Treatment of pemphigus vulgaris and foliaceus with efgartigimod, a neonatal Fc receptor inhibitor: a phase II multicentre, open-label feasibility trial.

BACKGROUND: Pemphigus vulgaris and pemphigus foliaceus are potentially life-threatening autoimmune disorders triggered by IgG autoantibodies against mucosal and epidermal desmogleins. There is an unmet need for fast-acting drugs that enable patients to achieve early sustained remission with reduced corticosteroid reliance. OBJECTIVES: To investigate efgartigimod, an engineered Fc fragment that inhibits the activity of the neonatal Fc receptor, thereby reducing serum IgG levels, for treating pemphigus. METHODS: Thirty-four patients with mild-to-moderate pemphigus vulgaris or foliaceus were enrolled in an open-label phase II adaptive trial. In sequential cohorts, efgartigimod was dosed at 10 or 25 mg kg-1 intravenously with various dosing frequencies, as monotherapy or as add-on therapy to low-dose oral prednisone. Safety endpoints comprised the primary outcome. The study is registered at ClinicalTrials.gov (identifier NCT03334058). RESULTS: Adverse events were mostly mild and were reported by 16 of 19 (84%) patients receiving efgartigimod 10 mg kg-1 and 13 of 15 (87%) patients receiving 25 mg kg-1 , with similar adverse event profiles between dose groups. A major decrease in serum total IgG and anti-desmoglein autoantibodies was observed and correlated with improved Pemphigus Disease Area Index scores. Efgartigimod, as monotherapy or combined with prednisone, demonstrated early disease control in 28 of 31 (90%) patients after a median of 17 days. Optimized, prolonged treatment with efgartigimod in combination with a median dose of prednisone 0·26 mg kg-1 per day (range 0·06-0·48) led to complete clinical remission in 14 of 22 (64%) patients within 2-41 weeks. CONCLUSIONS: Efgartigimod was well tolerated and exhibited an early effect on disease activity and outcome parameters, providing support for further evaluation as a therapy for pemphigus.

EuroGuiDerm Guideline on the systemic treatment of Psoriasis vulgaris - Part 2: specific clinical and comorbid situations.

This evidence- and consensus-based guideline on the treatment of psoriasis vulgaris was developed following the EuroGuiDerm Guideline and Consensus Statement Development Manual. The second part of the guideline provides guidance for specific clinical and comorbid situations such as treating psoriasis vulgaris patient with concomitant psoriatic arthritis, concomitant inflammatory bowel disease, a history of malignancies or a history of depression or suicidal ideation. It further holds recommendations for concomitant diabetes, viral hepatitis, disease affecting the heart or the kidneys as well as concomitant neurological disease. Advice on how to screen for tuberculosis and recommendations on how to manage patients with a positive tuberculosis test result are given. It further covers treatment for pregnant women or patients with a wish for a child in the near future. Information on vaccination, immunogenicity and systemic treatment during the COVID-19 pandemic is also provided.

DLQI-R scoring improves the discriminatory power of the Dermatology Life Quality Index in patients with psoriasis, pemphigus and morphea.

