Crossreactivity between allergens in natural rubber latex and banana studied by immunoblot inhibition

Background An association between allergic reactions to natural rubber latex and to banana has been reported but the immunochemical properties of the putative crossreacting allergens remain unknown. Obfective To study extracts of banana and natural rubber latex and sera from latex-allergic patients for possible crossreacting allergens and IgE antibodies. Methods Sera from 22 latex-allergic patients and 22 control subjects with no evidence of allergy to latex or to banana were studied. All patients had positive and controls negative reactions in skin-prick testing using an eluate of latex gloves. IgE antibodies to natural rubber latex and to banana were evaluated by immunoblotting and by radioailergosorbent test (RAST) and crossreactivity between allergens in banana and natural rubber latex by immunoblot inhibition. Skin-prick testing was used to examine in vivo reactivity to banana. Results Ten of the 22 (45%) latex-allergic patients sera recognized altogether 14 allergens in banana by immunoblotting. The most frequently identified banana allergens were 23, 32, 36, 39 and 47kDa proteins. The banana skin-prick test was positive in 14 of 18 (78%) latex-allergic patients studied and banana RAST in 12 of 14 patient sera tested. Fourteen of 21 interviewed patients reported symptoms from eating or handling bananas. In immunoblot inhibition studies a dose-dependent inhibition of IgE binding to banana extract with natural rubber latex proteins was observed in all five patient sera tested and, likewise, the binding of IgE to natural rubber latex extract was inhibited with banana proteins in four of the five patient sera. Conclusions The present results confirm the existence of crossreacting allergens in natural rubber latex and banana and provide new information on the immunochemical nature and heterogeneity of these allergens.