Recalcitrant pyoderma gangrenosum: treatment with thalidomide

Treatment of Pyoderma Gangrenosum

Pyoderma gangrenosum is a rare neutrophilic dermatosis that results in painful cutaneous ulcers and is frequently associated with underlying hematologic disorders, inflammatory bowel disease, or other autoimmune disorders. Pathogenesis involves an imbalance between proinflammatory and anti-inflammatory mediators, leading to tissue damage from neutrophils. First-line treatment options with the greatest evidence include systemic corticosteroids, cyclosporine, and tumor necrosis factor alpha inhibitors. Other steroid-sparing therapies such as dapsone, mycophenolate mofetil, intravenous immunoglobulin, and targeted biologic or small molecule inhibitors also have evidence supporting their use. Wound care and management of underlying associated disorders are critical parts of the treatment regimen.

Neutrophilic and eosinophilic dermatoses associated with hematological malignancy

Cutaneous manifestations of hematologic malignancy represent both a clinical challenge for the treating physician and a pathophysiological model for advancing the knowledge on individual neoplasms. Indeed, a growing body of evidence supports the concept of recurrent molecular defects associating with specific clinical features, as best exemplified by VEXAS. Herein neutrophilic and eosinophilic dermatoses of potential interest for both hematologists and dermatologists will be reviewed, including subcorneal pustular dermatosis-type IgA pemphigus, neutrophilic eccrine hidradenitis, Sweet's syndrome as well as myelodysplasia cutis and VEXAS, pyoderma gangrenosum, eosinophilic annular erythema, eosinophilic dermatosis of hematological malignancy, Wells syndrome and cutaneous involvement in hypereosinophilic syndromes. Possible management approaches are discussed for each, emphasizing scenarios that require treatment of the underlying condition to achieve remission at the skin level.

Pyoderma Gangrenosum: An Updated Literature Review on Established and Emerging Pharmacological Treatments

Pyoderma gangrenosum is a rare inflammatory skin disease classified within the group of neutrophilic dermatoses and clinically characterized by painful, rapidly evolving cutaneous ulcers with undermined, irregular, erythematous-violaceous edges. Pyoderma gangrenosum pathogenesis is complex and involves a profound dysregulation of components of both innate and adaptive immunity in genetically predisposed individuals, with the follicular unit increasingly recognized as the putative initial target. T helper 17/T helper 1-skewed inflammation and exaggerated inflammasome activation lead to a dysregulated neutrophil-dominant milieu with high levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-1α, IL-8, IL-12, IL-15, IL-17, IL-23, and IL-36. Low-evidence studies and a lack of validated diagnostic and response criteria have hindered the discovery and validation of new effective treatments for pyoderma gangrenosum. We review established and emerging treatments for pyoderma gangrenosum. A therapeutic algorithm based on available evidence is also provided. For emerging treatments, we review target molecules and their role in the pathogenesis of pyoderma gangrenosum.

Pyoderma gangrenosum: From historical perspectives to emerging investigations

Pyoderma gangrenosum (PG) is a rare disease of unknown aetiology, first described over a century ago. Initially thought to have an infectious cause, and now primarily considered an autoinflammatory condition, PG continues to be poorly understood, commonly misdiagnosed, and difficult to treat. In this review, we discuss the journey of our understanding of PG to date, including first descriptions, challenges with diagnosis, presumed pathogenesis, and treatments used. We highlight major historical landmarks and their importance, explain the rationale behind current investigations, note outstanding gaps in knowledge, and explore the future directions of PG research. We summarise what we have known, what we are working on knowing, and what we have yet to explore about PG, illustrating overall trends to invigorate future research.

