[Systemic mixed connective tissue disease--Sharp's syndrome].

Sharp's syndrome is a systemic mixed connective tissue disease that is defined with specific ribonucleoprotein antibody (U1RNP). The key diagnostic criterion is positive antinuclear antibodies in stain form. The disease is primarily localized on joints, muscles and skin; however, there are not widely used diagnostic criteria. There are USA, Mexican and Japanese diagnostic criteria. A 18-year-old male who fulfilled Sharp's diagnostic criteria is presented in the paper. In this patient the disease was manifested in pleura and pericardium. We wish to point out the importance of immunologic approach to the aetiology of pleural and pericardial inflammatory effusions in young patients, as well as the therapeutical dilemmas in the treatment of the disease.