Ilya Kirgner

Messenger RNA-based vaccines against COVID-19 induce a robust anti-SARS-CoV-2 antibody response with potent viral neutralization activity. Antibody effector functions are determined by their constant region subclasses and by their glycosylation patterns, but their role in vaccine efficacy is unclear. Moreover, whether vaccination induces antibodies similar to those in patients with COVID-19 remains unknown. We analyze BNT162b2 vaccine-induced IgG subclass distribution and Fc glycosylation patterns and their potential to drive effector function via Fcγ receptors and complement pathways. We identify unique and dynamic pro-inflammatory Fc compositions that are distinct from those in patients with COVID-19 and convalescents. Vaccine-induced anti-Spike IgG is characterized by distinct Fab- and Fc-mediated functions between different age groups and in comparison to antibodies generated during natural viral infection. These data highlight the heterogeneity of Fc responses to SARS-CoV-2 infection and vaccination and suggest that they support long-lasting protection differently.

Treatment with intensive chemotherapy regimens is frequently complicated by severe thrombocytopenia. During the period of severe thrombocytopenia, anticoagulant treatment is not uncommonly indicated for thromboembolic events or thromboprophylaxis in these patients. We report 10 hematological patients treated with intensive chemotherapy protocols that were anticoagulated with enoxaparin for catheter related central venous thrombosis and thromboprophylaxis. During the period of severe thrombocytopenia the dosages of enoxaparin were reduced and no major bleeding occurred. Based on our experience we suggest that reduced dosages of low molecular weight heparins may be used relatively safely during transient severe thrombocytopenia.

ABSTRACT: Rilzabrutinib is a covalent, reversible Bruton tyrosine kinase inhibitor targeting multiple immune thrombocytopenia (ITP)-related mechanisms. The phase 3 LUNA3 study in previously treated adults with persistent/chronic ITP evaluated oral rilzabrutinib 400 mg twice daily (n = 133) vs placebo (n = 69) for 24 weeks. At baseline overall, median age was 47 years, 63% female, 7.7 year median ITP duration, and 28% prior splenectomy. Overall (N = 202), 85 (64%) rilzabrutinib and 22 (32%) placebo patients achieved platelet response (≥50 × 109/L or 30 × 109/L to <50 × 109/L and doubled from baseline) during the first 12 weeks and were eligible to continue. The primary end point, durable platelet response (platelet count ≥50 × 109/L for ≥two-thirds of ≥8 of the last 12 of 24 weeks without rescue therapy), was observed in 31 (23%) rilzabrutinib vs 0 placebo patients (P < .0001). All secondary efficacy end points were significantly superior for rilzabrutinib (P < .05). Median time to first platelet response was 15 days in rilzabrutinib responders. Rilzabrutinib significantly reduced rescue therapy use by 52% (P = .0007) and improved week 25 bleeding scores (P = .0006). Improved physical fatigue was sustained from week 13 (P = .01) through 25 (P = .0003). Treatment-related adverse events were mainly grade 1/2. One rilzabrutinib patient with multiple risk factors had serious treatment-related grade 3 peripheral embolism (lower left leg), and another died from unrelated pneumonia. Rilzabrutinib in patients who failed multiple previous ITP therapies showed rapid and durable platelet response, reduced rescue medication and bleeding, improved physical fatigue, and favorable safety. Trial registration: www.clinicaltrials.gov (#NCT04562766) and www.clinicaltrialsregister.eu (#2020-002063-60).

OBJECTIVE: Approximately 10% of Philadelphia (Ph)-negative myeloproliferative neoplasms (NPM) are diagnosed at young adulthood. We aim to define the features of this group. METHODS: A multicenter retrospective study, including patients 18-45 years of age, diagnosed with Ph-negative MPN between 1985 and 2017. RESULTS: One hundred nine patients were included, 37 with polycythemia vera (34%), 54 with essential thrombocytosis (50%), 15 with primary myelofibrosis (PMF) (14%), and 3 with MPN unclassifiable (3%). Median age was 33 years and 62 (57%) were females. During a median follow-up of 8 years, 39 patients (37%) had at least one thrombotic event. 30/39 of events were venous (77%), 23/30 of which were splanchnic (77%). In 14/39 (36%), thrombosis preceded MPN diagnosis. In a multivariable analysis, only splenomegaly predicted for thrombosis (HR 5.6, CI: 1.4-22). The 10-year risk for secondary myelofibrosis was similar for ET and PV (0.13 vs 0.19, P = 0.51). The 10-year risk for leukemic transformation or mortality was significantly higher for PMF (0.3, P = 0.04). CONCLUSIONS: The risks of mortality and of progression to MF/leukemia in young adults are similar to older population. Thrombotic events are frequently a presenting sign with a high incidence of venous, in particular splanchnic, events.