Materials and methods
This prospective case-control study included 53 patients with clinically and histopathologically confirmed psoriasis (28 with associated comorbidity and 25 without comorbidity) and 52 healthy volunteers. All the procedures followed the Helsinki declaration and the study was approved by the local clinical research ethics committee (Approval date and number: 2020-02/16). Written Informed consent was also obtained from all the subjects.
Pregnant or breastfeeding females, patients under 18 years old, those who were on systemic treatment, patients with accompanying infections or malignancies were excluded. Patients who have received topical treatment or phototherapy within the last month or systemic treatment within the last three months were also ruled out.
All subjects underwent a physical examination and laboratory investigations including serum ChT levels, complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum lipid levels. The Psoriasis Area and Severity Index (PASI) and disease duration were also recorded for all patients.
Blood samples from all subjects were taken in the morning after at least 8-10 hours of fasting. Blood taken into plain tubes was allowed to clot for 30 minutes and then centrifuged at 2000g for 10 minutes. Routine biochemical tests were immediately performed from some of the serum formed, and some were stored at -80 ° C for measuring ChT levels. Complete blood count was studied on Sysmex XN1000 (Sysmex Corp. ®, Kobe, Japan) device from blood samples taken into K2EDTA tubes. Routine biochemistry and hormone tests were studied in Cobas c702 (Roche Diagnostics®, Japan) autoanalyzer systems using standard laboratory methods.
ChT activity was measured by the method proposed by Hollak et al.5. According to this method, the patient’s serum was incubated with a substrate containing 4- methylumbelliferyl-chitotrioside under 37 °C for 2 h. Fluorescence was detected as excitation 360 nm and emission 445 nm (Modulus microplate fluorometer, Turner Biosystems, Inc., California, USA). Results were given as μmol/ml/h.