The Effect of Sensitization to House Dust-Mites on Onset of Pollinosis

It has been reported that the sensitization to house dust-mites (HD-mites) is one factor which affects the onset of Japanese cedar (JC) pollinosis. So, we investigated whether sensitization to HD-mites affected the incidence and age of onset of JC pollinosis in 126 outpatients and 351 medical students.Allergic subjects who visited allergy clinics in Hirosaki University Hospital were classified into two groups based on the CAP results for JC and HD-mites; one was JC-positive and HD-mite-negative, and the other was JC-positive and HD-mite-positive. The former showed a higher age at onset of JC pollinosis than the latter. With regard to the CAP score for JC, there were no significant differences. This result seems to suggest that sensitization to HD-mites affects the onset of JC pollinosis.The medical students were also divided in the same manner. The incidence of JC pollinosis in the JC-positive and HD-mite-negative group was significantly higher than that in the JC-positive and HD-mite-positive group. Regarding orchard grass (OG) pollinosis, the incidence in the HD-mite-negative group was significantly higher than that in the HD-mite-positive group. Since pollinosis is related to the degree of exposure to the dominant pollen antigen, the students were divided by their native area (Kanto area, JC dominant; Tohoku/Hokkaido area, OG dominant). The incidence of JC pollinosis was highest in JC-positive and HD-mite-negative students from the Kanto area, and that of OG pollinosis was highest in OG-positive and HD-mite-negative students from the Tohoku/Hokkaido area. These results suggested that exposure to the dominant pollen antigen is most important to onset of pollinosis, although sensitization to HD-mites affects the onset of JC pollinosis.