849 Üreten, et al: Neutrophil CD64 in BD Neutrophil CD64 Expression in Behçet’s Disease KEMAL ÜRETEN, IHSAN ERTENLI, M. AKIF ÖZTÜRK, SEDAT KIRAZ, A. MESUT ONAT, MURAT TUNCER, HAMZA OKUR, ALI AKDOGAN, SULE APRAS, and MERAL ÇALGÜNERI ABSTRACT. Objective. Hyperfunction of neutrophils is a characteristic finding in Behçet’s disease (BD). Microbial agents have been proposed as causative agents in the disease flares. Fc gamma receptor 1 (CD64) is not normally expressed by neutrophils of healthy individuals, but is upregulated by these cells in response to microbial wall components and proinflammatory cytokines. The degree of poly- morphonuclear leukocyte (PMN) CD64 expression is different in autoimmune diseases and systemic infectious diseases. We investigated PMN CD64 expression in patients with BD. Methods. Thirty-seven patients with active BD (M/F: 18/19, mean age: 34.4 ± 9.7 yrs), 35 patients with inactive BD (M/F: 11/24, mean age: 35.9 ± 11.6 yrs), 27 patients with culture proven infections (M/F: 19/8, mean age: 54.4 ± 15.2 yrs), 31 healthy controls (M/F: 14/17, mean age: 37.7 ± 8.7 yrs), and 42 patients with active inflammatory disease (M/F: 13/29, mean age: 39.3 ± 14.9 yrs) were enrolled in this study. Flow cytometry was used to assess the prevalence of CD64-bearing PMN in whole blood samples. Results. The prevalence of CD64-bearing PMN was significantly higher in patients with infectious disease (77.1 ± 18.4), inflammatory disease (37.1 ± 27.5), and active BD (48.9 ± 22.5) than in healthy controls (9.5 ± 7.8) or patients with inactive BD (12.9 ± 9.5). CD64 expression was similar in controls and patients with inactive BD. In the infectious disease group, expression of CD64 was significantly higher than in the active BD and active inflammatory disease groups, while there was no significant difference between the groups of patients with active BD and inflammatory disorders. Conclusion. Neutrophil CD64 expression increases during exacerbation of BD. This increase appears to be a non-specific inflammatory response and does not reflect PMN activation triggered by a living microorganism. (J Rheumatol 2005;32:849–52) Key Indexing Terms: BEHÇET’S DISEASE DISEASE ACTIVATION CD64 NEUTROPHIL From the Departments of Rheumatology and Pediatric Hematology, Hacettepe University School of Medicine; and the Department of Rheumatology, Gazi University School of Medicine, Ankara, Turkey. K. Üreten, MD; I. Ertenli, MD, Department of Rheumatology, Hacettepe University; M.A. Öztürk, MD, Department of Rheumatology, Gazi University School of Medicine; S. Kiraz, MD; A.M. Onat, MD, Department of Rheumatology; M. Tuncer, MD; H. Okur, PhD, Department of Pediatric Hematology; A. Akdogan, MD; S. Apras, MD; M. Çalgüneri, MD, Department of Rheumatology, Hacettepe University. Address reprint requests to Dr. M.A. Öztürk, Ostim mahallesi, 89. sokak, AK-84 sitesi, A-2 blok, no: 8, Yenimahalle, Ankara, 06170 Turkey. E-mail:makifozturk@yahoo.com Accepted for publication December 20, 2004. Behçet’s disease (BD) is a multisystem, chronic inflamma- tory disease of unknown etiology. The disease course is typ- ically characterized by recurrent inflammatory attacks and periods of remission. Microbial agents have been proposed as causative agents in exacerbations of BD 1-3 . In addition, neutrophil over-activation is a well known phenomenon, and there is evidence for the in vivo primed state of neu- trophils in BD 2-5 . Fc receptors are found on the cell mem- brane of leukocytes and are functional in both innate and adaptive immune responses. Among the Fc receptors, Fcγ receptor 1 (CD64) is constitutively expressed on macrophages, monocytes, and eosinophils. However, CD64 is not normally expressed by polymorphonuclear leukocytes (PMN) of healthy individuals, but is stored intracellularly and mobilized as a physiological response to microbial wall components, complement split products, and some proin- flammatory cytokines 6-9 . In a recent study, CD64 expression on the neutrophil sur- face was greater in autoimmune diseases than on neutrophils of patients with noninflammatory disease, and CD64 expression on PMN from patients with systemic infectious diseases was greater than on those from patients with non- inflammatory and inflammatory diseases 9 . Therefore, autoimmune disorders and systemic infections have distinct patterns of PMN CD64 expression. Using flow cytometric analysis, we investigated whether the prevalence of PMN bearing CD64 was increased in patients with active compared to inactive BD and to patients with culture proven infections and healthy controls. Since PMN activation is not a specific feature of BD and may also be seen in other vasculitic syndromes and connective tissue disorders, patients with various inflammatory diseases other than BD were included in this study as disease controls. MATERIALS AND METHODS Patients. The study comprised 5 groups: 37 patients with active BD (M/F: 18/19, mean age: 34.4 ± 9.7 yrs), 35 patients with inactive BD (M/F: 11/24, mean age: 35.9 ± 11.6 yrs), 27 patients with culture proven infections (M/F: 19/8, mean age: 54.4 ± 5.2 yrs), 31 healthy controls from the hospital staff Personal non-commercial use only. The Journal of Rheumatology Copyright © 2005. All rights reserved. www.jrheum.org Downloaded on February 1, 2022 from