John Koo

University of California, San Francisco, San Francisco, California, United States

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Publications (131)319.07 Total impact

  • Eva Wang, John Koo, Elie Levy
    Journal of the American Academy of Dermatology 08/2014; 71(2):391–393. · 4.91 Impact Factor
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    ABSTRACT: Phototherapy is often used to treat inflammatory skin conditions such as psoriasis and eczema. Much progress has recently been made in understanding the mechanisms underlying the local, cutaneous immune effects induced by phototherapy. Unlike many immunosuppressive drugs used in the management of inflammatory skin disease, phototherapy not only targets effector immune cells but also appears to up-regulate regulatory T cells (Tregs). Additionally, phototherapy reverses epidermal barrier abnormalities common in these diseases, allowing for restoration of cutaneous homeostasis. J Drugs Dermatol. 2014;13(5):564-568.
    Journal of drugs in dermatology: JDD 05/2014; 13(5):564-8. · 1.16 Impact Factor
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    ABSTRACT: Patients with psoriasis have been shown to have a higher prevalence of other autoimmune diseases including celiac disease, a condition marked by sensitivity to dietary gluten. A number of studies suggest that psoriasis and celiac disease share common genetic and inflammatory pathways. Here we review the epidemiologic association between psoriasis and celiac disease and perform a meta-analysis to determine whether patients with psoriasis more frequently harbor serologic markers of celiac disease. We also examine whether a gluten-free diet can improve psoriatic skin disease.
    Journal of the American Academy of Dermatology 04/2014; · 4.91 Impact Factor
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    ABSTRACT: Patients with psoriasis are increasingly turning to the use of alternative and complementary medicine to manage their psoriasis. Patients often inquire about what dietary supplements may be beneficial, including the use of oral vitamin D, vitamin B12, selenium, and omega-3 fatty acids in fish oils. In this review we examine the extent to which each of these common nutritional interventions has been studied for the treatment of psoriasis. We weighed evidence from both controlled and uncontrolled prospective trials. The evidence of benefit was highest for fish oils. For other supplements, there is need for additional large, randomized clinical trials to establish evidence of efficacy.
    Journal of the American Academy of Dermatology 04/2014; · 4.91 Impact Factor
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    ABSTRACT: One of the most frequently asked questions by patients with psoriasis is whether dietary changes can improve their condition. Included in this discussion is whether dietary weight loss can benefit their skin disease. Obesity has been associated with a proinflammatory state and several studies have demonstrated a relationship between body mass index and psoriasis severity. However, the question of whether weight loss interventions can impact psoriasis outcome is less clear. Here, we review the literature to examine the efficacy of weight loss interventions, both dietary and surgical, on psoriasis disease course.
    Journal of the American Academy of Dermatology 04/2014; · 4.91 Impact Factor
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    ABSTRACT: The efficacy of biologic therapy in treating plaque-type psoriasis is well documented. However, there is less data for use in other psoriasis subtypes, such as erythrodermic and generalized pustular psoriasis. We sought to review the safety and efficacy of biologic medications in the treatment of these severe subtypes of psoriasis and to identify strategies to help clinicians optimally manage these patients. We searched Pubmed for English language literature that assessed the use of biologic medication to treat erythrodermic or generalized pustular psoriasis. The primary literature included cases reports, cases series, and open-label, uncontrolled trials. There were no head-to-head studies or other controlled trials. In both erythrodermic and generalized pustular psoriasis, infliximab was used to treat over half of the reported cases. Other biologic medications that were successfully used included etanercept, ustekinumab, adalimumab, and anakinra. Most cases reported improvement with biologic therapy. Serious adverse events were reported in 10-12% of the patients. Although the evidence is limited, biologic therapy appears to be effective in treating erythrodermic and generalized pustular psoriasis. In order to assess the comparative efficacy and safety of the biologic medications, larger controlled studies are needed. J Drugs Dermatol. 2014;13(3):342-354.
