Over-expression of tumor necrosis factor-α in vitiligo lesions after narrow-band UVB therapy: an immunohistochemical study

Focus on Anti-Tumour Necrosis Factor (TNF)-α-Related Autoimmune Diseases

Anti-tumour necrosis factor (TNF)-α agents have been increasingly used to treat patients affected by inflammatory bowel disease and dermatological and rheumatologic inflammatory disorders. However, the widening use of biologics is related to a new class of adverse events called paradoxical reactions. Its pathogenesis remains unclear, but it is suggested that cytokine remodulation in predisposed individuals can lead to the inflammatory process. Here, we dissect the clinical aspects and overall outcomes of autoimmune diseases caused by anti-TNF-α therapies.

Evaluation of the Langerhans cells role in vitiligo and its relationship to NB-UVB

BACKGROUND

Langerhans cells (LCs) are antigen-presenting cells that are characterized by CD1a and CD207/langerin expression. The disturbance in the communication network among keratinocytes, melanocytes, and antigen-presenting cells may be involved in vitiligo pathogenesis.

AIMS

The current work aims to detect and quantify LCs in involved skin of patients affected by vitiligo before and after treatment with NB-UVB using CD1a immunohistochemistry, in addition to correlate percentage of LCs with the clinicopathological parameters.

METHODS

Twenty vitiligo patients and 10 age and sex matched controls were investigated. Patients were received NB-UVB thrice weekly for 12 weeks.

RESULTS

There was a significant reduction in LCs percentage in skin affected by vitiligo before treatment in comparison with normal skin. About 65% (13/20) of vitiligo patients responded to NB-UVB, and the liability to respond was correlated with LCs percentage in specimens before treatment. However, there was no statistical difference between specimens before and after treatment regarding LCs percentage.

CONCLUSIONS

Reduction in LCs in vitiligo may be a sign of active disease and melanocytes destruction. The percentage of LCs affects response to NB-UVB since higher percentage is associated with greater response to therapy. Therefore, modulation of LCs as a type of immunotherapy could be beneficial in improvement of vitiligo.

Immunohistochemistry of Janus Kinase 1 (JAK1) Expression in Vitiligo

Background

Vitiligo is a chronic autoimmune disease in which the destruction of melanocytes causes white spots on the affected skin. Janus kinase (JAK) is a family of intracellular, non-receptor tyrosine kinases that transduce cytokine-mediated signals via the JAK–signal transducer and activator of transcription pathway. The aim of the present study is to explore the possible role of JAK1 in the pathogenesis of vitiligo using immunohistochemical methods.

Methods

The current study was conducted in a sample of 39 patients who presented with vitiligo and 22 healthy individuals who were age and sex matched as a control group. We used immunohistochemistry to evaluate JAK1 status (intensity and distribution) and assess the percentage of residual melanocytes using human melanoma black 45 (HMB45).

Results

Intense and diffuse JAK1 expression was significantly more likely to indicate vitiliginous skin compared to normal skin (p < .001). Strong and diffuse JAK1 expression was associated with short disease duration, female sex, and lower percentage of melanocytes (detected by HMB45) (p < .05).

Conclusions

JAK1 may be involved in the pathogenesis of vitiligo, as indicated by intense and diffuse expression compared to control and association with lower percentage of melanocytes detected by HMB45 immunostaining.

