Leendert Porcelijn

The incidence, risk factors and outcome of transfusion-related acute lung injury in a cohort of cardiac surgery patients: a prospective nested case control study

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Both antibodies and bioactive lipids that have accumulated during storage of blood have been implicated in TRALI pathogenesis. In a single-center, nested, case-control study, patients were prospectively observed for onset of TRALI according to the consensus definition. Of 668 patients, 16 patients (2.4%) developed TRALI. Patient-related risk factors for onset of TRALI were age and time on the cardiopulmonary bypass. Transfusion-related risk factors were total amount of blood products (odds ratio [OR] = 1.2; 95% confidence interval [CI], 1.03-1.44), number of red blood cells stored more than 14 days (OR = 1.6; 95% CI, 1.04-2.37), total amount of plasma (OR = 1.2; 95% CI, 1.03-1.44), presence of antibodies in donor plasma (OR = 8.8; 95% CI, 1.8-44), and total amount of transfused bioactive lipids (OR = 1.0; 95% CI, 1.00-1.07). When adjusted for patient risk factors, only the presence of antibodies in the associated blood products remained a risk factor for TRALI (OR = 14.2; 95% CI, 1.5-132). In-hospital mortality of TRALI was 13% compared with 0% and 3% in transfused and nontransfused patients, respectively (P < .05). In conclusion, the incidence of TRALI is high in cardiac surgery patients and associated with adverse outcome. Our results suggest that cardiac surgery patients may benefit from exclusion of blood products containing HLA/HNA antibodies.

The divergent clinical presentations of transfusion-related acute lung injury illustrated by two case reports.

Background:Transfusion of erythrocytes is associated with increased morbidity in certain patient groups. Storage time of erythrocytes may contribute to respiratory complications. Using a syngeneic in vivo transfusion model, we investigated whether transfusion of stored rat erythrocytes causes lung injury in healthy and in lipopolysaccharide-primed rats in a “two-hit” model of lung injury. Methods:Rats were infused with aged rat erythrocytes (14 days of storage) and washed aged erythrocytes or supernatant of aged erythrocytes. Controls received fresh rat erythrocytes (0 days of storage) or saline. In the “two-hit” model of lung injury, lipopolysaccharide was used as a “first hit” before transfusion. Rat and control human erythrocyte products were analyzed for lysophosphatidylcholine accumulation. Results:In healthy rats, transfusion of aged erythrocytes caused mild pulmonary inflammation but no coagulopathy. In lipopolysaccharide-pretreated rats, transfusion of aged erythrocytes augmented lung injury by inducing coagulopathy, both in the pulmonary and systemic compartment, when compared with transfusion with fresh erythrocytes. When transfused separately, supernatant of aged erythrocytes, but not washed aged erythrocytes, mediated coagulopathy in the “two-hit” model. Analysis of the supernatant of aged erythrocytes (rat and human) showed no lysophosphatidylcholine accumulation. Conclusions:Transfusion of aged erythrocytes induces lung injury in healthy rats. In a “two-hit” model, injury induced by aged erythrocytes was characterized by coagulopathy and was abrogated by washing. Washing of aged erythrocytes may decrease pulmonary complications in patients with an inflammatory condition who are exposed to a blood transfusion.

Regulated glycosylation patterns of IgG during alloimmune responses against human platelet antigens

Various biological activities of immunoglobulin G (IgG) including antibody-dependent cellular cytotoxicity (ADCC) are modulated by the structural features of the N-glycans in the Fc part. In this study, we describe a population of IgG1 alloantibodies which are formed during pregnancy against human platelet antigens (HPA) of the fetus, causing fetoneonatal alloimmune thrombocytopenia. By analyzing the Fc-glycosylation of the pathogenic, affinity-purified IgG1 alloantibodies at the glycopeptide level using mass spectrometry, we found markedly decreased levels of core-fucosylation as well as increased levels of galactosylation and sialylation as compared to glycosylation patterns of total serum IgG1 of the same patients. Because IgG1 Fc-core-fucosylation is known to influence ADCC activity, modulation of core-fucosylation may have a profound effect on disease severity and prognosis. Studies in large patient cohorts will have to be performed to establish such correlations. Moreover, experiments in animal models as well as in vitro immunological tests will be needed to unravel the mechanisms regulating IgG Fc glycosylation.

