Wurster S, et al. – The prime focus of this research was to gain an overview of the intra– and inter–individual variability in Aspergillus fumigatus reactive T–helper cells, among healthy adults. This study also analyzed its link with environmental mould exposure. The data yielded evidence regarding the intra–individual variability in A. fumigatus reactive T–cell frequencies and its linkage to mould encounter. Fungus reactive T cells were to be considered as a valued tool for the evaluation of environmental mould exposure.