c-ANCA as a serological pitfall

Cutaneous vasculopathy associated with cocaine use

“…Other complications could be caused by one or more contaminants of cocaine. Street market cocaine is frequently adulterated or "cut" with various powdery fillers, such as baking soda, various sugars, or other stimulants, to increase its weight (8). Recently, various complications of cocaine have been linked to levamisole, an antihelminthic drug belonging to the class of imidazothiazole derivatives (9).…”

Rheumatic manifestations of cocaine use

“…This vasculitis can vary in the number and type of organs involved and in the overall severity of disease. These patients can present with cutaneous vasculitis, nasal septal destruction, pauci-immune crescentic glomerulonephritis and a characteristic autoantibody profile that includes detection of cytoplasmic-staining antineutrophil cytoplasmic antibodies (c-ANCAs) by immunofluorescence with specificity for the target antigen proteinase-3 (PR-3) confirmed by immunoassay [7][8][9]. Although the development of GPA in the setting of cocaine use may be coincidental, the authors of these series strongly suggest a causal relationship between the two [7,8].…”

“…Unfortunately, ANCA serologies are generally unhelpful as well in distinguishing between these two syndromes, as patients with CIMDL may be either ANCA positive or negative [20]. Some patients test positive for c-ANCA and PR-3 [9,20]. Some patients test positive for c-ANCA and PR-3 [9,20].…”

Leukocytoclastic Vasculitis and Dysesthesias in Lower Limbs

“…12 Indeed, it has been observed that HIV may induce ANCA in 20% to 83% of cases probably by means of a polyclonal B cell activation, especially in cases with hypergammaglobulinemia. 12,13 Similarly, the ''borderline'' positivity for antinuclear antibody in the absence of any other sign or symptom suggesting a connective tissue disease has also been interpreted as a nonspecific immune reactivity in the context of the viral infection.…”