The heat shock proteins hsp90 and hsp70 have been shown to be over-expressed in peripheral blood mononuclear cells from SLE patients. We show, however, that transcription of the three genes encoding the small hsp ubiquitin is not enhanced in these patients. The over expression of hsp90 and hsp70 in SLE is likely therefore to reflect cellular events resulting in the specific induction of these hsps rather than a generalized induction of all hsp synthesis due to the stress of the disease or the presence of fever.