BACKGROUND: The Dermatology Life Quality Index (DLQI) rates 'not relevant' responses (NRRs) as the item on the questionnaire having no impact on the patients' lives at all. The DLQI-Relevant (DLQI-R) is a recently developed scoring that adjusts the total score of the questionnaire for the number of NRRs indicated by a patient. OBJECTIVES: To compare the discriminatory power of the original and DLQI-R scoring approaches in terms of absolute and relative informativity. METHODS: Cross-sectional data from 637 patients with morphea, pemphigus and psoriasis were used for the analyses. To assess absolute and relative informativity, Shannon's index and Shannon's evenness index were calculated for the 10 items on the questionnaire and for DLQI and DLQI-R total scores. RESULTS: Mean DLQI and DLQI-R scores of patients were 6·13 vs. 6·91. In the subset of patients with NRRs (n = 261, 41%), absolute informativity was higher with the DLQI-R scoring for all eight items with NRR options in all three conditions. The DLQI-R exhibited a better relative informativity in 8, 8 and 6 items in pemphigus, morphea and psoriasis, respectively. The DLQI-R led to an improvement in average item-level informativity in all DLQI score bands up to 20 points. Regarding total scores, the DLQI-R produced both a higher absolute and relative informativity in all three conditions. CONCLUSIONS: In patients with morphea, pemphigus and psoriasis, DLQI-R scoring improves the discriminatory power of the questionnaire by benefiting from the additional information in NRRs. DLQI-R scoring may be useful both in clinical practice and research. A scoring chart has been developed to aid physicians with scoring. What's already known about this topic? The original scoring of the Dermatology Life Quality Index (DLQI) rates 'not relevant' responses as the item of the questionnaire having no impact on the patients' lives at all. DLQI-Relevant (DLQI-R) is a new scoring developed in 2018 that adjusts the total score of the questionnaire for the number of 'not relevant' responses indicated by patients. The discriminatory power of the DLQI-R compared with the DLQI has not yet been investigated. What does this study add? In patients with psoriasis, pemphigus and morphea, DLQI-R scoring improves the discriminatory power of the questionnaire by benefiting from the additional information in 'not relevant' responses. What are the clinical implications of this work? DLQI-R scoring may help to more accurately quantify patients' health-related quality of life both in clinical practice and research. A scoring chart has been developed to aid physicians with scoring.

EuroGuiDerm Guideline on the systemic treatment of Psoriasis vulgaris - Part 1: treatment and monitoring recommendations.

This evidence- and consensus-based guideline on the treatment of psoriasis vulgaris was developed following the EuroGuiDerm Guideline and Consensus Statement Development Manual. The first part of the guideline includes general information on the scope and purpose, health questions covered, target users and strength/limitations of the guideline. Suggestions for disease severity grading and treatment goals are provided. It presents the general treatment recommendations as well as detailed management and monitoring recommendations for the individual drugs. The treatment options discussed in this guideline are as follows: acitretin, ciclosporin, fumarates, methotrexate, adalimumab, apremilast, brodalumab, certolizumab pegol, etanercept, guselkumab, infliximab, ixekizumab, risankizumab, secukinumab, tildrakizumab and ustekinumab.

Validity of the EQ-5D in patients with pemphigus vulgaris and pemphigus foliaceus.

BACKGROUND: No studies to date have employed the EuroQoL EQ-5D questionnaire to assess health-related quality of life (HRQoL) in patients with pemphigus. OBJECTIVES: To evaluate the HRQoL of patients with pemphigus by the EQ-5D and to analyse the convergent and known-groups validity of the EQ-5D in this patient population. METHODS: Between 2014 and 2017, a multicentre cross-sectional study was carried out. Outcome measures included the five-level EQ-5D (EQ-5D-5L), Dermatology Life Quality Index (DLQI), Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and an average pain intensity visual analogue scale (VAS) for the past 3 months. RESULTS: In total, 109 consecutive patients with pemphigus participated in the study (mean age 57 years; 64% women). Among the EQ-5D dimensions, the most problems were reported regarding pain/discomfort (50%), mobility (43%) and anxiety/depression (43%). No significant difference was found in mean EQ-5D index scores between patients with pemphigus vulgaris and those with pemphigus foliaceus (0·81 vs. 0·86, P = 0·14). The mean EQ-5D index scores of patients with limited, moderate, significant and extreme pemphigus were 0·88, 0·82, 0·72 and 0·67, respectively (P = 0·001). The number of comorbidities was associated with greater impairment in EQ-5D index scores (P < 0·001). DLQI (rs = -0·62, P < 0·001) and the average pain intensity VAS (rs = -0·59, P < 0·001) more strongly correlated with the EQ-5D index scores than did ABSIS (rs = -0·40, P < 0·001). CONCLUSIONS: This is the first study employing the EQ-5D questionnaire in pemphigus. The EQ-5D is a valid measure of HRQoL in patients with pemphigus that can be useful both in clinical practice and in economic evaluations to assess the health gains associated with new effective treatments.

The management and genetic background of pityriasis rubra pilaris: a single-centre experience.

