psoriasis is an autoimmune disease that appears on the skin , transmits genetically , and affects approximately 2% of the world 's population , with men and women being equally affected ( 1 ) .
it is a complex genetic disease with environmental and genetic components and in fact , the term represents a clinically heterogeneous group of diseases including psoriasis vulgaris , pustular psoriasis , psoriasis arthritis , erythrodermic psoriasis , nail psoriasis and psoriasis inversa ( 2 ) .
the most common phenotype is chronic plaque psoriasis with well - demarcated lesions typically located in the scalp and on the extensor surfaces ( 3 ) .
although psoriasis is clinically and histologically well characterized , its pathogenesis is unknown in detail , and unlike other autoimmune diseases , does not have a generally accepted animal model .
our knowledge about its pathogenesis is derived exclusively from clinical studies and translational science performed in psoriatic patients .  
pathological conditions can induce some quality and quantity changes in sera and these characteristic changes provide a favorable biomarker to distinguish between healthy and sick states
. global gene expression ( 4 - 6 ) and protein analysis ( 7 ) in psoriasis have been investigated previously . also , other aspects such as role of vitamins ( 8) , immnunoglubolins ( 9 ) , micrornas ( 10 ) , adipokines and cytokines ( 11 ) and methylglyoxal ( 12 ) in the pathophysiology of this autoimmune disease have been studied .
proteomic studies also are used in the evaluation of this disorder , but there are few published data about serum proteom alteration in psoriatic patients ( 13 , 14 ) and more studies on this topic are needed .
proteome analysis can be regarded as a peptide screening approach aimed at documenting the overall distribution of proteins in cells , organs , or other samples ( 15 ) .
therefore , the aim of this study was to explore serum proteomics patterns of psoriatic patients by using two dimensional gel electrophoresis ( 2-de ) followed by maldi / tof - tof .
twenty cases of white patients with psoriasis vulgaris , 10 males and 10 females ( mean  sd age 41.4212.7 years ) , and sixteen healthy control peoples , 8 males and 8 females ( mean  sd age 46.9016.7 years ) were enrolled in the study .
all patients were diagnosed as having psoriasis vulgaris and had no prior history of other diseases or any medications which may complicate the analysis since two months ago .
fasting blood samples were taken from the cubical vein into sterile vacutainers without anticoagulant and after centrifugation ( 2000 g , 10min ) , serum stored at -20c until used .
protein concentration was determined according to the method proposed by bradford , using bovine serum albumin ( bsa ) as a standard protein ( 16 ) .
tca / acetone precipitation ( 17 ) and aurum serum protein mini kit ( 18 ) were used to remove high abundant proteins .
processed serum samples were analyzed by sds - page in the presence of 2-mercaptoethanol ( 2-me ) according to the laemmli method ( 19 ) using the running and stacking gel of 12% and 3.0% acrylamide ( w / v ) , respectively .
two - dimensional gel electrophoresis was performed according to the previously reported methods and resolved proteins were detected by staining with either cbb r-250 or silver nitrate , but omitting the glutaraldehyde fixation ( 20 ) . for each serum sample analysis ,
2-d gels were scanned and analyzed by melanie software , version 6.0.2.0 . for maldi / tof - tof analysis ,
the protein spots of interest were excised carefully and analyzed by maldi / tof- tof by the  the technology facility proteomics & analytical biochemistry laboratory  ( the university of york , uk ) .
database interrogation was performed using the national center for biotechnology information ( ncbi ) databases on a gps workstation . in order to highlight the serum proteome changes in psoriasis patients ,
image analysis has been performed on three replicates , and variations on spots ' area were confirmed by statistical analysis .  
differences between the healthy and disease sera were determined by two independent sample t test .
using spss version 16 , a p - value equal to 0.05 was considered statistically significant .
differences between the healthy and disease sera were determined by two independent sample t test .
using spss version 16 , a p - value equal to 0.05 was considered statistically significant .
the serum protein yield in untreated , tca / acetone or aurum kit treated serums are summarized in table 1 .
figure 1 depicts typical sds - page results of serum proteins obtained by different treatments , and in each sample protein in 2 l of serum were loaded to the gel .
a comparison of the proteomics patterns of health and patient serum gels , as well as both high protein depletion methods are shown in figure2 .
patient serum treated with tca / acetone has four spots more than patient serum depleted with aurum serum protein mini kit ( figure 2b and 2d , spot no .
as shown in figure 2 , nine protein spots were subjected to maldi / tof - tof analysis .
table 2 lists the identities of the proteins which were analyzed in this experiment using maldi / tof - tof and summarizes the differences in existence , absence or alteration in expression of spots between the two depletion methods and between patient and health control serums .
it was found that three distinct proteins including different isoforms of 1-at ( according to a previous unpublished report by wieland et al ) , retinol binding protein ( rbp ) and keratin 10 suffer changes in psoriatic serum against control healthy human serum .
