Henk Schonewille

Alloimmunization after blood transfusion in patients with hematologic and oncologic diseases

BACKGROUND: Because of intensive marrow depression and improved survival, patients with hematologic and oncologic malignancies are dependent on transfusion for a longer period. It has been advocated that these patients should receive blood that is matched for blood group antigens other than ABO and D. A retrospective study was performed on the rate of alloimmunization against red cell antigens in 564 patients with malignant hematologic diseases over a period of 10 years.

Red blood cell alloimmunization in sickle cell disease patients in Uganda

BACKGROUND: Blood transfusion is an integral part in the management of sickle cell disease (SCD) patients. Alloimmunization is a recognized complication of red blood cell (RBC) transfusions with consequences including delayed hemolytic transfusion reactions and difficulties in getting compatible blood for future transfusions. The objective of this study was to determine the frequency of RBC alloimmunization in SCD patients in Uganda where pretransfusion screening for alloantibodies is not practiced.

RBC antibody persistence.

BACKGROUND: A person exposed to foreign blood group antigens may produce antibodies. The persistence of antibodies varies among people and among antibodies. A study was performed to investigate the persistence of clinically significant RBC alloantibodies over a period of 20 years.

Long-term neurodevelopmental outcome after intrauterine transfusion for hemolytic disease of the fetus/newborn: the LOTUS study

OBJECTIVE To determine the incidence and risk factors for neurodevelopmental impairment (NDI) in children with hemolytic disease of the fetus/newborn treated with intrauterine transfusion (IUT). STUDY DESIGN Neurodevelopmental outcome in children at least 2 years of age was assessed using standardized tests, including the Bayley Scales of Infant Development, the Wechsler Preschool and Primary Scale of Intelligence, and the Wechsler Intelligence Scale for Children, according to the childrens age. Primary outcome was the incidence of neurodevelopmental impairment defined as at least one of the following: cerebral palsy, severe developmental delay, bilateral deafness, and/or blindness. RESULTS A total of 291 children were evaluated at a median age of 8.2 years (range, 2-17 years). Cerebral palsy was detected in 6 (2.1%) children, severe developmental delay in 9 (3.1%) children, and bilateral deafness in 3 (1.0%) children. The overall incidence of neurodevelopmental impairment was 4.8% (14/291). In a multivariate regression analysis including only preoperative risk factors, severe hydrops was independently associated with neurodevelopmental impairment (odds ratio, 11.2; 95% confidence interval, 1.7-92.7). CONCLUSION Incidence of neurodevelopmental impairment in children treated with intrauterine transfusion for fetal alloimmune anemia is low (4.8%). Prevention of fetal hydrops, the strongest preoperative predictor for impaired neurodevelopment, by timely detection, referral and treatment may improve long-term outcome.

Red-blood-cell alloimmunization and number of red-blood-cell transfusions

Background  Patients receiving red‐blood‐cells may form antibodies against the alloantigens expressed by red‐blood‐cells, with the risk of serious morbidity and the need for extensive phenotype‐matching in subsequent transfusions. The incidence of alloimmunization is considered variable for specific patient groups and for first time antibody formation. We therefore studied the cumulative incidence of the first formed alloantibody as a function of red‐blood‐cells exposure.

Alloimmunization to red blood cell antigens after universal leucodepletion. A regional multicentre retrospective study.

Leucodepletion has been shown to reduce human leucocyte antigen immunization, but studies on the effect of leucodepletion on red cell alloimmunization reported discordant results. We conducted a retrospective multicentre study to determine whether prestorage filter leucodepletion alters the development of clinically significant red blood cell alloimmunization against the Rhesus, Kell, Duffy, Kidd and MSs blood group systems. Two periods were investigated, 2 years before and 2 years after universal leucodepletion. Comparisons were made between the transfused patient cohorts. To control for changes not related to leucoreduction, we compared antibody incidence with antibody prevalence in the two study periods. Newly detected antibodies (n = 4770) were found in 4115 patients from 19 participating hospitals. Of these, 857 antibodies in 659 patients were because of transfusions given in the study periods. The immunization risk was 0·13% for both periods. No differences were found regarding incidence of new antibodies, nor for patients regarding age, sex, previous antibodies, multiple antibodies, additional antibodies, number of transfusions, transfusions episodes and days from transfusion to date of immunization. In conclusion, compared with buffy‐coat leucoreduction, universal prestorage filter leucodepletion did not alter the development of clinically significant red blood cell alloimmunization.

Immunosuppressants and alloimmunization against red blood cell transfusions

Patients receiving red blood cell (RBC) transfusions are at risk of developing alloantibodies against donor RBC antigens. The risk of alloimmunization is dependent on the number of units administered and patients genetic predisposition, but has also been suggested to be modulated by a patients clinical profile. Our aim was to examine whether immunosuppressants suppress the development of clinically relevant RBC antibodies.

