Latent class analysis of a series of 717 patients with vitiligo allows the identification of two clinical subtypes

Understanding of Pathomechanisms and Clinical Practice for Vitiligo

Vitiligo is a disease caused by the acquired depletion of melanocytes and/or melanocyte precursor cells in response to genetic and environmental factors, resulting in depigmentation of the entire body. It is roughly divided into segmental and non-segmental vitiligo, and it has been found that abnormalities of melanocytes themselves and dysregulation of autoimmune responses to melanocytes are greatly involved in the pathology of non-segmental vitiligo. Segmental vitiligo pathology is largely unknown; however, it has been suggested that it may be caused by skin or melanocyte mosaicism. Treatments for vitiligo include topical therapy, ultraviolet therapy, and surgical transplantation, and it is extremely important to correctly understand the pathology to perform optimal treatment. In recent years, the development of vitiligo treatments using Janus kinase (JAK) inhibitors has progressed rapidly. We herein outline the latest pathology of vitiligo, from general vitiligo treatment to the progress of clinical trials using JAK inhibitors, along with what clinicians should consider in archiving precision medicine, including my own ideas thereon.

Improved Disease Course Associated With Early Initiation of Biologics in Polyarticular Juvenile Idiopathic Arthritis: Trajectory Analysis of a Childhood Arthritis and Rheumatology Research Alliance Consensus Treatment Plans Study

OBJECTIVE

To investigate the effects of early introduction of biologic disease-modifying antirheumatic drugs (bDMARDs) on the disease course in untreated polyarticular juvenile idiopathic arthritis (JIA).

METHODS

We analyzed data on patients with polyarticular JIA participating in the Start Time Optimization of Biologics in Polyarticular JIA (STOP-JIA) study (n = 400) and a comparator cohort (n = 248) from the Childhood Arthritis and Rheumatology Research Alliance Registry. Latent class trajectory modeling (LCTM) was applied to identify subgroups of patients with distinct disease courses based on disease activity (clinical Juvenile Arthritis Disease Activity Score in 10 joints) over 12 months from baseline.

RESULTS

In the STOP-JIA study, 198 subjects (49.5%) received bDMARDs within 3 months of baseline assessment. LCTM analyses generated 3 latent classes representing 3 distinct disease trajectories, characterized by slow, moderate, or rapid disease activity improvement over time. Subjects in the rapid improvement trajectory attained inactive disease within 6 months from baseline. Odds of being in the rapid improvement trajectory versus the slow improvement trajectory were 3.6 times as high (95% confidence interval 1.32-10.0; P = 0.013) for those treated with bDMARDs ≤3 months from baseline compared with subjects who started bDMARDs >3 months after baseline, after adjusting for demographic characteristics, clinical attributes, and baseline disease activity. Shorter disease duration at first rheumatology visit approached statistical significance as a predictor of favorable trajectory without bDMARD treatment.

CONCLUSION

Starting bDMARDs within 3 months of baseline assessment is associated with more rapid achievement of inactive disease in subjects with untreated polyarticular JIA. These results demonstrate the utility of trajectory analysis of disease course as a method for determining treatment efficacy.

Vitiligo: Translational research and effective therapeutic strategies

This is an exciting phase of vitiligo research with the current understanding of vitiligo pathogenesis and its translation to successful treatment. The pathogenetic origin of vitiligo revolves around autoimmunity with supporting role from many other factors like oxidative stress, inherent melanocyte defects, or defective keratinocytes and fibroblasts. Vitiligo can be classified into segmental or non-segmental depending upon the clinical presentation, or it can be classified as progressing or stable based on the activity of the disease. Vitiligo treatments need to be stratified depending upon which type of vitiligo we are treating and at which phase the vitiligo patient presents to us. There are two different aims of treatment of vitiligo. The first involves rescuing the melanocytes from the damage to arrest the depigmentation. The second strategy focuses on replenishing the melanocytes so that successful repigmentation is achieved. It is also important to maintain the disease in a stable phase or prevent relapse. As stability in non-segmental vitiligo is a dynamic process, maintenance of the stability of repigmentation is also an important consideration in the management of vitiligo. In this review, we shall briefly discuss the current options and future insight into the management of vitiligo.

A Nationwide, Multicentric Case-Control Study on Vitiligo (MEDEC-V) to Elicit the Magnitude and Correlates

Background:

Vitiligo is an acquired, idiopathic, and common depigmentation disorder. The values of various epidemiologic parameters are often doubtful due to the methodological weaknesses of the studies.

Aims:

To elicit the magnitude of various epidemiological parameters and important correlates of vitiligo.