in contrast with our results , in a previous study conducted by williamson et al ( 2013 ) it has been reported that abundance of more than 50 proteins was altered in psoriatic patent versus health ones . between these proteins ,
there are several reasons for this dissimilation such as differences in sample preparation , protein enrichment and detection .  
several investigators have emphasized the role of proteolytic enzymes , especially serine proteases in the pathogenesis of psoriasis ( 2 , 21 , 23 ) . in the psoriatic lesion ,
mctc cells ( mast cells that contain several serine protease ) are predominantly responsible for the mast cell infiltration into the papillary dermis ( 21 ) .
alpha 1-at is a glycoprotein with serine protease inhibition activity that interacts with and inhibits elastases , cathepsin g and chymase , and plays a role in reducing tissue inflammation .
there are several investigations about the role of 1-at in the pathogenesis of psoriasis ( 22 , 23 ) . in our study
, two variants of 1-at were identified that were only detected in the serum of the psoriatic patients , and were not detectable in healthy controls .
one of these variants existed in four isoforms with mw / pi about 22000/6 - 7 which contained 197 amino acids .
all previously reported1-ats are different from this new variant in mw and pi and there are no reports on previous studies about this variant . as shown in figure 2 , in patient serum depleted with aurum serum protein mini kit ,
the main cause of this condition is the elimination of immunoglobulins from serum by using aurum serum protein mini kit , and therefore the 1-ats isoforms that create complexes with them are also removed from the serum .
thus , new complexes of ig- 1-at were found in psoriatic serum but the existence of ig- 1-at complexes were also reported in relatively longstanding studies in different joint diseases such as ankylosing spondylitis and rheumatoid arthritis ( 24 ) .
vitamin a ( retinol ) and its derivatives play different roles in the body ( 25 , 26 ) , and within the blood , free retinol binds to retinol binding protein ( rbp ) , its serum transport protein .
some investigators have indicated that rbp is present in the intercellular spaces of the epidermis ( 27 ) .
retinol can store in keratinocytes and convert to all - trans retinoic acid ( atra ) ( 28 ) .
rbp is involved in the regulation of intracellular retinoid concentrations and a decrease in patient serum rbp concentration , as seen in our study , causes psoriatic lesions .
one protein with pi / mw about 4.8/40000 existed in the serum of one patient , which was not observed in healthy human serum and by ms analysis , was identified as keratin 10 ( k10 ) .
keratins are intermediate filament - forming proteins that provide mechanical support and fulfill a variety of additional functions in epithelial cells ( 29 ) .
these proteins are grouped into two classes , the neutral - basic type ii ( k1-k8 ) and the acidic type i ( k9-k20 ) ( 30 ) .
however , when keratinocytes begin terminal differentiation , they move upward , become postmitotic , and switch to the expression of a keratin pair k1-k10 ( 31 ) . under hyperproliferative conditions , such as
psoriasis , downregulation of k10 occurs in keratinocytes , but there is one report of expression of k10 increase in lesional and symptomless skin of spreading psoriasis ( 32 ) .
however in this study , for the first time , k10 in the serum of patients with psoriasis vulgaris was found .
this increase may be due to epidermal apoptosis that causes k10 leaking to the serum of psoriatic patients .
with an analysis of sera 2d maps , it has been possible to describe a pattern of proteins up- and down - regulation upon disease conditions . in conclusion , we here provide serum proteome analysis of patients with psoriasis .
nine proteins were differentially expressed in the psoriasis vulgaris group , as compared to the normal group of these proteins . using specific elisa or western blot assay for all of these proteins will provide a more complete evaluation of these valuable changes .
 objective(s ) : psoriasis is an autoimmune disease that appears on the skin . 
 although psoriasis is clinically and histologically well characterized , its pathogenesis is unknown in detail . 
 the aims of this study were to evaluate the proteome of psoriatic patients ' sera and to compare them with those of normal healthy human to find valuable biomarkers.materials and methods : in a case - control study , twenty cases of white patients with psoriasis vulgaris , 10 males and 10 females and sixteen healthy controls , 8 males and 8 females were enrolled in the study . 
 the serum protein expression patterns obtained after depletion of albumin were compared by using two dimensional gel electrophoresis ( 2-de ) coupled to maldi / tof - tof to identify disease associated proteins.results : differential expression of nine protein spots representing four unique proteins including alpha-1 antitrypsin , retinol binding protein , keratin 10 and an unknown protein ( with pi 6.47 and molecular weight of 19941 da ) , between psoriatic and healthy human serum were found . 
 furthermore , expression of four new alpha-1 antitrypsin isoforms with different molecular weight and isoelectric point were observed in psoriatic serums in this research for the first time.conclusion : a unique proteomic profiling with abnormal expression of alpha-1 antitrypsin and presence of keratin 10 in sera of psoriasis patients were observed that may constitute new and useful findings of psoriasis and offer a clue to a better understanding of the inflammatory pathway . 
Introduction
Materials and Methods
Statistical analysis
Results
Discussion
Conclusion