Combining these data with transcriptomic analyses, flow cytometry, confocal microscopy, urine proteomics, and serum ELISA, we identified Lysosomal‐associated membrane protein 1 (LAMP1) as a differentially abundant protein on the surface of neutrophils from lupus patients and identified soluble LAMP1 in urine and serum as correlating with proliferative lupus nephritis. The gene discussed is LAMP1; the disease is systemic lupus erythematosus.