Panniculitides are a heterogeneous group of inflammatory dermatoses involving the subcutaneous fatty tissue. In this study, the researchers included formalin‐fixed paraffin‐embedded skin biopsies from 25 patients suffering from panniculitis. The cohort of the research was divided into n = 10 erythema nodosum 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. Double immunofluorescence assessed the presence of neutrophils and NETs using antibodies against elastase, a neutrophilic marker, and citrullinated histone 3, a marker of NETs.
The study revealed that the average percentages (±SEM) of elastase‐positive neutrophils showing NETs were 44% ± 3% in erythema nodosum and 43% ± 7% lobular panniculitis. The difference was not statistically significant. It reflects the implication of NETs not only in severe scarring lobular panniculitis but also in mild non‐scarring self‐remitting reactive inflammation such as erythema nodosum. They located NETs in the interlobular septa in the erythema nodosum and the inflamed fat lobules in lobular panniculitis in tissues. The researchers are still studying this matter in search of some more outcomes from the research.