T-cell receptor repertoire expression in workers with occupational asthma due to platinum salt

Abstract

There is a high incidence of asthma, rhinitis, conjunctivitis and contact urticaria in workers of precious metal refineries. Symptoms are closely associated with sensitization to halogenated platinum compounds, as assessed by skin-prick test. The aim of the present study was to examine the molecular mechanisms involved by describing the T-cell receptor (TCR) repertoire distribution of peripheral blood mononuclear cells (PBMCs) without and after in vitro stimulation with sodium hexachloroplatinate. PBMCs of 17 sensitized subjects with work-related asthma and a positive skin-prick test result to sodium hexachloroplatinate and of 15 nonexposed subjects were isolated and TCR expression determined by flow cytometry. Furthermore, the sodium hexachloroplatinate-mediated in vitro effects on the frequency of Vβ-expressing T-cells, the proliferation response and the expression of cell surface molecules like CD71, CD25, CD95 and HLA-DR were studied. CD3-positive lymphocytes of platinum salt-sensitized workers had a significantly higher frequency of Vα2a+, Vβ11+ and Vβ21.3+ T-cells than controls (p<0.01, p<0.01 and p<0.001 respectively). In vitro stimulation of PBMCs from platinum salt-sensitized as well as control subjects with sodium hexachloroplatinate increased the percentage of CD3-positive cells bearing specific TCRs, especially Vβ5.3, Vβ6.7, Vβ8a, Vβ20 and Vβ21.3. This effect was time- and dose-dependent. The present results indicate that the frequencies of Vα2a-, Vβ11 and Vβ21.3-bearing blood T-cells and platinum salt-induced lymphocyte proliferation are strongly enhanced in subjects who suffer from asthma due to platinum salt. In addition, in vitro stimulation with sodium hexachloroplatinate modulates the frequencies of certain T-cell receptor-bearing T-cells.