to-treat analysis: 51% of the transfusion-treatment periods in the control arm and 54% in the intervention arm (95% confidence interval [CI], -6 to 11; P = .012 for noninferiority). However, in the per-protocol analysis, the difference in grade 2 or higher bleeding was 8%: 44% in the control arm and 52% in the intervention arm (95% CI -2 to 18; P = .19 for noninferiority). Transfusion increment parameters were ∼50% lower in the intervention arm. There was no difference in the proportion of patients developing HLA class I alloantibodies. In conclusion, the noninferiority criterion for pathogen-inactivated platelets was met in the intention-to-treat analysis. This finding was not demonstrated in the per-protocol analysis. This trial was registered at The Netherlands National Trial Registry as #NTR2106 and at www.clinicaltrials.gov as #NCT02783313.