Penile pyoderma gangrenosum: Successful treatment with thalidomide

Pyoderma gangrenosum (PG) is a rare ulcerating inflammatory neutrophilic dermatosis. Different clinical manifestations have been described, including ulcerative, pustular and bullous, and vegetative variants. Classic PG usually occurs on the lower extremities (~70% of cases) but can also involve the hands, head, neck, and scrotum. Genital involvement of PG has rarely been reported. Treatment of the genital PG is usually difficult and resistance to conventional therapeutic regimens was frequently observed. The present authors reported a 16-year-old male patient who presented with progressive genital ulceration for 3 weeks. He was treated successfully low dose thalidomide (50 mg/d) and minocycline.

Pyoderma Gangrenosum versus Chronic Venous Ulceration: Comparison of Diagnostic Features

Background:

Diagnosis of pyoderma gangrenosum can be difficult, leading to overdiagnosis or underdiagnosis.

Objective:

To identify clinical features helpful in establishing a diagnosis of pyoderma gangrenosum and to compare the characteristics of patients with pyoderma gangrenosum with those of patients with chronic venous ulcers.

Method:

A retrospective chart review was performed in 28 patients with typical pyoderma gangrenosum and compared with the clinical features in 28 patients with chronic venous ulcers.

Results:

(1) Even when other body sites are affected, pyoderma gangrenosum usually affects the upper and lower legs and feet or peristomal sites compared with chronic venous ulcers that are limited to the lower legs and feet. (2) Pyoderma gangrenosum can be associated with systemic diseases, especially inflammatory bowel disease. (3) Pustules and purulent discharge are features of pyoderma gangrenosum but not of chronic venous ulcers. (4) Crater-like holes or cribriform scarring is commonly seen in pyoderma gangrenosum but not in chronic venous ulcers. (5) Pathergy is a specific but not sensitive finding of pyoderma gangrenosum. It does not occur in patients with chronic venous ulcers.

Conclusions:

Diagnosis of pyoderma gangrenosum should be considered in patients with purulent ulcers affecting the legs or peristomal sites. To confirm the diagnosis, specific features should be sought, including pathergy, crater-like holes or cribriform scarring, and association with inflammatory bowel disease. Other causes of ulceration should be excluded.

Treatment of pyoderma gangrenosum with thalidomide in a myelodysplastic syndrome case

Thalidomide may be used as a treatment option for pyoderma gangrenosum (PG) and myelodysplastic syndrome (MDS). Herein, we aimed to report a patient who was treated well with thalidomide and whose diagnosis was PG with MDS. A 61-year-old man with painless ecchymotic lesions in his right upper extremity was admitted to the hospital in Isparta, Turkey, in January 2015. The lesions were diagnosed as PG. In his anamnesis, it was found that he was diagnosed with MDS 6 years ago and had been treated with cyclosporine at 2×100 mg for 5 years, which was stopped in January 2015. Aspiration from liver lesion revealed the presence of Mycobacterium tuberculosis, so antituberculosis treatment was started. Bone marrow investigation revealed MDS-refractory anemia with excess blasts (7%). For lesions in bilateral upper extremities, thalidomide treatment was started at 50 mg/d. After 1 month from the initiation of thalidomide treatment, the lesions in upper extremities had disappeared. In the literature, there are some reports of patients with PG who were successfully treated with thalidomide. Our patient is a complicated case who simultaneously has MDS, PG, and tuberculosis infection. The reason for thalidomide usage in our patient was the need of immune modulation without immune suppression. Our patient has tolerated the drug well, and excellent response was obtained after 1 month of initiation of thalidomide treatment. To conclude, thalidomide is a very effective drug acting as an immune modulator, which is useful in the clinical management of both MDS and PG.

Thalidomide in dermatology: revisited

The use of thalidomide in relation to dermatology is well- known and enough data is available in the literature about various aspects of thalidomide. Despite being an interesting and useful drug for many dermatoses, it is associated with many health hazards including the birth defects, phocomelia. We hereby present a comprehensive review about thalidomide and its application in dermatology.

