Living in damp buildings has been associated with airway symptoms, suspected to be due to inflammatory reactions. The relationship between home exposure to mould and signs of inflammation was, therefore, studied. Nonsmoking subjects with a high (G-high, > 4.0 ng x m(-3), n = 17) or low (G-low, < 2.0 ng x m(-3), n = 18) amount of airborne beta(1 --> 3)-D-glucan, an indicator of mould biomass, in the home were recruited. Blood samples were analysed for granulocytic enzymes, T-cell subsets and the secretion of cytokines from in vitro incubated peripheral blood mononuclear cells (PBMCs). In the G-high group, the proportion of cytotoxic T-cells (CD8+S6F1+) was lower and secretion of tumour necrosis factor-alpha from PBMCs higher than in the G-low group. There were no significant differences in secretion of interferon gamma and interleukin (IL)-4 from PBMCs between the two groups. Among nonatopic subjects, the ratio between interferon gamma and IL-4 was significantly higher in the G-high group than in the G-low group and was related to the amount of beta(1 --> 3)-D-glucan in the home. No significant differences were found regarding secretion of IL-10 or IL-Ibeta from PBMCs, eosinophil cationic protein or myeloperoxidase in serum, or differential cell counts in blood. The effects found on inflammatory markers in relation to beta(1 --> 3)-D-glucan in the home suggest upregulation of some parts of the inflammatory/immunological system due to mould exposure.