Sensitization to Zygophyllum fabago pollen. A clinical and immunologic study.

Zygophyllum fabago is a herbaceous plant found widely in the Mediterranean area. There are no previous reports of its allergenicity. An aerobiologic and clinical survey was conducted in Murcia, southern Spain, to determine the quantity of airborne pollen and establish the possible role of this pollen as a cause of allergic symptoms. With a Hirst volumetric trap, we determined the atmospheric concentrations of this pollen in 1993, 1994, 1995, and 1996. Of 1180 patients tested, 181 (15.34%) had a positive skin test. To determine its allergenicity, we divided 47 patients into three groups: in group 1, all the patients had symptoms of rhinoconjunctivitis plus asthma; in groups 2 and 3, rhinoconjunctivitis. In group 1, we performed a bronchial provocation test (BPT); in groups 2 and 3, we performed nasal provocation (NPT) and conjunctival provocation (CPT) tests, respectively. SDS-PAGE was used to characterize the antigenic fractions and RAST inhibition to determine cross-reactivity with other pollens. The pollen dispersion period is from May to September (445 grains/m3). BPT was positive in 13 of 15 patients, NPT in 14 of 16 patients, and CPT in 13 of 16 patients. RAST inhibition revealed cross-reactivity with Mercurialis, Ricinus, Olea, and Betula. SDS-PAGE identified 25 IgE antibody-binding components, five of which (60, 65, 41, 38, and 15.5/14.7 kDa) were recognized by 40% of the sera. By SDS-PAGE immunoblotting with sunflower antiprofilin rabbit serum and affinity chromatography we established that the Z. fabago extract has profilin. This study shows that this pollen becomes airborne and elicits an IgE response which triggers respiratory symptoms in allergic subjects.