Abstract
The present study was designed to investigate seasonal changes in immune responses to Japanese cedar (Cryptomeria japonica (CJ)) pollen allergens in humans with CJ pollinosis. Peripheral blood samples were collected from eighteen patients with CJ pollinosis before and after the CJ pollen season (April 2000, January 2001, April 2001 and September 2001). Seasonal changes in not only IgE responses but also T cell proliferative responses were analyzed before and after CJ pollen season. Two patterns of seasonal changes in immune responses among pollinosis patients were apparent. In one pattern, immune responses at the T cell and IgE level are induced during the pollen scattering season and decrease gradually after the season ends, as reported previously (variable group). In the second pattern, the immune responses do not decrease and are maintained until the next pollen season (continuous group). Patients in the latter group suffer from CJ pollinosis for long periods of time and their nasal symptoms appear earlier than in the variable group. DNA typing of HLA-class II antigens revealed that the genotype frequency of DPB 1*0501 was higher in pollinosis patients, but no difference was observed between the variable group and the continuous group. In conclusion, this study suggests that early nasal symptoms in CJ pollinosis patients are the result of immune responses that have been maintained at a high level since the last pollen season.
