A variety of studies have stressed the importance of the control of inflammatory cell longevity and the balance of pro-survival and pro-apoptotic signalling. Recently,
asthma was found to be associated with reduced apoptosis of inflammatory cells in lung tissue. The aim of the study was to investigate the systemic activation of apoptosis pathways using
cDNA array technology in atopy and
asthma. Eighteen atopic asthmatics (AA), eight atopic non-asthmatic (AN) and 14 healthy control subjects (C) were included in the study. Peripheral blood mononuclear cells were separated with gradient centrifugation,
mRNA purified and the reverse-transcribed probes hybridized to
cDNA arrays. The signals were compared by standardizing to the 100 most expressed genes and group differences assessed with the Mann-Whitney U-test. We found a concerted up-regulation of several pro-survival
cytokines and
growth factors in AN and AA. FAS and FASL were not differentially expressed, but FAST
kinase was over-expressed in AN and AA. The tumour
necrosis factor pathway was activated in AN and AA with increased
cytokine and receptor levels and increased
TRAF2, an intracellular signalling product. There were indications of a down-regulated p53 system. In contrast, the Bcl-2 family of genes showed a net pro-apoptotic profile in AN and AA. The group of
caspases showed a constant gene expression pattern in all groups. In conclusion, significant differences in the expression of apoptosis-related genes were found in peripheral blood of atopic individuals with and without
asthma.
cDNA array technology proved to be useful and may be complementary to
DNA-based studies in order to analyse interactive and multidimensional pathways as shown here for apoptosis.