Background and Aims

Renal involvement in systemic lupus erythematosus (SLE) include several pathological conditions, but mostly, it is associated with immune complex-induced glomerular disease.

Methods

Pauci-immune glomerulonephritis is a rare condition in patients with SLE, so we report two cases.

Results

Case 1: 39 years old female diagnosed previously as having SLE with articular, cutaneous and renal involvement, antinuclear and anti-dsDNA antibodies presense. First renal biopsy disclosed diffuse lupus nephritis (LN) (type IV A/C). It was used to treat with cyclophosphamide and mycophenolate. Due to persistence of a protein/creatinine ratio 400-600 mg/g, normal urinary sediment, high levels of anti-ds DNA antibodies, low levels of C3 and absence of antineutrophil cytoplasmic antibodies (ANCA), another renal biopsy was performed showing class IV-S LN with pauci-immune features by immunofluorescence.

Case 2: 75 years old female diagnosed previously as having SLE with severe thrombocytopenia that required methylprednisolone, immunoglobulins, rituximab, spelenctomy and eltrombopag. Antinuclear, anti-dsDNA and antiphospholipid antibodies presence. First renal biopsy disclosed focal LN (type III A/C), treated with mycophenolate. Due to an increase of the protein/creatinine ratio to 2009 mg/g, normal urinary sediment, high levels of anti-ds DNA antibodies, low levels of C3/C4 and absence of ANCA, another renal biopsy was performed showing class III-S LN with pauci-immune features by immunofluorescence.

Conclusions

Pauci-immune glomerulonephritis have been found to be ANCA positive, but 10–30% of the cases can be ANCA negative. Although LN is widely associated with a full-house pattern in immunofluorescence, it is known that pauci-immune glomerulonephritis is a rare variant of LN, so is important realize renal biopsy.