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Investigating the presence of neutrophil extracellular traps in septal and lobular cutaneous panniculitides
Author(s) -
Safi Rémi,
El Hasbani Georges,
Bardawil Tara,
Abbas Ossama,
Kibbi AbdulGhani,
Nassar Dany
Publication year - 2021
Publication title -
international journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 93
eISSN - 1365-4632
pISSN - 0011-9059
DOI - 10.1111/ijd.15450
Subject(s) - panniculitis , erythema nodosum , medicine , pathology , neutrophil elastase , neutrophil extracellular traps , inflammation , immunology , disease
Background Panniculitides are a heterogeneous group of inflammatory dermatoses involving the subcutaneous fatty tissue. Histologically, they are classified into septal and lobular panniculitis, according to the predominant localization of the inflammatory infiltrate. Neutrophils are frequently found in panniculitis, mainly at the early stages. Here, we investigated whether neutrophils contribute to various types of cutaneous panniculitis by releasing neutrophil extracellular traps (NETs). Materials and Methods Formalin‐fixed paraffin‐embedded skin biopsies from 25 patients with panniculitis were included in the study. Our cohort was divided into n = 10 erythema nodosum (septal panniculitis) and n = 15 lobular panniculitis, including n = 7 lupus panniculitis, n = 1 pancreatic panniculitis, n = 1 Weber‐Christian disease, n = 1 deep fungal infection, n = 2 lipodermatosclerosis, and three cases did not have an identified etiology. The presence of neutrophils and NETs was assessed by double immunofluorescence using antibodies against elastase, a neutrophilic marker, and citrullinated histone 3, a marker of NETs. Results The mean percentages (±SEM) of elastase‐positive neutrophils showing NETs were 44% ± 3% in erythema nodosum and 43% ± 7% in lobular panniculitis. The difference was not statistically significant and reflects the implication of NETs not only in severe scarring lobular panniculitis but also in benign non‐scarring self‐remitting reactive inflammation such as erythema nodosum. In tissues, NETs were located in the interlobular septa in erythema nodosum and in the inflamed fat lobules in lobular panniculitis. Conclusions NETs are massively present in septal and lobular subtypes of panniculitides, suggesting their involvement in tissue damage.