20 J Contemp Med Sci | Vol. 1, No. 4, Autumn 2015: 20–22 Research Objective Psoriasis is a disease characterised by T-cell-mediated hyperproliferation of keratinocytes initiated by antigen-presenting cells on the skin. Environmental factors including streptococcus infections and multiple genetic components may be responsible for the pathogenesis of the disease. This study was performed to assess the association between antistreptolysin-O (ASO) serum level and chronic plaque psoriasis. Methods Serum level of ASO was measured in 45 doctor-diagnosed psoriatic patients with an age range of 10–50 years attending the dermatology outpatient clinic in Al-Hussein Medical City in Kerbala Province – Iraq during the period from March 2014 through July 2015. Psoriatic patients with chronic plaque type were selectively recruited to the study. Another 20 age- and gender-matched persons were chosen as healthy control group. Serum level of ASO was estimated in all patients and control group using enzyme-linked immunosorbent assay (ELISA). Findings Data revealed a significantly increased serum ASO level in the chronic plaque-type psoriatic patients compared to the healthy control group (P-value < 0.05). Conclusion The present study suggests that serum ASO level could be associated with the immunopathogenesis and/or susceptibility to this type of psoriasis. Keywords chronic plaque psoriasis, anti-streptolysin-O Association between antistreptolysin-O serum level and chronic plaque psoriasis in Iraqi patients Abeer T Al-Hassnawi,a Ali Mansoor Al-Ameria & Huda H Al-Hassnawib Introduction Psoriasis is a chronic skin disease characterised by hyperprolif- eration of keratinocytes with different clinical types. A number of environmental factors are believed to contribute in the dis- ease causation. Streptococcus pyogenes infection is thought to have a distinct relationship with the activation of psoriasis.1 This finding was preceded by Norrlind in 1955, who pointed out the occurrence of a streptococcal upper respiratory infec- tion 1–2 weeks prior to the appearance of the skin lesions in about two-thirds of patients with psoriasis.2 Following this observation, the presence of streptococci in the throat swab cultures of these patients, as well as the seropositivity of antist- reptococcal antibodies were shown. One of the suggested immunopathogenesis of psoriasis is the role of Th17 lymphocytes and its related cytokine action, which increase TGF-β production and mucosal defence during streptococcal skin infections. Streptococcal infections lead to production of interleukin 6, which along with TGF-β, results in a differentiation of Th17 at that location. Furthermore, the presence of IL-6 and TGF-β enhances neutrophils and mono- nuclear cells migration to the region. With the production of myeloperoxidase and elastase by neutrophils, skin lesion of psoriasis might be mediated.3,4 The present study aims to investigate the association between serum antistreptolysin-O (ASO) level in patients with chronic plaque psoriasis by using ELISA technique. Methods Forty-five patients with chronic plaque psoriasis attending the outpatient clinic of Dermatology in Al-Hussein Medical City, Kerbala province/ Iraq, between March 2014 and July 2015, as well as 20 persons as healthy control group were recruited. Informed consent was obtained from each participant prior to the study. Patients clinically diagnosed with chronic plaque psoriasis were selected as case group. Serum level of ASO was estimated in all patients and controls by ELISA technique using (Creative Diagnostics-USA) ELISA kit according to the instructions of the kit company. Statistical Analysis Statistical analysis was done by using statistical analysis soft- ware, Graph pad prism version 6. Student’s t-test was used to calculate the significance of difference in mean serum levels of ASO between psoriatic patients and control group and F-test was used to compare variances of the two groups. In addition, R2-test was used to predict the association between ASO level and occurrence of chronic plaque psoriasis. A P-value < 0.05 was considered significant.5 Results Data from the current study reveal a significant difference in the mean serum ASO level between patients with chronic plaque psoriasis and the control group; 21.4 IU/ml, versus 10.63 IU/ml, with (P < 0.05), as shown in Table 1. Upon anal- ysis of results to predict the association of elevated serum ASO level with occurrence of chronic plaque psoriasis, the fol- lowing data were obtained: Overall, there was significant difference in ASO titre status between patients and control. Discussion It has been stated that latent or chronic tonsillitis and phar- yngitis caused by streptococci are the main infections associ- ated with psoriasis. Moreover, some streptococcal dermatitis and vulvovaginitis/balanoposthitis infections mostly seen aDepartment of Microbiology, College of Medicine, University of Kerbala, Holy Kerbala, Iraq. bDepartment of Microbiology, College of Medicine, University of Babylon, Babylon, Iraq. Correspondence to Ali Mansoor Al-Ameri (email: alimansoor699@gmail.com). (Submitted: 18 August 2015 – Revised version received: 4 September 2015 – Accepted: 6 September 2015 – Published online: Autumn 2015) ISSN 2413-0516 21J Contemp Med Sci | Vol. 1, No. 4, Autumn 2015: 4–8 Research Antistreptolysin-O serum level and chronic plaque psoriasis in Iraqi patientsAli Mansoor Al-Ameri et al. during childhood can induce psoriasis. Therefore, in acute exacerbations of guttate psoriasis, bacterial culture should be obtained from the patients. Determination of serum level of antibodies against streptolysin, a