ANCA seropositivity in HIV: a serological pitfall.
In systemic vasculitis, cytoplasmic staining in ethanol-fixed neutrophilic granulocytes, i.e. cytoplasmic antineutrophilic cytoplasmic antibody (c-ANCA), is generally considered a highly significant serological marker. When a patient presents with upper airway or renal symptomatology and seropositivity to c-ANCA, a Wegener's granulomatosis is usually easily diagnosed by performing a biopsy of the diseased organ. However, not every ANCA-positive patient with pulmonary inflammation is suffering from Wegener's disease. In some cases of upper airway or pulmonary symptomatology, the a priori chance of having Wegener's disease is low despite a positive ANCA. A coincidental positivity of ANCA may then lead to clinicians jumping to conclusions. We present a 40-year-old man who was falsely suspected of having Wegener's disease because of upper airway symptomatology and c-ANCA positivity. Specificity analysis revealed that he was negative to antibodies for proteinase-3, but positive to myeloperoxidase. The potential serological pitfall of the supposedly specific c-ANCA is discussed.
Jansen
T L Th A
TL
Department of Rheumatology, Leeuwarden Medical Centre, Leeuwarden, Netherlands. T.Jansen@znb.nl
van Houte
D
D
de Vries
T
T
Wolthuis
A
A
D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology*; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D019084:Fluorescent Antibody Technique, Indirect; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D006679:HIV Seropositivity / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D008297:Male; D013902:Radiography, Thoracic
D019268:Antibodies, Antineutrophil Cytoplasmic