Improvement in psoriasis after intradermal administration of heat-killed Mycobacterium vaccae

Management of Infections in Psoriatic Patients Treated with Systemic Therapies: A Lesson from the Immunopathogenesis of Psoriasis

Modern treatments continue to be developed based on identifying targets within the innate and adaptive immune pathways associated with psoriasis. Whilst there is a sound biologic rationale for increased risk of infection following treatment with immunomodulators, the clinical evidence is confounded by these agents being used in patients affected with several comorbidities. In an era characterized by an ever greater and growing risk of infections, it is necessary to always be updated on this risk. In this mini-review, we will discuss recent updates in psoriasis immunopathogenesis as a rationale for systemic therapy, outline the risk of infections linked to the disease itself and systemic therapy as well, and provide an overview of the prevention and management of infections.

Psoriasis treatment: Unconventional and non-standard modalities in the era of biologics

Psoriasis is a potentially debilitating inflammatory dermatosis affecting 0.2%-4.8% of the population worldwide causing a significant occupational, personal or psychosocial morbidity to these patients for life. The basic aim of psoriasis therapy is to control the disease to maximum possible extent and improve the patient’s quality of life. Management of triggers for flare-ups, lifestyle modifications, and dietary supplements are often recommended. Intermittent or rotational therapy with frequent alterations in treatment options is usually needed to reduce toxicity of anti-psoriatic drugs in the absence of safer alternatives. Currently, several biological agents categorized as either T-cell targeted (e.g., Alefacept, Efalizumab) or cytokine modulating (e.g., Adalimumab, Infliximab, Etanercept) are available for treating severe psoriasis. However, their high cost is often precluding for most patients. The usefulness of systemic (methotrexate, cyclosporine, acitretin or several other therapeutic agents) or topical (tar, anthralin, corticosteroids or calcipotriol ointments, phototherapy with or without psoralens) therapies has been well established for the management of psoriasis. The literature is also replete with benefits of less used non-standard and unconventional treatment modalities (hydroxycarbamide, azathioprine, leflunomide, mycophenolate mofetil, isotretinoin, fumarates, topical calcineurin inhibitors, peroxisome proliferator-activated receptors agonists, statins, sulfasalazine, pentoxifylline, colchicine, grenz ray therapy, excimer laser, climatotherapy and balneophototherapy, peritoneal dialysis, tonsillectomy, ichthyotherapy, etc.). These can be used alternatively to treat psoriasis patients who have mild/minimal lesions, are intolerant to conventional drugs, have developed side effects or achieved recommended cumulative dose, where comorbidities pose unusual therapeutic challenges, or may be as intermittent, rotational or combination treatment alternatives.

Complete genome sequence of Mycobacterium vaccae type strain ATCC 25954

Mycobacterium vaccae is a rapidly growing, nontuberculous Mycobacterium species that is generally not considered a human pathogen and is of major pharmaceutical interest as an immunotherapeutic agent. We report here the annotated genome sequence of the M. vaccae type strain, ATCC 25954.

Prospects for vaccines for allergic and other immunologic skin disorders

The human skin hosts a variety of immune response-associated components that together form the skin immune system. Any abnormality in the functioning of the skin immune system leads to a variety of dermatologic complications, including dermatitis, psoriasis, and eczema. Exposure to antigens/allergens can lead to allergic skin disorders such as atopic dermatitis, urticaria, and allergic contact dermatitis. Recent investigations have provided new insights into the immunologic processes leading to the development of skin diseases. T cells play a central role in the activation and regulation of immune responses by recognizing antigen and inducing cytokine production. Despite advances in the understanding of the immunologic events leading to the development of skin diseases, no effective prevention measure exists. Current therapeutic treatments are based on either alleviating the symptoms or suppressing the immune system with immunosuppressive drugs. Allergen-specific immunotherapy is expected to induce specific T cells that abolish allergen-induced proliferation of T helper cells, as well as their cytokine production. Recent approaches using recombinant protein, polycytosine guanine oligonucleotides, and plasmid DNA for vaccination suggest the possibility of protection against these skin disorders. The involvement of T cells in psoriasis indicates that the development of a T-cell receptor peptide vaccine may be beneficial. Dendritic cell-based vaccines using tolerogenic dendritic cells that can induce T-cell tolerance have been shown to be useful in dealing with autoimmune disorders and allergic conditions. In the light of these developments, this article presents the current status and prospects of developing vaccines for allergic and other immunologic skin disorders.

