Un­der­stand­ing al­ler­gic symp­toms and ige

Cel­e­brat­ing the 50 year an­niver­sary of the dis­cov­ery of Im­munoglob­u­lin E

In Flight Magazine - - BIG, BUTCH & UNSTOPPABLE -

Most peo­ple are aware that al­ler­gic symp­toms are caused by the re­lease of pow­er­ful sig­nal sub­stances such as his­tamine that can cause ev­ery­thing from mild re­ac­tions such as a runny nose or skin rash to se­vere symp­toms such as asthma, eczema and even sys­temic shock. But it wasn’t un­til the 1980s that sci­en­tists un­der­stood how these symp­toms came about – or the cen­tral part that IgE an­ti­bod­ies played in the process. In prin­ci­ple, al­ler­gic re­ac­tions are mis­guided in­flam­ma­tory re­ac­tions trig­gered by nor­mally harm­less sub­stances from our day-to-day en­vi­ron­ment – al­ler­gens. An al­ler­gen is typ­i­cally a pro­tein found in for ex­am­ple plant pol­lens, an­i­mal dan­der and foods such as peanut, egg and milk. In al­ler­gic in­di­vid­u­als, one or more of these al­ler­gens may be recog­nised as po­ten­tially dan­ger­ous. On first ex­po­sure, their im­mune sys­tem starts to pro­duce an­ti­bod­ies that can bind to that anti­gen to pro­tect the in­di­vid­ual in the fu­ture. In atopic al­lergy (the most com­mon type of al­lergy), the an­ti­body formed is IgE. It was dis­cov­ered that an al­ler­gic in­di­vid­ual’s ‘mem­ory’ of hav­ing first been ex­posed to an al­ler­gen is stored as IgE an­ti­bod­ies at­tached side-by-side on a spe­cial type of white blood cell. These blood cells, known as mast cells, con­tain the pow­er­ful sig­nal sub­stances that on their re­lease cre­ate the in­flam­ma­tory re­sponse we call al­lergy. On sec­ond ex­po­sure, sen­si­tized in­di­vid­u­als may suf­fer a re­ac­tion if the al­ler­gen cross-links ad­ja­cent IgE an­ti­bod­ies, trig­ger­ing the re­lease of the in­flam­ma­tory chem­i­cals from in­side the mast cell. This is why mea­sur­ing lev­els of IgE an­ti­bod­ies in blood is a good way of de­ter­min­ing the risk of al­ler­gic re­ac­tion, and why IgE-test­ing is still a leader in al­lergy di­ag­nos­tics. The rest is his­tory. IgE his­tory.

Re­search in the 80’s demon­strated ex­actly how IgE binds to other com­pounds, based on a deeper in­sight into IgEre­cep­tors, which opened the door to a bet­ter un­der­stand­ing of the ori­gin of al­ler­gic symp­toms.

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