ABSTRACT
There is little doubt that the immune system is abnormal in myelodysplastic syndromes (MDS), but exactly how it is impaired and why remains in dispute. Some evidence points to a fundamental defect at a stem cell level that permeates the lymphoid system in the same way that the myeloid system is affected. However, it is possible that all the immune system abnormalities can be explained by defects in the effector functions of phagocytic cells or by dysfunctional antigenic presentation by dendritic cells of myelomonocytic origin. This is the fourth in a series of reviews that this author has written on this subject (1-3) and in order to avoid duplicate publication, extensive reference to the first three articles is made. This chapter concentrates on new information and insights since 1995.
