Research tools and techniques - Assessment of disease severity based on PASI index: Mild (PASI<10), Moderate (PASI from 10 to less than 20), Severe (PASI>=20). PASI= 0.1 (E+I+D) Ah+0.2 (E+I+D) Au+0.3 (E+I+D) At+0.4 (E+I+D) Al - Evaluation of treatment results: clinical effectiveness is calculated by percentage reduction of PASI according to the formula: (PASI before treatment - PASI after treatment) / PASI before treatment 100).