Letter to the Editor Relapse of thrombotic thrombocytopenic purpura after COVID-19 vaccineWe report a case of a 48-year-old white female patient with a history of relapsing thrombotic thrombocytopenic purpura (TTP). The patient has been known to our department since 2015 when she was diagnosed for the first time with TTP with a high antibody titer (99 U/mL) against ADAMTS13 (A Disintegrin And MeTalloproteinase with a Thrombo-Spondin type 1 motif, member 13) and very low ADAMTS13 activity (Fluorescent Resonance Energy Transfer [FRET] assay: <3 %, normal range 45-138 %). She was treated with ten plasma-exchange (PEX) procedures and corticosteroids and obtained a complete remission. Her first relapse, in February 2019, presented as ecchymoses and severe thrombocytopenia; she was successfully treated again with seven PEX procedures and steroids. Afterwards, the patient was well and periodic blood cell counts (every 6 months, last check performed in October 2020) were normal. On March 12, 2021 the patient was referred to the emergency room of the city hospital of Mantua for a new onset of ecchymoses on both arms and forearms without any other symptoms or signs. The complete blood count demonstrated mild normocytic anemia (hemoglobin 11.5 g/dL, normal range 12.3-14.5 g/dL), moderate thrombocypenia (platelet count 94 × 10 9 /L, normal range 150− 400 × 10 9 /L), a coagulation profile and renal function within the normal range, and moderately increased lactate dehydrogenase (LDH, 637 UI/L, normal range 150-450 UI/L). On a peripheral blood smear, there were about 10 % schistocytes. ADAMTS13 activity was markedly reduced (FRET assay: <3 %) with a high titer of anti-ADAMTS13 antibodies (88 U/mL). Six days before the TTP relapse (March 6, 2021), the patient had received the second dose of the anti-COVID-19 vaccine produced by Pfizer-BioNTech (the first dose had been administered on February 11, 2021). At hospital admission the molecular search of SARS-COV-2 on nasopharyngeal swab was negative while anti-SARS-COV-2 IgG antibodies were 105 UA/mL (chemiluminescent immunoassay DiaSorin, positive >15 UA/mL). The patient was promptly treated with seven PEX procedures and steroids, with a rapid and excellent response (normalization of platelet count and LDH after the third PEX). This is the first case reported in literature of a TTP relapse following anti-COVID-19 vaccination. Other cases of vaccine-related thrombotic microangiopathies have been described, possibly related to the immune dysregulation and/or complement activation triggered by vaccination, particularly against influenza [1][2][3][4]. Further studies are needed to verify the possible association between microangiopathic thrombotic disorders with an autoimmune pathogenesis and the administration of vaccines against COVID-19. ContributionC.S. and A.A.
ABO blood group antigens are complex carbohydrate molecules expressed on the surface of red blood cells and a variety of human cells and tissues. It is well known that ABO blood type exerts a profound influence on hemostasis, being a major determinant of von Willebrand factor (VWF), and consequently factor VIII, plasma levels. In this review, we will focus on the molecular mechanisms underlying the interaction between ABO blood group and VWF in normal and pathological conditions.
Ruxolitinib (RUX) is extensively used in myelofibrosis (MF). Despite its early efficacy, most patients lose response over time and, after discontinuation, have a worse overall survival (OS). Currently, response criteria able to predict OS in RUX-treated patients are lacking, leading to uncertainty regarding the switch to second-line treatments. In this study, we investigated predictors of survival collected after six months of RUX in 209 MF patients participating in the real-world ambispective observational RUXOREL-MF study (NCT03959371). Multivariable analysis identified the following risk factors: (i) RUX dose <20 mg twice daily at baseline, month 3, and 6 (hazard ratio, HR, 1.79, 95% confidence interval, CI, 1.07-3.00, p=0.03), (ii) palpable spleen length reduction from baseline ≤30% at month 3 and 6 (HR 2.26, 95% CI 1.40-3.65, p=0.0009), (iii) red blood cell (RBC) transfusion need at month 3 and/or 6 (HR 1.66, 95% CI 0.95-2.88, p=0.07), and (iv) RBC transfusion need at all time points, i.e. baseline and months 3 and 6 (HR 2.32, 95% CI 1.19-4.54, p=0.02). Hence, we developed a prognostic model, named Response to Ruxolitinib after 6 months (RR6), dissecting three risk categories: low (median OS not reached), intermediate (median OS 61 months, 95% CI 43-80), and high (median OS 33 months, 95% CI 21-50). The RR6 model was validated and confirmed in an external cohort comprised of 40 MF patients. In conclusion, the RR6 prognostic model allows for the early identification of RUX-treated MF patients with impaired survival who might benefit from a prompt treatment shift.
Hemophilia B is a recessive X-linked bleeding disorder characterized by deficiency of the coagulation factor IX (FIX). In hemophilia B patients the severity of the bleeding phenotype is related to the degree of the FIX defect. Hemophilia B treatment has improved greatly in the last 20 years with the introduction first of plasma-derived and then of recombinant FIX concentrates. Replacement therapy may be administered through on-demand or prophylaxis regimens, but the latter treatment modality has been shown to be superior in prevention of hemophilic arthropathy and in improvement of patients’ quality of life. The purpose of this narrative review is to summarize the current knowledge on treatment strategies for hemophilia B, focusing on recombinant FIX products either clinically used or in development. There is only one rFIX product that is licensed to treat hemophilia B patients; from the analysis of the literature data presented in this review, the authors conclude that this rFIX product has demonstrated an excellent safety profile and excellent clinical efficacy for halting and preventing bleeds in hemophilia B patients. While prophylaxis has emerged as the best therapeutic strategy for such patients because of its ability to prevent hemophilic arthropathy and to improve patients’ quality of life, the pharmacokinetically tailored dosing of rFIX is another key point when planning hemophilia B treatment, as it allows optimization of the factor concentrate usage. Further clinical studies are needed to better assess the safety and efficacy (ie, the incidence of adverse reactions and inhibitor development) of newer rFIX products.
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