Unusual causes of cutaneous ulceration

Skin ulceration is a major source of morbidity and is often difficult to manage. Ulcers caused by an inflammatory cause or microvascular occlusion are particularly challenging in terms of diagnosis and treatment. The management of such ulcers requires careful assessment of associated systemic conditions and a thorough analysis of the ulcer's clinical and histologic findings. In this article, the authors discuss several examples of inflammatory ulcers and the approach to the diagnosis and treatment of these ulcers.

Innovative uses of thalidomide

Thalidomide is approved for treating erythema nodosum leprosum and multiple myeloma, but it has also emerged as a useful treatment option for many refractory dermatologic disorders. Some of the innovative but off-label uses of thalidomide include aphthous stomatitis, Behçet's disease, lupus erythematosus, prurigo nodularis, sarcoidosis, actinic prurigo, graft-versus-host disease, Langerhans cell histiocytosis, erythema multiforme, lichen planus, Kaposi sarcoma, Jessner lymphocytic infiltrate, uremic pruritus, pyoderma gangrenosum, scleroderma, scleromyxedema, and necrobiosis lipoidica. This article reviews the background, pharmacology, and innovative uses of thalidomide in dermatology.

Mycophenolate mofetil in pyoderma gangrenosum

Recently, the use of mycophenolate mofetil (MMF) has expanded in dermatological practice. Three patients with PG received MMF in conjunction with prednisone and a fourth patient received MMF monotherapy daily. MMF in combination with prednisone in three of our patients and alone in our fourth patient induced healing of their ulcers. The first patient tolerated MMF apart from gastrointestinal upset, while treatment in our second patient was complicated by staphylococcal and pseudomonal sepsis. The third patient complained of palpitations and headaches.

Basic approach to inflammatory ulcers

Cutaneous ulcers are a difficult problem. A multidisciplinary approach is often adapted in caring for patients with nonhealing wounds. Internists, surgeons, dermatologists, and nurses must work together to provide a patient with the most comprehensive care possible. Dermatologists are consulted for a number of reasons, particularly if the ulcers are secondary to an inflammatory process. In this discussion, we describe a basic and useful approach to the diagnosis and management of inflammatory ulcers. The spectrum of these conditions is wide, ranging from vasculitis, to pyoderma gangrenosum, to ulcers resulting from the antiphospholipid syndrome and cryoprecipitates. The present authors will emphasize that the approach needs to be all-encompassing, and not focused on the ulceration alone. Certain clues are critical to diagnosis. The management, whereas often difficult, can be very rewarding.

Rheumatoid arthritis in dermatology

Rheumatoid arthritis (RA) is a chronic progressive disorder characterized by symmetric inflammatory arthritis in association with systemic symptoms. Although considered a "joint disease," RA is associated with involvement in diverse organ systems, including the skin. Common manifestations include Raynaud phenomenon, rheumatoid nodules, and rheumatoid vasculitis. As with other extra-articular manifestations, dermatologic involvement tends to occur in patients with more severe RA. In addition to manifestations related to the disease, there are also sundry dermatologic reactions related to the medications used to treat RA. Understanding the etiology and therapy for cutaneous manifestations of RA will help optimize patient care.

Thalidomide: dermatological indications, mechanisms of action and side-effects

Thalidomide was first introduced in the 1950s as a sedative but was quickly removed from the market after it was linked to cases of severe birth defects. However, it has since made a remarkable comeback for the U.S. Food and Drug Administration-approved use in the treatment of erythema nodosum leprosum. Further, it has shown its effectiveness in unresponsive dermatological conditions such as actinic prurigo, adult Langerhans cell histiocytosis, aphthous stomatitis, Behçet's syndrome, graft-versus-host disease, cutaneous sarcoidosis, erythema multiforme, Jessner-Kanof lymphocytic infiltration of the skin, Kaposi sarcoma, lichen planus, lupus erythematosus, melanoma, prurigo nodularis, pyoderma gangrenosum and uraemic pruritus. This article reviews the history, pharmacology, mechanism of action, clinical uses and adverse effects of thalidomide.

