Immunophenotype in orofacial granulomatosis with and without Crohn's disease

The aim of this investigation was to characterise and compare the inflammatory infiltrates in patients with orofacial granulomatosis solely (OFG-S) and OFG with coexisting Crohn's disease (OFG+CD). Biopsy specimens with granulomas were obtained from patients with OFG-S (n=11) and OFG+CD (n=11) and immunostained with antibodies against CD1a, CD3, CD4, CD8, CD11c, CD20, CD68 and mast cell tryptase, followed by quantitative analysis. Analyses of the connective tissue revealed a significantly higher number of CD3-expressing T cells and CD11c-expressing dendritic cells in the connective tissue of patients with OFG-S compared to patients with OFG+CD. Mast cells displayed a high level of activation, although no significant difference was detected when comparing the two groups. The results show a different composition of the inflammatory infiltrate in patients with OFG-S compared to patients with OFG+CD. The present observations support that partly-divergent immune mechanisms are involved in these two different subcategories of OFG.