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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.

<b><i>Background:</i></b> Lichen planus (LP) is a chronic autoimmune inflammatory mucocutaneous disease. Interleukin (IL)-17 is the signature cytokine of T-helper 17 cells, involved in the aetiology of many autoimmune and inflammatory disorders. Vitamin D has an immune-regulatory role and suppresses IL-17 production via direct transcriptional inhibition of IL-17 gene expression. <b><i>Objective:</i></b> To explore the relationship of IL-17 and vitamin D levels with LP, and the possible inter-relationship between IL-17 and vitamin D. <b><i>Methods:</i></b> The study enrolled 30 patients with LP and 30 healthy controls. Blood samples and skin biopsies were taken from all participants for evaluation of serum vitamin D, and serum and tissue IL-17 levels using enzyme-linked immunosorbent assay (ELISA). <b><i>Results:</i></b> Patients had significantly higher serum and tissue IL-17 (<i>p</i> &#x3c; 0.001 for both), as well as significantly lower serum vitamin D levels and more deficient patterns of vitamin D status than controls (<i>p</i> &#x3c; 0.001 for both). In the patient group, there was a statistically significant positive correlation between extent of the disease and serum IL-17. There was no direct statistical correlation between IL-17 levels and serum vitamin D in either patients or controls. <b><i>Conclusion:</i></b> This study confirms a previously suggested role of IL-17 in the pathogenesis of LP and suggests its relation to the extent and severity of the disease. We also found an association between vitamin D deficiency and LP. However, a direct relationship between IL-17 and vitamin D deficiency could not be clarified.

Background Hand eczema is the most common occupational skin disease. The etiology is multifactorial. Systemic alitretinoin, a pan-retinoic receptor agonist, has proven efficacy in the treatment of recalcitrant chronic hand eczema; however, its precise mechanism of action in hand eczema is not fully understood.Aims Assessment of the level of expression of retinoid receptors (RAR and RXR) in the skin of patients with hand eczema in an attempt to explain their possible role in the pathogenesis of the disease.Methods Thirty patients with hand eczema and 30 age-and sex-matched healthy controls were included. Full clinical examination was done, and tissue levels of retinoic acid receptor (RAR) and retinoid x receptor (RXR) were measured by quantitative real-time PCR (qRT-PCR). ResultsThe levels of RAR and RXR expression were significantly downregulated in the patient group compared to the control group; (P < 0.001) for both. In addition, there was a statistically significant negative correlation between Osnabr€ uck Hand Eczema Severity Index (OHSI) and the levels of RAR and RXR expression (P < 0.001).Conclusion Deficient retinoid receptor expression has a primary role in the pathogenesis, clinical phenotype, and severity of hand eczema and sheds light on the mechanism of action of retinoids in the treatment of chronic hand eczema.

Background/Objectives: Pityriasis lichenoides chronica (PLC) lesions are reported to subside with post-inflammatory hypopigmentation (PIH); hence, the most widely perceived nature of hypopigmented macules in PLC is PIH. However, to the best of our knowledge, no studies describing histopathological findings in these lesions are reported in literature. The aim of this study is to evaluate the hypopigmented lesions encountered in PLC patients and to shed light on their histopathological features. Methods:A cross-sectional observational study included twenty-one patients with PLC recruited in a period of twelve months. Clinical characteristics of each patient were collected. A skin biopsy from hypopigmented lesions whenever present was taken and assessed with routine haematoxylin and eosin stain.Results: Seventeen patients (81%) were less than 13 years old. Most patients (85.7%) demonstrated diffuse distribution of lesions. Hypopigmented lesions were present on the face in 12 (57.14%) patients. Histopathologically, hypopigmented lesions showed features of post-inflammatory hypopigmentation in 19% of patients, residual PLC in 52.4% and active PLC 28.6% of patients. Conclusion:Hypopigmented lesions in PLC were noted mainly in younger ages, histopathologically they may show features of active or residual disease, beyond post-inflammatory hypopigmentation. Consequently active treatment for patients presenting predominantly with hypopigmented lesions could be required to control the disease.

BACKGROUND Nail psoriasis has a major negative impact on the physical and psychological aspects of the patient's life. Treatment is often unsatisfactory because of the difficult penetration of the drug into the nail. OBJECTIVE To compare the efficacy of fractional CO 2 laser monotherapy versus combined fractional CO 2 laser and calcipotriol/betamethasone ointment preparation in treatment of nail psoriasis. PATIENTS AND METHODS Thirty patients with nail psoriasis with at least 2 affected fingernails were recruited for this study. Target NAPSI (tNAPSI) score was calculated at the start of the study and at 3 months after the last laser session. One affected fingernail of each patient received 6 sessions of fractional CO 2 laser with 4-week intervals. Another affected fingernail of each patient received topical betamethasone/calcipotriol ointment once daily in addition to the 6 fractional CO 2 laser sessions. RESULTS In the monotherapy group, there was significant improvement in the nail matrix score, nail bed score, and tNAPSI score. In the combined therapy group, there was significant improvement in nail bed score and tNAPSI score, but nail matrix score showed no statistically significant improvement. Overall, there was no statistically significant difference between the 2 studied groups. CONCLUSION Fractional CO 2 laser can be an effective and promising new treatment for nail psoriasis.

The exact aetiology of pityriasis lichenoides chronica (PLC) remains unknown. While phototherapy is the most investigated therapeutic modality, azithromycin has been used scarcely. The aim of this study is to evaluate the therapeutic efficacy of azithromycin in the treatment of PLC compared to NB-UVB and evaluating the presence of streptococcal infection as a possible etiological factor in PLC patients. The study was designed as a randomised controlled trial. Twenty-four patients with PLC were randomly allocated into either azithromycin (n = 13, standard dose every 10 days) or NB-UVB (n = 11, thrice weekly) groups. End of study (EOS) was either complete clearance of lesions or a maximum of 8 weeks. Therapeutic efficacy was defined as percent reduction in lesions and was calculated for the rash as a whole, erythematous papules alone, and hypopigmented lesions alone and graded into complete, very-good, good, poor or no response. Anti-streptolysin O titre (ASOT), anti-deoxyribonuclease B titre (anti-DNaseB) and throat culture were evaluated at day 0. No significant difference existed between both groups as regards therapeutic efficacy. At EOS, NB-UVB achieved significantly more percent reduction in the extent of hypopigmented lesions and consequently in the rash as a whole (p = 0.001, p = 0.034, respectively). The extent of the rash as a whole was significantly less in the NB-UVB at EOS (p = 0.029, respectively). The effect of NB-UVB on hypopigmented lesions appeared early at week 4 of treatment. Only two patients, one from each group, relapsed during the 3 month follow-up. Evidence of recent streptococcal infection was present in 79% of the cases, mainly in the form of elevated ASOT (94.7%). It was significantly more encountered in young children (< 13 years) (p = 0.03) and was associated with more extent of erythematous papules and consequently with more extent of the rash as a whole (p = 0.05 and p = 0.01, respectively). It did not affect outcome of therapy at EOS. Azithromycin did not show more favorable response in patients with recent streptococcal infection. Therapeutic efficacy of azithromycin is comparable to NB-UVB in treatment of PLC; however, NB-UVB is superior in management of hypopigmented lesions. It is highly suggested that PLC could be a post streptococcal immune mediated disorder.Registration number: ClinicalTrials.gov, NCT03831269.

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