Is there a role for tumor necrosis factor-alpha inhibitors and especially thalidomide in dermatology?

Because of the relative shortcomings and their side effects of the available anti-inflammatory drugs such as systemic nonsteroids, corticosteroids, and immunosuppressive drugs, and since tumor necrosis factor-a plays a major role in noninfectious inflammatory and autoimmune disorders, tumor necrosis factor-a inhibitory drugs and the available tumor necrosis factor-a inhibitory biologic modifying reagents are described. Among the drugs reviewed are pentoxifylline, thalidomide, etanercept, infliximab, and adalimumab. Their relative effectiveness and side effects are reported and recommendations are made.

Thalidomide Induces Apoptosis in Human Monocytes by Using a Cytochrome c-Dependent Pathway

Thalidomide has been shown to be an effective treatment in various immunologic diseases such as Crohn's disease and rheumatoid arthritis. Its major effect is thought to be mediated by the inhibition of TNF-alpha, but the exact mechanism of action is still uncertain. Recent observations could demonstrate that the induction of monocyte apoptosis is a common feature of a variety of anti-inflammatory agents. Therefore, we investigated the role of thalidomide on monocyte apoptosis. Treatment with thalidomide resulted in apoptosis of human peripheral blood monocytes in a time- and dose-dependent manner as demonstrated by annexin V staining. Monocyte apoptosis required the activation of caspases, as combined stimulation by thalidomide together with the broad caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone markedly prevented monocyte cell death. Apoptosis was triggered by a CD95/CD95 ligand, TNF-RI, and TRAIL-R1 independent pathway with an inhibition of AKT-1 kinase and consecutive mitochondrial release of cytochrome c, followed by the proteolytic activation of initiator caspase-9 and effector caspase-3. Our data suggest that thalidomide-induced monocyte apoptosis is at least partially mediated by a mitochondrial signaling pathway and might contribute to the complex immunomodulatory properties of the drug.

Optimal treatment of pyoderma gangrenosum

The optimal treatment of pyoderma gangrenosum includes a combination of local wound care and systemic medications. Oral and pulse intravenous corticosteroids have traditionally been the most commonly recommended first-line systemic therapies. Cyclosporine, with or without corticosteroids, has more recently emerged as a first-line systemic treatment. A multitude of immunosuppressive and immune-modulating medications, as well as antimicrobial agents with anti-inflammatory properties have also been widely prescribed. Often, it is difficult to achieve control of aggressive cases of pyoderma gangrenosum, necessitating administration of a combination of systemic therapies. Furthermore, patients recalcitrant to one or many medications are frequently reported. Concomitant disease, intolerance to a class of medications, and the patient's response to prior therapies can help guide a practitioner in choosing the optimal treatment of pyoderma gangrenosum.

Dermatologic and nondermatologic uses of thalidomide

OBJECTIVE

To review published data on thalidomide, with emphasis on current knowledge about mechanism of action, new and/or potential dermatologic and nondermatologic therapeutic applications, well-known and emerging adverse effects, and current indications for its safe use.

DATA SOURCES

Review articles, in vitro research studies, references from retrieved articles, case reports, and clinical trials were identified from a computerized literature search using MEDLINE and OVID (1966-January 2003) and on the Cochrane Clinical Trials Register (January 2003). Information available from meetings' abstract books, Internet, or pharmaceutical companies was also considered.

STUDY SELECTION AND DATA EXTRACTION

All articles identified as relevant, including those from non-English literature, were considered in an attempt to provide to the reader both the theoretical basis and practical guidelines for thalidomide pharmacotherapy.

