Should HLA and HPA-matched platelet transfusions for patients with Glanzmann Thrombasthenia or Bernard-Soulier syndrome be standardized care? A Dutch survey and recommendations.

BACKGROUND: Glanzmann thrombasthenia (GT) and Bernard-Soulier syndrome (BSS) patients require frequent platelet transfusions and hence have an increased risk for alloimmunization against donor Human Leukocyte Antigens (HLA) when no HLA-matching is performed. Knowing that Human Platelet Antigens (HPA) are located on the platelet glycoproteins that can be absent in these patients, preventive HPA-matching may also be considered. Uniform recommendations on this topic lack in transfusion guidelines making standard practice unclear, therefore, we aimed to provide a framework for matched platelet transfusions. STUDY DESIGN AND METHODS: We conducted a targeted literature search and a national survey of Dutch (pediatric) hematologists from July to September 2021. RESULTS: We found 20 articles describing platelet transfusion policies in 483 GT-patients and 29 BSS-patients, both adults and children. Twenty surveys were returned for full analysis. All responders treated patients with platelet disorders, including GT (n = 36 reported) and BSS (n = 29 reported). Of respondents, 75% estimated the risk of antibody formation as "likely" for HLA and 65% for HPA. Formation of HLA antibodies was reported in 5 GT and in 5 BSS-patients, including one child. Fifteen respondents gave preventive HLA-matched platelets in elective setting (75%). Three respondents additionally matched for HPA in GT-patients (15%). Main argument for matched platelet transfusions was preventing alloimmunization to safeguard the effectivity of 'random' donor-platelets in acute settings. CONCLUSION: Elective HLA-matching for GT and BSS-patients is already conducted by most Dutch (pediatric) hematologists. HPA-matching is mainly applied when HPA-antibodies are formed. Based on the current literature and the survey, recommendations are proposed.

Correction of murine Bernard-Soulier syndrome by lentivirus-mediated gene therapy.

Bernard-Soulier syndrome (BSS) is an inherited bleeding disorder caused by a defect in the platelet glycoprotein (GP) Ib-IX-V complex. The main treatment for BSS is platelet transfusion but it is often limited to severe bleeding episodes or surgical interventions due to the risk of alloimmunization. We have previously reported successful expression of human GPIbα (hGPIbα) in human megakaryocytes using a lentiviral vector (LV) encoding human GP1BA under control of the platelet-specific integrin αIIb promoter (2bIbα). In this study, we examined the efficacy of this strategy for the gene therapy of BSS using GPIbα(null) as a murine model of BSS. GPIbα(null) hematopoietic stem cells (HSC) transduced with 2bIbα LV were transplanted into lethally irradiated GPIbα(null) littermates. Therapeutic levels of hGPIbα expression were achieved that corrected the tail bleeding time and improved the macrothrombocytopenia. Sequential bone marrow (BM) transplants showed sustained expression of hGPIbα with similar phenotypic correction. Antibody response to hGPIbα was documented in 1 of 17 total recipient mice but was tolerated without any further treatment. These results demonstrate that lentivirus-mediated gene transfer can provide sustained phenotypic correction of murine BSS, indicating that this approach may be a promising strategy for gene therapy of BSS patients.

Fetomaternal platelet immunization associated with maternal Bernard-Soulier syndrome.

Our objective was to describe the clinical outcome and the association of fetomaternal platelet immunization in pregnancies with maternal Bernard-Soulier syndrome. We conducted an observational study of two mothers, six pregnancies, and six neonates, with special emphasis on platelet antibodies and thrombocytopenia-associated complications. The first woman presented with platelet-associated autoantibodies and thrombocytopenia, but her three newborn infants showed normal platelet count and function. The other woman had three pregnancies, all of which were complicated by severe fetal and neonatal alloimmune-type thrombocytopenia, without demonstrable antibodies. We concluded that fetomaternal immunization with severe fetal and neonatal thrombocytopenia may be encountered even in the absence of demonstrable antibodies.

