Amicrobial pustulosis of the folds associated with auto-immune disorders. A case report with an analysis of cytokine expression profile in skin lesions of cutaneous neutrophilic lupus.

A new entity was described by Crickx et al. in 1991, associating amicrobial pustulosis of the folds with systemic lupus erythematosus in young females. It is proposed to regroup this entity under the name of 'neutrophilic cutaneous lupus'. We report a case of a 13-year-old girl with a pustular eruption of the cutaneous folds and scalp associated with undetermined connective tissue disease. We performed a screening for the expression of 174 cytokines in the pustules and compared it with other pustular diseases (acne flare, acute generalized exanthematous pustulosis, pustulosis of Sneddon and Wilkinson). Matrix metalloproteinase 9 and Siglec-5 (CD170) were highly expressed in all types of pustules and reflect high neutrophil density. Amicrobial pustulosis of the folds was characterized by a higher expression of interleukin (IL) 1alpha, IL-2 receptor alpha, macrophage colony-stimulating factor, insulin-like growth factor binding protein 1, brain-derived neurotrophic factor, tumour necrosis factor (TNF) alpha and a lower expression of CD14, IL-1beta, IL-12, soluble TNF receptors I and II, growth-regulated oncogene alpha, fibroblast growth factor 4 and vascular endothelial growth factor as compared to the controls.