Presence of bacteria and innate immunity of intestinal epithelium in childhood celiac disease.
OBJECTIVE
Exposure to gliadin and related prolamins and appropriate HLA-DQ haplotype are necessary but not sufficient for contracting celiac disease (CD). Aberrant innate immune reactions could be contributing risk factors. Therefore, jejunal biopsies were screened for bacteria and the innate immune status of the epithelium investigated.


METHODS
Children with untreated, treated, challenged CD, and controls were analyzed. Bacteria were identified by scanning electron microscopy. Glycocalyx composition and mucin and antimicrobial peptide production were studied by quantitative RT-PCR, antibody and lectin immunohistochemistry.


RESULTS
Rod-shaped bacteria were frequently associated with the mucosa of CD patients, with both active and inactive disease, but not with controls. The lectin Ulex europaeus agglutinin I (UEAI) stained goblet cells in the mucosa of all CD patients but not of controls. The lectin peanut agglutinin (PNA) stained glycocalyx of controls but not of CD patients. mRNA levels of mucin-2 (MUC2), alpha-defensins HD-5 and HD-6, and lysozyme were significantly increased in active CD and returned to normal in treated CD. Their expression levels correlated to the interferon-gamma mRNA levels in intraepithelial lymphocytes. MUC2, HD-5, and lysozyme proteins were seen in absorptive epithelial cells. beta-defensins hBD-1 and hBD-2, carcinoembryonic antigen (CEA), CEA cell adhesion molecule-1a (CEACAM1a), and MUC3 were not affected.


CONCLUSIONS
Unique carbohydrate structures of the glycocalyx/mucous layer are likely discriminating features of CD patients. These glycosylation differences could facilitate bacterial adhesion. Ectopic production of MUC2, HD-5, and lysozyme in active CD is compatible with goblet and Paneth cell metaplasia induced by high interferon-gamma production by intraepithelial lymphocytes.
Forsberg
Göte
G
Department of Clinical Microbiology and Immunology, Umeå University, Umeå, Sweden.
Fahlgren
Anna
A
Hörstedt
Per
P
Hammarström
Sten
S
Hernell
Olle
O
Hammarström
Marie-Louise
ML
D000293:Adolescent; D001419:Bacteria / Q000302:isolation & purification; D001483:Base Sequence; D016022:Case-Control Studies; D002446:Celiac Disease / Q000276:immunology* / Q000382:microbiology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D015169:Colony Count, Microbial; D046508:Culture Techniques; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology*; D007150:Immunohistochemistry; D007223:Infant; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology; D007421:Intestine, Small / Q000473:pathology* / Q000648:ultrastructure*; D008297:Male; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D011336:Probability; D012329:RNA, Bacterial; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D018709:Statistics, Nonparametric
D012329:RNA, Bacterial