1497 Castellino, et al: Thrombocytosis in SLE Personal non-commercial use only. The Journal of Rheumatology Copyright © 2007. All rights reserved. Thrombocytosis in Systemic Lupus Erythematosus: A Possible Clue to Autosplenectomy? GABRIELLA CASTELLINO, MARCELLO GOVONI, NAPOLEONE PRANDINI, GESSICA LIMPIDO, SIMONE BERNARDI, DIANA CAMPIONE, FRANCESCO LANZA, and FRANCESCO TROTTA ABSTRACT. Objective. Thrombocytosis can be due to a myeloproliferative disorder or to a reactive or secondary process; among these are connective tissue disorders, in particular systemic lupus erythematosus (SLE). Besides being an expression of active disease, this unusual finding has also been described in SLE com- plicated by autosplenectomy. We evaluated the prevalence of thrombocytosis in a series of SLE patients and its relationship to functional asplenia. Methods. Platelet count was evaluated in 465 consecutive Caucasian patients with SLE (387 women, 78 men, median age 54 yrs). Thrombocytosis was defined as platelet count > 400 × 10 9 /l in at least 3 blood samples. All patients with thrombocytosis underwent peripheral blood smears for erythrocyte abnormalities and instrumental spleen evaluation. Results. Seventeen patients (3.7%) with thrombocytosis were observed. Peripheral blood smear showed Howell-Jolly bodies, spherocytes, and target cells in 3/17 patients (17.6%). In the same 3 patients, ultra- sound and computed tomography failed to evidence the spleen, and liver-spleen scans showed absence of splenic uptake (a finding indicative of functional autosplenectomy). One satisfied criteria for antiphospholipid syndrome (APS), and the other 2 patients had positive IgG antiphospholipid antibod- ies (aPL) at medium titer. Conclusion. The sudden appearance and persistence of thrombocytosis or even the apparent reversal of thrombocytopenia in patients with SLE should raise suspicion of autosplenectomy, in particular if sec- ondary APS or aPL is present. (First Release June 1 2007; J Rheumatol 2007;34:1497–501) KeyIndexingTerms: SYSTEMIC LUPUS ERYTHEMATOSUS THROMBOCYTOSIS AUTOSPLENECTOMY ANTIPHOSPHOLIPID ANTIBODIES From the Unità Operativa di Reumatologia, Unitá Operativa di Ematologia and Servizio di Medicina Nucleare, Università degli Studi di Ferrara, and Azienda Ospedaliera–Universitaria “Arcispedale S. Anna,” Ferrara,Italy. G. Castellino, MD, Unitá Operativa di Ematologia; M. Govoni, MD, Associate Professor; G. Limpido, MD, Fellow in Rheumatology; S.Bernardi,MD,FellowinRheumatology;F.Trotta,MD,Professorof Rheumatology, Chief, Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Ferrara; N. Prandini, MD, Assistant, Nuclear Medicine Department, Arcispedale S. Anna; D.Campione,ResearchFellow;F.Lanza,MD,Assistant,Departmentof Hematology,ArcispedaleS.Anna. AddressreprintrequeststoDr.G.Castellino,RheumatologyUnit, Department of Clinical and Experimental Medicine, University of Ferrara, Corso della Giovecca 203, 44100 Ferrara, Italy. E-mail: gabriella_castellino@yahoo.it Accepted for publication February 26, 2007. Thrombocytosis is typically discovered as an incidental labo- ratory abnormality when the routine complete blood count is obtained. By far, the most common cause of thrombocytosis is a reactive or secondary process 1 : connective tissue disorders, in particular systemic lupus erythematosus (SLE), are listed among these. Besides being an expression of active disease, this finding has also been described in the setting of SLE com- plicated by autosplenectomy, suggesting that thrombocytosis may be an indicator of autosplenectomy 2,3 . While true con- genital asplenia is a coincidental finding in SLE, acquired functional asplenia is described in 3% to 7% of cases 4-7 . Among the possible pathogenetic explanations are splenic vasculitis and antiphospholipid-related coagulopathy. We evaluated the prevalence of thrombocytosis in a series of patients with SLE and its relationship to functional asplenia. MATERIALS AND METHODS With informed consent and ethics committee approval, the platelet count was determined in 465 consecutive Caucasian SLE patients (387 women, 78 men; mean age 54 yrs, range 20–89 yrs; median disease duration 6 yrs, range 3 mo to 25 yrs) fulfilling the 1982 American College of Rheumatology criteria for the disease 8 . Serological tests included antinuclear antibodies (ANA; by indirect immunofluorescence method with HEp-2 substrate), anti-DNA antibody (indi- rect immunofluorescence with Crithidiae luciliae substrate and by enzyme immunoassay), antibodies to extractable nuclear antigen (ENA; by ELISA), antiphospholipid antibodies (aPL; standardized ELISA kit), and lupus antico- agulant (LAC; by kaolin clotting time and Russell’s viper venom test). Thrombocytosis was defined as a platelet count > 400 × 10 9 /l in at least 3 blood samples taken during 3 consecutive visits 3 months apart from each other. All patients with thrombocytosis underwent a peripheral blood smear and abdominal ultrasonography (US). Peripheral blood smears were stained with May-Grunwald Giemsa. In addition, a peripheral blood smear was performed in 20 consecutive SLE patients without thrombocytosis (6 with secondary APS) matched for sex, age, and disease duration. In the presence of erythrocyte abnormalities (Howell-Jolly bodies, sphe- rocytes, increased number of “pitted” erythrocytes) and in the absence of US spleen visualization, a computed tomography (CT) scan and a selective liver- www.jrheum.org Downloaded on January 12, 2022 from