his or her being is N~， s ~，stem is perfect， not eon tlx marveiol<br >n s unique identitv complex immune ~vskm~. The contrcG thai l~rc ~，l<br >e: my mind， or my coils， macropha~，es mlct o{her cellular agerds of im~<br > immure， system nitv from attacking host tissue can fail. ()r an anti<br >llldid，llR. From be- cml so closdv rusemble host tissue that l.he ath~d，<br >ike the porter who cells do m~t distinguish friend from foc a biolo~<br >Nve club， contmu- analogk e t~ "frie:~dlv fire." Such mall:m~(iion pro(<br >ntities that are part tates multiple sclerosis， rheumatoid arthritis， svste<br >those that are not. lupus， mvasthcmia grads and a deprcs<n，~]y long<br > r 1993 isstlo of ，q</ of: other autoimmunc， diseases.<br >ritafi~e portrait of .Sometimes lilt imi/lune svsteln o.ln <lcl {oo ~<br >L~ld ot medical <mcl ously， l)efense against parasik，s depends im tilt a<br > itv to produce ]aEe 0nlt~tln{.s o| <ill alltibody，<br >tes tim system has munoglobulhl fil (lgE). In lhe artificial envirt)nnlcn<br >kiilcts o! alitm l.m~- industria! society， par<lsites seldom thrcatt，l~ 011VOl<br >laps in tile l:t~rm {~f hc alth Bereft o! its primary tar~4el tglT.， produccc:<br >in-studded surface copious amounls， triggers allergic rc， aclions t~ ~>tl<br >unlcmshes what is relatively benign antigens lurking in the exlrt nal<br >primary agents of virommmt or di~ t<br >mlclcvtcs and netl-- In mmxinolo~y as in other discipliiics， knowk，c<br >d other defunsivc， is power. ，rixquisite ul~derst<lndin~ of thc inlnlui/c s<br > cn~ulf anti digest b. m s structure and hJncti，，m h<m < nabIc，d rttst，，mll<br ><，ing a barrage of to begin to equip clinician~> with powrrtuI wt，af>~<br > a~aillsl， dtltoinlllltlnc disc"ase， int:ccl.iotls ciiseasr t~<br >; own lissuc，s this allergy. New weapons againsl calk:er and ck，tl w，/v~<br >e moilths before induce the acceptano， of surgical f，>rafts <ire<br >m learns tc~ re!cog- prospect. The immtme svstem ilsrlt， clinici<ms arc<br >tv s own tissues， covering， is a powerful lnedic<il and surgical im<br > histocompatibil- lllen{.<br >t( molecule s are Disease， however， has not vet iorlcqtud !he<br >an individual be- lau~_;h. AI[)S so far resists all dforts ，/1 dlemic， iI tl<br > cilancc t)t <illvt)no 13iellt or prevention. Still some combr{ c~/n bc tak<br >411(_ molecules is ttad lily struck even 10 years earlier m>l enotl<br >