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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.