SEASONAL RISE IN INTERLEUKIN-4 DURING POLLEN SEASON IS RELATED TO SEASONAL RISE IN SPECIFIC IGE FOR POLLENS BUT MOT FOR MITES

Since IL-4 plays a key role in inducing and increasing the generation of not only primary polyclonal but also secondary specific IgE respons es by B lymphocytes, a seasonal increase in IL-4 is likely to be invol ved in such seasonal rises in specific IgE in seasonal allergic rhinit is. The first aim of this study was to investigate the possible season al increase in serum IL-4 in patients with seasonal allergic rhinitis due to Japanese cedar pollens. If serum IL-4 increases in response to seasonal pollen exposure and is responsible for the seasonal increase in pollen-specific IgE in sera, this increase in IL-4 might theoretica lly affect specific IEE synthesis for other allergens. The second aim was to investigate the effect of natural pollen exposure on serum conc entrations of house dust mite-specific IgE in patients who have season al allergic rhinitis and concurrent perennial allergic rhinitis due to house dust miles. This study included 55 adult patients with seasonal and perennial allergic rhinitis due to Japanese cedar pollens and Der matophagoides farinae (D. farinae). Venous blood was collected twice f rom each patient, before and during the cedar pollen season 1996, to d etermine IL-4, cedar pollen-specific IgE and D. farinae-specific IgE i n sera. Both IL-4 and pollen-specific IgE in sera were significantly i ncreased during the pollen season, and the seasonal increase rate in p ollen-specific IgE was significantly correlated with the seasonal incr ease rate in IL-4. By contrast, D. farinae-specific IgE was not change d during the pollen season in these patients. In conclusion, an elevat ion of IL-4 in sera during the pollen season may play an important par t in the seasonal rise in pollen-specfic IgE, and enhancement of speci fic IgE synthesis is likely to need not only an increase in IL-4 but a lso an increase in the number and/or capacity of specific IgE-secretin g B cells.