The aim of this study was to investigate whether man-made mineral fibers (M
MMF) induce apoptosis of human peripheral blood mononuclear cells (PBMC), a
s we recently demonstrated for chrysotile B. In vitro cultivation of PBMC w
ith various MMMF as well as chrysotile B clearly produced apoptotic cells.
The alteration of the expression for apoptosis related genes at the mRNA le
vel during in vitro cultures of PBMC with various MMMF revealed upregulatio
n of Flice and Apaf-1 genes and down regulation of TNF receptor 1 and Bid g
enes. These results indicate that MMMF induce apoptosis of PBMC in a simila
r manner to chrysotile B. However, the process may be mediated not only by
the Fas-related apoptotic pathway but also a mitochondrial pathway. Thus, o
ne should be aware that respiratory and immunological abnormalities may occ
ur in workers who are exposed to MMMFs.