What question did this study set out to answer?

This research investigates the occurrence of acute renal failure in patients with dual positivity for MPO and PR3 antibodies, particularly in the context of systemic lupus erythematosus (SLE).

May 20, 2026

A35-20 Acute Renal Failure in Setting of Mpo/pr3 Anca Vasculitis and Systemic Lupus Erythematous Overlap

Puntos clave

This research investigates the occurrence of acute renal failure in patients with dual positivity for MPO and PR3 antibodies, particularly in the context of systemic lupus erythematosus (SLE).
Patient case report of a 74-year-old female with eGFR decline and symptoms of nephritic syndrome.
Serological tests were performed to identify P-ANCA, MPO, and PR3 antibodies; renal biopsy was attempted.
Treatment included IV methylprednisolone, oral prednisone, and prophylaxis for pneumonia.
Patient exhibited acute renal failure with eGFR dropping from 23 to 7.
Dual positivity for MPO and PR3 antibodies was detected, along with a diagnosis of SLE.
Early intervention with hemodialysis and immunosuppressive therapy was initiated, emphasizing the need for broad differential diagnoses in nephritic syndrome.

Resumen

Abstract Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) includes rare autoimmune conditions that result in inflammation of blood vessels and can be categorized into one of five syndromes. The three main syndromes include granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). Perinuclear staining (P-ANCA) is most associated with myeloperoxidase (MPO) antibody (Ab) positivity, whereas cytoplasmic staining (C-ANCA) is most associated with proteinase 3 (PR3) Ab positivity. In the setting of AAV, dual positivity to MPO and PR3 is uncommon. The patient is a 74-year-old female with a past medical history of Hashimoto’s hypothyroidism initially had an outpatient basic metabolic panel (BMP) which showed an estimated glomerular filtration rate (eGFR) of 23. Since the patient was previously in CKD stage IIIb, a repeat BMP was ordered as outpatient and the result of the serology showed eGFR of 7. The patient was informed by her nephrologist to go to the emergency department (ED). In the ED, the patient complained of decreased appetite, nausea, and fatigue. Her daughter, who was her main caregiver, noticed the patient having increased shortness of breath and oliguria and hematuria. Autoimmune etiology of nephritic syndrome was suspected early, and serologies were obtained. The patient was found to have a P-ANCA pattern, MPO Ab and PR3 Ab positivity. Antinuclear antibodies (ANA) and anti-double stranded DNA (dsDNA) Ab were also detected, and systemic lupus erythematosus (SLE) was also diagnosed. Although renal biopsy was obtained, insufficient glomeruli were obtained for diagnosis to be made. However, CT chest suggested vasculitis given multiple nodular ground glass opacities throughout the left lung. The patient required placement of a tunneled central venous catheter for hemodialysis three times weekly. She received three days of 1000 mg IV methylprednisolone which was followed by 60 mg of oral prednisone daily. The patient was simultaneously started on 1500 mg of atovaquone daily for pneumocystis jirovecii pneumonia prophylaxis. Discharge was delayed due to difficulty in establishing outpatient hemodialysis. She was discharged with close follow up with rheumatology, nephrology, and pulmonology. Overlap of AAV and SLE vasculitis is atypical. Within AAV, positivity to both MPO and PR3 antibodies is furthermore rare. In patients with acute renal failure consistent with nephritic syndrome, maintaining broad differentials including autoimmune etiologies is imperative. High suspicion, early diagnosis, and subsequent treatment can result in positive outcomes for patients afflicted with pulmonary and renal manifestations of AAV and SLE. This abstract is funded by: None

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