Ampicillin-Specific Antibody and Delayed Hypersensitivity Skin Tests to Ampicillin in Patients with Acute Infectious Mononucleosis

Summary Ampicillin-specific IgM, IgG, and IgE antibodies were determined in 14 patients with acute infectious mononucleosis and in three healthy control subjects using modifications of a solid-phase radioimmunoassay [1]. There were no statistically significant differences when the results from tests of patient and control sera were compared to each other or to the results from tests of the buffer solution (control). No subject had an immediate reaction to intradermal ampicillin; only two patients with infectious mononucleosis had a delayed response. Other investigators have reported immediate skin test responses to ampicillin [2] and IgM and IgG antibody-like activity to ampicillin [3] in patients with infectious mononucleosis. The present results suggest that patients with infectious mononucleosis do not spontaneously produce antibodies to ampicillin and that an alternative explanation for the ampicillin-related rash in these patients must be sought.