Precipitating antibodies tonuclear antigens insystemic vasculitis

SUMMARY We haveexamined serafrom61patients withsystemic vasculitis forprecipitating antibodies tocomponents ofsaline tissue extracts. Precipitins wererareinpatients with polyarteritis nodosa (PAN)andtheir absence helped todistinguish PAN fromvasculitis associated withother connective tissue diseases. Precipitins weredetected insomepatients withother vasculitides. Previously described precipitating antibodies (anti-Ro [SSA] and anti-La [SSB]) wererestricted toa fewpatients withfeatures ofsystemic lupus erythematosus (SLE). A different, asyetunidentified, precipitin whichreacted witha component ofrabbit thymus extract butnotcalf thymus orhumanspleen extracts was detected inmanypatients withrheumatoid disease. Thisprecipitin waspresent inall patients withactive rheumatoid vasculitis (RV)aswellas52%ofpatients with uncomplicated butactive rheumatoid synovitis. Higher titres ofprecipitating antibody werepresent inpatients withactive RV thanthose withinactive RV oruncomplicated rheumatoid synovitis, andserial studies showedagoodcorrelation between afall in antibody titre andhealing ofvasculitis withtreatment. Thesestudies suggest that this unidentified precipitin maybeanimportant marker ofRV.