    Journal of drugs in dermatology: JDD 03/2014; 13(3):342-54. · 1.16 Impact Factor
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    ABSTRACT: Abstract Background: Psoriasis is a chronic skin condition traditionally believed to involve the Th1 pathway. Recently, the IL-23/Th17/IL-17 pathway has been highlighted in the pathogenesis of psoriasis and other autoimmune inflammatory conditions. From a clinician's perspective, we sought to review the basic science data relevant to IL-17's role in psoriasis pathogenesis. Methods: We performed a Pubmed and Web of Knowledge search for English articles starting from 1990 that discussed the Th17 pathway. Search terms such as "IL-17" and "psoriasis" were utilized. Results: The IL-17 pathway is regulated by IL-23, a cytokine that is vital for the expansion and maintenance of the Th17 cell population. Th17 derived cytokines (IL-17A, IL-17F, IL-17A/F and IL-22) were elevated in both psoriasis-like murine models and human psoriatic lesional biopsies. Ixekizumab (anti-IL-17A) treatment of psoriasis was found to normalize levels of IL-17 downstream gene products. Conclusion: Both preclinical and clinical studies support the central role of IL-17 in the pathogenesis of psoriasis.
    Journal of Dermatological Treatment 02/2014; · 1.50 Impact Factor
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    ABSTRACT: Abstract Background: Studies investigating the molecular basis of psoriasis have established the central roles of TNFα, interleukin (IL)-12, IL-22 and IL-23 and there is increasing evidence that IL-17 plays a critical role in the complex pathophysiology. Preclinical studies suggest that IL-17 is a desirable therapeutic target for psoriasis treatment. Methods: We reviewed the results of the phase II clinical trials for the anti-IL-17 agents secukinumab, ixekizumab and brodalumab in order to assess the efficacy and safety profile of each agent. Results: By week 12, the proportion of patients reaching Psoriasis Area and Severity Index (PASI 75) was comparable among the most efficacious dosage between the different agents (secukinumab 82%, ixekizumab 83% and brodalumab 82%; p < 0.001 compared to placebo for all agents). The safety profiles of the agents were similar with the most frequently reported adverse events of nasopharyngitis, upper respiratory infections and injection site reaction. A small percentage of patients experienced low-grade neutropenia that was predominantly transient and asymptomatic. Conclusion: The anti-IL-17 agents demonstrated a rapid and robust clinical improvement accompanied by a favorable short-term safety profile. The results of the phase II trials support the theory that the IL-17 pathway is an essential target in psoriasis treatment.
    Journal of Dermatological Treatment 02/2014; · 1.50 Impact Factor
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    ABSTRACT: Abstract Background: Generalized UVB phototherapy has been established as an effective and safe treatment for chronic plaque-type psoriasis for decades and in recent years, targeted 308-nm excimer laser has emerged as an equally safe and more effective treatment option. While traditional dosimetry for laser has been determined either through minimal erythema dose (MED) or a combination of the patient's Fitzpatrick skin type and the level of plaque induration, we have developed "Plaque-based Sub-blistering Dosimtery" based on observations that administering anywhere from 8 to 16 multiples of MED to psoriatic plaques has resulted in clearance after one treatment with longer remission rates than the traditional dosing protocol. Case report: The authors describe a case in which a patient achieved PASI 75 following only two treatments with 308 nm excimer laser using this new protocol. Biopsies taken before and after treatment reveal a dramatic decrease in CD4 + T cells as well as TNF-alpha- and IL-2-producing T cells. Conclusion: This case demonstrates using a more aggressive dosing protocol determined by plaque testing is well-tolerated and can lead to excellent clearance with minimal side effects and comorbidity.
