Clinical characterization of polycythemia vera associated with IgA nephropathy in a single Chinese center: A case series

Polycythemia vera (PV) is a myeloproliferative neoplasm which is characterized by excessive production of erythrocytes as well as myeloid and megakaryocytic proliferation. PV associated with IgA nephropathy (IgAN) has rarely been reported in the literature. The long-term renal prognosis of these patients is unknown. METHODS: Clinical and pathological characteristics of 7 patients with renal biopsy-proven IgAN associated with PV were retrospectively analyzed. RESULTS: The 7 patients were all males, with a mean age of 49.1 ± 18.8 years when admitted to our hospital. Systemic symptoms include: hypertension in case 2, 3, 5, and 6, splenomegaly in case 2, 4, and 5, and multiple lacunar infarction in case 6. Bone marrow biopsy test revealed relative erythroid hyperplasia and atypical megakaryocyte proliferation which consistent with a chronic myeloproliferative neoplasm. All patients had JAK2V617F and BCR-ABL tested, and JAK2V617F positive in 2 patients. Mild mesangial proliferation was observed in 5 patients and moderate/severe mesangial proliferation in 2patients. Immunofluorescence mainly showed diffuse granular deposition of dominant IgA in mesangium. After follow-up of 56.7 ± 44.0 months, hemoglobin level was 144 ± 29 g/L and hematocrit lever was 0.470 ± 0.03, compared with 187 ± 29 g/L and 0.563 ± 0.087 respectively when admitted to our hospital. The urine protein was 0.85 ± 0.64 g/24 h compared with 3.97 ± 4.68 g/24 h. Case 3 progressed to end stage renal disease and had received hemodialysis for 5 years before renal transplantation. CONCLUSIONS: The results of this study showed that PV associated with IgAN mainly occurs in males and is often accompanied by hematuria and mild-to-moderate renal insufficiency. The long-term prognosis was good for most patients, and few progressed relatively quickly to end stage renal disease.