Indian Journal of Dermatology
ORIGINAL ARTICLE
Year
: 2022  |  Volume : 67  |  Issue : 4  |  Page : 319--323

Assessment of CXCL10 Before and after narrow band UVB phototherapy in non-segmental vitiligo patients


Sherief M Hussein1, Mohammed Abd El Hakim Sorour2, Mahitab Samir1, Shaimaa Ahmed Abd El Azim3, Ahmed Hossain4,  
1 From the Department of Dermatology and Venereology, Medical Division, National Research Centre, Dokki, Giza, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
3 Department of Clinical Pharmacology, Maadi Military Hospital, Cairo, Egypt
4 Department of Quality Training, Arab Academy for Science Technology and Maritime Transport-Cairo Campus, Cairo, Egypt

Correspondence Address:
Sherief M Hussein
Department of Dermatology and Venereology, National Research Centre, Dokki, Giza, P. O - 12622
Egypt

Abstract

Background: Vitiligo is a common depigmenting skin disorder characterized by white macules and patches accompanied by local melanocyte loss, caused by autoimmune destruction. Vitiligo is classified into two major forms: segmental vitiligo (SV) and non-segmental vitiligo (NSV). It was also found that the IFN-ȣ/CXCL10 axis is functionally required for both progression and maintenance of the disease. Chemokine 10 (CXCL10) is a pro-inflammatory chemokine which was found to be elevated in the serum of vitiligo patients. UVB has been found to be a useful therapy that results in rapid repigmentation in NSV patients. Objectives: To evaluate CXCL10 in vitiligo patients before and after narrow band UVB (NB-UVB) phototherapy, which if targeted could provide new insights for therapeutic intervention for vitiligo. Patients and Methods: The study included 25 active NSV patients who were able to comply with the study protocol in the Center of Excellence, Dermatology Outpatient Clinic, National Research Center, Egypt (February 2020–2021). All recruited patients were subjected to documentation of complete history. Dermatological assessment of vitiligo lesions, including vitiligo area score index (VASI) score, CXCL10 and extent of the disease were performed. A 3 mm punch biopsy from active vitiligo lesion (site of biopsy) was taken before and after treatment by NB-UVB, and then immunohistochemical staining was performed to evaluate expression of CXCL10. Results: After treatment by NB-UVB there was a significant decrease in VASI score, extent of the disease and CXCL10 expression. Conclusion: The decrease in CXCL10 levels could be attributed to the effect of NB-UVB which leads to decrease in IFN-γ level, necessary to release CXCL10 through its pathway resulting in repigmentation and decrease in the extent of the disease and VASI scores.



How to cite this article:
Hussein SM, Hakim Sorour MA, Samir M, Abd El Azim SA, Hossain A. Assessment of CXCL10 Before and after narrow band UVB phototherapy in non-segmental vitiligo patients.Indian J Dermatol 2022;67:319-323


How to cite this URL:
Hussein SM, Hakim Sorour MA, Samir M, Abd El Azim SA, Hossain A. Assessment of CXCL10 Before and after narrow band UVB phototherapy in non-segmental vitiligo patients. Indian J Dermatol [serial online] 2022 [cited 2022 Nov 26 ];67:319-323
Available from: https://www.e-ijd.org/text.asp?2022/67/4/319/360299


Full Text



 Introduction



Vitiligo is an autoimmune disease that affects the skin (and sometimes mucous membranes). The disease progressively damages the melanocytes, causing appearance of patchy depigmentation. Vitiligo is classified into two major forms: segmental vitiligo (SV) that varies in shape, but not linked to autoimmune disorders and non-segmental vitiligo (NSV) that is often symmetrically distributed including acrofacial, mucosal, generalized, universal, mixed and rare variants.[1] NSV arises from an autoimmune response against melanocytes in the skin.[2]

Interferon-γ (IFN-γ) is the predominant cytokine expressed in vitiliginous skin, produced by CD8+ T cells.[3] Binding of IFN-γ to its receptor triggers JAK-STAT path resulting in CXCL9 and CXCL10 secretion in skin [Figure 1] via the cognate receptor CXCR3, CXCL9.[4] This promotes the enrolment of melanocyte-specific CD8+ T cells to skin, while CXCL10 indorses their localization in epidermis intensifying inflammation via a positive feedback mechanism. Serum CXCL10 in vitiligo patients also links with disease severity and its elevation may be a biomarker in observing disease progression.[2],[5] IFN-γ in turn hinders melanogenesis and induces melanocyte apoptosis. Other studies suggested that IFN-γ, its receptor, STAT1, CXCL10 and CXCR3 are crucial for hypopigmentation in vitiligo.[1]{Figure 1}

