Introduction Patients with myeloproliferative neoplasms (MN) have the complication in both side of hemostasis – related to bleeding and thrombosis. The major goal of therapy is to reduce thrombosis risk, which impacts MN morbidity and mortality. However, in lifelong evaluating quality of life during the disease course, the bleeding has also important role. Acquired von Willebrand disease (AvWD) may result from increased proteolysis together with platelet activation, which leads to reduced von Willebrand factor activity (vWFact). Holding hemostatic balance in prophylactical management to prevent complications is challenging, and understanding predicting factors valuable for physician. Approximately 60% of patients with MN carry a genetic mutation: it's suggested that in MPN thrombocytosis has a higher risk of bleeding than thrombosis, aspirin may exacerbate this risk of bleeding in CALR-mutated essential thrombocythemia (ET) and JAK2 V617F mutation increases risk of thrombotic complications. We analyzed our MN patient cohort to lab analysis related to hemostasis and genetic testing in order to have better understanding in the patient's profile [1] [2] [3].

Background: In the course of lymphoproliferative diseases, an immunodeficiency of humoral or cellular origin has been described. Infectious complications of common or atypical origin alter patients’ lifestyles or result in severe, life-threatening hospitalizations. Hematology patients are prone to opportunistic infections after viral infection. In Estonia, chemotherapy for haematological patients is mainly covered in two regional centers in Tartu (University Hospital) and in Tallinn. The outpatient consultations are also covered in other parts of Estonia. In times of pandemic, when lockdowns are changing the situation and it has been difficult to travel to large centers, local hematology care needs for high-risk hematology elderly patients are growing. Aims: In the case of lymphoproliferative diseases, a secondary immune deficiency with severe infections can develop during the course of therapy, which is objectively discovered by immunoglobulin testing (IgG), and replased by immunoglobulin substitution. According to Kreuth IV, the value for prophylactic IgG replacement therapy is below 4g/l Methods: Review of the 20 case records of the two hospitals in Estonia, in Pärnu and in Kuressaare. Results: There are in regulare treatment or watching in Pärnu center and in Kuressaare center about 80 patients with lymphoproliferative disease. From them needed according to IgG status below 7(ref 7-16) 20 patients. The mean age of patisents is 70.8 (range 38-89). The mean basic IgG (ref 7-16) in patients in Immunoglobulin treatment is 4,49 (range 3.3-6).The intervall for prophylactic replasment was 4.6 or 8 weeks in 20 patients. From those 8 patients had SARS-Cov2 during this period, no patient was dying because of SARS-Cov2 infection and in 4 patients there was SARS-COV2 IgG pos later, in one patients SARS-COV2 IgG was negative afther the severe infection, in 3 patients is SARS-COV2 IgG not known afther frecovery from disease. Two patents died: one of secondary Pulm tumor related infection and one of sigmoidal ca, who had 6 months earlyer COVID19 severe infection. From 20 patients 9 diceided to have vaccination and 6 got no SARS-COVIgG antibodyes afther that. All patients had during 01.06.2019- 01.02. 2022 years in some period immunosupressive treatment. Summary/Conclusion: We recommend the individualized protection of vulnerable hematologyc diseases patients with long-term illness. Secondary immunodeficient patients need during pandemic when hospital beds are overgrown immunoglobulin replasmenttherapy to prevent their unneccesary hospitalization.