Serum levels of soluble CD23 in patients with asthma or rhinitis monosensitive to Parietaria. Its relation to total serum IgE levels and eosinophil cationic protein during and out of the pollen season

The diagnostic value for allergies of the low affinity IgE receptor and its soluble circulating fragment (sCD23) remains unclear. In particular, littl e is know about seasonal influences on serum sCD23 levels in subjects with pollen allergy. In the present study, to gain insight into pathophysiologic al role of sCD23, we have analyzed, in blood from patients allergic to Pari etaria sCD23, IgE, and eosinophil cationic protein (ECP) serum levels. IgE were assessed as atopy markers and ECP as an inflammation marker. Patients were studied during and out of pollen season, and results were compared to those obtained in nonallergic subjects. The study population included 42 no nsmoking outpatients, living in Palmero (Sicily, Italy) or in other west Si cilian towns, with a clinical diagnosis of seasonal asthma or rhinitis and monopositive skin test to Parietaria pollen. The group of asthmatic subject s consisted of 25 patients who had one or more of the usual asthma symptoms (wheezing, dyspnea, and cough) only during the pollen season. The group of rhinitis patients consisted of 17 patients, who, during pollen season, had the nasal symptoms (nasal blockage, sneezing, nasal itching, and rhinorrho ea) but no signs of asthma. As a control group, we studied 10 nonatopic sub jects from laboratory staff. They had no history of seasonal or perennial r hinitis, asthma, or urticaria and had negative skin tests to a panel of all ergies. Soluble CD23, IgE, and ECP were assessed in blood during and out of pollen season. Total serum IgE levels were clearly higher in atopic patien ts, as classically established. Concerning sCD23 serum levels, a similar pa ttern of results was obtained. Accordingly, significant correlations were s hown between the levels of sCD23 and IgE in all groups of patients. A compl etely different pattern was observed by analyzing serum ECP levels because ECP levels were significantly increased only in asthmatic patients during p ollen season. Accordingly, no significant correlations were observed betwee n the levels of sCD23 and those of ECP. Identifying immune factors associat ed with the development of atopy can enhance our understanding of the in vi vo mechanisms involved and may have utility in paradigms designed to preven t diseases. As demonstrated by the close correlation with total serum IgE v alues and the lack of correlation with serum ECP values, serum levels of sC D23 appear to be an additional marker for the diagnosis of atopy but not fo r the follow-up of allergic diseases.