Lupus Nephritis - Histology

What is Lupus Nephritis?

Lupus nephritis is an inflammation of the kidneys caused by systemic lupus erythematosus (SLE), an autoimmune disease. The condition occurs when the body's immune system mistakenly attacks its own tissues, including the kidneys. This can lead to impaired kidney function and, in severe cases, kidney failure.

Histological Features of Lupus Nephritis

Histologically, lupus nephritis is characterized by a variety of changes in the glomeruli, tubules, interstitium, and blood vessels of the kidneys. These changes can be observed and classified through kidney biopsy.

Glomerular Changes

The glomeruli often show a range of alterations, including increased cellularity, capillary wall thickening, and the presence of immune complexes. Key features include:

Mesangial proliferation: Increase in mesangial cells and matrix.
Endocapillary proliferation: Involves endothelial cells, mesangial cells, and infiltrating leukocytes.
Wire loop lesions: Immune complex deposition leading to capillary wall thickening.
Crescents: Proliferation of cells in Bowman's space, often indicating severe disease.

Tubulointerstitial Changes

In lupus nephritis, the tubulointerstitial compartment may show signs of inflammation, fibrosis, and tubular atrophy. These changes can contribute significantly to the overall renal dysfunction in affected patients.

Vascular Changes

The blood vessels in the kidneys may also be affected, showing signs of vasculitis, thrombi, or immune complex deposition. These vascular changes can exacerbate the damage to the renal tissue and impair kidney function.

Classification of Lupus Nephritis

The International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification system is commonly used to categorize lupus nephritis based on histological findings:

Class I: Minimal mesangial lupus nephritis
Class II: Mesangial proliferative lupus nephritis
Class III: Focal lupus nephritis
Class IV: Diffuse lupus nephritis
Class V: Membranous lupus nephritis
Class VI: Advanced sclerosing lupus nephritis

Diagnosis and Prognosis

Diagnosis of lupus nephritis typically involves a combination of clinical, laboratory, and histological evaluations. A renal biopsy is essential for accurate classification and assessment of the extent of renal involvement. The prognosis varies depending on the class and severity of the histological findings. Early diagnosis and treatment are crucial for improving outcomes.

Treatment

Treatment of lupus nephritis aims to reduce inflammation and suppress the immune response. Common therapies include corticosteroids, immunosuppressive drugs, and biologics. The choice of treatment often depends on the histological class and severity of the disease.

Conclusion

Lupus nephritis is a complex condition with diverse histological manifestations. Understanding these changes is essential for accurate diagnosis, classification, and management. Ongoing research continues to enhance our knowledge and treatment of this challenging disease.