DATA SYNTHESIS

Thalidomide has hypnosedative, antiangiogenic, antiinflammatory, and immunomodulatory properties. Moreover, it has been shown to selectively inhibit the production of tumor necrosis factor-alpha and reduce the expression of various integrin receptors on the membrane of leukocytes and other cell types in a dose-dependent fashion. Controlled trials demonstrated the efficacy of thalidomide in a number of diseases, including erythema nodosum leprosum, lupus erythematosus, aphthosis, graft-versus-host disease, prurigo nodularis, and actinic prurigo. Single case reports or studies in small series have also suggested a possible role for thalidomide in numerous other dermatologic and nondermatologic disorders. Possibly severe and sometimes irreversible risks related to the clinical use of thalidomide include teratogenicity and neurotoxicity.

CONCLUSIONS

Although teratogenicity and neurotoxicity are significant adverse effects requiring cautious use, thalidomide is an effective therapeutic modality in a variety of difficult-to-treat disorders and, providing careful selection of patients, should offer an acceptable risk-to-benefit ratio.

An open-label study of thalidomide for maintenance therapy in responders to infliximab in chronically active and fistulizing refractory Crohn's disease

BACKGROUND

Infliximab, a chimeric monoclonal antibody to tumour necrosis factor-alpha, is a new potent therapy for active Crohn's disease, but induces short-lived improvements.

AIM

To evaluate the efficacy of thalidomide, a drug with anti-tumour necrosis factor-alpha activity, for the maintenance of infliximab-induced response in refractory Crohn's disease.

METHODS

Fifteen patients with severe, refractory disease (10 females, five males; mean age, 40 years; eight with luminal disease, two with fistulizing disease and five with both luminal and fistulizing disease) were started on thalidomide (100 mg daily), 29 +/- 10 days after they had responded to infliximab (5 mg/kg infusions).

RESULTS

The median follow-up period was 238 days (range, 10-458 days) from the initiation of thalidomide and 265 days (range, 10-537 days) from the last infliximab infusion. The median Crohn's disease activity indices were 322 (range, 170-525), 119 (range, 24-503) and 35 (range, -60-360) before infliximab, at the initiation of thalidomide and at the end of follow-up, respectively. Remission rates on thalidomide were 92%, 83% and 83% at 3, 6 and 12 months, respectively, after the last infliximab infusion (Kaplan-Meier). Four patients (two in remission) stopped thalidomide for suspected adverse effects. Side-effects (drowsiness, rash and peripheral neuropathy) were mild and mostly transient.

CONCLUSIONS

Thalidomide appears to be an effective and relatively safe drug to maintain response to infliximab in chronically active and fistulizing refractory Crohn's disease.

Targeting tumor necrosis factor alpha. New drugs used to modulate inflammatory diseases

Since its discovery, the understanding of the roles for TNF-alpha in human biology and disease has grown. Receptors for TNF are found on virtually all cell types, and many physiologic processes seem to be altered by TNF-alpha. The understanding of how TNF-alpha is involved in the pathophysiology of diseases, such as inflammatory diseases, has allowed the development of new drugs that can interfere with excess TNF-alpha and thus has allowed novel therapies for rheumatoid arthritis and Crohn's disease. As the role of TNF-alpha in other diseases becomes better understood, such TNF-alpha-modulating drugs may find further applications. In the skin, TNF-alpha is prominent cytokine that seems to be important in allergic and irritant contact dermatitis and inflammatory skin conditions. Modulating TNF-alpha activity in the skin may provide therapeutic benefits for a variety of skin conditions (Table 4). Tumor necrosis factor-alpha levels are elevated in skin lesions of psoriasis. A few reports have already suggested that etanercept and infliximab may offer a therapeutic effect in patients with psoriasis. Clinical studies evaluating the true efficacy of these drugs in psoriasis are under way. Specifically, the authors and others are involved in a double-blind, placebo-controlled study to assess the efficacy of etanercept for psoriasis. Thalidomide has been used off-label with some success to treat a number of dermatologic diseases, including several inflammatory skin conditions. Etanercept and infliximab might perhaps prove efficacious for inflammatory skin conditions as well. Finally, it is possible that drugs targeting TNF-alpha may have yet-unrecognized serious side effects. Because TNF-alpha seems to be a central cytokine in UVR-induced apoptosis, the chronic use of TNF-alpha-altering drugs might increase the risk for skin cancers. Tumor necrosis factor-alpha also plays some role in cutaneous wound healing; the effect these drugs might have on this process is also unknown at this time. Certainly, much is already [table: see text] known about TNF-alpha and how it plays many central roles. This understanding has allowed the development of useful new drugs for intractable disease. As the understanding of TNF-alpha and other cytokine biology increases, so will the number of potential therapeutic agents.

