Since little is known about the expression pattern in even the most common (systemic) autoimmune diseases, we examined the role of three Bcl-2 family members, B cell lymphoma-2 (Bcl-2), B cell lymphoma extra-large (Bcl-XL), and myeloid cell leukemia-1 (Mcl-1) in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This evidence concerns the gene MCL1 and systemic lupus erythematosus.