C4A and systemic lupus erythematosus: Currently, commonly utilized laboratory markers for diagnosing SLE, particularly LN include, antinuclear antibodies (ANA), anti-double-stranded deoxyribonucleic acid (anti-dsDNA) antibodies, serum complements (C3 and C4), serum creatinine (SCr), urinary protein, and glomerular filtration rate7,8.