Allergy refers to hypersenstivity reaction induced by chemical mediators released from mast cells and basophils activated by binding allergens contained in house dust, animal dander, pollen, fungus, food and others to IgE(reaginic antibldy)bound on these cells.
The significance of low affinity Fc receptor for IgE(Fcε R Ⅱ, CD23, Fcε R Ⅱ/CD23) on B` lymphocytes, monocytes, eosinophils and platelets, and of soluble Fcε R Ⅱ/CD23 (sFcε R Ⅱ/CD23) has been demonstrated to be essential in IgE synthesis in allergic disease.
It has also been suggested that complicated mechanism might exist in the regulation of IgE production in human. And recently, from in vitro studies of human B lymphocytes from peripheral blood, interleukin 4(IL-4, or formery B-cell stimulating factor-1, BSF-1) was found to play a central role in the regulation of IgE production, while it has been suggested that in vivo IgE synthesis could be further modulated by the release of soluble Fcε R Ⅱ/CD23 (sFcε R Ⅱ/CD23). However, the exact relationship between in vivo IgE production and IL-4 and/or Fcε R Ⅱ/CD23 are not understood well enough so far due to the study difficulties inherent in vivo studies, stemming from their extremely small amount in serum, their very short half life, and various biological factors influencing on them.
To elucidate further on these issues, this study was performed by measuring sFcε R Ⅱ/CD23, IL-4 activities and IgE level in the serum samples from 25 children with acute extrinsic asthma and comparing them with those from the 10 healthy normal subjects without allergic symptoms.
The results of the study were as follows:
1. The concentrations of sFcε R Ⅱ/CD23 in the serum varied regardless of the age of the study subjects and the severity of their allergic symptoms, but the concentrations in the study group was significantly higher than in the control group (p<0.05).
2. The activities of IL-4 in the serum varied also regardless of the age of study subjects and the severity of their allergic symptoms, and significant difference in the activities was not observed between the study group and the control.
3. The concentrations of sFcε R Ⅱ/CD23 was relatively lower in the allergic study subjects with low serum IL-4, while they were higher in the study subjects with high serum IL-4 (p<0.05).
4. The serum IgE values were remarkably higher in the allergic study group than in the control group (p<0.01), but significant correlation was not observed between the serum sFcε R Ⅱ/CD23 and the serum IgE values (P>0.1).
5. Significant correlation was not observed again between the serum IL-4 and the serum IgE either in the study group or in the control group.
In conclusion, these results indicate that sFcε R Ⅱ/CD23 is meaningfully involved in the regulation of serum IgE synthesis in allergic subjects and that sFcε R Ⅱ/CD23 is modulated by IL-4. The variabilities of the data are assumed to be attributed to various biological factors which could exist in in vivo system.
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