Inclusion Criteria:

- Males and females 18-80 years

- Able and willing to give written informed consent, and to comply with the
requirements of the study protocol.

- Fulfilling the ACR 1987 revised diagnostic criteria for the diagnosis rheumatoid
arthritis, or the diagnostic criteria by Moll and Wright for the diagnosis psoriatic
arthritis, or the modified New York diagnostic criteria for ankylosing spondylitis.

- Clinical indication for starting treatment with methotrexate, TNFalpha- inhibitor or
combination therapy.

- Use of reliable method of contraception for women with childbearing potential.

Exclusion Criteria:

- Lack of cooperativity

- Positive serology for hepatitis B or C

- History of positive HIV status.

- History of tuberculosis or untreated tuberculosis.

- PPD more than 15 mm in previously BCG immunized subjects. PPD 6 mm or more if not
previously BCG immunized.

- Histoplasmosis or Listeriosis

- Persistent or recurrent infections

- Any inflammatory disease of permanence not related to RA, PSA or AS.

- Pregnancy or breast-feeding.

- Use of prednisolone more than 10 mg daily for 2 weeks at inclusion.

- Use of TNFalpha-inhibitor the last 4 weeks.

- History of cancer.

- Uncontrolled diabetes.

- Congestive heart failure (Nyha 3-4)

- Recent stroke (within 3 months)

- Previous diagnosis or signs of central nervous system demyelinating disease.

- Previously diagnosed immunodeficiency.