The pathogenesis of autoimmune diseases is only partially understood.
In particular, the question remains why many nuclear proteins have bee
n identified as autoantigens. One possible mechanism for an autoimmune
response to nuclear proteins involves their exposure to the immune sy
stem. In this report we discuss currently available data on the exposu
re of nuclear proteins by expression at the cell-surface. Although the
pathways of surface expression remain unclear, the presence of nuclea
r proteins at the cell-surface might reflect a pathological reaction l
eading to an exposure of epitopes, e.g. to self-reactive B-cells. It i
s suggested that cell-surface expression of intracellular proteins can
contribute to the generation of autoimmune diseases.