[Bernard-Soulier syndrome during pregnancy: a case report]. / Przebieg ciazy, porodu i pologu u pacjentki z rozpoznaniem zespolu Bernarda-Soulier.

The Bernard-Soulier syndrome (B-S s.) is rare autosomal recessive bleeding disorder. It is characterized by prolonged bleeding time, fail to agglutinate with ristocetin and a normal to decreased number of unusually large platelets whose membrane lack glycoproteins complex GP Ib/IX/V. The manifestation of the disease may differ in consecutive pregnancies of the same patient. Presently we describe 24 years old white women diagnosed with B-S s. at the age of 22. Two years later she become pregnant. During the pregnancy platelet counts ranged from 26 x 10(9)/1 to 51 x 10(9)/1, without sings of bleeding. Because of the risk of immunization against GP Ib/IX, with might lead to severe isoimmune neonatal thrombocytopenia, 4 times during pregnancy she had done MAIPA-test (monoclonal antibody immobilization of platelet antigens). Specific antibodies were not detected. Subsequent ultrasounds with biophysical profile revealed normal fetus growth. Spontaneous labour in 38th week of gestation. The use of single-donor platelets, intravenous desmopressin and tranexamic acid was found to be useful in controlling postpartum vaginal bleeding in the patient.

Acquired Bernard-Soulier syndrome: a case with necrotizing vasculitis and thrombosis.

We describe a patient with positive antinuclear antibodies, polyclonal gammopathy and high level of circulating immunocomplexes, resulting in vascular purpura. In addition, the patient had a slightly prolonged bleeding time and an isolated defect of ristocetin-induced platelet aggregation (RIPA) in platelet-rich plasma (PRP). The patient's plasma also inhibited RIPA in normal PRP and in normal platelet suspension. The activity and multimeric structure of plasmatic von Willebrand factor showed no alteration. We could demonstrate an autoantibody against platelet membrane glycoprotein (GP) Ib, using an ELISA-type assay. These data suggest an acquired Bernard-Soulier syndrome. We suggest that the patient had an immunocomplex-mediated leukocytoclastic vasculitis accompanied by production of antinuclear autoantibodies as well as the presence of an autoantibody against GPIb. The titer of the anti-GPIb antibody, however, was too low to induce significant platelet-type bleeding tendency, only laboratory alterations were found. Moreover, in a later stage of her disease, she developed a severe necrotizing vasculitis which was followed by a deep venous thrombosis.

Varicella-associated thrombocytopenia: autoantibodies against platelet surface glycoprotein V.

Varicella zoster infection in children can be complicated by acute idiopathic thrombocytopenic purpura (ITP). To determine the etiologic mechanism of this thrombocytopenia, we studied three children with clinically diagnosed varicella infection. Immunoblot analysis of these patients' anti-platelet antibodies identified a unique band at 85 kD. Characterization of this protein revealed that it was platelet surface glycoprotein V (GPV) because it was not affected by a disulfide bond reduction but was cleaved by thrombin. Bernard-Soulier syndrome (BSS) platelets deficient in GPIb-IX and GPV did not react with the sera from our varicella-infected study patients. There was no apparent cross-reactivity between anti-varicella antibody and patients' anti-GPV Ig. We report here the first cases of GPV as the target antigen in autoimmune thrombocytopenia.

An acquired-pseudo Bernard Soulier syndrome occurring with autoimmune chronic active hepatitis and anti-cardiolipin antibody.

A case of autoimmune chronic active hepatitis with unusual extrahepatic manifestations is described. The patient exhibited marked thrombocytopenia and platelet aggregation dysfunction and morphological changes suggesting an acquired Bernard Soulier-type syndrome. This has not previously been described in association with chronic active hepatitis. The patient also demonstrated significant titres of anti-cardiolipin antibodies. This is also a new finding in association with both the liver and platelet diseases. The platelet aggregation deficit was transferable in the patient's serum rather than being intrinsic to the platelets. The three previously reported cases of acquired Bernard Soulier are reviewed and possible mechanisms for the platelet dysfunction are discussed.

