Non infective colitis in infancy: evidence in favour of minor immunodeficiency in its pathogenesis.

Forty two infants below the age of two years presenting with chronic non infective diarrhoea and shown to have histologically proven colitis were investigated over a five year period at this hospital. Allergic colitis was the most common cause of colitis accounting for sixty two percent of the cases. Other colitides diagnosed included: non specific colitis, autoimmune enterocolitis and ulcerative colitis accounting for 9.5% each, severe combined immunodeficiency 7.1% and Crohn's disease 2.8%. A positive family history and a personal history of atopy was obtained in 47.6% and 28.6% of the cases. Serum immunoglobulin A, IgG2 and IgG4 were very low in over 50% of the infants with colitis. Sixty six percent of those with severe combined immunodeficiency, autoimmune enterocolitis and ulcerative colitis (n = 11) had low CD3 and CD4 T lymphocytes with an accompanying elevated CD8 in 2/3 of those with severe combined immunodeficiency. T lymphocytes were normal in those with allergic colitis. We conclude that infants with proven non infective colitis show as a group a high prevalence of IgA, IgG2 and IgG4 deficiency. It is likely that this minor deficiency of mucosal associated immunoglobulin production have a role in the pathogenesis of the colitic process.