Comparison of cytokine secretion profiles provoked in mice by glutaraldehyde and formaldehyde

Background: Glutaraldehyde and formaldehyde are commonly used sterilizing agents that are known skin sensitizers. There is some controversy, however, regarding their capacity to cause respiratory allergy. The authors have demonstrated previously that topical exposure of mice to chemical contact allergens such as 2,4-dinitrochlorobenzene (DNCB) or respiratory allergens such as trimellitic anhydride (TMA) induces characteristic cytokine secretion profiles consistent with the selective activation of T helper 1 (TH1)- and TH2-type cells, respectively. Objective: To investigate the quality of immune response provoked following topical exposure of mice to these materials. Methods: BALB/c strain mice were exposed topically to 50% formaldehyde or to various concentrations of glutaraldehyde in acetone. Control animals were treated concurrently with the reference contact allergen DNCB (1% in acetone:olive oil [AOO]) or with the reference respiratory sensitizer TMA (10% in AOO). Thirteen days after the initiation of exposure, draining lymph node cells (LNCs) were cultured for 12-120h and cytokine content of supernatants analysed by cytokine-specific enzyme-linked immunosorbent assay. Results: DNCB-α and formaldehyde-activated LNCs produced high levels of the TH1-type cytokine interferon γ, but little of the TH2-type products interleukins 4 and 10. TMA-and glutaraldehyde- stimulated LNCs displayed the converse TH2-type pattern of cytokine expression. Conclusions: These data are consistent with glutaraldehyde, but not formaldehyde, having significant potential to cause allergic sensitization of the respiratory tract.