    Journal of Dermatological Treatment 02/2014; · 1.50 Impact Factor
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    ABSTRACT: Abstract Background: The combination of phototherapy and topical therapy is one of the most widely used treatment modalities for moderate to severe psoriasis. The development of targeted phototherapy with excimer laser and new topical spray formulations has made these therapies both more convenient and more effective. In this open label pilot study, we aim to assess the efficacy of combination therapy using 308-nm excimer laser, clobetasol propionate spray and calcitriol ointment for the treatment of moderate to severe generalized psoriasis. Methods: In this 12-week study, patients with moderate to severe psoriasis received twice weekly treatment with XTRAC® Velocity 308-nm excimer laser combined with clobetasol propionate twice daily followed by calitriol ointment twice daily. Results: To date, 21 patients have completed the protocol. By week 12, 76% of the patients had a reduction in Psoriasis Area and Severity Index by at least 75% (PASI-75) and 52% had a Physicians Global Assessment of "clear" or "almost clear". Conclusions: Excimer laser therapy combined with an optimized topical regimen that includes clobetasol spray followed by calictriol ointment appears to be an effective treatment for moderate to severe generalized psoriasis that avoids the risk of serious internal side effects associated with many systemic agents.
    Journal of Dermatological Treatment 02/2014; · 1.50 Impact Factor
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    ABSTRACT: Regulatory T cells (Tregs), which are characterized by expression of the transcription factor Foxp3, are a dynamic and heterogeneous population of cells that control immune responses and prevent autoimmunity. We recently identified a subset of Tregs in murine skin with properties typical of memory cells and defined this population as memory Tregs (mTregs). Due to the importance of these cells in regulating tissue inflammation in mice, we analyzed this cell population in humans and found that almost all Tregs in normal skin had an activated memory phenotype. Compared with mTregs in peripheral blood, cutaneous mTregs had unique cell surface marker expression and cytokine production. In normal human skin, mTregs preferentially localized to hair follicles and were more abundant in skin with high hair density. Sequence comparison of TCRs from conventional memory T helper cells and mTregs isolated from skin revealed little homology between the two cell populations, suggesting that they recognize different antigens. Under steady-state conditions, mTregs were nonmigratory and relatively unresponsive; however, in inflamed skin from psoriasis patients, mTregs expanded, were highly proliferative, and produced low levels of IL-17. Taken together, these results identify a subset of Tregs that stably resides in human skin and suggest that these cells are qualitatively defective in inflammatory skin disease.
    The Journal of clinical investigation 02/2014; · 15.39 Impact Factor
  • Cutis. 02/2014; 93(2):E1-2.
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    ABSTRACT: Patient satisfaction has been and is of growing importance in healthcare. Recent healthcare initiatives aim to provide physicians with performance feedback reports based partially on patient completed surveys; thus, patient satisfaction will be an even more important determinant of high quality care. In the field of dermatology, patient satisfaction is particularly relevant and at times difficult to achieve, since many patients are plagued with chronic skin diseases often requiring intensive topical regimens or undesirable systemic immunosuppressants. The discussion of patient satisfaction is usually restricted to encounters with the general clinic population leaving encounters with difficult patients largely underreported; therefore, we provide examples of more common difficult patient encounters a dermatologist may face with specific recommendations on how to best optimize patient satisfaction.
    Clinics in Dermatology. 01/2014;
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    ABSTRACT: Abstract Psoriasis is a chronic skin disorder that affects 1% to 3% of the general population worldwide. Streptococcal infection, especially streptococcal pharyngitis, has been shown to be a significant trigger of psoriasis in some patients, possibly by sensitizing T cells to keratin epitopes in the skin. Due to the role of the palatine tonsils as an immunological organ that may generate autoreactive T cells, tonsillectomy has been investigated as a treatment for psoriasis. Tonsillectomy originally gained acceptance in Japan as a treatment for palmoplantar pustulosis, a condition that shares features with pustular psoriasis. Subsequently, tonsillectomy has been used for the treatment of plaque psoriasis and guttate psoriasis. Recently, the first randomized, controlled clinical trial of tonsillectomy was performed. Here, we review the available evidence for the benefit of tonsillectomy as a treatment for palmoplantar pustulosis and psoriasis. We also discuss molecular studies aimed at understanding the role of tonsils in skin disease.
