Tetanus toxoid as an antigen for delayed cutaneous hypersensitivity.

We studied the usefulness of tetanus toxoid (TT) as a skin test antigen in assessing cellular immune function. Hospitalized patients were skin tested with four antigens, and the response rates between these antigens were compared. Candida and mumps antigens resulted in significantly more positive responses than did TT or PPD. The response rate to the TT significantly declined in older patients, suggesting these persons may not be adequately immunized against tetanus. We found TT is not as useful as Candida or mumps antigens in the evaluation of cellular immune function in a hospitalized population but it may have some usefulness in the evaluation of energy. Negative skin test results may convert to positive after patients receive an immunizing dose of TT, as shown by our data. In addition, there were several patients with a positive response to TT and negative responses to the other common skin test antigens.