title: Serum prolidase level in ankylosing spondylitis: low serum levels as a new potential gold standard biomarker for disease activity.
abstract: Ankylosing spondylitis (AS) is a chronic inflammatory disorder that mainly affects the sacroiliac joints and axial skeleton. The aim of this study was to assess serum prolidase level (SPL) and its association with disease activity in patients with AS. This prospective study included 75 AS patients. Thirty age- and gender-matched healthy controls were enrolled. AS patients were considered as active if BASDAI score was ≥4 or inactive if BASDAI score was <4. There were 34 AS patients in the active group and 41 AS patients in the inactive group. Anti-TNF-monoclonal antibody treatment was started in patients in the active group. These active patients were reassessed 6 months later. BASDAI, ASDAS, visual analogue scale, short-form-general health survey questionnaire, C-reactive protein, erythrocyte sedimentation rate and SPL were measured in all AS patients before and after treatment. The SPL was significantly lower in inactive AS patients than in control group, and also, SPL was significantly lower in active AS patients than in inactive patients. All activity parameters were successful in separating active and inactive AS patients. However, the only parameter that could distinguish active patients from inactive patients was prolidase. The optimum cutoff point of SPL to identify patients with active AS was 23.13 ng/mL with sensitivity, specificity, positive predictive value and negative predictive value of 100 %. Serum prolidase level was successful in measuring disease activity and had as high sensitivity and specificity as BASDAI and was superior to other activity parameters.
authors.affiliation: Department of Physical Treatment and Rehabilitation, Erciyes University Medical School, 38039, Kayseri, Turkey.
authors.forename: Sevgi
authors.initials: S
authors.lastname: Baspinar
authors.affiliation: Department of Physical Treatment and Rehabilitation, Erciyes University Medical School, 38039, Kayseri, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kırnap
authors.affiliation: Department of Internal Medicine, Kayseri Training and Research Hospital, 38010, Kayseri, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Baspınar
authors.affiliation: Department of Internal Medicine and Clinical Nutrition, Kayseri Training and Research Hospital, Atatürk Avenue Hastane street No:78, Kocasinan, 38010, Kayseri, Turkey. osdizdar@gmail.com.
authors.forename: Oguzhan Sıtkı
authors.initials: OS
authors.lastname: Dizdar
authors.affiliation: Department of Biochemistry, Kayseri Training and Research Hospital, 38010, Kayseri, Turkey.
authors.forename: Derya
authors.initials: D
authors.lastname: Kocer
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D004150:Dipeptidases / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D004150:Dipeptidases; C022449:proline dipeptidase
keywords: Activity; Ankylosing spondylitis; BASDAI; Prolidase