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Advances in dermatology and venereology Acta Dermato-Venereologica
Expression of Antimicrobial Peptides in Nail Psoriasis and Normal Nails
Ieva SAULITE 1 , 3 , Mara PILMANE 2 and Janis KISIS 3
1
Faculty of Continuing Education , 2 Institute of Anatomy and Anthropology , and 3 Department of Infectology and Dermatology , Rīga Stradiņš University , Dzirciema Street 16 , LV-1007 Riga , Latvia . E-mail : ieva . sauliite @ gmail . com Accepted Dec 15 , 2016 ; Epub ahead of print Dec 16 , 2016
Despite persistent exposure to microbial agents , the nail unit appears to be capable of ensuring efficient innate immune defence . In the human nail , antimicrobial peptides ( AMPs ), which are small molecules with a broad spectrum of innate defence properties , may play an important role ( 1 , 2 ). Although the specific arrangement of the nail ’ s immune components is poorly understood , one could speculate that a well-developed immune defence may require the correct expression and localization of AMPs . Nevertheless , the exact contribution of AMPs both in homeostasis and disease has yet to be defined .
In psoriatic skin plaques , the levels of several AMPs are reported to be highly upregulated ( 3 ). Furthermore , AMPs of the cathelicidin and defensin groups are suggested to be decisive players in psoriasis pathogenesis ( 3 , 4 ). Hence , based on data from plaque psoriasis studies , one could hypothesize AMP upregulations in nails with psoriasis and that AMP upregulation would result in decreased secondary infections . However , in nail psoriasis , an increased coincidence of onychomycosis has been reported ( 5 , 6 ).
Because the exact consequences of psoriatic inflammation in the nail unit are unknown and might differ from the ones described in the skin ( 7 ), we evaluated the AMP profile in the human nail apparatus . Specifically , we determined the presence and distribution of AMPs of the cathelicidin ( LL-37 ) and beta defensin ( hβD-2 , hβD-3 and hβD4 ) groups in psoriatic nail apparatus specimens and compared them to clinically normal nails .
METHODS
The patient group with nail psoriasis included 20 patients ( 18 to 70 years of age ). Nail unit tissue specimens ( 5 mm in diameter ) were obtained from the nail bed using a punch biopsy technique . Inclusion criteria were : i ) a clinical diagnosis of nail psoriasis with nail bed involvement ( 8 , 9 ); ii ) a pathohistological diagnosis of nail psoriasis ( 8 ).
For the control group , 26 necropsies from human cadaver nail units ( nail bed and nail matrix ) were obtained ( within 12 h of the death ) and included for further evaluation . Only nail apparatuses with normal clinical and pathohistological appearance were included in the study . Exclusion criteria for both groups included : i ) the presence of any disease in the medical history that might affect nails ( except psoriasis in the psoriatic nail group ); ii ) a positive Periodic acid-Schiff ( PAS ) reaction and / or fungal culture of the nail sample ; iii ) history of any local or systemic anti-bacterial , anti-fungal , anti-inflammatory , immunosuppressive , or immunomodulating treatment received within the last month .
Immunohistochemistry . Four µ m sections of paraffin-embedded nail biopsy specimens were treated with antibodies for LL-37 ( rabbit ; 1:200 ; Biorbyt , UK ), hβD-2 ( goat ; 1:100 ; Bio-Techne , UK ), hβD-3 ( rabbit ; 1:1000 ; Novus Biologicals , USA ) and hβD-4 ( mouse ; 1:100 ; Santa Cruz Biotechnology , USA ) ( 10 ). Immunostaining was assessed semi-qantitatevly by grading the stained cells in the visual field ( 11 ). Non-parametric statistics using the Mann-Whitney U-test display the ranking differences between the control group and studied group .
RESULTS
In both the psoriatic and control groups , we observed LL-37 positive cells ; however , more positive cells were present in nail psoriasis samples . In psoriasis-affected nails , numerous (+++) positive cells were observed in the epithelial layer of the nail bed . Interestingly , in the control group , only moderate (++) numbers of LL-37 positive cells were present ( Fig . 1 a and b ; Table I ). Further , in the control group samples , LL-37 immunoreactivity was evenly distributed throughout the nail unit , including proximal and distal nail matrixes .
Fig . 1 . Detection of antimicrobial peptides by immunohisto chemistry in psoriatic nail beds ( a , c , e ) compared to controls ( b , d , f ). ( a ) Abundance of LL-37-positive cells in the psoriatic nail bed and ( b ) a moderate number of LL- 37 positive cells in the control nail bed ; numerous and moderate numbers of hBD-2 positive cells were observed in psoriatic ( c ) and control nail beds ( d ); numerous hBD-3 positive cells were detected in psoriatic ( e ) and few in control nail beds ( f ) ( original magnification : X250 ). doi : 10.2340 / 00015555-2605 Acta Derm Venereol 2017 ; 97 : 644 – 645
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2017 Acta Dermato-Venereologica .