    Journal of Dermatological Treatment 11/2013; · 1.50 Impact Factor
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    ABSTRACT: Abstract Background: Topical corticosteroids are a mainstay of therapy for inflammatory skin disorders. Hypothalamic-pituitary-adrenal (HPA) axis suppression is a potential systemic risk of topical steroid use. Our aim was to review available data on the risk of HPA axis suppression associated with long-term topical steroid use and to distinguish between pathologic and physiologic adrenal suppression. Methods: We performed a PubMed search for literature that evaluated the risk of HPA axis suppression associated with topical steroid use. Results: Fifteen of sixteen clinical trials reviewed did not report any pathologic adrenal suppression. In the single clinical trial that reported pathologic adrenal suppression, the patients used twice the maximum recommended amount of clobetasol propionate continuously for as long as 18 months. Physiologic adrenal suppression was seen as early as 1-2 weeks after treatment with class I-IV topical corticosteroids. In about half of these patients, cortisol levels spontaneously returned to normal within a few weeks, despite continuous therapy. Conclusion: Even when adrenal suppression occurs, topical corticosteroids are unlikely to be associated with clinical signs or symptoms of HPA axis suppression and are extremely safe as long as they are used within the current safety guidelines.
    Journal of Dermatological Treatment 10/2013; · 1.50 Impact Factor
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    ABSTRACT: Over the past 2 decades, considerable progress has been made to further elucidate the complex pathogenesis of psoriasis, facilitating the development of a new armamentarium of more effective, targeted therapies. Despite these important advances, substantial deficits remain in our understanding of psoriasis and its treatment, necessitating further research in many areas. In the sixth section of the American Academy of Dermatology Psoriasis Guidelines of Care, gaps in research and care were identified. We discuss the most important gaps in research that currently exist and make suggestions for studies that should be performed to address these deficits. These encompass both basic science and clinical research studies, including large, prospective epidemiologic studies to determine the true prevalence and natural history of psoriasis; further molecular studies in patients with psoriatic and psoriatic arthritis to understand the function of psoriasis susceptibility genes and to identify novel therapeutic targets; studies to examine the role of environmental factors in the development of psoriasis; further investigation of the relationship between psoriasis and cardiometabolic disease; studies that examine the role of adjunctive therapies such as psychological interventions in appropriate patient groups; and finally, studies to identify biomarkers of disease severity and treatment response to optimize patient therapy.
    Journal of the American Academy of Dermatology 10/2013; · 4.91 Impact Factor
  • Journal of drugs in dermatology: JDD 10/2013; 12(10):1089. · 1.16 Impact Factor
  • Journal of the American Academy of Dermatology 10/2013; 69(4):648-9. · 4.91 Impact Factor
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    ABSTRACT: Abstract Background: Over the past 15 years, biologic medications have greatly advanced psoriasis therapy. However, these medications may lose their efficacy after long-term use, a concept known as biologic fatigue. We sought to review the available data on biologic fatigue in psoriasis and identify strategies to help clinicians optimally manage patients on biologic medications in order to minimize biologic fatigue. Methods: We reviewed phase III clinical trials for the biologic medications used to treat psoriasis and performed a Pubmed search for literature that assessed the loss of response to biologic therapy. Results: In phase III clinical trials of biologic therapies for the treatment of psoriasis, 20-32% of patients lost their PASI-75 response during 0.8-3.9 years of follow-up. A study using infliximab reported the highest percentage of patients who lost their response (32%) over the shortest time-period (0.8 years). Although not consistently reported across all studies, the presence of anti-drug antibodies was associated with the loss of response to treatment with infliximab. Conclusion: Biologic fatigue may be most frequent in those patients using infliximab. Further studies are needed to identify risk factors associated with biologic fatigue and to develop meaningful anti-drug antibody assays.
