Rheumatol Int (2012) 32:3857–3862 DOI 10.1007/s00296-011-2302-3 123 ORIGINAL ARTICLE Serum levels of soluble CD26 and CD30 and their clinical signiWcance in patients with rheumatoid arthritis Hasan Ulusoy · Ayhan Kamanli · Necip Ilhan · Omer Kuru · Sule Arslan · Gokhan Alkan · Salih Ozgocmen Received: 28 August 2011 / Accepted: 10 December 2011 / Published online: 23 December 2011  Springer-Verlag 2011 Abstract The aim of this study was to assess serum levels and clinical signiWcance of soluble CD26 (sCD26) and sol- uble CD30 (sCD30) in patients with rheumatoid arthritis (RA). Forty-eight patients with RA and 30 healthy controls were enrolled. Serum sCD26 and sCD30 levels were mea- sured using ELISA. Serum sCD26 levels were signiWcantly lower (P = 0.011), whereas sCD30 levels were higher (P = 0.008) in patients with RA than controls. Serum levels of sCD30 correlated signiWcantly with clinical and labora- tory parameters of disease activity like erythrocyte sedi- mentation rate, C-reactive protein, disease activity scores- 28 and health assessment questionnaire score; however, sCD26 levels did not correlate any of these activity parame- ters. These results suggest that serum sCD30 levels increased and correlated signiWcantly with disease activity, indicating a novel follow-up parameter in RA. Serum levels of sCD26 may be lessen but not related to disease activity in RA. Keywords Rheumatoid arthritis · Disease activity · CD26 · CD30 Introduction T lymphocytes function as “maestros” directing inXamma- tion in autoimmune diseases [1]. During their proliferation process, cluster diVerentiation-4 + (CD4 + ) naive T-lympho- cytes diVerentiate into T helper-1 (Th1) or Th2 subgroups depending on the presence of cytokines. Th1 cells activate cellular immunity and produce proinXammatory cytokines such as interleukin-2 (IL2), IL3, interferon-gamma (INF-) and tumor necrosis factor-alpha (TNF-). Th2 cells activate humoral activity, and produce anti-inXammatory cytokines such as IL4, IL10, and IL13 [2, 3]. Cytokine pattern detected in rheumatoid synovitis supports dominancy of Th1 cells. In arthritic joints, TNF- and INF- are found in higher levels, while IL4 is rarely detected [1, 4]. Besides, levels of IL12, which converts CD4 + T lymphocytes into Th1 cells are also increased [5]. On the other hand, higher concentrations of IL10 and IL6 cytokines detected in aVected joints indicate an increase in the activity of Th2 cells [1, 3, 5]. Today, the severity of inXammation in arthritic joints is thought to be due to the imbalance between proinXammatory (Th1 type) and anti-inXamma- tory (Th2 type) cytokines [3, 6, 7]. CD26 molecule is a transmembrane glycoprotein which is expressed in higher amounts by Th1 cells and used as a H. Ulusoy (&) · A. Kamanli · G. Alkan Division of Rheumatology, Department of Physical Medicine and Rehabilitation, Firat University, Faculty of Medicine, Elazig, Turkey e-mail: ulusoyh@mynet.com N. Ilhan Department of Biochemistry, Firat University, Faculty of Medicine, Elazig, Turkey O. Kuru Division of Rheumatology, Department of Physical Medicine and Rehabilitation, Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey S. Arslan Department of Physical Medicine and Rehabilitation, Gaziosmanpasa University, Faculty of Medicine, Tokat, Turkey S. Ozgocmen Division of Rheumatology, Department of Physical Medicine and Rehabilitation, Erciyes University, School of Medicine, Gevher Nesibe Hospital, Kayseri, Turkey