BACKGROUND: Pityriasis rubra pilaris (PRP) is a rare chronic inflammatory dermatosis with multifactorial aetiology. It is known that particular caspase recruitment domain family member 14 (CARD14) gene mutations are associated with familial PRP and certain forms of psoriasis. Additionally, few data are available about the role of CARD14 gene variants in sporadic PRP. The clinical picture is variable for the different types of PRP, therefore choosing the adequate treatment is often difficult, furthermore there are no specific guidelines for therapy. OBJECTIVE: Our aim was to survey the efficacy of the applied therapies and to screen the CARD14 gene variants in our PRP patients. METHODS: In this retrospective study, patients diagnosed with PRP between 2006 and 2016 at our clinic were involved. Besides the follow-up study of the treatments, the genetic analysis of CARD14 gene was performed. RESULTS: We analysed 19 patients, among whom 17 were diagnosed with type I, one with type III, and one with type V PRP. The majority of the patients were successfully treated with acitretin in combination with systemic corticosteroids, and the remaining patients were treated with other systemic therapies with diverse effects. The genetic screening of CARD14 gene revealed two previously described mutations (rs114688446, rs117918077) and six polymorphisms (rs28674001, rs2066964, rs34367357, rs11653893, rs11652075, rs2289541). Ten of 19 patients carried different CARD14 genetic variants either alone or in combination. CONCLUSION: Based on our experience, we propose that acitretin and an initial combination of short-term systemic corticosteroid therapy could be a successful treatment option for PRP. Although we identified several CARD14 variants in almost half of our cases, we did not find a correlation between the therapeutic response and the genetic background. Our data support the previous observation that CARD14 genetic variants are not specific to PRP, although they may indicate chronic inflammation.

Patient-assigned health utility values for controlled and uncontrolled pemphigus vulgaris and foliaceus.

BACKGROUND: The assessment of health-related quality of life (HRQoL) in patients with pemphigus is now of increasing interest due to the availability of highly effective new therapies. Preference-based HRQoL values or health utilities required for medical and financial decision-making are not yet available directly from pemphigus patients. OBJECTIVE: To obtain health utility values for current health and hypothetical health states from the perspective of pemphigus patients. METHODS: A cross-sectional questionnaire survey was carried out with pemphigus patients. Disease severity was rated by Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). Patients were asked to evaluate their current health as well as three common hypothetical pemphigus health states [uncontrolled pemphigus vulgaris (PV), uncontrolled pemphigus foliaceus (PF) and controlled PV/PF] by using composite time trade-off (cTTO). Multiple regression was applied to explore determinants of utility values. RESULTS: Responses of 108 patients (64.8% women, mean age 57.4 years) were analysed. Mean ABSIS score was 11.6. The mean utility values for the hypothetical uncontrolled PV, uncontrolled PF and controlled PV/PF health states were 0.41, 0.52 and 0.66 with cTTO. The mean cTTO scores for current health were higher compared with the hypothetical health states (0.76; P < 0.001). Patients with higher ABSIS, worse pain intensity scores and those having a caregiver reported lower utility values for current health (P < 0.05). CONCLUSIONS: In pemphigus, HRQoL impairment expressed in utility values seems to be considerable, especially in comparison with other chronic dermatological conditions (e.g. psoriasis, atopic eczema, chronic hand eczema). These health utilities inform physicians, policymakers and funders about the overall extent of health loss in pemphigus and provide evidence to guide medical decisions and cost-effectiveness analyses of treatment strategies. Future research is needed to evaluate the caregiver burden in pemphigus.

Splicing factors differentially expressed in psoriasis alter mRNA maturation of disease-associated EDA+ fibronectin.

The EDA+ fibronectin splicing variant is overexpressed in psoriatic non-lesional epidermis and sensitizes keratinocytes to mitogenic signals. However, regulation of its abundance is only partially understood. In our recent cDNA microarray experiment, we identified three SR-rich splicing factors-splicing factor, arginine/serine-rich 18 (SFRS18), peptidyl-prolyl cis-trans isomerase G (PPIG), and luc-7 like protein 3 (LUC7L3)-which might be implicated in the preactivated states of keratinocytes in psoriatic non-involved skin and could also contribute to the regulation of fibronectin mRNA maturation. In this study, we investigated the role of LUC7L3, PPIG, and SFRS18 in psoriasis and in the mRNA maturation process of fibronectin. Regarding tissue staining experiments, we were able to demonstrate a characteristic distribution of the splicing factors in healthy, psoriatic non-involved and involved epidermis. Moreover, the expression profiles of these SR-rich proteins were found to be very similar in synchronized keratinocytes. Contribution of splicing facwwtors to the EDA+ fibronectin formation was also confirmed: their siRNA silencing leads to altered fibronectin mRNA and protein expression patterns, suggesting the participation in the EDA domain inclusion. Our results indicate that LUC7L3, PPIG, and SFRS18 are not only implicated in EDA+ fibronectin formation, but also that they could possess multiple roles in psoriasis-associated molecular abnormalities.

