The role of RNP, Sm, and SS-A/Ro-specific antisera from patients with lupus erythematosus in inducing antibody-dependent cellular cytotoxicity (ADCC) of targets coated with nonhistone nuclear antigens

To better understand potential antibody-dependent mechanisms of tissue damage in lupus erythematosus (LE), an examination of whether antibodies to nonhistone nuclear antigens in LE patients' sera can induce ADCC of cellular targets coated with the corresponding antigens was undertaken. With high titer anti-RNP sera, significant ADCC was seen with monocyte (P < 0.01). T-lymphocyte (P < 0.001), and low-density lymphocyte (P < 0.001) effectors. Using monocyte effectors, significant ADCC was seen with anti-RNP (P < 0.01), anti-Sm (P < 0.01), and anti-SSARo (P < 0.01), with the most profound lysis being with the anti-SSARo sera. Neutrophils were ineffective in any nuclear antigen-antibody system tested. The effective mononuclear cell-mediated ADCC seen with anti-RNP, anti-Sm, and anti-SSA antisera may be related to the mononuclear cell-associated tissue change seen in cutaneous lupus lesions.