HLA-DRB1 associations in individuals with single and multiple clinically relevant red blood cell antibodies

A minority of red blood cell (RBC) alloantigen–exposed persons form antibodies. Responders are at high risk of developing additional antibodies upon subsequent transfusions. Several studies showed an association between particular HLA‐DRB1 phenotypes and the development of specific RBC antibodies. This study evaluates the presence of HLA‐DRB1 antigens in individuals with single or multiple RBC antibody specificities to explore whether the response against RBC antigens is associated with a summation of particular HLA‐DRB1 susceptibility antigens.

Red-blood-cell alloimmunisation in relation to antigens' exposure and their immunogenicity: a cohort study

BACKGROUND Matching donor red blood cells based on recipient antigens prevents alloimmunisation. Knowledge about the immunogenicity of red-blood-cell antigens can help optimise risk-adapted matching strategies. We set out to assess the immunogenicity of red-blood-cell antigens. METHODS In an incident new-user cohort of previously non-transfused, non-alloimmunised white patients receiving non-extended matched red-blood-cell transfusions in six Dutch hospitals between 2006 and 2013, we determined the cumulative number of mismatched red-blood-cell units per patient. We used multiple imputation to address missing antigen data. Using Kaplan-Meier analysis, we estimated cumulative alloimmunisation incidences per mismatched antigen dose as a measure of immunogenicity. FINDINGS Of 54 347 patients assessed, 21 512 were included in our study. Alloantibodies occurred in 474 (2·2%) of all transfused patients, with cumulative alloimmunisation incidences increasing up to 7·7% (95% CI 4·9-11·2) after 40 units received. The antigens C, c, E, K, and Jk(a) were responsible for 78% of all alloimmunisations in our cohort. K, E, and C(w) were the most immunogenic antigens (cumulative immunisation incidences after 2 mismatched units of 2·3% [95% CI 1·0-4·8] for K, 1·5% [0·6-3·0] for E, and 1·2% [0·0-10·8] for C(w)). These antigens were 8·7 times (for K), 5·4 times (for E), and 4·6 times (for C(w)) as immunogenic as Fy(a). The next most immunogenic antigens were, in order, e (1·9 times as immunogenic as Fy(a)), Jk(a) (1·9 times), and c (1·6 times). INTERPRETATION Red-blood-cell antigens vary in their potency to evoke a humoral immune response. Our findings highlight that donor-recipient red-blood-cell matching strategies will be most efficient when primarily focusing on prevention of C, c, E, K, and Jk(a) alloimmunisation. Matching for Fy(a) is of lower clinical relevance. Variations of antigen frequencies determined by ethnic background prevent extrapolating these conclusions to non-white populations. FUNDING None.

Long-Term follow up after intra-Uterine transfusionS; the LOTUS study

BackgroundThe Leiden University Medical Center (LUMC) is the Dutch national referral centre for pregnancies complicated by haemolytic disease of the fetus and newborn (HDFN) caused by maternal alloimmunization. Yearly, 20-25 affected fetuses with severe anaemia are transfused with intra-uterine blood transfusions (IUT). Mothers of whom their fetus has undergone IUT for HDFN are considered high responders with regard to red blood cell (RBC) antibody formation. Most study groups report high perinatal survival, resulting in a shift in attention towards short- and long-term outcome in surviving children.Methods/DesignWe set up a large long-term observational follow-up study (LOTUS study), in cooperation with the Sanquin Blood Supply Foundation and the LUMC departments of Obstetrics, Neonatology and ImmunoHematology & Bloodtransfusion.The first part of this study addresses several putative mechanisms associated with blood group alloimmunization in these mothers. The second part of this study determines the incidence of long-term neurodevelopment impairment (NDI) and associated risk factors in children treated with IUT. All women and their life offspring who have been treated with IUT for HDFN in the LUMC from 1987-2008 are invited to participate and after consent, blood or saliva samples are taken. RBC and HLA antigen profile and antibodies are determined by serologic or molecular techniques. Microchimerism populations are tested by real time polymerase chain reaction (RT PCR).All children are tested for their neurological, cognitive and psychosocial development using standardised tests and questionnaires. The primary outcome is neurodevelopmental impairment (NDI), a composite outcome defined as any of the following: cerebral palsy, cognitive or psychomotor development < 2 standard deviation, bilateral blindness and/or bilateral deafness.DiscussionThe LOTUS study includes the largest cohort of IUT patients ever studied and is the first to investigate post-IUT long-term effects in both mother and child. The results may lead to a change in transfusion policy, in particular future avoidance of certain incompatibilities. Additionally the LOTUS study will provide clinicians and parents better insights in the long-term neurodevelopmental outcome in children with HDFN treated with IUTs, and may improve the quality of antenatal counselling and long-term guidance.