Neutrophil-to-lymphocyte ratio: a biomarker for predicting systemic involvement in adult IgA vasculitis patients.

BACKGROUND: IgA vasculitis (IgAV) is a small-vessel leucocytoclastic cutaneous vasculitis, often associated with kidney and gastrointestinal (GI) manifestations. Although predictive factors for systemic involvement have been extensively studied in children, there is paucity in the literature regarding adult patients. Neutrophil-to-lymphocyte ratio (NLR) is an inflammatory marker, used to assess systemic inflammation in various diseases. OBJECTIVE: We sought to evaluate whether NLR can be used for predicting renal and GI involvement in adult IgA vasculitis patients. METHODS: This was a retrospective review of adult patients who were diagnosed with IgAV at our institution between 2004 and 2016. RESULTS: A total of 40 patients met our inclusion criteria. Half of the enrolled patients had clinical symptoms suggestive of systemic involvement, of which 6 (15%) had only renal, 3 (7.5%) had only GI and 11 (27.5%) had both renal and GI involvement. Pretreatment NLR was significantly associated with renal and/or GI manifestations of the disease (P < 0.001). The optimal cut-off value of NLR, for predicting systemic involvement was 3.34, with a specificity of 95% and a sensitivity of 85%. In addition, pretreatment NLR was also found to be significantly correlated with the severity of the systemic manifestations of IgAV (P = 0.022). CONCLUSION: This study suggests that NLR is a potential indicator for prognosticating systemic involvement in adult IgAV.

S2k guideline for treatment of cutaneous lupus erythematosus - guided by the European Dermatology Forum (EDF) in cooperation with the European Academy of Dermatology and Venereology (EADV).

Cutaneous lupus erythematosus (CLE) is a rare inflammatory autoimmune disease with heterogeneous clinical manifestations. To date, no therapeutic agents have been licensed specifically for patients with this disease entity, and topical and systemic drugs are mostly used 'off-label'. The aim of the present guideline was to achieve a broad consensus on treatment strategies for patients with CLE by a European subcommittee, guided by the European Dermatology Forum (EDF) and supported by the European Academy of Dermatology and Venereology (EADV). In total, 16 European participants were included in this project and agreed on all recommendations. Topical corticosteroids remain the mainstay of treatment for localized CLE, and further topical agents, such as calcineurin inhibitors, are listed as alternative first-line or second-line topical therapeutic option. Antimalarials are recommended as first-line and long-term systemic treatment in all CLE patients with severe and/or widespread skin lesions, particularly in patients with a high risk of scarring and/or the development of systemic disease. In addition to antimalarials, systemic corticosteroids are recommended as first-line treatment in highly active and/or severe CLE. Second- and third-line systemic treatments include methotrexate, retinoids, dapsone and mycophenolate mofetil or mycophenolate acid, respectively. Thalidomide should only be used in selected therapy-refractory CLE patients, preferably in addition to antimalarials. Several new therapeutic options, such as B-cell- or interferon α-targeted agents, need to be further evaluated in clinical trials to assess their efficacy and safety in the treatment of patients with CLE.

European consensus-based (S2k) Guideline on the Management of Herpes Zoster - guided by the European Dermatology Forum (EDF) in cooperation with the European Academy of Dermatology and Venereology (EADV), Part 2: Treatment.

