This project is an extension of earlier investigations concerning the biomedical effects of algae and house dust mites in patients with clinical house dust allergy. In the prior study, the allergenicity of algae and mites was confirmed but the serial sampling data of both organisms did not correlate with the peak symptomatic period of the indoor heating season. Better correlations between density data and temporal occurrence of grass, mold and ragweed seasons were observed. Therefore, this study is desinged to test the significance of algae and mites as independent or co-allergens in pollen and mold allergic patients, as compared to dust sensitive individuals. The possible priming effects of algae or mites upon clinical sensitivity to grass, molds, ragweed and dust allergens will also be evaluated. The mite microhabitat environment will be investigated in greater detail because our current sampling data do not confirm the previously reported high density of mites in mattress sites. Serial sampling in homes will include decline-action of live and dead adult mites, protonymphs, tritonymphs and immunochemical analyses of disintegrated antigens in house dust.