Worldwide vaccination against SARS-CoV-2 has allowed the detection of hematologic autoimmune complications. Adverse events (AEs) of this nature had been previously observed in association with other vaccines. The underlying mechanisms are not totally understood, although mimicry between viral and self-antigens plays a relevant role. It is important to remark that, although the incidence of these AEs is extremely low, their evolution may lead to life-threatening scenarios if treatment is not readily initiated. Hematologic autoimmune AEs have been associated with both mRNA and adenoviral vector-based SARS-CoV-2 vaccines. The main reported entities are secondary immune thrombocytopenia, immune thrombotic thrombocytopenic purpura, autoimmune hemolytic anemia, Evans syndrome, and a newly described disorder, so-called vaccine-induced immune thrombotic thrombocytopenia (VITT). The hallmark of VITT is the presence of anti-platelet factor 4 autoantibodies able to trigger platelet activation. Patients with VITT present with thrombocytopenia and may develop thrombosis in unusual locations such as cerebral beds. The management of hematologic autoimmune AEs does not differ significantly from that of these disorders in a non-vaccine context, thus addressing autoantibody production and bleeding/thromboembolic risk. This means that clinicians must be aware of their distinctive signs in order to diagnose them and initiate treatment as soon as possible.

Primary immune thrombocytopenia (ITP) is a complex autoimmune disease whose hallmark is a deregulation of cellular and humoral immunity leading to increased destruction and reduced production of platelets. The heterogeneity of presentation and clinical course hampers personalized approaches for diagnosis and management. In 2021, the Spanish ITP Group (GEPTI) of the Spanish Society of Hematology and Hemotherapy (SEHH) updated a consensus document that had been launched in 2011. The updated guidelines have been the reference for the diagnosis and management of primary ITP in Spain ever since. Nevertheless, the emergence of new tools and strategies makes it advisable to review them again. For this reason, we have updated the main recommendations appropriately. Our aim is to provide a practical tool to facilitate the integral management of all aspects of primary ITP management.

Primary immune thrombocytopenia (ITP) is an autoimmune disorder that causes low platelet counts and subsequent bleeding risk. Although current corticosteroid-based ITP therapies are able to improve platelet counts, up to 70% of subjects with an ITP diagnosis do not achieve a sustained clinical response in the absence of treatment, thus requiring a second-line therapy option as well as additional care to prevent bleeding. Less than 40% of patients treated with thrombopoietin analogs, 60% of those treated with splenectomy, and 20% or fewer of those treated with rituximab or fostamatinib reach sustained remission in the absence of treatment. Therefore, optimizing therapeutic options for ITP management is mandatory. The pathophysiology of ITP is complex and involves several mechanisms that are apparently unrelated. These include the clearance of autoantibody-coated platelets by splenic macrophages or by the complement system, hepatic desialylated platelet destruction, and the inhibition of platelet production from megakaryocytes. The number of pathways involved may challenge treatment, but, at the same time, offer the possibility of unveiling a variety of new targets as the knowledge of the involved mechanisms progresses. The aim of this work, after revising the limitations of the current treatments, is to perform a thorough review of the mechanisms of action, pharmacokinetics/pharmacodynamics, efficacy, safety, and development stage of the novel ITP therapies under investigation. Hopefully, several of the options included herein may allow us to personalize ITP management according to the needs of each patient in the near future.

Avatrombopag is the newest thrombopoietin receptor agonist (TPO‐RA) approved to treat immune thrombocytopenia (ITP). Real‐world evidence regarding effectiveness/safety is limited. The Spanish ITP Group (GEPTI) performed a retrospective study with patients starting avatrombopag for the first time. A total of 268 ITP patients were recruited. The median (interquartile range [IQR]) follow‐up time was 47.5 (30.4–58.9) weeks. Among the 193 patients with baseline platelet counts <50 × 10⁹/L, 174 (90.1%) of them achieved response (PC ≥50 × 10⁹/L), and 113 (87.6%) of the 129 who persisted on avatrombopag at last visit had platelet levels above such threshold. Results were similar when only those patients switching to avatrombopag due to previous treatment failure were considered (n = 104). Patients reached response in 13 (7–21) days. Among patients with baseline levels ≥50 × 10⁹/L, 73/75 (97.3%) reported response, which was maintained by 53 (94.6%) of the 56 who continued on avatrombopag at the end of the study. Loss‐of‐response was always <10%. ITP duration did not influence response. Approximately 79% (34/43) of heavily pretreated (≥4 lines) patients with baseline platelet counts <50 × 10⁹/L switching after previous failure achieved PC ≥50 × 10⁹/L. Previous use of eltrombopag and/or romiplostim did not influence response, regardless of whether previous TPO‐RA(s) succeeded or failed. Avatrombopag allowed dose‐reduction/suspension of corticosteroids in 40/50 (80.0%) patients with baseline platelet counts <50 × 10⁹/L. Overall, 40/268 (14.9%) thrombocytosis and 12/268 (4.5%) thromboembolic events were reported. Our real‐world cohort supports the use of avatrombopag to manage ITP, regardless of disease severity and treatment history.

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.

Polycythemia vera (PV) and essential thrombocythemia (ET) are chronic myeloproliferative neoplasms (MPNs), often associated with mutations in JAK2 , CALR , and MPL . Differentiating PV from ET can be challenging in borderline cases, particularly when hemoglobin (Hb), hematocrit (Hct) and erythropoietin (EPO) values are inconclusive. Functional iron parameters and JAK2 variant allele frequency (VAF) may provide additional discriminatory value. To assess the diagnostic utility of transferrin saturation index (TSI), serum ferritin, EPO, and JAK2 VAF in distinguishing PV from ET, and to evaluate their association with mutational profiles. We conducted a retrospective, single-center study including 260 adult patients diagnosed with PV or ET between 2009 and 2024. Demographic, clinical, molecular, and laboratory parameters—including ferritin, TSI, EPO, Hb, Hct, and JAK2 VAF—were analyzed. Comparative and correlation analyses were performed using appropriate statistical tests. Compared to ET, patients with PV had significantly lower ferritin (median: 35.65 vs. 95.05 ng/mL), TSI (12.9% vs. 21.64%), and EPO (2.23 vs. 6.11 mIU/mL), but higher Hb (17.7 vs. 14.3 g/dL) and Hct (54.6% vs. 43.0%) (all p < 0.001). TSI discriminated PV from ET better than ferritin (p < 0.001 vs. p = 0.128). Among JAK2-mutated cases, VAF was higher in PV than ET (median: 48% vs. 21%, p = 0.003). VAF correlated inversely with ferritin, TSI, and EPO, and positively with Hct. TSI and JAK2 VAF outperform ferritin as diagnostic markers to differentiate PV from ET. Integrating functional iron parameters with molecular data improves diagnostic accuracy, particularly in clinically ambiguous cases, and supports their inclusion in MPN diagnostic algorithms.