Polycytemia Vera

The goal of this observational study is to learn how the immune system responds to myeloproliferative neoplasms (MPN) in adults with known or suspected MPN. Researchers also want to identify immune cells that could help develop future immune-based treatments for MPN. The main questions it aims to answer are: * Are there T cells in the bone marrow that can recognize MPN cells? * Which targets (antigens) on MPN cells are recognized by these immune cells? * Can researchers identify T cell receptors (TCRs) that may be used in future TCR-based therapies? Researchers will study samples from adults with polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF), post-PMF, or unclassifiable MPN. Samples from healthy donors without blood disorders will also be included for comparison. By providing blood and bone marrow samples, participants will: * Allow researchers to study immune cells and genetic material from these samples * Allow researchers to perform laboratory tests to study how immune cells recognize MPN cells Researchers will use laboratory methods such as genetic sequencing, cell analysis, and cell culture experiments to better understand immune responses in MPN. Participants will not receive direct medical benefit from this study. The results may help researchers better understand MPN and support the future development of immune-based therapies.

This retrospective study aims to evaluate the effectiveness and safety of Ropeginterferon Alfa-2b (BESREMI) in patients with Polycythemia Vera (PV). Eligible patients have a confirmed PV diagnosis according to current criteria, have received at least one dose of Ropeginterferon, and have complete clinical and laboratory data available. The primary objective is to analyze the time course of hematologic response (complete or partial, CHR/PR) according to ELN criteria, and to identify clinical and treatment-related factors associated with achieving and maintaining response. Secondary objectives include time to response, duration of response, progression-free survival, thromboembolic event rate, safety and tolerability, treatment discontinuation, dose modifications and adherence, normalization of hematologic parameters, and changes in JAK2 V617F allele burden. Data will be collected retrospectively from medical records at participating centers.