- Cathepsin-L influences the expression of extracellular matrix in lymphoid organs and plays a role in the regulation of thymic output and of peripheral T cell number. Lombardi, G., Burzyn, D., Mundiñano, J., Berguer, P., Bekinschtein, P., Costa, H., Castillo, L.F., Goldman, A., Meiss, R., Piazzon, I., Nepomnaschy, I. J. Immunol. (2005)