Expression of Janus Kinase 1 in vitiligo & psoriasis before and after narrow band UVB: a case-control study

Janus kinases (JAKs) are non-receptor protein tyrosine kinases that are expressed in many tissues. Once the JAKs are activated, a cascade of further signaling events is triggered involving phosphorylation of selected receptor chain tyrosines, binding of signal transducer and activator of transcription (STAT) proteins and phosphorylation of these STATs. Due to their ability to selectively modulate immune function, targeted JAK inhibitors are promising candidates for some skin diseases such as psoriasis and atopic dermatitis. The aim of this study was to assess the level of JAK1 in both vitiligo and psoriasis patients before and after treatment with NB-UVB which is considered a gold standard therapy for both diseases. This study was conducted on 10 patients with psoriasis, 10 patients with vitiligo and 10 controls. JAK1 levels before and after treatment with NB-UVB 311 nm (36 sessions) were measured using Western blot assay. The level of JAK1 was significantly higher in vitiligo and psoriasis patients than controls. There was a decline in the level of JAK1 after treatment, which was statistically significant. VASI and PASI scores of patients decreased after treatment with NB-UVB. In psoriatic patients, the JAK1 level positively correlated with the female participants, disease duration and PASI change. It was concluded that JAK1 plays a role in the pathogenesis of both vitiligo and psoriasis based on its upregulated level before treatment and downregulated level after treatment. This raises the possibility of using the JAK1 inhibitors as targeted immunotherapy for vitiligo and psoriasis.

Effect of narrow band ultraviolet B phototherapy as monotherapy or combination therapy for vitiligo: a meta-analysis

BACKGROUND

The treatment of vitiligo is still one of the most difficult dermatological challenges, although there are many therapeutic options. Narrow band ultraviolet B (NB-UVB) phototherapy is considered to be a very important modality for generalized vitiligo.

OBJECTIVE

The aim of this study was to explore whether a combination of NB-UVB and topical agents would be superior to NB-UVB alone for treating vitiligo.

METHODS

We searched the electronic databases such as PUBMED, EMBASE, Cochrane Library, and Web of Science. The primary outcome was the proportion of ≥50% repigmentation (a clinical significance), and secondary outcome was the proportion of ≥75% repigmentation (an excellent response).

RESULTS

Seven randomized controlled trials (RCTs) involving 240 patients (413 lesions) were included in this meta-analysis. The study showed no significant difference between NB-UVB combination therapy (NB-UVB and topical calcineurin inhibitor or vitamin D analogs) and NB-UVB monotherapy in the outcomes of ≥50% repigmentation and ≥75% repigmentation. However, lesions located on the face and neck had better results in ≥50% repigmentation (RR = 1.40, 95% CI 1.08-1.81) and ≥75% repigmentation (RR = 1.88, 95% CI 1.10-3.20) with NB-UVB and topical calcineurin inhibitor combination therapy vs. NB-UVB monotherapy.

CONCLUSIONS

The meta-analysis suggested that adding neither topical calcineurin inhibitors nor topical vitamin-D3 analogs on NB-UVB can yield significantly superior outcomes than NB-UVB monotherapy for treatment of vitiligo. However, addition of topical calcineurin inhibitors to NB-UVB may increase treatment outcomes in vitiligo affecting face and neck.

Review of narrowband ultraviolet B radiation in vitiligo

Vitiligo is a common, acquired pigmentary disorder of unknown etiology with great impact on patient’s appearance and quality of life. It presents a therapeutic challenge to many dermatologists. Photochemotherapy using psoralen and ultraviolet A (UVA) therapy, topical and oral immunosuppresants, as well as cosmetic camouflage are also commonly employed with varying clinical efficacy. Phototherapy is a popular treatment option, which includes both of the generalized ultraviolet B (UVB) therapies, broadband UVB and narrowband UVB (NB-UVB). It has been used favorably, both alone as well as in combination with other agents like topical calcineurin inhibitors, vitamin-D analogs. Combination therapies are useful and may provide quicker regimentation and treat vitiligo with an additive mechanism of action than UVB phototherapy. Advances in technology may lead to the continuing use of UVB phototherapy as a treatment for vitiligo through the development of sophisticated devices and delivery systems as well as innovative application methods. These will provide increased therapeutic options for all vitiligo patients, particularly those with refractory disease. In this article, I have reviewed the available data pertaining to efficacy and safety issues for NB-UVB as monotherapy, its comparison with psoralen plus UVA and other modes of phototherapy, combination regimens that have been tried and future prospects of NB-UVB in vitiligo.

