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Potential factors influencing antigen detection in immunoassays for measuring rat or mouse aeroallergen (i.e., assay setup, antigen specificities, standard extracts used, and antigen decay) were investigated in a three‐country study (the UK, The Netherlands, Sweden). An inhibition enzyme immunoassay (EIA) setup gave nominal rat urinary allergen (RUA) sample values seven times higher than a sandwich EIA setup utilizing identical antibodies and standards. In immunoblotting experiments, pooled patient serum and polyclonal rabbit antibodies partly detected different rat antigens; monoclonal antibody specificity could not be determined. Immunoblot detection of mouse urinary antigens (MUA) by the polyclonal rabbit antibodies from all laboratories was similar. In both the RUA and the MUA assays, urinary antigen standards were detected with similar potency, except purified Rat n 1, which was an inefficient inhibitor in the RUA RAST inhibition. In the sandwich EIA RUA assays, a rat room‐dust extract was detected with 700–800‐fold less sensitivity than rat urine, whereas in the RAST RUA assay, dust inhibited equally with rat urine. Simulated decay did not decrease the potency of urinary antigen in any assay. Thus, assay setup and choice of detection antibodies strongly influence the nominal allergen levels. We recommend the use of standardized and characterized antibodies and standard extracts in sandwich EIAs to measure airborne rodent urinary allergens. Abbreviations: NHLI: National Heart and Lung Institute, London, UK; WAU: Wageningen Agricultural University, Wageningen, The Netherlands; NIWL: National Institute for Working Life, Solna, Sweden; Ab: antibody; mAb: monoclonal antibody; EIA: enzyme immunoassay; RAST: radioallergosorbent test; RIA: radioimmunoassay; MUA: mouse urinary allergen; RUA: rat urinary allergen; BSA: bovine serum albumin; HSA: human serum albumin; PBS: phosphate‐buffered saline; PTFE: polytetrafluoroethylene... [ABSTRACT FROM AUTHOR]

Airborne laboratory‐animal allergens can be measured by several methods, but little is known about the effects of important differences in methodology. Therefore, methods used in research projects in The Netherlands, the UK, and Sweden were compared. Seventy‐four sets of three parallel inhalable dust samples were taken by a single operator in animal facilities in the three countries, and analyzed in parallel by the three institutes for rat and mouse urinary allergen. Rat‐allergen levels measured by RAST inhibition (UK) were 3000 and 1700 times higher than levels measured by enzyme immunoassay (EIA)‐sandwich methods with polyclonal rabbit (The Netherlands) or monoclonal mouse (Sweden) antibodies, while the difference between the two EIA‐sandwich methods was much smaller: a factor of 2.2. For mouse allergen, an inhibition radioimmunoassay (RIA) with rabbit antimouse antibodies (UK) gave 4.6 and 5.9 times higher concentrations than sandwich EIAs with rabbit polyclonal antibodies (Sweden and The Netherlands), while the difference between the two sandwich EIAs was, on average, 1.6‐fold. Thus, although levels of rat and mouse aeroallergens are significantly correlated, the assay type gives large differences in absolute concentrations, and interlaboratory technical differences affect even the same assay type. Conversion factors can aid comparison between studies, and, in the long term, assay standardization is desirable. Abbreviations: NHLI: National Heart and Lung Institute (UK); WAU: Wageningen Agricultural University (The Netherlands); NIWL: National Institute for Working Life (Sweden); EIA: enzyme immunoassay; RAST: radioallergosorbent test; RIA: radioimmunoassay; MUA: mouse urinary allergen; RUA: rat urinary allergen; BSA: bovine serum albumin; HSA: human serum albumin; PBS: phosphate‐buffered saline; PTFE: polytetrafluoroethylene (Teflon); CI: confidence interval. [ABSTRACT FROM AUTHOR]

Unlabelled: The scientific literature on health effects from dampness in buildings, including mite exposure over the period 1998-2000 has been reviewed by an European group (EUROEXPO) of eight scientists in experience from medicine, epidemiology, toxicology and engineering. Forty studies deemed relevant have been the foundation for the conclusions. Dampness in buildings is a risk factor for health effects among atopics and non-atopics both in domestic and in public environments. However, the literature is not conclusive in respect of causative agents, e.g. mites, microbiological agents and organic chemicals from degraded building materials. There is a strong need for more multidisciplinary studies including expertise from all relevant areas. A general conclusion from the work was that there is a strong need for multidisciplinary reviews in scientific journals of articles dealing with associations between indoor environmental factors and health effects., Practical Implications: There is good evidence for a true association between dampness in buildings and health. As the causative factors behind this association are not known, the main focus in practical investigations should be on finding out and remediate the reasons for the humidity problem.