IgA Nephropathy Due to Polycythemia Vera

Introduction: Polycythemia Vera (PV) can manifest with mutations in the JAK2 gene and affects bone marrow, spleen, and liver. Kidney involvement is rare, but when it occurs, over 50% of cases have glomerular hyperfiltration. We present an unusual instance of PV associated with IgA nephropathy. Case Description: A 41-year-old male with hypertension (HTN) and PV presented with 24-hour urine protein level of 3.6g and microscopic hematuria. His hemoglobin level was 17.1g/dL, red blood cell count was 6.23m/mm3, and serum erythropoietin level was 8U/l (normal). JAK2-V617F mutation, CALR and MPL were negative. Kidney biopsy showed IgA nephropathy with secondary features like thrombotic microangiopathy (see image 1), segmental fibrinoid necrosis and segmental sclerosis. Serum complements 3 and 4, hepatitis panel, and antibody serologies tested negative. With concern for PV associated IgA nephropathy, bone marrow biopsy and next generation sequencing (NGS) was recommended. Given benefit of sodium glucose co-transporter 2 inhibitors in IgA Nephropathy, and proteinuria, empagliflozin 10mg daily was added to his regimen of losartan 100mg for HTN. On follow up, spot urine protein/creatinine ratio was 1.4g/g, with continued microscopic hematuria. Discussion: PV associated IgA Nephropathy is rare. A thorough work up should be done for new-onset proteinuria, and kidney biopsy is often indicated. As kidney dysfunction is a later complication and has guarded prognosis, early diagnosis and more awareness is needed to help establish defined therapies.Image 1IgA on IF