Anomalous leukopoiesis in two patients with Crohn's disease

Crohn's disease is a major form of chronic inflammatory bowel disease in the western world. The molecular genetic basis of Crohn's disease is unknown. In this study, we present evidence for anomalous leukopoiesis-namely, the generation of a leukocyte subset characterized by aberrant expression of gammadelta T cell receptor (gammadeltaTCR) with or without CD19 on a myeloid background-in two patients with Crohn's disease. The aberrant cells of patient 1 have the surface phenotype gammadeltaTCR + CD19 - CD14 + CD64 +. The aberrant cells of patient 2 have the surface phenotype gammadeltaTCR + CD19 + CD14 - CD64 + CD16 + CD13 + CD33 +. The results presented here are significant both in light of recent speculation that a critical defect in Crohn's disease may be at the level of hematopoiesis and because the CD19 gene lies within the region on chromosome 16 that corresponds with the Crohn's disease susceptibility locus IBD1.