Materials and Methods:

Every vitiligo patient attending the outpatient department of medical colleges spread over most of the Indian states were examined over a period of 1 year. Various epidemiological and clinical variables were examined and compared with age and sex-matched controls (registered in the Clinical Trial Registry of India CTRI/2017/06/008854).

Results:

A total of 4,43,275 patients were assessed in 30 medical colleges from 21 Indian states. Institutional prevalence of vitiligo was 0.89% (0.86% in males and 0.93% in females, P < 0.001). The mean age at presentation and mean age at onset were 30.12 ± 17.97 years and 25.14 ± 7.48 years, respectively. Head–neck was the most common primary site (n = 1648, 41.6%) and most commonly affected site (n = 2186, 55.17%). Most cases had nonsegmental vitiligo (n = 2690, 67.89%). The disease started before 20 years of age in more than 46% of cases. About 77% of all cases had signs of instability during the last 1 year. The family history, consanguinity, hypothyroid disorders, and depressed mood were significantly (P < 0.001) higher among the cases. First, second, and third-degree family members were affected in 269 (60.04%), 111 (24.78%), and 68 (15.18%) cases, respectively. Work-related exposure to chemicals was significantly higher among cases (P < 0.008). Obesity was less common among vitiligo cases [P < 0.001, odds ratio (OR) 0.78, 95% confidence interval (CI): 0.71–0.86].

Conclusion:

This is one of the largest studies done on vitiligo in India. The prevalence of vitiligo was found to be 0.89% among hospital attendees. Prevalence of vitiligo was higher among females than in males and prevalence of family history, consanguinity, hypothyroid disorders were higher in vitiligo than among controls.

Classification and diagnosis of vitiligo

Vitiligo is a relatively common, acquired hypopigmentary disorder caused by the loss of epidermal melanocytes. It is characterized by asymptomatic, well-circumscribed round to oval-shaped whitish patches that vary in size. Depending on various clinical features, vitiligo is classified into several types, that is, non-segmental, segmental, and undetermined/unclassified vitiligo. The uniform classification of vitiligo is very important in predicting its clinical course and prognosis and communication among researchers. In particular, segmental vitiligo is a highly distinctive subtype of vitiligo considering its clinical features and prognosis. It usually has an onset early in life and spreads rapidly within the affected area limited to one segment of the integument. Signs of vitiligo activity such as Koebnerʼs phenomenon, trichrome vitiligo, inflammatory vitiligo, and confetti-like lesions give useful information to start treatments to block the progression of the disease. Lastly, other hypopigmentary disorders should be distinguished from vitiligo to make the correct diagnosis and prescribe the right treatment. In this report, I review the clinical features of vitiligo, various subtypes according to classification, and the importance for differential diagnosis of hypopigmentary disorders from vitiligo.

Developing a latent class analysis model to identify at-risk populations among people using medicine without prescription

INTRODUCTION

There exist limited strategies to address the issue of topical medication without prescription (MWP) use.

MATERIAL AND METHODS

A survey with pre-coded questionnaires was conducted with 210 patients following up in the dermatology clinic of a tertiary care center. The knowledge and attitude scores were regressed against demographics and exploratory practice questions, and latent class analysis was carried out to check any particular set of characteristics associated with study subpopulations.

RESULTS

Forty-seven (22%) participants were found using topical antimicrobial containing MWP. Participants with good knowledge score had 3.41 (95% C.I. = 1.68-7.33), 2.99 (1.37-6.73), and 2.49 (1.26-5.15) times association with opting of distance as the prime reason for availing topical MWP, habit of always reading the accompanying drug leaflet, and understanding that OTC topical medication may change the effect of the already prescribed drugs. Participants with good attitude score showed 2.76 (1.50-5.13) times association with limiting the use of steroid containing topical MWP. Latent class analysis identified one subset of participants having lesser knowledge and attitude scores and quoted financial reasons for the procurement of MWP; however, it was found to have greater income as compared to remaining participants.

CONCLUSION

The strategy to identify the target patient audience so as to deliver patient education intervention programs, regarding safe and effective use of MWP was built.

Vitiligo: A Review

Vitiligo, a common depigmenting skin disorder, has an estimated prevalence of 0.5–2% of the population worldwide. The disease is characterized by the selective loss of melanocytes which results in typical nonscaly, chalky-white macules. In recent years, considerable progress has been made in our understanding of the pathogenesis of vitiligo which is now clearly classified as an autoimmune disease. Vitiligo is often dismissed as a cosmetic problem, although its effects can be psychologically devastating, often with a considerable burden on daily life. In 2011, an international consensus classified segmental vitiligo separately from all other forms of vitiligo, and the term vitiligo was defined to designate all forms of nonsegmental vitiligo. This review summarizes the current knowledge on vitiligo and attempts to give an overview of the future in vitiligo treatment.