The production of a new extracellular putative long-chain saturated polyester by smooth variants of Mycobacterium vaccae interferes with Th1-cytokine production

Mycobacterium vaccae is of major pharmaceutical interest as an immunotherapeutic agent. Although M. vaccae 15483 ATCC(T) strain displays smooth and rough colonial morphologies on solid culture media, it is not known in which conditions M. vaccae switches from one colonial morphotype to the other or whether there are biological differences, especially immunological, between them. We have found that the change from a smooth to rough stable variant occurs spontaneously at 30 degrees C. The analysis of the composition of the cell wall in both variants showed that the smooth morphotype presents an extracellular material that has never previously been described and was identified as a long-chain saturated polyester that, interestingly, is not produced by the rough morphotype. Our results also indicate that this compound could be implicated in the spreading ability of smooth colonies. Proliferation, IFN-gamma and IL-12(p40) production by splenocyte cultures was significantly higher in mice immunised with the rough variant compared with those immunised with the smooth one. This latter finding suggests that the different colonial morphology of M. vaccae may affect the immunomodulatory effects induced from M. vaccae preparations.

Study on pancreatic lymphatics in nonobese diabetic mouse with prevention of insulitis and diabetes by adjuvant immunotherapy

The present study has investigated the relationship between pancreatic lymphatics, infiltrating cells, and insulitic development after a single injection of complete Freund's adjuvant (CFA) given at an early age in the nonobese diabetic (NOD) mice. No CFA-treated NOD mice developed hyperglycemia, whereas most CFA-untreated mice died of diabetes at the age of 20-30 weeks. In untreated NOD mice, the increased infiltration of dendritic cells (DCs) and T-lymphocytes into the pancreatic islets appeared to be consistent with the increased expression of the secondary lymphoid chemokine (CCL21) and CD(31) by the endothelial cell lining of inter- and intralobular lymphatics. As the infiltration became severe, the reaction products of CCL21 and CD(31) were distributed in the nucleus and cytoplasm of lymphatic endothelial cells (LECs), through which DCs and T-lymphocytes migrated frequently. Administration of CFA reduced the number of infiltrating DCs and T-lymphocytes, but did not affect macrophage infiltration. The peri-insulitis occurred in numerous islets of CFA-treated NOD mice without the appearance of the intraislet infiltration and islet-associated lymphoid-like tissues. Furthermore, significant suppression of CCL21 and CD(31) was demonstrated on the infiltrating cells to the islets and islet-associated lymphatics. The abluminal endothelial cell lining of lymphatic vessels exhibited weaker immunoreactivity of CCL21 and CD(31) in comparison with the luminal surfaces. The reaction product of 5'-nucleotidase (5'-Nase) was evenly deposited on LECs, which were the absence of open junctions, cytoplasmic protrusions, and vesicles. CFA treatment influenced the migratory processes of the infiltrating cell, which were closely related with structural changes of pancreatic lymphatics and inhibited insulitic development. These findings suggest that in CFA-treated NOD mice, the suppression of insulitis and prevention of diabetes are secondary to the functional modulation of pancreatic lymphatics and infiltrating cells.

Novel pharmacological approaches in the treatment of psoriasis

Progress in the understanding of psoriasis as a T-cell mediated inflammatory disease has led to the development of new immunomodulatory therapies. Currently the main focus is on the so-called biologics (or biological agents), including fusion proteins, monoclonal antibodies, cytokines and selective receptors. They mainly target single steps in the complex cascade of humoral and cellular inflammatory immuno-mechanisms that finally lead to the accelerated growth of epidermal and vascular cells in the psoriatic lesions. The most promising and advanced biological agents are discussed along with their influence on the critical pathophysiological steps in psoriasis, including depletion of T cells, blockade of initial T-cell activation and T-cell receptor (TCR) stimulation, blockade of costimulatory signals and T-cell proliferative signals as well as restoration of the T helper type 1 (Th1)/Th2 balance by diminishing type 1 cytokines and administration of type 2 cytokines. In addition to the biological agents, further development of 'classical' dermatological therapies, such as retinoids, or the discovery of new indications for non-dermatological agents contribute to the novel pharmacological approaches in the treatment of psoriasis.

Complete Freund's adjuvant promotes the increases of IFN-gamma and nitric oxide in suppressing chronic arthritis induced by pristane

The aim of this study was to determine therapeutic effects of complete Freund's adjuvant (CFA) on the progression and relapsing of pristine-induced arthritis (PIA) and investigate the mechanism involved. Chronic relapsing arthritis was induced by pristine in LEW rats. After onset of arthritis, rats were intradermally injected CFA and rats in control group were injected the same volume of PBS. Arthritis was monitored visually, and joint pathology was examined histologically. Cytokine mRNA expression in inguinal lymph nodes was assessed by RT-PCR. The levels of nitric oxide (NO) in serum were measured by colorimetric assay. The results showed that CFA significantly suppressed the progression and relapsing of PIA. Relapsing rate of PIA in CFA-treated group was 12.5% and it was 85.7% in PBS-control group (P < 0.005). CFA markedly inhibited the infiltration of inflammatory cells and cartilage damage in the joints of CFA-treated rats and promoted the increases of IFN-y mRNA and NO levels. The present study provided an implication that adjuvant therapy may be a new strategy for the treatments of rheumatoid arthritis (RA) and other chronic inflammatory diseases.