A prominent lack of IgG1 Fc-fucosylation of platelet-alloantibodies in pregnancy

Immunoglobulin G (IgG) formed during pregnancy against human platelet antigens (HPAs) of the fetus mediates fetal or neonatal alloimmune thrombocytopenia (FNAIT). Because antibody titer or isotype does not strictly correlate with disease severity, we investigated by mass spectrometry variations in the glycosylation at Asn297 in the IgG Fc because the composition of this glycan can be highly variable, affecting binding to phagocyte IgG-Fc receptors (FcγR). We found markedly decreased levels of core fucosylation of anti-HPA-1a-specific IgG1 from FNAIT patients (n = 48), but not in total serum IgG1. Antibodies with a low amount of fucose displayed higher binding affinity to FcγRIIIa and FcγRIIIb, but not to FcγRIIa, compared with antibodies with a high amount of Fc fucose. Consequently, these antibodies with a low amount of Fc fucose showed enhanced phagocytosis of platelets using FcγRIIIb(+) polymorphonuclear cells or FcγRIIIa(+) monocytes as effector cells, but not with FcγRIIIa(-) monocytes. In addition, the degree of anti-HPA-1a fucosylation correlated positively with the neonatal platelet counts in FNAIT, and negatively to the clinical disease severity. In contrast to the FNAIT patients, no changes in core fucosylation were observed for anti-HLA antibodies in refractory thrombocytopenia (post platelet transfusion), indicating that the level of fucosylation may be antigen dependent and/or related to the immune milieu defined by pregnancy.

Screening in pregnancy for fetal or neonatal alloimmune thrombocytopenia: systematic review

Please cite this paper as: Kamphuis M, Paridaans N, Porcelijn L, De Haas M, van der Schoot C, Brand A, Bonsel G, Oepkes D. Screening in pregnancy for fetal or neonatal alloimmune thrombocytopenia: systematic review. BJOG 2010;117:1335–1343.

A novel flow cytometry-based platelet aggregation assay

The main function of platelets is to maintain normal hemostasis. Inefficient platelet production and/or defective platelet function results in bleeding disorders resulting from a wide range of genetic traits and acquired pathologies. Several platelet function tests have been developed for use in the clinic and in experimental animal models. In particular, platelet aggregation is routinely measured in an aggregometer, which requires normal platelet counts and significant blood sample volumes. For this reason, the analysis of thrombocytopenic patients, infants, and animal models is problematic. We have developed a novel flow cytometry test of platelet aggregation, in which 10- to 25-fold lower platelet counts or sample volumes can be used, either of platelet-rich plasma or whole blood from human subjects or mice. This setup can be applied to test in small assay volumes the influence of a variety of stimuli, drugs, and plasma factors, such as antibodies, on platelet aggregation. The presented principle stands as a novel promising tool, which allows analysis of platelet aggregation in thrombocytopenic patients or infants, and facilitates studies in platelets obtained from experimental animal models without the need of special devices but a flow cytometer.

Transfusion-related acute lung injury reports in the Netherlands: an observational study

BACKGROUND: Transfusion‐related acute lung injury (TRALI) is a serious, sometimes fatal complication of transfusion, attributed to white blood cell (WBC)‐reactive antibodies present in the blood product. This study investigated incidence and etiology in the Netherlands.

Anti-HPA-9bw (Maxa) fetomaternal alloimmunization, a clinically severe neonatal thrombocytopenia: difficulties in diagnosis and therapy and report on eight families

BACKGROUND: Fetal or neonatal alloimmune thrombocytopenia (FMAIT) results from a maternal alloimmunization against fetal platelet (PLT) antigens. In Caucasian persons, HPA‐1a is the most frequently implicated antigen. During the past few years, FMAIT has been reported associated with rare or private antigens.

Prevalence of leucocyte antibodies in the Dutch donor population

Introduction  Donor leucocyte antibodies have been associated with transfusion‐related acute lung injury (TRALI) and can be present in allo‐exposed donors. Donor deferral policies aiming at excluding allo‐exposed donors are increasingly implemented worldwide. We aimed at assessing the prevalence of leucocyte antibodies in different subgroups of allo‐exposed donors in the Dutch donor population.

Neutrophil antigen 5b is carried by a protein, migrating from 70 to 95 kDa, and may be involved in neonatal alloimmune neutropenia

BACKGROUND: Neutrophil antigen 5b has been described as involved in transfusion reactions and not in neonatal alloimmune neutropenia.