Tumour necrosis factor-α inhibition can stabilize disease in progressive vitiligo

Tumour necrosis factor (TNF)-α, a proinflammatory cytokine central to many autoimmune diseases, has been implicated in the depigmentation process in vitiligo. We review its role in vitiligo by exploring its pro- and anti-inflammatory properties and examine the effects of blocking its actions with TNF-α antagonist therapeutics in reports available in the literature. We found that TNF-α inhibition halts disease progression in patients with progressive vitiligo but that, paradoxically, treatment can be associated with de novo vitiligo development in some patients when used for other autoimmune conditions, particularly when using adalimumab and infliximab. These studies reinforce the importance of stating appropriate outcomes measures, as most pilot trials propose to measure repigmentation, whereas halting depigmentation is commonly overlooked as a measure of success. We conclude that TNF-α inhibition has proven useful for patients with progressive vitiligo, where TNF-α inhibition is able to quash cytotoxic T-cell-mediated melanocyte destruction. However, a lingering concern for initiating de novo disease will likely prevent more widespread application of TNF inhibitors to treat vitiligo.

Interferon-γ induces senescence in normal human melanocytes

BACKGROUND

Interferon-γ (IFN-γ) plays an important role in the proceedings of vitiligo through recruiting lymphocytes to the lesional skin. However, the potential effects of IFN-γ on skin melanocytes and the subsequent contribution to the vitiligo pathogenesis are still unclear.

OBJECTIVE

To investigate the effects of IFN-γ on viability and cellular functions of melanocytes.

METHODS

Primary human melanocytes were treated with IFN-γ. Cell viability, apoptosis, cell cycle melanin content and intracellular reactive oxygen species (ROS) level were measured. mRNA expression was examined by real-time PCR. The release of interleukin 6 (IL-6) and heat shock protein 70 (HSP-70) was monitored by ELISA. β-galactosidase staining was utilized to evaluate melanocyte senescence.

RESULTS

Persistent IFN-γ treatment induced viability loss, apoptosis, cell cycle arrest and senescence in melanocytes. Melanocyte senescence was characterized as the changes in pigmentation and morphology, as well as the increase of β-galactosidase activity. Increase of p21Cip1/Waf1 protein was evident in melanocytes after IFN-γ treatment. IFN-γ induction of senescence was attenuated by siRNAs against p21, Janus kinase 2 (JAK2) or signal transducer and activator of transcription 1 (STAT1), but not by JAK1 siRNA nor by p53 inhibitor pifithrin-α. IFN-γ treatment increased the accumulation of intracellular ROS in melanocytes, while ROS scavenger N-acetyl cysteine (NAC) effectively inhibited IFN-γ induced p21 expression and melanocyte senescence. IL-6 and HSP-70 release was significantly induced by IFN-γ treatment, which was largely inhibited by NAC. The increase of IL-6 and HSP-70 release could also be observed in senescent melanocytes.

CONCLUSION

IFN-γ can induce senescence in melanocytes and consequently enhance their immuno-competency, leading to a vitiligo-prone milieu.

The role of tumor necrosis factor-α in the pathogenesis of vitiligo

Vitiligo is an acquired immune disorder of the skin characterized by the presence of white depigmented macules. Its immunopathogenesis is not completely understood, but inflammatory alterations in the skin microenvironment, and particularly increased expression of the cytokine tumor necrosis factor-α (TNFα), are thought to be essential regulators of melanocyte dysfunction and death. In this article we review the evidence that implicates TNFα in the pathogenesis of vitiligo, including studies on serum and tissue levels of TNFα, TNFα gene polymorphisms, in vitro studies, and therapeutic trials using TNFα inhibitors. TNFα emerges as a complex mediator with apparently conflicting roles in vitiligo.