CARICA-PAPAYA POLLEN ALLERGY

Background: Carica papaya (CP) trees are widely cultivated in tropical and subtropical areas; however, CP pollen allergy has not been previo usly described. Objective: To study patients with CP pollen hypersensi tivity. Methods: A CP pollen extract was elaborated. Skin prick tests (SPTs) with this extract, as well as with commercial papaya fruit and papain extracts, were performed. Specific IgE levels to CP pollen, pap aya fruit, and papain were determined. Specific conjunctival challenge tests to the CP pollen extract were also performed. RAST inhibition s tudies among CP pollen, papaya fruit, and papain were carried out. Twe nty atopic patients were used as a control group for in vivo and in vi tro tests. Results: Six patients with clinical histories of seasonal r hinoconjunctivitis or bronchial asthma in relation to CP trees exposur e, suggestive of IgE-mediated respiratory allergy, were studied. Comme rcial SPT and specific serum IgE to papaya fruit and papain were posit ive in our patients. An IgE-mediated hypersensitivity to a CP pollen e xtract was demonstrated in all patients, by means of SPTs, specific se rum IgE determinations, and conjunctival challenge tests. Control atop ic subjects showed negative SPTs, specific IgE, and conjunctival chall enge tests to the CP pollen extract. On PAST inhibition studies using CP pollen extract in solid phase, a significant crossreactivity was fo und among CP pollen, papaya fruit, and papain. Conclusions: Our study suggests that papaya flower pollen is able to induce respiratory IgE-m ediated;allergy. The existence of common allergens among papaya flower pollen, papaya fruit, and papain has been demonstrated by PAST inhibi tion.