Depression of cell-mediated immunity in old age and the immunopathic diseases, lupus erythematosus, chronic hepatitis and rheumatoid arthritis.

Cell-mediated immunity was assessed in man by summation of positive delayed hypersensitivity (DHS) responses to five test antigens, Candida, mumps, trichophyton, tuberculin and streptokinase-streptodornase (Varidase). The study included forty-four controls comprising healthy persons and hospital inpatients with minor illnesses, forty-five aged persons, twenty-four patients with active chronic hepatitis (ACH), nine with systemic lupus erythematosus (SLE) and fourteen patients with rheumatoid arthritis. For controls and the group with ACH, cell-mediated immunity was assessed also by transformation of blood lymphocytes with phytohaemagglutinin (PHA). The incidence of positive DHS responses to all antigens fell with advancing age, and responsiveness was significantly lower in all three groups of immunopathic disease, particularly ACH. Prednisolone was not associated with significantly depressed DHS reactions, but combined prednisolone and azathioprine were. Weak DHS responses were associated significantly with low titres of natural antibody to flagellin and with lower humoral immune responses to flagellin. Lymphocyte transformation in response to PHA in ACH was significantly less than in healthy controls. Thus certain autoimmune diseases show an immunological imbalance in the form of depressed cell-mediated immunity to extrinsic antigens and hyperactive' humoral immune responses to self' antigens and selected extrinsic antigens.