Juan C. Andreu-Ballester, Carlos Garcia-Ballesteros, Victoria Amigo, Ferran Ballester, Rafael Gil-Borrás, Ignacio Catalán-Serra, Angela Magnet, Soledad Fenoy, Carmen del Aguila, Jose Ferrando-Marco, Carmen Cuéllar

The cause of Crohn's Disease (CD) remains unknown. Recently a decrease in the global lymphocyte population in the peripheral blood of CD patients has been reported. This decrease was more evident in γδ T lymphocytes, especially γδ CD8+T subsets. Furthermore, a decrease of IL-7 was also observed in these patients. We propose the hypothesis that microsporidia, an obligate intracellular opportunistic parasite recently related to fungi, in CD patients can take advantage of the lymphocytes and IL-7 deficits to proliferate and to contribute to the pathophysiology of this disease.