Successful use of phlebotomy to treat severe secondary polycythemia due to chronic lung disease

Updated threshold, renewed problems: should the diagnostic criteria of polycythemia vera be reconsidered? A retrospective cross-sectional cohort study

OBJECTIVE

This aim of this study was to evaluate hemoglobin and hematocrit values of polycythemia vera and secondary polycythemia patients with updated World Health Organization thresholds. In addition, by determining our own threshold values, we aimed to demonstrate the necessity of bone marrow biopsy and genetic analysis to be used for further diagnosis in patients with high-normal hematocrit and hemoglobin values.

METHODS

A cross-sectional and retrospective study was performed with the medical records of patients from Eskisehir City Hospital hematology clinics and outpatient clinics between July 1, 2019 and July 1, 2020. The study included patients with polycythemia, divided into two groups according to polycythemia vera and secondary polycythemia. A bone marrow biopsy was performed on patients with either Janus kinase mutation positivity and/or subnormal erythropoietin levels. Receiver operating characteristics analysis was used to find threshold values, and the diagnostic efficiency of these values in differentiating World Health Organization thresholds in 2008 and 2016 was evaluated.

RESULTS

A total of 73 patients were included. The median age was 43.5 years (min: 18; max: 84). The hematocrit value of 54.1 was predicted to diagnose polycythemia vera with a sensitivity of 45% and a specificity of 80%. Subsequent analysis revealed that an hemoglobin value of 17.7 was indicative of diagnosing polycythemia vera with a sensitivity of 60% and a specificity of 63%. The mean follow-up length was 6.4 months (2-12).

CONCLUSION

Our study demonstrated that modified World Health Organization criteria might lead to unnecessary additional tests for polycythemia vera patients with high-normal hemoglobin and hematocrit values.

Phlebotomy-induced iron deficiency attenuates the pulmonary toxicity of paraquat in mice

Phlebotomy is an effective method in the prevention and treatment of some poisonings, among which iron deficiency is a well-known consequence. Given the role of iron in paraquat (PQ) toxicity, the present study investigated the effectiveness of phlebotomy in PQ pulmonary toxicity. After conducting preliminary studies, the duration time of phlebotomy was set to be seven days. Then, the mice were divided into nine separate groups. Groups 1-3 received a single dose of normal saline, and 5 and 10 mg/kg of PQ, respectively, and phlebotomy was not performed on them (NPG status). The animals in groups 4-6 first underwent phlebotomy for seven days and then received a single dose of normal saline, and 5 and 10 mg/kg of PQ (PBPT status). Groups 7-9 first received a single dose of normal saline, and 5 and 10 mg/kg of PQ and then underwent phlebotomy for seven days (PAPT status). Seven days after acute exposure to PQ, the animals were anesthetized and biochemical biomarkers as well as lung tissue changes were evaluated. The findings showed that phlebotomy before and after PQ toxicity significantly decreased serum iron compared to NPG condition. In the PBPT status, phlebotomy could prevent PQ toxicity by increasing the activity of catalase and superoxide dismutase (SOD) and decreasing the activity of myeloperoxidase (MPO), and the levels of hydroxyproline and lipid peroxidation in the lung tissue. In the PAPT status, a significant improvement was observed in SOD and MPO activities compared to the NPG status. Confirming the biochemical findings, the histological results indicated higher effectiveness of phlebotomy in preventing PQ toxicity (PBPT) compared to its therapeutic effects (PAPT). Considering the role of iron in PQ toxicity, it appears that the reduction of serum iron levels during phlebotomy can be effective in preventing lung injuries caused by PQ and improving the performance of the pulmonary antioxidant system.