    Journal of Dermatological Treatment 07/2013; · 1.50 Impact Factor
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    ABSTRACT: Abstract Objective: Moderate-to-severe psoriasis is a chronic skin condition that often requires systemic therapy and biologics are the newest systemic treatment available. A favorable aspect of biologics is that they are thought to have minimal risks for drug-drug interactions compared to oral systemic medications such as cyclosporine and methotrexate. However, this assumption has not been recently or adequately reviewed. We reviewed the literature to identify possible drug-drug interactions with biologics and other medications. Methods: We searched PubMed for published case reports, clinical studies, reviews, and FDA labels discussing possible drug-drug interactions with biologics for the treatment of moderate to severe psoriasis. Results: There were only a small number of published articles describing drug-drug interactions with biologics. Our review identified two case reports, five clinical studies, and three pharmacokinetics reviews. The majority of articles did not observe clinically relevant drug-drug interactions with biologics. FDA labels do suggest a possible relationship between tumor necrosis factor alpha (TNF-alpha) inhibitors and cytochrome P450 (CYP) activity. Conclusion: The paucity of information regarding drug-drug interactions reaffirms the idea that biologics have limited susceptibility to drug-drug interactions compared to other oral medications. Further studies are needed to adequately assess drug-drug interactions with biologics.
    Journal of Dermatological Treatment 07/2013; · 1.50 Impact Factor

Publication Stats

1k Citations
319.07 Total Impact Points

Institutions

  • 2000–2014
    • University of California, San Francisco
      • Department of Dermatology
      San Francisco, California, United States
  • 2013
    • Mount Sinai Medical Center
      New York City, New York, United States
  • 2012–2013
    • The University of Arizona
      • College of Medicine
      Tucson, AZ, United States
    • University of Utah
      Salt Lake City, Utah, United States
    • University of Miami
      • Department of Dermatology and Cutaneous Surgery
      Coral Gables, FL, United States
    • University of San Francisco
      San Francisco, California, United States
  • 2006–2013
    • University of Southern California
      • Keck School of Medicine
      Los Angeles, California, United States
    • Washington University in St. Louis
      San Luis, Missouri, United States
  • 2005–2013
    • San Francisco VA Medical Center
      San Francisco, California, United States
    • University of California, Davis
      • Department of Dermatology
      Davis, California, United States
    • Wake Forest School of Medicine
      Winston-Salem, North Carolina, United States
    • Oregon Health and Science University
      Portland, Oregon, United States
  • 2011
    • University of Toronto
      • Department of Medicine
      Toronto, Ontario, Canada
    • University of Illinois at Chicago
      Chicago, Illinois, United States
    • New York Medical College
      New York City, New York, United States
  • 2008–2011
    • Baylor Health Care System
      Dallas, Texas, United States
    • Mount Sinai School of Medicine
      • Department of Medical Education
      Manhattan, NY, United States
    • Wayne State University
      • Department of Dermatology
      Detroit, MI, United States
  • 2006–2011
    • University of California, Irvine
      • • Department of Medicine
      • • Dermatology
      Irvine, California, United States
  • 2010
    • Harbor-UCLA Medical Center
      Torrance, California, United States
    • Geisel School of Medicine at Dartmouth
      Hanover, New Hampshire, United States
  • 2005–2010
    • University of Pittsburgh
      • Department of Dermatology
      Pittsburgh, Pennsylvania, United States
  • 2009
    • Lucile Packard Children’s Hospital at Stanford
      Palo Alto, California, United States
  • 2004–2006
    • CSU Mentor
      Long Beach, California, United States
    • Wake Forest University
      • Department of Dermatology
      Winston-Salem, North Carolina, United States
  • 2003
    • Henry Ford Hospital
      Detroit, Michigan, United States