Eosinophilic vasculitis in connective tissue disease

Area of Science:

• Rheumatology
• Immunology
• Pathology

Background:

• Connective tissue disease (CTD) commonly presents with neutrophilic and lymphocytic vascular inflammation.
• A distinct subset of eight CTD patients exhibited eosinophilic vasculitis, prompting further investigation.
• This study aimed to characterize this eosinophilic variant of vasculitis in CTD patients.

Purpose of the Study:

• To characterize a distinct variant of vasculitis in connective tissue disease (CTD) characterized by eosinophilic infiltration.
• To compare the clinical and laboratory findings of eosinophilic vasculitis with neutrophilic vasculitis in CTD patients.

Main Methods:

• Compared clinical and laboratory data from eight CTD patients with eosinophilic vasculitis and nine with neutrophilic vasculitis.
• Utilized indirect immunofluorescence to detect eosinophil major basic protein (MBP), neutrophil elastase, and mast cell tryptase in lesional tissue.
• Assayed serum MBP levels and eosinophil survival-enhancing activity in a subset of patients.

Main Results:

• Eosinophilic vasculitis patients presented with hypocomplementemia and peripheral blood eosinophilia, elevated serum MBP, and prolonged eosinophil survival.
• Immunofluorescence revealed prominent angiocentric eosinophil MBP staining and diminished mast cell tryptase in eosinophilic vasculitis.
• Neutrophilic vasculitis patients lacked peripheral eosinophilia, showed variable hypocomplementemia, and had prominent neutrophil elastase staining.

Conclusions:

• Eosinophilic vasculitis in CTD with hypocomplementemia is associated with vessel wall destruction mediated by cytotoxic eosinophil granule MBP.
• Eosinophils are implicated as key mediators of vascular damage in this specific vasculitis subtype.
• Diminished perivascular mast cells suggest mast cell degranulation may play a role in the pathogenesis.