Analysis of natural history of Japanese cedar pollinosis.

BACKGROUND: The marked increase in the incidence of Japanese cedar (Cryptomeria japonica; JC) pollinosis is a social problem in Japan. Elucidation of its natural history is, therefore, essential. METHODS: Cross-sectional and vertical-sectional studies were performed regarding the effects of aging on sensitization to Japanese cedar pollen (JCP) and development of JC pollinosis by measuring serum IgE titers to JCP and by oral examination of residents of the Maruyama Town, Chiba, Japan from 1995 to 2001. We also studied the incidence of its spontaneous remission and the background factors. RESULTS: In a vertical-sectional study, the serum IgE titer to JCP was strongly influenced by the amounts of pollen scattered. An increase in age by 6 years did not reduce the IgE titer to JCP in subjects in their 40s. However, in subjects aged 60 or more, annual differences in the JCP count did not affect serum IgE titer to JCP, which remained low even after a season with a high pollen count. In subjects with JC pollinosis aged over 40 showing a CAP RAST score of more than 2 to JCP in 1995, spontaneous remission of JC pollinosis was observed in 16.1% over a period of 6 years. Factors affecting spontaneous remission include sex, age at the time, serum IgE titer to JCP and age at first onset of JC pollinosis. CONCLUSIONS: The CAP RAST score was strongly associated with spontaneous remission in the multivariable model.

The effect of Japanese cedar-specific immunotherapy on cytokine production in peripheral blood mononuclear cells.

The most common cause of seasonal allergic rhinitis in Japan is the Japanese cedar (JC). Recently, a pullulan-conjugated antigen (CS-560) has been developed to reduce adverse effects and to enhance the effect of JC-specific immunotherapy (IT). If the mechanism of IT can be fully elucidated and the treatment can be used safely and with specificity, IT should be reconsidered as a superior treatment for JC pollinosis. Thirteen patients with JC pollinosis who received IT were compared to 10 patients who did not receive IT. All patients were followed through two pollen seasons by means of allergy diaries. Peripheral blood mononuclear cells (PBMC) were collected before IT and just before each pollen season, and these were stimulated with pollen extract. The concentrations of IL-4, IL-5, IL-13 and IFN-gamma in the culture supernatants were determined using an ELISA. Furthermore, messenger (m)RNA expressions of IL-4 and IL-5 from cultured PBMC were also studied. As a result of the allergy diaries, we confirmed the clinical efficacy of CS-560. The symptom-medication scores were significantly decreased by IT. The levels of IL-4, IL-5 and IL-13 declined only in the IT group. However, the level of IFN-gamma did not change in either group. IL-4 and IL-5 mRNA expressions were inhibited in the IT group compared to that in the non-IT group. In conclusion, specific IT for JC pollinosis using CS-560 clearly modified cytokine expression by PBMC.