Herpes zoster (HZ, shingles) is a frequent medical condition which may severely impact the quality of life of affected patients. Different therapeutic approaches to treat acute HZ are available. The aim of this European project was the elaboration of a consensus-based guideline on the management of patients who present with HZ, considering different patient populations and different localizations. This interdisciplinary guideline aims at an improvement of the outcomes of the acute HZ management concerning disease duration, acute pain and quality of life of the affected patients and at a reduction in the incidence of postherpetic neuralgia (PHN) and other complications. The guideline development followed a structured and pre-defined process, considering the quality criteria for guidelines development as suggested by the AGREE II instrument. The steering group was responsible for the planning and the organization of the guideline development process (Division of Evidence-Based Medicine, dEBM). The expert panel was nominated by virtue of clinical expertise and/or scientific experience and included experts from the fields of dermatology, virology/infectiology, ophthalmology, otolaryngology, neurology and anaesthesiology. Recommendations for clinical practice were formally consented during the consensus conference, explicitly considering different relevant aspects. The guideline was approved by the commissioning societies after an extensive internal and external review process. In this second part of the guideline, therapeutic interventions have been evaluated. The expert panel formally consented recommendations for the treatment of patients with HZ (antiviral medication, pain management, local therapy), considering various clinical situations. Users of the guideline must carefully check whether the recommendations are appropriate for the context of intended application. In the setting of an international guideline, it is generally important to consider different national approaches and legal circumstances with regard to the regulatory approval, availability and reimbursement of diagnostic and therapeutic interventions.

European consensus-based (S2k) Guideline on the Management of Herpes Zoster - guided by the European Dermatology Forum (EDF) in cooperation with the European Academy of Dermatology and Venereology (EADV), Part 1: Diagnosis.

Herpes zoster (HZ, shingles) is a frequent medical condition which may severely impact the quality of life of affected patients. Different therapeutic approaches to treat acute HZ are available. The aim of this European project was the elaboration of a consensus-based guideline on the management of patients who present with HZ, considering different patient populations and different localizations. This interdisciplinary guideline aims at an improvement of the outcomes of the acute HZ management concerning disease duration, acute pain and quality of life of the affected patients and at a reduction of the incidence of postherpetic neuralgia and other complications. The guideline development followed a structured and predefined process, considering the quality criteria for guidelines development as suggested by the AGREE II instrument. The steering group was responsible for the planning and the organization of the guideline development process (Division of Evidence based Medicine, dEBM). The expert panel was nominated by virtue of clinical expertise and/or scientific experience and included experts from the fields of dermatology, virology/infectiology, ophthalmology, otolaryngology, neurology and anaesthesiology. Recommendations for clinical practice were formally consented during the consensus conference, explicitly considering different relevant aspects. The guideline was approved by the commissioning societies after an extensive internal and external review process. In this first part of the guideline, diagnostic means have been evaluated. The expert panel formally consented recommendations for the management of patients with (suspected) HZ, referring to the assessment of HZ patients, considering various specific clinical situations. Users of the guideline must carefully check whether the recommendations are appropriate for the context of intended application. In the setting of an international guideline, it is generally important to consider different national approaches and legal circumstances with regard to the regulatory approval, availability and reimbursement of diagnostic and therapeutic interventions.

Abnormal regulation of fibronectin production by fibroblasts in psoriasis.

BACKGROUND: Data indicate that in psoriasis, abnormalities are already present in nonlesional skin. Transforming growth factor-ß and keratinocyte growth factor (KGF), together with fibronectin and α5ß1 integrin, were suggested to play a crucial role in the pathogenesis of psoriasis by influencing inflammation and keratinocyte hyperproliferation. OBJECTIVES: To investigate the expression of KGF, fibroblast growth factor receptor (FGFR)2, fibronectin (FN) and extra domain A (EDA)-positive FN in healthy and nonlesional psoriatic skin, and to study the effect of KGF on the regulation of FN and EDA(+) FN production by fibroblasts. METHODS: Healthy, nonlesional psoriatic skin and lesional psoriatic skin were immunostained for α5 integrin, KGF, FGFR2, EDA(+) FN and signal transducer and activator of transcription (STAT)1. KGF-treated cell cultures were analysed for FN and EDA(+) FN mRNA and protein by real-time reverse-transcriptase polymerase chain reaction and flow cytometry, respectively. The major downstream signalling of KGF was investigated by blocking experiments using inhibitors of mitogen-activated protein kinase (MAPK) kinase (MEK1), AKT1/2, STAT1 and STAT3. RESULTS: The expression of α5 integrin, EDA(+) FN, KGF and its receptor FGFR2 is elevated in psoriatic nonlesional skin compared with healthy skin. KGF mildly induced EDA(+) FN, but not FN expression in healthy fibroblasts through MAPK signalling. Fibroblasts express the FGFR2-IIIc splice variant. STAT1 negatively regulates both FN and EDA(+) FN expression in healthy fibroblasts, and this regulation is compromised in fibroblasts derived from nonlesional psoriatic dermis. We detected active STAT1 in healthy and lesional skin, similarly to a previous report. However, in the nonlesional skin STAT1 activation was absent in tissues far away from lesions. CONCLUSIONS: The production of FN and EDA(+) FN by fibroblasts and the signalling of STAT1 are abnormally regulated in psoriatic nonlesional skin.

