Metabolite-specific (IgG) and drug-specific antibodies (IgG, IgM) in two cases of trimethoprim-sulfamethoxazole-induced immune thrombocytopenia

Transfusion. 1987 May-Jun;27(3):262-5. doi: 10.1046/j.1537-2995.1987.27387235635.x.


Two cases of trimethoprim-sulfamethoxazole (TMP-SMX)-induced immune thrombocytopenia are reported in which unusual drug-dependent platelet antibodies were demonstrated by immunofluorescence and enzyme-linked immunosorbent assay. Whereas two distinct sulfamethoxazole-dependent antibodies of the IgG and IgM class were detectable in the serum of one patient, the serum of the other patient contained a platelet antibody exclusively reactive with N-4-acetyl-sulfamethoxazole, a metabolite of sulfamethoxazole. Urine from a healthy volunteer collected after administration of therapeutic doses of TMP-SMX proved to be an appropriate source of ex vivo metabolites for antibody testing. The results of this study stress the role of metabolite-specific antibodies in drug-dependent immune thrombocytopenia and underscore the necessity of including metabolite preparations of drugs in serologic analyses.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antibodies / immunology*
  • Antibody Formation
  • Antibody Specificity*
  • Blood Platelets / immunology
  • Dose-Response Relationship, Drug
  • Drug Combinations / adverse effects
  • Drug Combinations / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Immunoglobulin G / immunology
  • Sulfamethoxazole / adverse effects*
  • Sulfamethoxazole / immunology
  • Thrombocytopenia / chemically induced*
  • Thrombocytopenia / immunology
  • Trimethoprim / adverse effects*
  • Trimethoprim / immunology
  • Trimethoprim, Sulfamethoxazole Drug Combination


  • Antibodies
  • Drug Combinations
  • Immunoglobulin G
  • Trimethoprim, Sulfamethoxazole Drug Combination
  • Trimethoprim
  • Sulfamethoxazole