16 May 2021
: Case report 
Hydralazine-Induced Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Asymptomatic and Renal-Restricted Presentation
Challenging differential diagnosis, Unusual setting of medical care, Rare disease, Adverse events of drug therapy
Wan Tu1ABCDEFG*, Barry Fayman1ADE, Stephen C. Ward2BDE, Yusufal Mamoon1ABD, Sabiha S. Bandagi3CDDOI: 10.12659/AJCR.931263
Am J Case Rep 2021; 22:e931263
Table 1. The patient’s serology results.
| Test | Titer/unit | Reference range | Result |
|---|---|---|---|
| Antinuclear antibody (ANA) | 1: 2560 (IFA homogeneous pattern) | <1: 80 | Positive |
| Anti-double stranded DNA (dsDNA) | EIA 89 IU/mL | EIA ≤29 IU/mL | Positive |
| Anti-Smith antibody | ENA <0.2 AI | ENA ≤0.9 AI | Negative |
| Anti-ribonuclear protein (RNP) antibody | ENA 0.3 AI | ENA ≤0.9 AI | Negative |
| Anti-chromatin antibody | 2.4 AI | ≤0.9 AI | Positive |
| Total complement, ch50 | 67 U/mL | 42–95 U/mL | Normal |
| Complement component C3 (C3) | 136 mg/dL | 81–157 mg/dL | Normal |
| Complement component C4 (C4) | 26 mg/dL | 13–39 mg/dL | Normal |
| Cytoplasmic antineutrophil cytoplasmic antibody (cANCA) | Negative | Negative | |
| Perinuclear antineutrophil cytoplasmic antibody (pANCA) | >1: 1280 | Negative | Positive |
| Atypical anti-neutrophilic cytoplasmic antibody | Negative | Negative | |
| Anti-proteinase 3 (PR3) antibody | 132.2 U | ≤20.0 U | Positive |
| Anti-myeloperoxidase (MPO) antibody | 104.0 U | ≤20.0 U | Positive |
| Rheumatoid factor | <10 IU/mL | 0–13 IU/mL | Negative |
| Anti-cyclic citrullinated peptide (CCP) antibody | <8 U | ≤19 U | Negative |
| Anti-centromere antibody | <0.2 AI | ≤0.9 AI | Negative |
| Anti-histone antibody | 3.2 U | 0.0–0.9 U | Positive |
| Anti-cardiolipin antibody | Negative | Positive | |
| Anti-scleroderma (scl70) antibody | <0.2 AI | ≤0.9 AI | Negative |
| Immunoglobulin G (IgG) | 1581 mg/dL | 610–1660 mg/dL | Normal |
| Immunoglobulin M (IgM) | 155 mg/dL | 35–242 mg/dL | Normal |
| Beta 2 glycoprotein 1 IgG Ab | 5.1 SGU | ≤20.0 SGU | Negative |
| Beta 2 glycoprotein 1 IgM Ab | 31.1 SMU | ≤20.0 SMU | Positive |
| Cryoglobulin | Negative | Negative | |
| Anti-glomerular basement membrane (GBM) antibody | 3 | 0–20 | Negative |
| EIA – enzyme immunoassay; ENA – epithelial cell-derived neutrophil attractant; IFA – indirect immunofluorescence assay. | |||