Flow cytometric analysis of autonomous growth of erythroid precursors in liquid culture detects occult polycythemia vera in the Budd-Chiari syndrome

Background/Aims: Hepatic vein thrombosis (Budd-Chiari syndrome) is associat ed with various hypercoagulable states, such as polycythemia vera (PV), pre sence of the lupus anticoagulant, paroxysmal nocturnal hemoglobinuria (PNH) and deficiencies of antithrombin III, protein C and protein S, In recent y ears, It has become evident that patients with the Budd-Chiari syndrome may have more than one risk factor that mag cause a state of hypercoagulabilit y, The aim of the current study was to assess the prevalence of occult PV i n patients with Budd-Chiari syndrome using a novel method for the detection of spontaneous erythroid growth. Methods: Twenty-two patients with Budd-Chiari syndrome were evaluated. As c ontrols, we studied normal donors and four patients with liver cirrhosis an d five patients with right-side heart failure, two conditions that in part mimic Budd-Chiari syndrome. The presence of PV was determined by flow cytom etric analysis of autonomous growth of erythroid precursors. Patients were considered as having occult PV if they had spontaneous erythroid cell growt h in the absence of erythropoietin and with no features of overt PV. Results: Cells from ten patients with Budd-Chiari syndrome demonstrated spo ntaneous erythroid cell growth; eight patients (32%) were found to have occ ult PV and two patients had overt PV. None of the controls had spontaneous erythroid growth. Of the eight Budd-Chiari patients with occult PV, six had one or more additional recognized hypercoagulable states, Seven patients ( 32%) had protein C deficiency, six patients (27%) had activated protein C r esistance, five (23%) had anti-cardiolipin antibodies, five (23%) had antit hrombin III deficiency, and four patients (18%) had protein S deficiency. T hree patients (14%) were homozygous to methyltetra hydrofolate reductase an d ten (45.5%) were heterozygous. One patient had PNH. Overall, in 12 patien ts there were two or more combined risk factors. Conclusions: Using a flow cytometric analysis of autonomous growth of eryth roid precursors we found a clear correlation between Budd-Chiari syndrome a nd occult PV.