Immune response to sulfamethoxazole in patients with AIDS

M. P. Daftarian, L. G. Filion, W. Cameron, B. Conway, R. Roy, F. Tropper, F. Diaz-Mitoma

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Antibody- and cell-mediated responses to sulfamethoxazole (SMX) were analyzed in AIDS patients with or without a history of hypersensitivity and in negative controls. In 20 of 20 (P < 0.01) human immunodeficiency virus (HIV)-seropositive patients with skin reactions to cotrimoxazole, we found SMX-specific antibodies, while only 9 of 20 and 17 of 20 HIV-seropositive patients without a history of hypersensitivity to cotrimoxazole had SMX-specific immunoglobulin M (IgM) and IgG, respectively. The levels of specific IgM and IgG were higher in patients with skin reactions than in patients without reactions (IgM, 1.0 ± 0.19 versus 0.47 ± 0.23 [P < 0.001]; IgG, 0.68 ± 0.15 versus 0.47 ± 0.14 [P < 0.001] [mean optical density values ± standard deviations]). Seronegative controls with no history of exposure to sulfa compounds did not have SMX-specific IgG or IgM antibodies, and controls with a history of intake of SMX with or without reactions had low levels of IgG and IgM. The SMX-specific IgG subclasses were exclusively IgG1 and IgG3. None of the patients had detectable SMX-specific IgE or IgA antibodies nor did they exhibit a cell-mediated response as measured by a lymphocyte proliferation assay. Antibodies to SMX recognized N-acetyl-sulfonamide, N-(2-thiazolyl)-sulfanilamide, sulfadiazine, and sulfisoxazole but did not recognize sulfanilamide or 3-amino-5-methyl isoxazole in an inhibition assay. It is not known whether the SMX-specific antibodies associated with hypersensitivity reactions to SMX in HIV-seropositive patients have a pathogenic role in these reactions. Sulfanilamide or 3-amino-5-methyl isoxazole, on the other hand, could be potential alternative therapies in HIV-seropositive patients with a history of skin reactions to SMX.

Original languageEnglish (US)
Pages (from-to)199-204
Number of pages6
JournalClinical and Diagnostic Laboratory Immunology
Issue number2
StatePublished - 1995

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Clinical Biochemistry
  • Microbiology (medical)


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