Complement activation within thecoeliac small intestine islocalised toBrunner's glands

localisation ofC3andofa neoantigen exposed only on theterminal C5b-9complement complex hasbeenperformed on smallintestinal biopsy sections fromnewlydiagnosed untreated coeliac patients, fromcoeliac patients onlong-term glutenfree diet andfromdisease controls. Levels ofC3weremarkedly increased intreated coeliac patients compared withcontrols. Staining ofC3was concentrated subepithelially andwithin thecentre ofthe lamina propria. Nostaining was detected atthese sites using antibody totheneoantigen, however, strongly suggesting thattheincreased levels ofC3 seeninthecoeliac patients was theresult of increased extravasation ofserum proteins rather thancomplement activation. Surprisingly, complement activation was detected within theglands ofBrunner. Positive staining using anti-C5b-9 neoantigen was foundinallcoeliac patients, bothtreated anduntreated. Threeofthe13disease controls also showedreactivity withthis antibody. Thisnovel finding suggests thatBrunner's glands, hitherto largely neglected structures, may play an important roleinthedevelopment ofcoeliac