Table 1.

Overview of major AMPs associated with HS pathology.

AMP	Charge	Antimicrobial activity	Expression in normal skin	Expression in HS	Methods of detection in HS	Chemokinetic activity	Ref.
LL-37	Cationic	Broad spectrum	Constitutive low levels in keratinocytes and mast cells	Induced in follicular keratinocytes and neutrophils	qPCR, IHC, ELISA, microarray	Neutrophils, dendritic, mast and T cells	(10, 37–45)
Defensins	Cationic	hBD-1 and -2 mainly Gram-negative bacteria, hBD-3 broad spectrum	hBD-1 constitutive low expression; hBD-2 and hBD-3 low expression in keratinocytes	hBD-1 suppressed/not regulated in keratinocytes; hBD-2 induced in keratinocytes and dermal macrophages; hBD-3 induced/not regulated in keratinocytes	qPCR, IHC, ELISA	Dendritic and T cells, promotes histamine release from mast cells	(44, 46–63)
DCD	Anionic	Mainly Gram-negative bacteria	Constitutive expression in eccrine sweat glands	Suppressed in eccrine sweat glands	qPCR, IHC, ELISA	N/A	(9, 59, 60, 64–68)
S100	Cationic	Broad spectrum	Rarely detected in healthy skin	Induced in epidermal keratinocytes	qPCR, IHC, ELISA, proteomics	Neutrophils and macrophages	(46, 51, 52, 54, 59, 60, 69–76)
Rnase7	Cationic	Broad spectrum	Constitutive expression in keratinocytes	Repressed/Induced/not regulated in keratinocytes	qPCR, IHC, ELISA	N/A	(44, 46, 59, 77)

The main AMPs with altered expression in HS include LL-37, hBD-1, hBD-2, hBD-3, DCD, S100s proteins, and RNAse 7. Multiple different methods have been utilized to assess their expression, including quantitative PCR (qPCR), immunohistochemistry (IHC), enzyme-linked immunoassay (ELISA) and proteomics. Some AMPs are consistently found deregulated including LL-37, hBD-2, DCD, and S100s proteins. However, the deregulation and directionality were not consistent for hBD-1, hBD-3, and RNAse 7 across studies. Ref.=references.