Reclassification of breast cancer: Towards improved diagnosis and outcome

BACKGROUND

The subtyping of breast cancer based on features of tumour biology such as hormonal receptor and HER2 status has led to increasingly patient-specific treatment and thus improved outcomes. However, such subgroups may not be sufficiently informed to best predict outcome and/or treatment response. The incorporation of multi-modal data may identify unexpected and actionable subgroups to enhance disease understanding and improve outcomes.

METHODS

This retrospective cross-sectional study used the cancer registry Surveillance, Epidemiology and End Results (SEER), which represents 28% of the U.S. population. We included adult female patients diagnosed with breast cancer in 2010. Latent class analysis (LCA), a data-driven technique, was used to identify clinically homogeneous subgroups ("endophenotypes") of breast cancer from receptor status (hormonal receptor and HER2), clinical, and demographic data and each subgroup was explored using Bayesian networks.

RESULTS

Included were 44,346 patients, 1257 (3%) of whom had distant organ metastases at diagnosis. Four endophenotypes were identified with LCA: 1) "Favourable biology" had entirely local disease with favourable biology, 2) "HGHR-" had the highest incidence of HR- receptor status and highest grade but few metastases and relatively good outcomes, 3) "HR+ bone" had isolated bone metastases and uniform receptor status (HR+/HER2-), and 4) "Distant organ spread" had high metastatic burden and poor survival. Bayesian networks revealed clinically intuitive interactions between patient and disease features.

CONCLUSIONS

We have identified four distinct subgroups of breast cancer using LCA, including one unexpected group with good outcomes despite having the highest average histologic grade and rate of HR- tumours. Deeper understanding of subgroup characteristics can allow us to 1) identify actionable group properties relating to disease biology and patient features and 2) develop group-specific diagnostics and treatments.

Labial vitiligo associated with a factice disorder: a case report

Introduction: Vitiligo is a non-contagious leukoderma. The loss of melanocytes result in a local hypopigmentation like white symmetrical plaques with sharp edges, most of the time surrounded by hyperpigmentation. It might be an auto immune disease with a genetic predisposition linked to psychological disorders. Oral mucosa vitiligo has rarely been described in the literature. Observation: A seventeen years old patient, native from North Africa, has consulted for a half left upper lip depigmentation appeared in October 2016. The dermatologist had made the diagnosis of vitiligo and prescribed vitamin C and folic acid, without any result. In July 2017, as the lesion has extended to the whole upper lip, the patient came to oral mucosa pathology consultation. Anamnesis revealed a chronic lips chewing. Clinical examination revealed a linear vermillion border depigmentation of the upper lip associated with peripheral pigment enhancement, as well as digital cutaneous involvement. The prescribed treatment was: tacrolimus 0.1% twice daily in local application, stopping practice disorder and sun protection. Comment: Diagnosis of vitiligo is based on clinical examination that can differentiate a segmental vitiligo (localized on at least one dermatomes) of a non-segmental vitiligo (acrofacial, generalized, universalis). Vitiligo of the oral mucosa is rare. It has mainly been described in India. Oral mucosa involvement would affect 55% of patient and the lip would be affected in almost one in two cases in this population. Conclusion: Oral mucosa vitiligo must be known by oral surgeon who has to master the diagnosis and treatments in association with dermatologist, given the concomitant skin involvement that is almost mandatory.

Therapeutic management of vitiligo

Affecting 0.5 % of the world's population, vitiligo is an acquired skin disorder that poses major challenges in terms of dermatological care. Characterized by patchy depigmentation, the disease is frequently associated with cosmetic disfigurement and considerable psychological distress. The primary pathophysiological causes for the loss of functional melanocytes are thought to include genetic predisposition, autoimmune mechanisms, and oxidative stress. The present article highlights treatment recommendations contained in the European guidelines as well as those provided by recent reviews on vitiligo. Current therapeutic options are based on three approaches: (1) Regulation of the autoimmune response using topical and systemic immunomodulatory agents (corticosteroids and calcineurin inhibitors); (2) decrease in oxidative stress in melanocytes by means of topical and systemic antioxidants; and (3) activation of melanocyte regeneration using phototherapy (UVB in particular) and transplantation of pigment cells. In addition, patients should be educated in techniques for cosmetic camouflage. Following successful repigmentation, application of calcineurin inhibitors is recommended to prevent recurrences. Combination therapies of the aforementioned approaches are generally considered to be more successful than monotherapies. Early initiation of treatment is associated with a more favorable prognosis. Using the above treatment options, it may be possible to halt disease progression, stabilize depigmented lesions, and achieve repigmentation. Only in exceptional cases should permanent depigmentation be considered as a possible option. New insights into the pathogenesis of vitiligo will likely give rise to novel therapeutic approaches.

