In systemic lupus erythematosus, autoantibodies can target which cellular components?

• A. Cell surface components only
• B. Nuclear proteins only
• C. Cell surface, cytoplasmic, and nuclear components
• D. Cytoplasmic enzymes only

Answer: (C)

In SLE, autoantibody production spans multiple cellular compartments because loss of tolerance leads to antibodies against a broad range of self-antigens. While nuclear antigens like DNA, histones, and ribonucleoproteins are classic targets and drive many disease manifestations through immune complex deposition, autoantibodies can also recognize components on the cell surface and in the cytoplasm. These antibodies can cause tissue injury either by forming circulating immune complexes that deposit in organs (such as kidneys) or by directly targeting and altering circulating cells (leading to cytopenias) and contributing to vascular inflammation. Antiphospholipid antibodies add a prothrombotic dimension as well. So, antibodies in lupus can target cell surface, cytoplasmic, and nuclear components, making that broad target range the best description.