Abstract: TH-PO1102
ANCA Reports: Clinical Value Beyond ANCA
Session Information
- Pathology and Lab Medicine
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1700 Pathology and Lab Medicine
Authors
- Rivas, Antonio, Harbor-UCLA Medical Center, Torrance, California, United States
- Shankar, Abhirami, Harbor-UCLA Medical Center, Torrance, California, United States
- Dai, Tiane, Harbor-UCLA Medical Center, Torrance, California, United States
- Adler, Sharon G., Harbor-UCLA Medical Center, Torrance, California, United States
Introduction
Improved indirect immunofluorescence (IIF) resolution with novel expanded ANCA pattern interpretation may suggest unsuspected autoimmune diseases. We report two cases where the ANCA was negative, but the report contributed to new diagnoses.
Case Description
Case 1: 34-year-old woman presented with nausea, rash, and autoimmune hepatitis (AIH) type 1. Renal biopsy was deferred due to thrombocytopenia. ANCA was negative but reported as “Specimen produced an unusual result which is unlikely to represent c-ANCA, p-ANCA, or atypical ANCA. It may represent ANCA-like autoantibodies associated with a variety of drugs or a conventional ANA. Consider requesting ANA.” Serologies showed positive ANA, anti-dsDNA, anti-actin antibodies and low C3 and C4. Liver and kidney function improved, rash worsened. She was newly diagnosed with SLE, and treatment was initiated. Case 2. 69-year-old woman presented with dyspnea. Evaluation included a positive ANA (speckled, 1:160), low C3 and normal C4. ANCA was negative but was reported as “This specimen produced an unusual result of unclear clinical significance. IIF was observed which does not meet the criteria for c-ANCA, p-ANCA, or atypical p-ANCA. This may be due to ANA or other autoantibodies besides those commonly associated with positive ANCA results”. Renal biopsy showed immune complex membranoproliferative pattern of injury not typical of SLE. The ANCA coupled to the biopsy stimulated additional serologies, showing positive SS-A, SS-B, lupus anticoagulant, β2-glycoprotein-1 and anti-cardiolipin antibodies. She left against medical advice.but returned one year later with a deep venous thrombosis. Repeat serologies for the anti-phospholipid syndrome (APLS) were confirmative.
Discussion
Recent changes to ANCA technical and interpretive performance may suggest the presence of nuclear autoreactive antibodies. In our cases, previously undiagnosed SLE and Sjogren's syndrome with APLS were discovered. Thus, "negative" ANCA antibody testing reports may now provide additional information that can stimulate a broader search for autoantibodies.