Thalidomide and Its Dermatologic Uses

This article reviews how the drug thalidomide can be used for various dermatologic disorders. Also included is a short discussion of the chemistry and physiologic mechanisms of thalidomide. Thalidomide, now available again in the United States, is another drug that can be considered by dermatologists for some severe, unusual disorders.

Thalidomide

Thalidomide has been successful in the treatment of several dermatologic conditions unresponsive to other agents. Further experience may lead to a better understanding of its mechanism of action in these various diseases. Thalidomide should be considered an extremely valuable therapeutic option in selected patients when the benefits clearly outweigh the risks of teratogenicity and peripheral neuropathy.

The Th1/Th2 paradigm in the pathogenesis of scleroderma, and its modulation by thalidomide

The immunity generated in response to an antigenic stimulus can result in at least two distinct subclasses of immune responses, commonly referred to as Th1 and Th2. This review describes Th1- and Th2-type immune responses in animal models and in human mediated disease. Evidence obtained from working within these models suggests that manipulating the Th1/Th2 balance in the immune response can alter disease processes. The possible application of this strategy in scleroderma is presented. The immune modulating effects of the drug thalidomide on Th1 and Th2 immunity are also described, along with the drug's potential application to disease processes like scleroderma.

Immune stimulation in scleroderma patients treated with thalidomide

Scleroderma (SSc) is a fibrosing connective tissue disease that is poorly responsive to any treatment, including immune suppression. SSc shares many characteristics with chronic graft-versus-host disease (GVHD). Because the immunomodulatory drug thalidomide has proven beneficial in chronic GVHD, we studied the immune response and clinical effects of thalidomide in SSc patients. We treated 11 SSc patients with thalidomide in an open label, dose escalating, 12 week study. Histologic comparison of skin biopsies showed changes in skin fibrosis and an increase in epidermal and dermal infiltrating CD8(+) T cells with thalidomide treatment. In thalidomide-treated SSc patients, plasma levels of IL-12 and TNF-alpha increased, while plasma IL-5 and IL-10 levels remained unchanged. These changes were associated with clinical effects, including dry skin, dermal edema, transient rashes, decreased gastroesophageal reflux symptoms, and healing of digital ulcers. When SSc PBMCs activated by anti-CD3 mAb were exposed to thalidomide, increases in both production of IL-2, IL-3, GM-CSF, and IFN-gamma and T cell expression of CD40L were observed. Thalidomide therefore appears to induce immune stimulation in SSc patients in association with clinical changes. However, it remains to be shown whether long-term enhancement of immune responses in SSc patients is clinically beneficial.

Recalcitrant pyoderma gangrenosum treated with thalidomide

Pyoderma gangrenosum is a painful, noninfectious, ulcerating skin disorder often associated with systemic disease. Thalidomide has been used to treat many inflammatory dermatologic conditions and has been reintroduced in the United States to treat immune-modulated diseases such as pyoderma gangrenosum. The patient described, a 47-year-old man, had histologically confirmed pyoderma gangrenosum that did not respond to treatment with several courses of methylprednisolone. The ulcer healed with 10 weeks of oral thalidomide administration.