Disease burden of patients with pemphigus from a societal perspective.

Introduction: Cost-of-illness studies are widely used for healthcare decision-making; however, no such study is available in pemphigus from the societal perspective. The purpose of this analysis was to estimate annual cost-of-illness per patient with pemphigus from a societal perspective. Areas covered: Between 2014 and 2017, a multicenter, cross-sectional study was carried out. Consecutive pemphigus patients aged ≥18 years were recruited at all four university dermatology departments in Hungary. Direct and indirect costs were calculated, including costs for treatments, outpatient visits, hospital admissions, informal care, travel costs and productivity loss. Generalized linear model was used to analyze predictors of costs. Atotal of 109 patients with pemphigus enrolled with amean age of 57.1 (SD 14.8) years. Total cost per pemphigus patient was €3,995 (SD €7,526) peryear, with productivity loss (58%) and informal care (19%) accounting for the majority. Annual means of 189 and 41 working hours were lost due to absence from work and reduced productivity, respectively. Younger age and pemphigus vulgaris were associated with higher costs (p < 0.05). Expert opinion: This is the first cost-of-illness study applying the societal perspective in pemphigus. Our results indicate a substantial economic burden on society, mainly driven by productivity loss and informal care.

Flow cytometric identification of proliferative subpopulations within normal human epidermis and the localization of the primary hyperproliferative population in psoriasis.

In this study we define the proliferative compartments of in vivo human epidermis, using specific antibodies related to cell differentiation (beta 1 and beta 4 integrins and K1/K10 differentiation keratins) and cell cycle (proliferating cell nuclear antigen [PCNA]) in combination with flow cytometric quantitation of the DNA content and optical characteristics of the cells. The beta 1 integrin (CD29) marked both of the potentially proliferative subsets in normal epidermis. One subset of normal epidermis is CD29+ K1/K10-, which was predominantly basal, and found to be comprised of slow cycling, small cells with primitive cytoplasmic organization. The vast majority (95.5%) of these cells were in a quiescent state (G0/early G1) as indicated by their lack of the cyclin, PCNA. The other proliferative subset of normal epidermis was CD29+ K1/K10+, which was suprabasal and occasional basal, highly proliferative, larger in size, and which exhibited a more complex cytoplasmic structure. Because early differentiation (K1/K10 expression) has begun in the CD29+ K1/K10+ subset, it is highly likely that they represent the proliferative population which is capable of transiently amplifying itself before terminal differentiation. Within lesional psoriatic epidermis, similar proliferative cell populations were present as in normal epidermis, and the hyperproliferative defect was localized to the beta 1 and beta 4 integrin+, K1/K10- populations, which in normal epidermis is basally located and quiescent with regard to cell cycle. In psoriatic epidermis, a six- to sevenfold increase in the number of cells in the S/G2+M phase of cell cycle was found among CD29+ K1/K10- cells (p < 0.05). Furthermore, all lesional K1/K10- cells showed high PCNA positivity, indicating that all these cells had been recently induced into cell cycle. By contrast, the proportion of cycling cells among lesional psoriatic CD29+ K1/K10+ keratinocytes was similar to normals. Anti-HLA-DR, CD45, and vimentin antibodies were used to concomitantly track the proliferative states of Langerhans cell, melanocyte, and infiltrating leukocyte populations. In normal epidermis, the cycling fractions (cells in S/G2/M phase) of these cells were similar to the CD29+K1/K10- keratinocytes, whereas in lesional epidermis their cycling pools were increased relative to normal, but not so much as the proliferative fractions of psoriatic CD29+ K1/K10- keratinocytes. These data demonstrate the use of simultaneous analysis of integrin expression, differentiation keratins, cyclin, cell cycle status, and optical characteristics of freshly isolated human epidermal cells. Such analysis allowed the physical identification and quantification of cy cling populations in normal human skin, and has enabled the precise location of the primary epidermal proliferative defect in psoriasis.

