Ahlroth M, Alenius H, Turjanmaa K, Mäkinen-Kiljunen S, Reunala T, Palosuo T
Department of Immunobiology, National Public Health Institute, Helsinki, Finland.
J Allergy Clin Immunol. 1995 Aug;96(2):167-73. doi: 10.1016/s0091-6749(95)70004-8.
An association between allergy to latex and avocado has been reported but the responsible cross-reacting allergens have not been identified or characterized.
Immunoblotting, immunoblot inhibition, and RAST inhibition methods were used to study cross-reactive proteins between natural rubber latex (NRL) and avocado. Sera from 18 patients with previously verified latex allergy were used as the source of IgE antibodies, and 11 of the patients underwent skin prick testing with fresh avocado.
Fourteen of the 18 sera (78%) had IgE antibodies that bound to a total of 17 avocado proteins with apparent molecular weights ranging from 16 to 91 kd. Ten most strongly reacting sera were used for immunoblot inhibition studies. When NRL proteins were used as soluble inhibitors, binding of IgE antibodies to solid-phase avocado proteins was inhibited in a dose-dependent manner: 100 micrograms of NRL proteins inhibited IgE binding to 15 of the 17 avocado proteins, and 10 micrograms caused inhibition to 13 protein bands. Comparably, soluble avocado proteins were able to inhibit IgE binding to solid-phase NRL. Corresponding RAST inhibitions were performed with two patient sera; in both, avocado inhibited IgE binding to NRL and in one NRL proteins inhibited IgE binding to avocado. Skin prick test responses to fresh avocado were positive in seven of the 11 patients with latex allergy who were tested.
The large number of inhibitable proteins in immunoblot experiments and clinical observations from skin prick tests suggest considerable immunologic cross-reactivity between NRL and avocado. The observed cross-reacting protein components may be responsible for the recently reported type I hypersensitivity reactions to NRL and avocado in patients with a preexisting allergy to either allergen.
已有报道称乳胶过敏与鳄梨过敏之间存在关联，但尚未确定或鉴定出起交叉反应作用的过敏原。
采用免疫印迹、免疫印迹抑制和RAST抑制方法研究天然橡胶乳胶（NRL）与鳄梨之间的交叉反应蛋白。18例先前已证实乳胶过敏患者的血清用作IgE抗体来源，其中11例患者用新鲜鳄梨进行皮肤点刺试验。
18份血清中的14份（78%）含有IgE抗体，这些抗体与总共17种鳄梨蛋白结合，其表观分子量在16至91kd之间。使用10份反应最强的血清进行免疫印迹抑制研究。当NRL蛋白用作可溶性抑制剂时，IgE抗体与固相鳄梨蛋白的结合呈剂量依赖性抑制：100微克NRL蛋白抑制IgE与17种鳄梨蛋白中的15种结合，10微克则抑制13条蛋白带。同样，可溶性鳄梨蛋白能够抑制IgE与固相NRL的结合。用两份患者血清进行了相应的RAST抑制试验；在两份试验中，鳄梨均抑制IgE与NRL的结合，在一份试验中NRL蛋白抑制IgE与鳄梨的结合。在接受检测的11例乳胶过敏患者中，7例对新鲜鳄梨的皮肤点刺试验反应呈阳性。
免疫印迹实验中大量可抑制的蛋白以及皮肤点刺试验的临床观察结果表明，NRL与鳄梨之间存在相当程度的免疫交叉反应。观察到的交叉反应蛋白成分可能是先前对任何一种过敏原过敏的患者最近报道的对NRL和鳄梨的I型超敏反应的原因。
