[Tylosin-specific proliferation in vitro of the peripheral blood mononuclear cells in occupational tylosin allergy].

Tylosin-specific lymphocyte proliferation in vitro and its restriction of HLA class II antigens have been investigated in 21 allergic workers exposed to tylosin. Nine workers from tylosin industry without allergic symptoms and five nonexposed nonallergic subjects served as controls. The results showed a significantly higher lymphocyte proliferative response to tylosin in allergic workers compared to control groups. Lymphocyte proliferation was observed in five workers with allergic complaints but negative skin tests. The tylosin concentration leading to maximal proliferative response varied from 10 to 1000 micrograms/ml among individuals. Six from seven workers with maximal response to the lowest concentration of tylosin carried HLA-DQ2 antigen. Lymphocyte from most control subjects did not respond in vitro to tylosin. Weak proliferative response to tylosin was observed in two workers without clinical symptoms of allergy. No association was found between lymphocyte reactivity to PHA and tylosin in the three studied groups. In conclusion, tylosin leads to a specific activation of T lymphocytes in occupationally sensitized workers. Possibly, the T cell recognition of the hapten/protein complex is restricted by HLA-DQ2 antigen in tylosin occupational allergy. Lymphocyte stimulation test can be used for the diagnosis of tylosin occupational allergy, as well as for the detection of latently sensitized workers.