streptococcal exotoxin can also be performed. Among these, the most commonly used is antistreptolysin.6,7 In our study, chronic plaque psoriasis patients were shown to have significantly higher ASO level compared to the control group (P < 0.05). These findings are consistent with many pre- vious studies in this field.8–12 All these studies showed signifi- cant differences (P < 0.05) with their respective controls. In a previous study, association between streptococcal infections and psoriasis was suggested in 18(56%) of the 32 patients, 31% had a history of sore throat 1 to 3 weeks before the appearance of rash and 17(85%) of the 20 patients with acute guttate psoriasis (AGP).9 Increased levels of antibodies to streptolysin O were also found in the serum of patients in response to infection with haemolytic streptococcus groups A, C or G. Streptococcal infection usually leads to eruptive guttate psoriasis, and dete- rioration of other clinical forms of psoriasis.13 Another study found ASO titre raised in 60% of AGP patients versus 6.6% in healthy control group.11 Another prospective cohort study described ASO serum level increased 10 times compared with their controls in chronic plaque psoriasis.12 In a retrospective cohort, about 30% of patients with chronic psoriasis stated that they had noted worsening of their disease in association with sore throat.14 An exacerbation of chronic plaque psoriasis only if streptococci were isolated 4 days or later after the onset of sore throat was observed.15 In addition, some studies proposed that the psoriasis patients with high ASO titres had guttate psoriasis more frequently compared with patients with normal ASO titres.10,16 Histopathological studies concerning examination of ton- sils performed after tonsillectomies confirmed that streptococci could persist in these tissues and could eventually colonise them.17 The microorganisms’ virulence factors like proteins M, Sfd1 and F1 are important regarding their role in tissue inter- nalisation of streptococci and in triggering psoriasis.2 Furthermore, antigen-specific T-lymphocyte response against Group A streptococci increases in patients with guttate and chronic plaque psoriasis and the association between acute infections and guttate psoriasis has been reported in patients with chronic plaque type psoriasis.18–20 Similarly, CD4+ and CD8+ cells isolated from psoriatic lesions were shown to be responsive to streptococcal peptidoglycan by proliferating and secreting interferon-γ.21 It was reported that streptococcal isolates from throat cul- tures of guttate psoriasis patients secreted streptococcus pyo- genes exotoxin C which, by acting as superantigen, triggers polyclonal expansion of Vβ2-bearing T cells.22 The outcome of all of the abovementioned studies were similar and supportive of the findings obtained from the cur- rent study. However, our study’s result is not in accordance with some previous similar works. These studies found that there is no significant difference in serum ASO levels in psori- asis patient and control group.19,23,24 Conclusion This study confirms an association between the increased serum level of ASO with the immunopathogenesis and/or sus- ceptibility to chronic plaque psoriasis. Recommendations Further prospective cohort studies with larger sample size are needed to investigate the exact role of streptococcal infection and thus ASO level on elaborations of chronic plaque psoriasis. Acknowledgments We thank God for help us performing this work. Great thanks to the staff members of dermatology outpatient clinic in Al-Hussein Medical City in Kerbala for their help in patients’ diagnosis and selection. We are grateful for the staff members of Hematology investigation Unit in Al-Hussein Medical City for assistance in sample collection and processing. We would like to thank Dr. Jalal Al-Karbalaee for his great support and kind cooperation to mount this work. Competing Interests None declared. Conflicts of Interest There is no conflicts of interest represented by financial or per- sonal relationships with any other people or organizations regarding this work.  Table 1. Serum level of ASO in patients with chronic plaque psoriasis and control group Subject Number ASO Mean (IU/ml ± SEM) Statistical analysis* Psoriatic patients 45 (21.4 ± 0.8521) Controls 20 (10.63 ± 0.8023) *Table Analysed Unpaired t-test data Column B control ASO vs. vs. Column A test ASO Unpaired t-test P-value < 0.0001 P-value summary **** Significantly different? (P < 0.05) Yes One- or two-tailed P-value? Two-tailed t, df t = 7.757 df = 63 How big is the difference? Mean ± SEM of column A 21.40 ± 0.8521, n = 45 Mean ± SEM of column B 10.63 ± 0.8023, n = 20 Difference between means −10.77 ± 1.389 95% confidence interval −13.55 to −7.997 R2 0.4885 F-test to compare variances F,DFn, Dfd 2.538, 44, 19 P-value 0.0306 P-value summary * Significantly different? (P < 0.05) Yes 22 J Contemp Med Sci | Vol. 1, No. 4, Autumn 2015: 20–22 Risk factors in patients with IHD Research Ali Mansoor Al-Ameri et.al References 1. Bos JD, de Rie MA, Teunissen MB, Piskin G. Psoriasis: dysregulation of innate immunity. Br J Dermatol. 2005;152(6):1098–7. doi: 10.1189/JLB.0109046 PMID: 15948970 2. Karabudak AÖ, Dogan B. Management of guttate psoriasis in patients with associated streptococcal infection. Dovepress J Psoriasis Target Ther. 2012:2: 89–94. doi: http://dx.doi.org/10.2147/PTT.S25211 3. Aujla SJ, Dubin PJ, Kolls JK. Th17 cells and mucosal host defense. Semin Immunol. 2007;19(6):377–82. doi: http://dx.doi.org/10.1016/j. smim.2007.10.009 PMID: 18054248 4. 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