Vitiligo: Focus on Clinical Aspects, Immunopathogenesis, and Therapy

Vitiligo is an acquired chronic depigmenting disorder of the skin, with an estimated prevalence of 0.5% of the general population, characterized by the development of white macules resulting from a loss of epidermal melanocytes. The nomenclature has been revised after an extensive international work within the vitiligo global issues consensus conference, and vitiligo (formerly non-segmental vitiligo) is now a consensus umbrella term for all forms of generalized vitiligo. Two other subsets of vitiligo are segmental vitiligo and unclassified/undetermined vitiligo, which corresponds to focal disease and rare variants. A series of hypopigmented disorders may masquerade as vitiligo, and some of them need to be ruled out by specific procedures including a skin biopsy. Multiple mechanisms are involved in melanocyte disappearance, namely genetic predisposition, environmental triggers, metabolic abnormalities, impaired renewal, and altered inflammatory and immune responses. The auto-immune/inflammatory theory is the leading hypothesis because (1) vitiligo is often associated with autoimmune diseases; (2) most vitiligo susceptibility loci identified through genome-wide association studies encode immunomodulatory proteins; and (3) prominent immune cell infiltrates are found in the perilesional margin of actively depigmenting skin. However, other studies support melanocyte intrinsic abnormalities with poor adaptation of melanocytes to stressors leading to melanocyte instability in the basal layer, and release of danger signals important for the activation of the immune system. Recent progress in the understanding of immune pathomechanisms opens interesting perspectives for innovative treatment strategies. The proof of concept in humans of targeting of the IFNγ /Th1 pathway is much awaited. The interplay between oxidative stress and altered immune responses suggests that additional strategies aiming at limiting type I interferon activation pathway as background stabilizing therapies could be an interesting approach in vitiligo. This review covers classification and clinical aspects, pathophysiology with emphasis on immunopathogenesis, and promising therapeutic approaches.

Classification of facial vitiligo: A cluster analysis of 473 patients

Vitiligo has a substantial negative impact on quality of life in affected patients, especially those with the involvement of the face. However, the current system can barely distinguish between specific patterns of facial involvement except for the segmental type when focusing only on facial lesions. We classified facial vitiligo into three distinct subtypes using cluster analysis based on facial topography (n = 473): centrofacial vitiligo (72.9%), panfacial vitiligo (18.0%), and hairline vitiligo (9.1%). Centrofacial vitiligo was the most common type and is thought to comprise the typical facial involvement of generalized vitiligo. Panfacial vitiligo was a distinct subtype with onset in old age and less involvement of other body parts. Hairline vitiligo was another distinct subtype with onset in old age and a poor response to conventional phototherapy. A relevant classification system could help us to explore the causes, anticipate the prognosis, and manage the condition in patients with vitiligo.

Quality of Life, Burden of Disease, Co-morbidities, and Systemic Effects in Vitiligo Patients

Vitiligo is a complex, systemic disease associated with many autoimmune and autoinflammatory conditions. Additionally, the cutaneous changes of vitiligo have significant effects on quality of life and self-esteem. Further efforts are needed to increase our understanding of vitiligo comorbidities as well as to increase awareness of the psychological effects of vitiligo.

Special Considerations in Children with Vitiligo

Childhood vitiligo differs from adult-onset vitiligo for several features including increased incidence of the segmental variant, higher prevalence of halo nevi, and more common family history for autoimmune diseases and atopic diathesis. The major differential diagnoses are the postinflammatory hypomelanoses for nonsegmental vitiligo and nevus depigmentosus for segmental vitiligo. From a therapeutic standpoint, early awareness of the diagnosis seems to correlate with a good treatment outcome in this age group.

Impact of Ultraviolet Light on Vitiligo

Vitiligo is a disorder of the melanocytes that results in a dynamic spectrum of skin depigmentation. Its etiology is complex and multifactorial, with data supporting several different hypotheses. Given its prominent phenotype, vitiligo has a significant negative impact on quality of life. Coupled with the chronic and incurable nature of the disease, this presents a formidable treatment challenge. Several treatment modalities have been instituted over the years, with varying efficacy. This chapter focuses on the use of ultraviolet light in vitiligo as an established therapeutic option.