Obstetric complications in a patient with Bernard-Soulier syndrome.

We describe the obstetric complications and management of a patient with Bernard-Soulier syndrome. Severe bleeding at the time of delivery and delayed postpartum hemorrhage were prominent features of her pregnancies. Further complicating this woman's pregnancies was the development of antibodies to platelet glycoprotein IB/IX, leading to neonatal alloimmune thrombocytopenia.

Flow cytometric analysis of platelet surface antigens.

A flow cytometric analysis of human platelet surface antigens was carried out using a panel of monoclonal antibody reagents. The reagents used were specific either for the GPIb or the GP IIb/IIIa complex, surface immunoglobulin, or von Willebrand factor (vWf). Indirect surface immunophenotypes were determined using an EPICS V flow cytometer and the monoclonal antibodies 6D1, 10E5, Plt-1, UR1663, anti-IgG, and anti-vWf. Platelets were obtained from normal individuals or patients with either Bernard-Soulier syndrome (BSS) or Glanzmann's thrombasthenia (GT). Normal platelets were positive for 10E5, 6D1, Plt-1, and UR1663 and showed negligible activity for anti-IgG and anti-vWf. Platelets from individuals with BSS showed a marked reduction in 6D1, while the platelets of a patient with GT showed a marked reduction in binding of 10E5, Plt-1, and UR1663. Differences between histograms for normal platelets and for platelets from individuals with BSS or GT were evaluated using the Kolmogorov-Smirnov test. Compared to normal platelets, the BSS and GT platelets contain at least 35-fold less of the GPIb and GP IIb/IIIa complex respectively. Flow cytometry is a useful and precise method for the study of normal and abnormal surface platelet phenotypes.

Pseudo-Bernard-Soulier syndrome: thrombocytopenia caused by autoantibody to platelet glycoprotein Ib.

The Bernard-Soulier syndrome is an inherited bleeding disorder that is due to a deficiency in platelet glycoprotein Ib. Bernard-Soulier platelets fail to agglutinate in response to ristocetin despite normal levels of factor VIII:von Willebrand factor. We report a patient who developed severe refractory thrombocytopenia postsurgically while receiving procainamide therapy. Thrombocytopenia was immune mediated since the patient's platelets bore high levels of antiplatelet antibody. Radioimmunoprecipitation studies demonstrated that the autoantibodies had specificity for platelet glycoproteins Ib and V as well as platelet HLA. The patient's plasma as well as purified immunoglobulin G completely inhibited the ristocetin-induced aggregation of normal platelets but did not inhibit adenosine diphosphate-induced aggregation. The laboratory studies revealed that this patient suffered from antibody-mediated thrombocytopenia with unusual characteristics that we have called pseudo-Bernard-Soulier syndrome.

Acquired Bernard-Soulier syndrome. Evidence for the role of a 210,000-molecular weight protein in the interaction of platelets with von Willebrand factor.

A patient with a lymphoproliferative disorder developed bleeding associated with a prolonged bleeding time and a selective defect of platelet aggregation in response to ristocetin. The patient's purified IgG was shown to inhibit aggregation of washed normal platelets by ristocetin and von Willebrand factor (F VIII:vWF). By Western blotting, it was shown that antibody bound specifically to an antigen of Mr 210,000 present on normal platelets but missing on platelets from patients with congenital Bernard-Soulier syndrome (BSS). Binding was effected by the F(ab)2 portion of the IgG, indicating the presence of an autoantibody rather than an immune complex. These results suggest that the 210,000-Mr protein is involved in the interaction of F VIII:vWF with platelets. Furthermore, we have demonstrated the apparent absence of an additional protein on congenital BSS platelets. Heat-aggregated IgG was also shown to bind to the 210,000-Mr protein, suggesting that this protein may function as an Fc receptor on platelets. The relationship of the 210,000-Mr protein to glycoprotein Ib and the precise role of this protein in the interaction of platelets with F VIII:vWF need to be characterized.