Gene expression profiles in human autoimmune disease

To acquire a functional view of human autoimmunity, we compared differences in gene expression (>4000 genes) in the peripheral blood mononuclear cells of normal individuals following immunization to those in individuals with four different autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, insulin dependent diabetes mellitus, and multiple sclerosis). Each individual from all disease groups displayed a similar pattern of gene expression that was highly distinct from the gene expression pattern of the immunized group. These findings indicate that the expression pattern accompanying autoimmunity is not simply a recapitulation of the immune response to non-self. Of note, expression levels of genes that encode key proteins in several distinct apoptosis pathways were markedly reduced in all autoimmune disease groups. Taken together, these data indicate that the pattern of gene expression describes a molecular portrait of autoimmunity that is constant among individuals with autoimmune disease but is independent of the specific autoimmune disease and the clinical parameters associated with any individual autoimmune disease.