Phototherapy is the main effective treatment modality for vitiligo patients. Narrow band UVB (NB-UVB) is a polychromatic light with a wavelength of 311–313 nm. It acts by stimulation of epidermal expression of IL-10, prompting differentiation of T-regulatory lymphocytes that constrains the action of auto reactive T lymphocytes and induction of apoptosis of T cells in vitiligionous skin. In addition, its major repigmentation effect is owing to enhancement of functional melanocytes in perilesional skin or immature melanocytes in hair follicles. This is known as “bio stimulation”.[6]

The exposure to UV light produces vitamin D in the skin, which has powerful anti-inflammatory activity owing to inhibition of interleukin (IL)-1 and interferon (INF) γ production. It also increases innate immunity by inducing antimicrobial peptides.[1]

 Patients and Methods



This study was performed in the Center of Excellence, Dermatology Outpatient Clinic, National Research Center, Egypt (February 2020–2021). The study was approved by the Ethics Committee. 25 active NSV patients were enrolled.

Inclusion criteria

Patients with active NSV >18 years old.

Exclusion criteria

Patients with universal and segmental vitiligo, those using topical or systemic therapy for vitiligo or immunosuppressant in the last 3 months were excluded. Pregnant and lactating mothers, patients with autoimmune disorder or malignancy, and those with contraindications to receive phototherapy (photosensitive disorders, history or existence of malignant or premalignant skin lesions) were all omitted from the study.

Methodology

The study started with a total of 40 patients, only 25 active NSV patients complied with the study protocol because of corona virus pandemic. All recruited patients were subjected to documentation of full history, clinical examination, blood sampling and skin biopsy. Contributors have written an informed approval.

Full history taking, included personal history (name and age), history of present illness (onset and duration), as well as, history of exposure to psychological stress. History of any systemic diseases such as diabetes, other autoimmune disease (e.g., thyroid disease); history of any other skin disease, photosensitive disorders or malignant skin lesions were also taken. Family history of appearance of vitiligo in one or more of the family members was recorded.

Clinical assessment

Dermatological inspection of vitiligo lesions were accomplished before and after treatment. This included distribution of lesions, their anatomical sites and their extent by percentage of body surface area and vitiligo area score index (VASI) score. Fraction of depigmentation from total body surface was assessed by hand-unit rule, that is, a lesion in the size of patient's palm is equivalent to 1% of the total body surface.[7]

VASI score

VASI score is assessed by the hand-unit rule. The patient's body is divided into five separate areas; hands, upper extremities (except hands), trunk, lower extremities (except feet), and feet. Axillary region is encompassed with upper extremities, while buttocks and inguinal areas are involved with lower extremities. Face and neck are not incorporated in the assessment, but can be considered separately. One hand unit of the patient is used to approximate the baseline percentage of vitiligo involvement of each body area. For each body section, the VASI is considered as product of vitiligo area in hand units (which were established as 1% per unit) and degree of depigmentation in each hand-unit-measured patch. Total body VASI is calculated by the following formula (possible range: 0–100).[8]

VASI = Σ(all body sites) (hand units) × (depigmentation) (range 0–100)

Skin Biopsy

A 3 mm skin punch biopsy was taken from active vitiligo lesion, and then preserved in paraffin for assessment of CXCL10 by immunohistochemistry.

Measurement of CXCL10 by Immunohistochemistry

Paraffin-embedded samples were cut into 4 mm segments. After deparaffinization with xylene and rehydration, antigen retrieval was accomplished using microwave in 10 mmol l−1 sodium citrate buffer (pH 6.0) for 20 min. Diaminobenzidine was used as colorant and hematoxylin as counterstain.

Image analysis

Immunostaining was visualised and photographed under a light microscope Olympus CX-41 with DP 12 Olympus digital camera (Olympus Optical Co., Japan).

Five tumor fields with the highest expression were selected and counted at high magnification (×200) numbers [Figure 2] and [Figure 3].{Figure 2}{Figure 3}

Measurement of serum CXCL10

A blood sample was obtained for measurement of CXCL10 level by enzyme-linked immunosorbent assay technique (ELISA) via human CXC-chemokine ligand 10 ELISA kit (bt-laboratory, China, No E3800Hu).

Phototherapy treatment

Patients received NB-UVB, through UV cabin (Waldmann GmbH, Germany) equipped with an integrated UV photometer, having 16 TL-01/100 W fluorescent lamps generating NB-UVB with a topmost emission at 311 nm. Three sessions per week were accomplished on non-consecutive days. Initial dose was estimated by the system devised in phototherapy unit in the National Research Center for vitiligo using phototherapy tables. During the session, the eye and genitals were covered.

Clinical follow-up was accomplished on weekly intervals. Initial dose started at 0.3 J/cm2. The dose was fixed when the patient shows a faint erythema; otherwise, an increment of 0.3 J/cm2 was added. Patients received a total of 36 sessions with no additional treatment given during the study.

