Methods of treating autoimmune diseases, such as diabetes, characterized by faulty MHC class I antigen complex presentation are disclosed which involve exposure of the immune system of an individual susceptible to such disease to correctly associated MHC class I antigen complexes. Such treatment may involve obtaining cells from the individual, treating the cells to correct faulty MHC class I antigen presentation, then reinfusing the treated cells. Alternatively, syngeneic or haplotype-matched allogeneic lymphoid cells expressing normal levels of MHC class I antigen complexes may be used or intact MHC class I antigen complexes isolated from such lymphoid cells may be used in such treatment.