Increased protection against bovine tuberculosis in the brushtail possum (Trichosurus vulpecula) when BCG is administered with killed Mycobacterium vaccae

SETTING

The Australian brushtail possum is the major wildlife reservoir for Mycobacterium bovis infection in New Zealand. Development of an effective tuberculosis vaccine for possums will reduce the spread of infection to cattle and farmed deer.

OBJECTIVES

To determine whether killed M. vaccae can improve the efficacy of vaccination with M. bovis bacillus Calmette Guerin (BCG) against bovine tuberculosis in the possum.

DESIGN

Groups of possums (n=6-8) were vaccinated via intranasal and intraconjunctival routes with BCG alone or BCG in combination with heat-killed M. vaccae. Controls were non-vaccinated or vaccinated with heat-killed M. vaccae alone. After challenge with virulent M. bovis, protection was assessed by a reduction in loss of body weight and bacterial counts in lungs and spleens. Blood lymphocyte proliferative responses to M. bovis purified protein derivative were monitored throughout.

RESULTS

The earliest lymphocyte responses following vaccination were from animals inoculated with BCG plus 100 microg heat-killed M. vaccae. Loss of body weight was significantly reduced in all BCG-vaccinated groups compared control groups. Spleen bacterial counts were significantly lower in animals vaccinated with M. vaccae plus BCG compared to the non-vaccinated group. Furthermore, vaccination with 100 microg M. vaccae plus BCG significantly reduced spleen bacterial counts compared to vaccination with BCG alone.

CONCLUSION

The possum infection model is one of the first to show that novel vaccine strategies may offer better protection against tuberculosis than BCG alone.

Complete Freund's adjuvant suppresses the development and progression of pristane-induced arthritis in rats

The present study produced the novel finding that treatment with a nonarthritogenic dose of Complete Freund's adjuvant (CFA) before the onset of pristane-induced arthritis (PIA) could prevent the development of PIA. Surprisingly, treatment with nonarthritogenic and arthritogenic doses of CFA could almost cure the ongoing PIA. CFA treatment also suppressed pathological changes, such as inflammatory cell infiltration, pannus formation, bone destruction, and new bone formation. The lymph node cells of rats with PIA suppressed by CFA showed significantly increased mRNA expression of IFN-gamma but no significant changes in mRNA expression of IL-2, TNF-alpha, IL-4, and IL-5 compared with those of rats in the control groups. The possible mechanisms of the suppressive effect of CFA on the development and progression of PIA were discussed in terms of the anti-inflammatory roles of IFN-gamma, nitric oxide, and heat-shock protein-specific T cell responses. The present study found a new therapeutic implication for the treatment of rheumatoid arthritis.

Prevention of experimental myointimal hyperplasia by immunomodulation

INTRODUCTION

we have tested the hypothesis that treatment with a mycobacterial preparation that modulates the antibody response, would diminish restenosis in a rat angioplasty model.

MATERIALS/METHODS

male Sprague-Dawley rats were used. All immunisations were given subcutaneously. Group A (control) received normal saline on days 0, 21, and 42. Group B received SRL172 on days 0, 21, and 42. Group C received SRL172 on days 0, 21, and 42, and hsp65/Incomplete Freund's on days 21 and 42. Group D received hsp65/Freund's on days 21 and 42. Right common carotid arteries were balloon-injured on day 63 using a standard technique known to produce MIH and animals were sacrificed on day 77. For each carotid 6 microm cross sections were cut from paraffin blocks. Cross-sectional areas were measured by computerised planimetry.

RESULTS

balloon injury resulted in MIH in all animals. Data represents mean+/-SEM for the percentage of area enclosed within the internal elastic lamina occupied by MIH (% MIH); which for groups A, B, C, and D was 85+/-11, 24+/-3, 27+/-7, and 17+/-3 respectively. All the treatment groups had significantly less MIH when compared to the control group but no statistically significant difference was found between any of the treatment groups.

CONCLUSIONS

this is the first report that immunomodulation with mycobacterial material suitable for use in man, can reduce MIH. Since such modulation has low risk, this raises the prospect of an important new therapeutic modality to combat restenosis.

