Back
Although anti-neutrophil cytoplasmic antibodies (ANCA) were first associated with primary vasculitides, it is now clear that 15-20% of lupus patients have detectable ANCA, in some cases even though histology is negative. They are the ones that make us suspect the positivity of these antibodies.
A 29-year-old female with SLE diagnosed in 2019 presented hematological and mucocutaneous disease, ANAs laboratories 1:160, with induction treatment for one year based on azathioprine, prednisone and maintenance with hydroxychloroquine. In 2021 she presents with proteinuria of 672 mg and hematuria, creatinine of 0.9 mg/dl, treatment with mycophenolic acid. One year later she had increased proteinuria 703 mg/dl, anti-DNA DS 175 U/ml (negative) C3 127 C4 25.3, ANCAs PR3 and MPO negative. She integrates hematuria proteinuria syndrome, without deterioration of renal function, eucomplementemic. Kidney biopsy active extracapillary hypercellularity, cellular crescents with active extracapillary lesion with fibrocellular crescents. Prominent and vacuolated podocytes, interstitium with patches of fibrosis with tubular atrophy, IFI with positive IGG, positive C3C granular pattern in the mesangium, determining active and chronic extracapillary proliferative glomerulonephritis with scant deposits of immune complexes (pauciimmune). By histopathology, due to cellular and fibrocellular crescents with pauciimmunity, ANCA-negative vasculitis is suspected. Therefore, treatment with cyclophosphamide was started, with subsequent improvement of proteinuria.
Crescentic glomerulonephritis is a severe form of glomerular lesion characterized by rupture of the glomerular basement membrane, cell proliferation within Bowman's space and fibrinoid necrosis, involving little or no immunoglobulin deposition at the glomerular level, which is why it is called pauciimmune.
This type of lesions associated with SLE are very rare and more in the context of negative ANCA, we present the case to take into account this type of histological presentation.