Colonic CD8 and gamma delta T-cell infiltration with epithelial damage in children with autism.
OBJECTIVE
We have reported colitis with ileal lymphoid nodular hyperplasia (LNH) in children with regressive autism. The aims of this study were to characterize this lesion and determine whether LNH is specific for autism.


METHODS
Ileo-colonoscopy was performed in 21 consecutively evaluated children with autistic spectrum disorders and bowel symptoms. Blinded comparison was made with 8 children with histologically normal ileum and colon, 10 developmentally normal children with ileal LNH, 15 with Crohn's disease, and 14 with ulcerative colitis. Immunohistochemistry was performed for cell lineage and functional markers, and histochemistry was performed for glycosaminoglycans and basement membrane thickness.


RESULTS
Histology demonstrated lymphocytic colitis in the autistic children, less severe than classical inflammatory bowel disease. However, basement membrane thickness and mucosal gamma delta cell density were significantly increased above those of all other groups including patients with inflammatory bowel disease. CD8(+) density and intraepithelial lymphocyte numbers were higher than those in the Crohn's disease, LNH, and normal control groups; and CD3 and plasma cell density and crypt proliferation were higher than those in normal and LNH control groups. Epithelial, but not lamina propria, glycosaminoglycans were disrupted. However, the epithelium was HLA-DR(-), suggesting a predominantly T(H)2 response.


CONCLUSIONS
Immunohistochemistry confirms a distinct lymphocytic colitis in autistic spectrum disorders in which the epithelium appears particularly affected. This is consistent with increasing evidence for gut epithelial dysfunction in autism.
University Department of Paediatric Gastroenterology, the Inflammatory Bowel Diseases Study Group, Royal Free and University College School of Medicine, London, United Kingdom.
R I
RI
Furlano
A
A
Anthony
R
R
Day
A
A
Brown
L
L
McGarvey
M A
MA
Thomson
S E
SE
Davies
M
M
Berelowitz
A
A
Forbes
A J
AJ
Wakefield
J A
JA
Walker-Smith
S H
SH
Murch
D000293:Adolescent; D001321:Autistic Disorder / Q000150:complications* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000150:complications / Q000276:immunology* / Q000473:pathology; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D008206:Lymphatic Diseases / Q000150:complications / Q000276:immunology* / Q000473:pathology; D008297:Male; D013601:T-Lymphocytes / Q000378:metabolism*