The effect of delipidated deglycolipidated (DDMV) and heat-killed Mycobacterium vaccae in asthma

Experimental and epidemiological evidence supports the hypothesis that exposure to mycobacteria has the potential to suppress the development of asthma and/or atopy and there are reports in the Chinese medical literature of repeated vaccination with inactivated BCG being effective in the management of asthma. Forty-three patients with stable moderately severe asthma who were skin prick test positive to house dust mite were randomized to receive two intradermal injections of either phosphate-buffered saline (placebo), heat-killed Mycobacterium vaccae (0.5 mg), or delipidated deglycolipidated Mycobacterium vaccae (DDMV) (0.05 mg). Markers of asthma severity were measured for 3 mo and blood eosinophil, IgE levels, and the T cell proliferative and cytokine responses were monitored. There were no significant differences between either treatment group and the placebo group for any of the outcome variables. There was also no difference between the treatment groups and placebo for eosinophil, IgE levels, or the T cell proliferative and cytokine response. The results indicate no effect of low dose intradermal DDMV or M. vaccae on asthma severity in patients with established asthma.

Improvement in psoriasis after intradermal administration of delipidated, deglycolipidated Mycobacterium vaccae (PVAC): results of an open-label trial

The aim of new treatments for psoriasis is to induce extended remissions with fewer side-effects. Previous studies suggest that Mycobacterium vaccae, a harmless organism prepared as a heat-killed suspension, may induce periods of remission in some psoriasis patients after intradermal administration. To assess a more potent derivative of M. vaccae, we conducted an open-label study in which 20 patients with moderate to severe psoriasis (Psoriasis Area and Severity Index of 12-35) received two intradermal inoculations of heat-killed, delipidated, deglycolipidated M. vaccae (DD-MVAC or 'PVAC') in lesion-free deltoid skin, separated by a period of 3 weeks. Twelve weeks after the injections, 13 out of 20 patients (65%) showed marked improvement in the PASI score (> 50% reduction), three were unchanged (< 25% reduction), three had worsened (> 5% increase), and one was withdrawn from the trial because of an exfoliative flare. At 24 weeks, 13 out of 19 patients continued to show > 50% improvement that, in some, lasted for 6 months or longer. Patients classified as good responders at 12 or 24 weeks were then offered additional PVAC injections after 24 weeks if the PASI reached 8 or higher. Intra-dermal administration of PVAC was safe, well tolerated, and induced clinically significant improvement in many psoriasis patients. A randomized, double-blind, controlled study is warranted.

Psoriasis: the future

The aetiology of psoriasis is still unclear but our knowledge of the psoriatic process has grown substantially over the last two decades. The future will undoubtedly bring advances in our understanding of the pathogenesis of psoriasis and, as a consequence, new therapies. Defining the molecular genetics of psoriasis will enhance our understanding of the disease process and hopefully facilitate the development of a representative animal model. This in itself will be a key step in the development and testing of new therapies. Precise identification of the immunological events involved in psoriasis will allow specific T-cell- and cytokine-targeted, and perhaps less toxic. immunotherapies. Anti-angiogenic agents that are in development for use in oncology may also be effective in psoriasis. The adaptation of current topical therapies such as retinoids and vitamin D analogues to produce more effective and better-tolerated formulations will also play a significant role in our future first-line management of patients. The increased recognition and better management of environmental trigger factors such as psychological distress will become an important factor in future psoriasis care. The development of physical therapies including photodynamic therapy and excimer lasers has the potential to expand the remit of psoriasis therapy. There is little doubt that the future for our patients with psoriasis is bright. However, this will only be achievable by a concerted research effort to understand all facets of this enigmatic disease ranging from the molecular to the environmental.

The ability of heat-killed Mycobacterium vaccae to stimulate a cytotoxic T-cell response to an unrelated protein is associated with a 65 kilodalton heat-shock protein

Exogenous antigens are generally presented by Class II major histocompatibility (MHC) molecules. When administered with an adjuvant, however, they are capable of inducing a CD8+ T-cell response where antigen recognition is associated with Class I MHC. Accordingly, immunization with soluble ovalbumin (OVA) alone does not activate CD8+ cytotoxic T cells (CTL) but when given in complete Freund's adjuvant (CFA), or in formulations of a number of novel adjuvants, an OVA-specific CD8+ CTL response can be detected. We show in this report that immunization with soluble OVA mixed with heat-killed Mycobacterium vaccae, but not with other common pathogenic and saprophytic mycobacteria, can activate OVA-specific CD8+ CTL. An OVA-specific CTL response is detected when mice are immunized by either the intraperitoneal or intranasal route and their spleen cells are re-stimulated in vitro. Adjuvant activity of heat-killed M. vaccae is present in M. vaccae culture filtrate, in soluble protein components of whole M. vaccae and in the 65 kDa heat-shock protein (hsp) of M. vaccae. Mycobacterium vaccae has previously been shown to have no adverse side-effects in humans. The current results suggest that M. vaccae may be useful as an adjuvant for vaccines and other immunotherapies where CD8+ CTL responses to exogenous proteins are crucial.