Kinetics and regulation of human keratinocyte stem cell growth in short-term primary ex vivo culture. Cooperative growth factors from psoriatic lesional T lymphocytes stimulate proliferation among psoriatic uninvolved, but not normal, stem keratinocytes.

Flow cytometric analysis of primary ex vivo keratinocyte cultures demonstrated that stem cells, (beta 1 integrin+, keratin 1/keratin 10 [K1/K10-], proliferating cell nuclear antigen [PCNA-] [Bata-Csorgo, Zs., C. Hammerberg, J. J. Voorhees, and K. D. Cooper. 1993. J. Exp. Med. 178:1271-1281]) establish such cultures. This methodology also enabled the quantitation of synchronized recruitment of these cells from G0 into G1 of the cell cycle (PCNA expression), which preceded bright beta 1 integrin expression. (beta 1 integrinbright expression has been shown to be a characteristic feature of keratinocyte stem cells in culture (Jones, P. H., and F. M. Watt. 1993. Cell. 73:713-724). Using the above assay, we determined whether lesional T lymphocytes in psoriasis could be directly responsible for the induction of the stem cell hyperproliferation that is characteristic of this disease. Indeed, CD4+ T lymphocytes, cloned from lesional psoriatic skin and stimulated by immobilized anti-CD3 plus fibronectin, promoted psoriatic uninvolved keratinocyte stem cell proliferation via soluble factors. This induction appeared to be through accelerated recruitment of stem cells from their quiescent state (G0) into cell cycle. By contrast, normal keratinocyte stem cells exhibited no such growth stimulation. Supernatants exhibiting growth induction all contained high levels of GM-CSF and gamma-IFN, low IL-3 and TNF-alpha, and variable IL-4. Only anti-gamma-IFN antibody was able to neutralize growth stimulatory activity of the supernatants on psoriatic uninvolved keratinocyte stem cells. However, because recombinant gamma-IFN alone inhibited growth in this assay, these data suggest that, in psoriasis, gamma-IFN acts cooperatively with other growth factors in the immune induction of cell cycle progression by the normally quiescent stem cell keratinocytes.

Fibronectin and alpha5 integrin regulate keratinocyte cell cycling. A mechanism for increased fibronectin potentiation of T cell lymphokine-driven keratinocyte hyperproliferation in psoriasis.

In addition to being T lymphocyte-driven, psoriasis may be due in part to abnormal integrin expression. Normal-appearing (uninvolved) skin from psoriatic patients was examined to determine whether altered fibronectin or its receptor expression is detectable before development of psoriatic lesions. In contrast to skin from normal subjects, we detect by immunofluorescence the abnormal presence of plasma fibronectin in the basal cell layer of the epidermis of psoriatic uninvolved skin. Furthermore, increased fibronectin exposure superinduces the in vitro cell cycle induction and expansion of psoriatic nonlesional keratinocytes in response to a cocktail of T cell lymphokines. Fibronectin alone also appeared to increase cell cycle entry among uninvolved but not normal keratinocytes. Concordantly, the alpha5 integrin fibronectin receptor, but not alpha2 or alpha3, is overexpressed in the in vivo nonlesional psoriatic epidermis. The involvement of alpha5beta1 in the early outgrowth of clonogenic keratinocytes in the ex vivo culture was demonstrated by the ability of anti-alpha5 mAb to inhibit keratinocyte growth on fibronectin. Thus, the fibronectin receptor appears to be one of the components required for the development of the hyperresponsiveness of psoriatic keratinocytes to signals for proliferation provided by lymphokines produced by intralesional T lymphocytes in psoriasis.