Effects of Biological Treatment on Blood Pressure and Endothelial Function in Patients With Rheumatoid Arthritis, Psoriatic Arthritis and Ankylosing Spondylitis

Inclusion Criteria: For patients suffering from rheumatoid arthritis: * rheumatoid arthritis diagnosed based on The American Rheumatism Association Criteria from 1987 * ineffective treatment with 2 disease-modifying antirheumatic drugs (DMARDs) for 6 months each, including treatment with maximal doses of methotrexate for at least 3 months (or intolerance to treatment) * high disease activity - Disease Activity Score 28 (DAS 28) \> 5,1 measured twice, with a 1-month interval * for patients with mainly lower limbs affected with DAS 28 \> 3,7 For patients suffering from Ankylosing Spondylitis: * Ankylosing Spondylitis diagnosed based on Modified New York Criteria * ineffective treatment with 2 non-steroidal anti-inflammatory drugs (administered separately) in maximal recommended or maximal tolerated dose for 3 months * high disease activity -Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) \> 4 measured twice, with a 12-week interval * spinal pain \> 4cm on 10cm Visual Analogue Scale (VAS) measured twice, with a 12-week interval * general disease activity assessment \> 5 (0-10 scale) performed after the 2nd VAS and BASDAI assessment For patients suffering from Psoriatic Arthritis: \- Psoriatic arthritis diagnosed based on the Bennett or Classification Criteria for Psoriatic Arthritis (CASPAR Criteria) If peripheral joints are affected: active disease assessed twice, with a 4-week interval on stable treatment, after 2 DMARDs treatment for at least 4 months Criteria of active disease (all have to be met): * At least 5 out of 66 joints swollen - assessed twice, with a 4-week interval * At least 5 out of 68 joints tender - assessed twice, with a 4-week interval * general disease activity assessment of 4 or 5 in the Likert scale (0- 5 scale) performed by patient * general disease activity assessment of 4 or 5 in the Likert scale (0- 5 scale) performed by physician * general disease activity assessment \> 5 (0-10 scale) performed after 2nd assessment of number of tender and swollen joints If axial joints are affected: * Sacroiliac joints affected according to the New York Criteria of Ankylosing Spondylitis * Active and severe disease assessed twice, with a 12-week interval, stable treatment, ineffective treatment with 2 nonsteroidal anti-inflammatory drugs (administered separately) in maximal recommended or maximal tolerated dose for 3 months each Criteria of active disease (all must be present): * BASDAI \> 4 measured twice, with a 12-week interval * spinal pain \> 4cm on 10 cm in the VAS measured twice, with a 12-week interval * general disease activity assessment \> 5 (0-10 scale) Patients can take steroid in stable dose within one month - maximal dose 10mg/day of prednisone. Exclusion Criteria: * non-consenting patient * pregnancy * breast-feeding * allergy for the drug or any component * cardiac insufficiency (NYHA III or IV) * active infection * infection within the last 3 months: hepatitis, pneumonia, pyelonephritis * opportunistic infection within the last 2 months: active infection of cytomegalovirus, Pneumocystis carinii * joint infection within the last 12 months * endoprosthesis infection within the last 12 months or any time if the joint was not replaced * exacerbation of lung-, kidney-, liver- or heart insufficiency during treatment * demyelinating disease or its symptoms * pancytopenia or aplastic anemia * pre-cancer stage * neoplasm within the last 5 years including solid tumors and neoplasm of haematopoietic or lymphatic system with risk of recurrence or progression * active alcoholic disease * chronic liver disease