Lupus nephritis and kidney transplantation: A narrative review of patient and graft outcomes

Table 2 Markers of disease activity in lupus nephritis

Marker	Type	Significance for disease activity	Clinical implications
Anti-dsDNA antibodies	Serological	Correlate with disease activity and renal involvement	Rising titers often precede LN flares; useful for monitoring
Serum creatinine	Clinical	Reflects renal function and progression	Elevated levels indicate impaired kidney function and possible ESKD
Complement C3 and C4	Serological	Low levels indicate complement consumption due to active immune complex disease	Hypocomplementemia is a marker of active LN and flare risk
Anti-C1q antibodies	Serological	Associated with immune complex deposition and LN activity	Predictive of renal involvement and poor prognosis
Anti-chromatin antibodies	Serological	Linked to active nephritis and systemic disease	May serve as adjunct marker for LN activity
Anti-Sm antibodies	Serological	Specific for SLE, associated with severe disease	Presence indicates higher risk of multi-organ involvement
Anti-ribosomal P autoantibodies	Serological	Associated with neuropsychiatric lupus and systemic activity	May complicate LN with extra-renal manifestations
Serum IFN-I	Serological	Reflects immune dysregulation and ongoing inflammation	Elevated levels linked to refractory disease and poor outcomes
MCP-1	Urinary	Marker of renal inflammation and monocyte recruitment	Elevated levels predict LN activity and progression
BAFF	Urinary	Promotes B-cell survival and autoantibody production	High levels associated with LN activity and relapse risk
MMP-7	Urinary	Reflects tissue remodeling and renal injury	Elevated levels linked to chronic damage and poor prognosis
IgG, IgA, IgM deposits	Histological (biopsy)	Indicate immune complex-mediated glomerular injury	Presence confirms LN diagnosis and activity
C1q, C3 deposits	Histological (biopsy)	Evidence of complement activation in renal tissue	Associated with active LN and severity of disease
Tissue ANA	Histological (biopsy)	Nuclear antigen deposition in kidney tissue	Supports diagnosis of LN and immune-mediated injury
Extraglomerular immune deposits	Histological (biopsy)	Indicate widespread immune complex deposition	Associated with severe LN and poor prognosis
Endothelial tubular reticulum inclusion bodies	Histological (biopsy)	Reflect interferon activity and immune activation	Linked to active LN and systemic disease burden

Anti-dsDNA: Anti-double-stranded deoxyribonucleic acid; LN: Lupus nephritis; ESKD: End-stage kidney disease; anti-C1q: Anti-complement component 1q; anti-Sm: Anti-Smith; SLE: Systemic lupus erythematosus; IFN-I: Type I interferon; MCP-1: Monocyte chemoattractant protein-1; BAFF: B-cell activating factor; MMP-7: Matrix metalloproteinase-7; Ig: Immunoglobulin; C3: Complement component 3; C1q: Complement component 1q; ANA: Antinuclear antibody.