Allergic individuals to Japanese cedar or orchard grass consist of two subgroups based on the sensitization to Dermatophagoides pteronyssinus

One hundred and twenty-six allergic subjects were divided into three groups based on the RAST results for Dermatophagoides pteronyssinus (D.p) and Japanese cedar (J.C.). We compared sex, age of examination for RAST, serum IgE, family history of allergic diseases, prevalence rate of bronchial asthma (BA) and allergic rhinitis (AR), and onset of AR among three groups. No significant difference in the other variables except serum IgE and prevalence rate of BA was found between the group with D.p-positive and J.C.-positive RAST and the group with D.p-positive and J.C.-negative RAST. The group with positive RAST for D.p and J.C. showed lower age of the examination, higher serum IgE, higher incidence of allergic family history, higher prevalence rate of BA, and lower onset age of AR than the group with negative RAST for D.p and positive RAST for J.C. We suggested that in J.C. RAST-positive group there might be two different subgroups distinguished by RAST result for D.p Similar results were obtained from the assessment of RAST for Orchard grass instead of J.C.