Presence of purpura is related to active inflammation in association with IL-5 in eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a relatively rare necrotizing vasculitis that causes asthma, nasal involvement, peripheral nerve disturbance, renal disorder, and cutaneous lesions like purpura and is characterized by eosinophil infiltration into the damaged tissue. Purpura is the most common cutaneous lesion, but it remains unknown whether this skin lesion is associated with disease activity of EGPA and laboratory data including interleukin (IL)-5, a target cytokine of this disease. We conducted a search of our hospital electronic records for cases of EGPA from the last 10 years. Symptoms related to EGPA (fever, asthma, nasal and cutaneous manifestations, neuropathy), the Birmingham Vasculitis Activity Score (BVAS), and laboratory parameters, such as eosinophil count, urinalysis, antineutrophil cytoplasmic antibody (ANCA), CRP, IgE and IL-5, before and during treatment were compared among the eligible cases. A total of 28 EGPA patients (21 females and 7 males) were selected. Almost all developed peripheral neuropathy. Fever occurred in 25%, nasal symptoms in 38.1% and purpura in 44%. Glomerulonephritis developed in 7.7%. One patient had cardiac involvement (3.6%). The laboratory data showed a marked increase in peripheral eosinophil count, CRP, serum IgE and serum IL-5. ANCA was positive in 15.4%. In the univariate analysis, presence of purpura was associated with increased CRP and IL-5, and high BVAS score. Multivariate analysis revealed a robust relationship between purpura and CRP. Our findings showed that presence of purpura was associated with increased CRP and IL-5, and high disease activity in EGPA.