A Practical Approach to the Diagnosis and Treatment of Vitiligo in Children

Vitiligo is a common inflammatory skin disease with a worldwide prevalence of 0.5% to 2.0% of the population. In the pediatric population, the exact prevalence of vitiligo is unknown, although many studies state that most cases of vitiligo are acquired early in life. The disease is disfiguring, with a major psychological impact on children and their parents. Half of vitiligo cases have a childhood onset, needing thus a treatment approach that will minimize treatment side effects while avoiding psychological impacts. Management of vitiligo should take into account several factors, including extension, psychological impact, and possible associations with other autoimmune diseases. This review discusses the epidemiology of vitiligo and outlines the various clinical presentations associated with the disorder and their differential diagnosis. In addition, the pathophysiology and genetic determinants, the psychological impact of vitiligo, and management strategies are reviewed.

Vitiligo

Vitiligo, an acquired pigmentary disorder of unknown origin, is the most frequent cause of depigmentation worldwide, with an estimated prevalence of 1%. The disorder can be psychologically devastating and stigmatising, especially in dark skinned individuals. Vitiligo is clinically characterised by the development of white macules due to the loss of functioning melanocytes in the skin or hair, or both. Two forms of the disease are well recognised: segmental and non-segmental vitiligo (the commonest form). To distinguish between these two forms is of prime importance because therapeutic options and prognosis are quite different. The importance of early treatment and understanding of the profound psychosocial effect of vitiligo will be emphasised throughout this Seminar.

Environment-induced lentigines: formation of solar lentigines beyond ultraviolet radiation

There is no doubt that ultraviolet radiation (UVR) contributes to the generation of acquired lentigines in human skin, as indicated by the term solar lentigo. A growing number of recent epidemiological and mechanistic studies, however, strongly suggest that in addition to UVR, other environmental factors contribute to lentigines' formation as well. We therefore here introduce the term 'environment-induced lentigo' (EIL) to refer to acquired pigment spots of human skin. In this view point, we (i) summarize the existing evidence to support a role of environmental toxicants other than UVR in the pathogenesis of EILs, (ii) we argue that activation of aryl hydrocarbon receptor (AHR) signalling by UVR and environmental toxicants is critically involved in triggering and sustaining a crosstalk between melanocytes, keratinocytes and fibroblasts, which then causes the development and persistence of EILs in human skin, and (iii) we discuss clinical implications for the prevention and treatment of EILs resulting from this concept.

Subphenotypes in acute respiratory distress syndrome: latent class analysis of data from two randomised controlled trials

BACKGROUND

Subphenotypes have been identified within heterogeneous diseases such as asthma and breast cancer, with important therapeutic implications. We assessed whether subphenotypes exist within acute respiratory distress syndrome (ARDS), another heterogeneous disorder.

METHODS

We used data from two ARDS randomised controlled trials (ARMA trial and ALVEOLI trial), sponsored by the National Heart, Lung, and Blood Institute. We applied latent class modelling to identify subphenotypes using clinical and biological data. We modelled data from both studies independently. We then tested the association of subphenotypes with clinical outcomes in both cohorts and with the response to positive end-expiratory pressure (PEEP) in the ALVEOLI cohort.

FINDINGS

We analysed data for 1022 patients: 473 in the ARMA cohort and 549 in the ALVEOLI cohort. Independent latent class models indicated that a two-class (ie, two subphenotype) model was the best fit for both cohorts. In both cohorts, we identified a hyperinflammatory subphenotype (phenotype 2) that was characterised by higher plasma concentrations of inflammatory biomarkers, a higher prevalence of vasopressor use, lower serum bicarbonate concentrations, and a higher prevalence of sepsis than phenotype 1. Participants in phenotype 2 had higher mortality and fewer ventilator-free days and organ failure-free days in both cohorts than did those in phenotype 1 (p<0·007 for all). In the ALVEOLI cohort, the effects of ventilation strategy (high PEEP vs low PEEP) on mortality, ventilator-free days and organ failure-free days differed by phenotype (p=0·049 for mortality, p=0·018 for ventilator-free days, p=0·003 for organ-failure-free days).

INTERPRETATION

We have identified two subphenotypes within ARDS, one of which is categorised by more severe inflammation, shock, and metabolic acidosis and by worse clinical outcomes. Response to treatment in a randomised trial of PEEP strategies differed on the basis of subphenotype. Identification of ARDS subphenotypes might be useful in selecting patients for future clinical trials.

FUNDING

National Institutes of Health.