Reactivities of systemic lupus erythematosus sera with cellular and virus antigen preparations

Sera of patients with systemic lupus erythematosus (SLE) showed significantly higher complement fixation reactivities with 8 of 10 virus antigen preparations compared to sera of normal subjects, including virus workers, confirming earlier observations. However, one-third of SLE sera were also reactive with cellular antigens, prepared in a manner identical to viral antigens, but from cells not infected with virus. By contrast, only one of 49 normal sera showed reactivity with one of nine cellular antigens, at a minimal titer. Apparently heightened reactivities of SLE sera with virus antigens could be explained in many instances on the basis of reactions with cellular antigens. Serum reactivities with nonviral tissue antigens in SLE must be considered in interpretation of immunologic studies related to viruses and SLE.