Loss of sialic acid from the carbohydrate side chains of platelet glycoproteins can affect platelet clearance, a proposed mechanism involved in the etiopathogenesis of immune thrombocytopaenia (ITP). We aimed to assess whether changes in platelet glycosylation in patients with ITP affected platelet counts, function, and apoptosis. This observational, prospective, and transversal study included 82 patients with chronic primary ITP and 115 healthy controls. We measured platelet activation markers and assayed platelet glycosylation and caspase activity, analysing samples using flow cytometry. Platelets from patients with ITP with a platelet count <30 × 10³/µL presented less sialic acid. Levels of α1,6-fucose (a glycan residue that can directly regulate antibody-dependent cellular cytotoxicity) and α-mannose (which can be recognised by mannose-binding-lectin and activate the complement pathway) were increased in the platelets from these patients. Platelet surface exposure of other glycoside residues due to sialic acid loss inversely correlated with platelet count and the ability to be activated. Moreover, loss of sialic acid induced the ingestion of platelets by human hepatome HepG2 cells. Changes in glycoside composition of glycoproteins on the platelets’ surface impaired their functional capacity and increased their apoptosis. These changes in platelet glycoside residues appeared to be related to ITP severity.

Podoplanin and CD44 are transmembrane glycoproteins involved in inflammation and cancer. In this paper, we report that podoplanin is coordinately expressed with the CD44 standard (CD44s) and variant (CD44v) isoforms in vivo—in hyperplastic skin after a pro-inflammatory stimulus with 12-O-tetradecanoylphorbol-13-acetate (TPA)—and in vitro—in cell lines representative of different stages of mouse-skin chemical carcinogenesis, as well as in human squamous carcinoma cell (SCC) lines. Moreover, we identify CD44v10 in the mouse-skin carcinogenesis model as the only CD44 variant isoform expressed in highly aggressive spindle carcinoma cell lines together with CD44s and podoplanin. We also characterized CD44v3-10, CD44v6-10 and CD44v8-10 as the major variant isoforms co-expressed with CD44s and podoplanin in human SCC cell lines. Immunofluorescence confocal microscopy experiments show that these CD44v isoforms colocalize with podoplanin at plasma membrane protrusions and cell–cell contacts of SCC cells, as previously reported for CD44s. Furthermore, CD44v isoforms colocalize with podoplanin in chemically induced mouse-skin SCCs in vivo. Co-immunoprecipitation experiments indicate that podoplanin physically binds to CD44v3-10, CD44v6-10 and CD44v8-10 isoforms, as well as to CD44s. Podoplanin–CD44 interaction is mediated by the transmembrane and cytosolic regions and is negatively modulated by glycosylation of the extracellular domain. These results point to a functional interplay of podoplanin with both CD44v and CD44s isoforms in SCCs and give insight into the regulation of the podoplanin–CD44 association.

Spain is one of the countries most strongly affected by the coronavirus (COVID-19) pandemic with more than 800,000 cases reported in the country as of October 5 [1]. In Madrid, the first reported c...

Background and Objectives: The aim of this study was to determine the impact of the COVID-19 pandemic on the lives of patients with immune thrombocytopaenia (ITP) treated at our hospital. Materials and Methods: The study was conducted in the Community of Madrid, which has the highest number of COVID-19 cases in Spain. We included 143 adult patients with ITP (130 with chronic ITP, 8 with persistent ITP, and 5 with newly diagnosed ITP). We conducted a telephone survey to collect the data and created a registry. Materials and Methods: Overall, 24 patients presented symptoms suggestive of COVID-19, which was confirmed by RT-PCR in 8 cases. The cumulative incidence of confirmed SARS-CoV-2 infection was higher in the patients with ITP than in the Madrid population. There were no differences in the disease incidence or clinical course of infection in the patients treated with immunosuppressants. Almost all of the patients reported adherence to the prescribed treatment, although 49.2% of the hospital visits were either cancelled or postponed, 17.2% because of the patients’ fear of coming to the centre. Nearly half of the cohort was considered vulnerable, and 17% had been granted a dependency or disability benefit. Conclusions: COVID-19 had a major impact on the psychosocial, occupational, and quality of care of patients with ITP.

Background: Thrombocytopenia is traditionally perceived as a bleeding-predominant condition; however, growing evidence indicates that many thrombocytopenic states are paradoxically associated with an increased risk of venous and arterial thrombosis. This dual hemostatic derangement poses major therapeutic challenges when anticoagulant or antiplatelet therapy is indicated, particularly in complex settings such as cancer-associated thrombosis, immune thrombocytopenia, and advanced liver disease. Methods: We conducted a narrative review of the literature published between January 2021 and May 2025 using PubMed and guideline repositories. Search terms included thrombocytopenia, anticoagulation, antiplatelet therapy, cancer-associated thrombosis, immune thrombocytopenia, and cirrhosis. International guidelines from ASH, ISTH, ASCO, EHA, ESC, and AHA were prioritized. Evidence was synthesized to define platelet-based safety thresholds and disease-specific management strategies. Results/Discussion: Thrombocytopenia does not uniformly confer protection against thrombosis. Platelet activation, endothelial dysfunction, inflammatory signaling, impaired fibrinolysis, and procoagulant microparticles contribute to a prothrombotic milieu despite reduced platelet counts. Most guidelines support full-dose anticoagulation at platelet counts ≥ 50 × 10⁹/L, with dose modification between 25 and 50 × 10⁹/L and treatment interruption below 25 × 10⁹/L, depending on thrombotic risk. Antiplatelet therapy requires stricter individualization, particularly regarding dual antiplatelet therapy. Conclusions: Management of antithrombotic therapy in thrombocytopenic patients requires a dynamic, individualized approach balancing ischemic and bleeding risks. Pragmatic algorithms may guide clinical decision-making while prospective data remain limited.