Acquired Erythrocytosis Upon Treatment with Infliximab for Ankylosing Spondylitis

摘要: To the Editor: We describe a patient with ankylosing spondylitis (AS) who was treated infliximab and developed polycythemia that Janus kinase 2 (JAK2)-negative (V617F exon 12 mutation). This is first report of AS erythrocytosis on treatment infliximab. A 31-year-old man Italian German ethnicity HLA-B27-positive started (5 mg/kg dose) in May 2007 because lack response to nonsteroidal antiinflammatory drugs. The disease showed excellent infliximab. He had 15-pack-year smoking history. Prior starting infliximab, April his hemoglobin 14.5 g/dl, hematocrit 45.5%, platelet count 334 x 103/μl. gradually (June 2008) 20.3 56.6%, 218 103/μl, referred hematology clinic July 2008. His peripheral blood smear noted be benign. Jak2 mutation negative including exons 12/14, erythropoietin level normal. Bone marrow biopsy revealed erythroid hyperplasia mild increase reticulin staining. aspirin therapeutic phlebotomies until decreased 43.6%, it has remained below 45% after months continued infliximab. Polycythemia suspected men when rises above 52% or concentration 18.5 g/dl; corresponding values for women are … Address correspondence Dr. M. Antonelli, Department Rheumatology, MetroHealth Medical Center, 2500 Drive, Cleveland, OH 44109. E-mail: mantonelli{at}metrohealth.org