Increased serum interleukin-6 levels in patients with hidradenitis suppurativa

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic, recurrent, and inflammatory skin disease. It has a complex etiology and is associated with genetic factors, sex hormones, bacterial infection, and immune dysfunctions [1]. Studies have indicated that a variety of cytokines such as tumor necrosis factor (TNF-), interleukin (IL)-1, and IL-10 are involved in the pathogenesis of HS [2, 3]. Interleukin-6 is a cytokine with a molecular weight between 21 and 30 kDa. Abnormal upregulation of IL-6 has been proved to play pathological roles in many inflammatory diseases such as rheumatoid arthritis and Crohn’s disease [4], and IL-6 is considered as an inflammatory marker [5, 6]. Recently, HS has been referred to be systemic auto-inflammatory disease [7].
Alterations of IL-6 levels in the serum of HS patients have not been reported and this study was aimed to measure the serum IL-6 levels in patients with HS.
This study was approved by the Ethics Committee of our hospital and conducted according the Declaration of Helsinki Principles, and all study subjects signed an informed consent form. Serum samples were obtained from 44 Chinese Han patients (36 men and 8 women) who met the diagnostic criteria for HS [1]. The patients were classified according to the Hurley stage [1]. The study participants included 18 cases of Hurley stage I patients, 12 cases of Hurley stage II patients, and 14 cases of Hurley stage III patients (Table 1). The differences in sex, age, and disease history among the three groups were not significant (p > 0.05). The healthy control group was comprised of 13 healthy volunteers without any abnormal clinical or laboratory findings (Table 1). The differences in sex and age between healthy control group and patient groups showed no significance (p > 0.05).
Morning fasting peripheral venous blood samples (4 ml) were collected from study subjects. After settling for 20 min, the samples were centrifuged (1000×g, 10 min, 4°C) and placed in a –80°C freezer for subsequent use. IL-6 ELISA reagent kit was purchased from eBioscience (San Diego, CA, USA; catalogue no. BMS213/2). The procedure was performed according to the kit instruction, and results were calculated when absorbance of each well was measured at 450 nm with a spectrophotometer (BioTek ELX 800, Winooski, VT, USA).
Statistical analysis was performed using the one-way analysis of variance for comparison between different groups, and the Mann-Whitney...


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