Palliative care in inflammatory bowel disease: an evidence-based approach

The management of the patient with inflammatory bowel disease (IBD) is challenging for both the physician and the patient. IBD imposes both a physical and emotional burden on patients' lives. Palliative care is important for IBD patients because it focuses on improving quality of life. While palliative care does not change the natural history of the disease, it provides relief from pain and other distressing symptoms. This article focuses on various aspects of care for IBD patients including pain control, management of oral and skin ulcerations, stomal problems in IBD patients, control of nausea and vomiting, management of chronic diarrhea and pruritus ani, evaluation of anemia, treatment of steroid-related bone disease, and treatment of psychological problems associated with IBD. Each of these areas is reviewed using an evidence-based approach. Evidence in category A refers to evidence from clinical trials that are randomized and well controlled. Category B Evidence refers to evidence from cohort or case-controlled studies. Category C is evidence from case reports or flawed clinical trials. Evidence from category D is limited to the clinical experience of the authors. Evidence labelled as category E refers to situations where there is insufficient evidence available to form an opinion. Algorithms for management of pain and nausea in IBD patients are presented.

Thalidomide therapy for patients with refractory Crohn's disease: an open-label trial

BACKGROUND & AIMS

Inhibition of tumor necrosis factor is a proposed mechanism for the anti-inflammatory properties of thalidomide. We performed an open-label trial of thalidomide in refractory Crohn's disease.

METHODS

Twenty-two patients with refractory Crohn's disease (Crohn's Disease Activity Index [CDAI] > 200 and/or draining perianal disease) initiated therapy with thalidomide, 200 mg at bedtime (18 patients), or 300 mg at bedtime (4 patients). CDAI and goal interval scores (GIS) were assessed at weeks 0, 4, and 12. Clinical response for patients with luminal disease was defined as reduction in CDAI score of >150 points and for fistula patients was 2 scores of >/=1+ in 3 parameters of the GIS. Clinical remission was defined as a total CDAI < 150 (luminal patients) or >/=2+ for all parameters of the GIS (fistula patients).

RESULTS

Nine patients with luminal disease and 13 with fistulas (16 male, 6 female) were enrolled. The median CDAI score at entry was 371 (95-468). Sixteen patients completed 4 weeks of treatment (12 clinical responses, 4 clinical remissions). All 14 patients completing 12 weeks met criteria for clinical response. Nine achieved clinical remission (3 luminal, 6 fistula patients). The median CDAI score was 175 (30-468; P < 0.001 vs. baseline).

CONCLUSIONS

Thalidomide is efficacious in some patients with refractory Crohn's disease.

Thalidomide increases human keratinocyte migration and proliferation

Thalidomide is reported to have therapeutic utility in the treatment of pyoderma gangrenosum, Behçet's disease, aphthous ulcers, and skin wounds. We investigated the effect of thalidomide on human keratinocyte proliferation and migration, two early and critical events in the re-epithelialization of skin wounds. Thalidomide at concentrations less than 1 microM did not affect keratinocyte viability. Using a thymidine incorporation assay, we found that thalidomide, at therapeutic concentrations, induced more than a 2. 5-fold increase in the proliferative potential of the cells. Keratinocyte migration was assessed by two independent motility assays: a colloidal gold assay and an in vitro scratch assay. At optimal concentrations, thalidomide increased keratinocyte migration on a collagen matrix more than 2-fold in the colloidal gold assay and more than 3-fold in the scratch assay over control. Although pro-migratory, thalidomide did not alter the level of metalloproteinase-9 secreted into culture medium. Thalidomide did, however, induce a 2-4-fold increase in keratinocyte-derived interleukin-8, a pro-migratory cellular autocrine factor. Human keratinocyte migration and proliferation are essential for re-epithelialization of skin wounds. Interleukin-8 increases human keratinocyte migration and proliferation and is chemotactic for keratinocytes. Therefore, thalidomide may modulate keratinocyte proliferation and motility by a chemokine-dependent pathway.