Provided herein are methods of diagnosing and monitoring disease activity and response to treatment in patients having systemic lupus erythematosus using panels of biomarkers, such as at least one biomarker selected from the group consisting of B-lymphocyte-bound C4d, erythrocyte-bound C4d, platelet-bound C4d, and erythrocyte complement receptor type 1, and one further biomarker selected from the group consisting of anti-MCV antibody and anti-nuclear antibody.