Circulating auto-antibodies to neutrophil cytoplasmic antigens in vasculitis. A report of 3 cases

Three patients are described who presented with symptoms and signs of a vasculitic illness but in whom a definite diagnosis was not made until the application of a test to detect auto-antibodies to neutrophil cytoplasmic antigens. There has long been a need for a diagnostic marker for the groups of diseases which fall into the broad classification of systemic vasculitides. Diagnosis of the patients as having either Wegener's granulomatosis or microscopic polyarteritis by the finding of this auto-antibody enabled a positive approach to treatment with combinations of immunosuppressive agents. In addition, serial measurement of the auto-antibody titres enabled monitoring of disease activity.