Churg-Strauss syndrome is a small vessel vasculitis associated with antineutrophil cytoplasmic antibodies (ANCA) in a significant proportion of patients. In this study a cross sectional analysis was performed of the clinical and histological features of patients with Churg-Strauss syndrome in relation to their ANCA status.

A cohort of 112 patients who were enrolled in multicentre treatment trials was selected. They were diagnosed with Churg-Strauss syndrome on the basis of current classifications and were less than 75 years of age. The presence of ANCA was detected by indirect immunofluorescence in 43 patients (38%), 39 of whom had ANCA of the perinuclear type (p-ANCA).

Patients with ANCA had a higher frequency of renal involvement (35% v 4%) and peripheral neuropathy (84% v 65%) than those without ANCA. In addition, vasculitis was more often observed in the biopsy specimens of the ANCA positive patients (79% v 39%). On the other hand, patients without ANCA were more likely to have fever (55% v 30%) and cardiac disease (49% v 12%). One limitation of the study was that patients who were initially ANCA negative were not retested.

The authors hypothesise the presence of two phenotypes of Churg-Strauss syndrome on the basis of the ANCA status. They conclude that the latter reflects the underlying pathophysiology of the disease, with the presence of ANCA favouring the likelihood of a vasculitis affecting certain organs. Further work is required to determine what effect these findings might have on treatment.