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CYTOKINE MRNA PROFILES FOR ISOCYANATES WITH KNOWN AND UNKNOWN POTENTIAL TO INDUCE RESPIRATORY SENSITIZATION
Citation:
Plitnick, L. M., S. E. Loveless, G. S. Ladics, M. P. Holsapple, R J. Smialowicz, M. R. Woolshiser, P. K. Anderson, C. Smith, AND MJK Selgrade. CYTOKINE MRNA PROFILES FOR ISOCYANATES WITH KNOWN AND UNKNOWN POTENTIAL TO INDUCE RESPIRATORY SENSITIZATION. TOXICOLOGY. Elsevier Ireland Limited, Limerick, Ireland, 207:487-499, (2005).
Impact/Purpose:
to better identify respiratory sensitizers
Description:
Cytokine mRNA Profiles for Isocyanates with Known and Unknown Potential to Induce Respiratory Sensitization. Plitnick, L.M., Loveless, S.E., Ladics, G.S., Holsapple, M.P., Smialowicz, R.J., Woolhiser, M.R., Anderson, P.K., Smith, C., Sailstad, D.M. and Selgrade, M.J.K (2002) Toxicol. Appl. Pharmacol.
Abstract:
Isocyanates are members of the low molecular weight (LMW) chemical class and have been implicated in respiratory as well as contact hypersensitivity reactions. In order to protect workers who come in contact with such chemicals, an assay to identify respiratory sensitizers is needed. Current methodologies are based on the suggestion that respiratory sensitizers may be identified by their ability to induce a cytokine profile characteristic of a Th2 T cell response (IL4, IL10 and IL13). Previous studies from this laboratory have shown that mRNA levels for Th2 cytokines are elevated in response to acid anhydrides with known respiratory sensitizing potential and these elevations may be detected by ribonuclease protection assay (RPA). In the current study, 6 additional chemicals (toluene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), isophorone diisocyanate (IPDI), p-tolyl (mono) isocyanate (TMI) and meta-tetramethylene xylene diisocyanate (TMXDI)) were evaluated for their ability to induce Th2 cytokine mRNA expression. RPA analysis showed that all 6 isocyanates tested induced the mRNA for cytokines characteristic of a Th2 response. Although the isocyanates tested appeared to differentiate into two groups, a high responding group and a low responding group, LLNAs confirmed that the doses chosen for the RPA were immunologically equivalent based on similar SI. In addition, 2 of the 3 low responders (TMI and TMXDI) induced levels of cytokine message statistically higher than DNCB, suggesting that all the isocyanates tested have the potential to induce respiratory hypersensitivity. Follow-up studies will be useful to determine whether these chemicals are actually sensitizers or if cytokine profiling is inappropriate for the identification of respiratory sensitizers.