Anti-Annexin V Antibodies in Primary Fibromyalgia Syndrome: Relation to Associated Sjögren’s Syndrome

Abstract

Fibromyalgia syndrome (FMS) is a complex disorder that affects up to 5 % of the general population worldwide, more frequently in women. Sjogren’s syndrome (SS), the second most common autoimmune rheumatic disease results from immune lymphocytes that infiltrate the lacrimal and salivary glands. The distinction between FMS patients and primary SS remains difficult. Damages to the lacrimal and salivary glands and development of SS may accompany various autoimmune diseases. Apoptosis (programmed cell death) plays a fundamental role in the pathogenesis of SS. Annexins are a group of highly conserved proteins which exert several regulatory functions on cell biology and are involved in numerous cell processes including apoptosis. The aim of this study was to measure the level of serum Anti-Annexin V antibodies in FMS patients diagnosed according to the American College of Rheumatology criteria [1] and to study their significance in relation to associated SS diagnosed according to the revised version of classification criteria [2]. Fifty-six female patients with primary FMS (mean age 35.36±7.53 years) and 30 age and sex matched healthy subjects were included as controls (33.53±5.16 years) were included. Serum IgG anti-annexin V antibodies titre was assessed. The FMS patients had a mean Widespread Pain Index (WPI) of 8.98±2.93 and a symptom severity scale score (SSSS) of 8.27±2.21. Twenty seven patients gave symptoms of dry eyes or mouth of which only 12 (21.43 %) had SS. Anti-annexin V antibody level was significantly higher in FMS patients (19.96±10.29 AU/ml) compared to control (7.32±3.42 AU/ml); being higher in those with SS (29.87±10.44 AU/ml) compared to those without (17.25±8.53 AU/ml)(p 0.002) (Fig. 1). Furthermore, serum anti-Ro, anti-La and SSSS were significantly higher in those patients with SS (17.67±10.01 U/ml, 23.75± 11.14 U/ml, 9.67±1.83) compared to those without SS (7.14± 3.17 U/ml, 8.5±3.69 U/ml, 8.11±2.17) (p 0.004, 0.001, 0.02 respectively). In the FMS patients, anti-annexin V antibodies significantly correlated with SSSS (r 0.39, p 0.003) while there was a tendency to correlate with WPI (r 0.24, p 0.07). Apoptosis plays a fundamental role in the pathogenesis of SS [3]. Autoantibodies in SS directed against nuclear and cytoplasmic antigens may consequently activate the apoptotic process [4]. The role of apoptosis in FMS is not known. Anti-Annexin V antibodies are elevated in FMS with special attention to those with associated SS. In addition to the other T. A. Gheita (*) :H. A. Raafat Rheumatology Department, Faculty of Medicine, Cairo University, Cairo, Egypt e-mail: gheitamer@hotmail.com