Serum and tissue CXCL10, extent of disease and VASI score were examined before and after phototherapy.

Statistical analysis

Data were gathered, reviewed and entered using Microsoft Excel. Data was analysed by Statistical Package for the Social Sciences (SPSS) version 22. Excel was used to tabulate the results.

For the quantitative variables which are normally distributed, paired t-test at P < 0.05 is used to declare the significant difference in serum CXCL10, VASI and extent of disease after using NB-UVB.[9]

 Results



A paired student t-test at P < 0.05 is used to illustrate a significant reduction in serum CXCL10, extent of disease and VASI score after vitiligo patients are exposed to 3 months of NB-UVB.

Clinical data of the patients

The study included 25 patients with NSV. The age range was between 19 and 67 (mean 39.04 ± 15.504), 10 of the patients were females (40%) and 15 were males (60%), 23 patients had no family history of vitiligo (92%), while 2 patients had positive family history (8%). Disease duration ranged from 1.5 to 14 years (mean 6.06 ± 3.392).

Clinical assessment

Clinical assessment of patients was through measuring extent of vitiligo lesions, and recording VASI scores before and after phototherapy. A significant reduction after 3 months of NB-UVB was detected in the extent of vitiligo lesions and VASI scores according to [Table 1].[9]{Table 1}

Immunohistochemical and serum levels assessment of CXCL10

A significant decrease was shown in CXCL10 levels after 3 months of NB-UVB, compared to their levels prior to treatment. Immunostaining showed positively stained lymphocytes before treatment with NB-UVB [Figure 2] and negatively stained lymphocytes after treatment with NB-UVB [Figure 3].

Clinicopathological correlation

NB-UVB significantly reduced CXCL10 in vitiligo patients, which accompanied the decrease in all clinical assessment values.

 Discussion



The study included 25 patients of active NSV. Serum and tissue CXCL10, and VASI scores were accomplished for each patient. A 3 mm skin biopsy was taken from each patient before treatment for active vitiligo lesions. Patients received 36 sessions of NB-UVB. After treatment, VASI score, blood sampling and skin biopsy were repeated for all patients. CXCL10 was assessed in skin biopsies and blood samples before and after treatment using immunohistochemistry and ELISA, respectively.

CXCL10 in vitiligo

Melanocyte-specific, cytotoxic CD8+ T cells are implicated in damage of melanocytes, via migration to the perilesional skin then become activated, inducing melanocytes apoptosis. They produce several cytokines, such as TNF-α and IFN-γ, which are primarily tangled in melanocytes destruction.[8] Interferon-γ is a vital cytokine accompanied with Th1 immune response, which prompts IFN-γ-inducible protein (IP)-10, likewise named (CXCL) 10, that binds to its specific receptor, chemokine (C-X-C motif) receptor (CXCR) 3, and adjusts immune responses by enrolment and motivation of T cells.[1],[10]

High level of CXCL10 is a marker of host immune response, especially of Th1. Vitiligo patients had a high level of CXCL10 in vitiliginous skin biopsies and blood samples which is also illuminated by Rashighi et al.[3] This follows what Wang et al.,[4] and Yang et al.[11] declared; that CXCL10 was found significantly raised in patients with stable vitiligo. Neutralization of CXCL10 significantly reduces depigmentation suggesting its critical role in progression and preservation of vitiligo and thus hindering CXCL10 is a targeted management approach.[10]

NB-UVB in vitiligo

NB-UVB is a leading treatment modality in vitiligo.[12] It increases expression of IL-10, stimulates differentiation of T-regulatory lymphocytes thus limiting action of T lymphocytes and induces T cell apoptosis in vitiligionous skin plus its role in repigmentation. Also produces vitamin D in the skin, which inhibits production of interferon (INF) γ, (IL)-1 and modulates IL-6.[1]

After 3 months of NB-UVB treatment, a significant decrease in the extent of vitiligo is observed in the patients with improvement in VASI scores matching what Khanna and Khandpur stated.

 Conclusion



Vitiligo is a complex depigmenting cutaneous condition, with progressive loss of melanocytes. Being an autoimmune T-cell mediated disease, vitiligo follows an IFN-γ pathway in its pathophysiology in addition to CXCL10 which is a major chemokine in this pathway. Decreased CXCL10 levels could be attributed to the effect of NB-UVB in decreasing IFN-γ level resulting in repigmention and cessation of disease progression.

Author's contribution

Dr Sherief Mahdy Hussein: Collection of patients, Paper work for ethics committee approval, writing and publishing the article.

Prof. Mohammed Sorour: Collection and analysis of blood samples.

Dr Mahitab Samir: Collection of biopsy samples and performing UVB sessions for patients.

Dr Shaimaa Ahmed: Data collection, writing and revision of the article.

Dr Ahmed Hossain: Statistical analysis of the data.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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