Abstract
In vitro lymphocyte transformation in response to phytohemagglutinin and streptolysin O and in vivo skin sensitization to 2,4-dinitrochloro-benzene has been studied in patients with Sjögren's syndrome and in normal controls of comparable age and sex. Both the in vivo and in vitro responses were significantly impaired in the Sjögren's patients as compared to the controls. This lack of response to mitogenic agents is probably due to an intrinsic defect in the lymphocytes rather than to a serum factor. The abnormalities were less marked in patients whose disease was localized to the parotid and lacrimal glands than in those with generalized disease, i.e., with complicating rheumatoid arthritis or pseudolymphoma.