Elevated numbers of proliferating mononuclear cells in the peripheral blood of psoriatic patients correlate with disease severity

Comorbidities in patients with psoriasis

Psoriasis is a common chronic inflammatory disease that is associated with serious comorbidities, including psoriatic arthritis, reduced quality of life, depression, malignancy, and cardiovascular comorbidities. Patients with psoriasis have been shown to have an increased incidence of metabolic syndrome and cardiovascular disease compared with the general population. The chronic inflammatory nature of psoriasis has been suggested to be a contributing and potentially independent risk factor for the development of cardiovascular comorbidities. Understanding the interrelationship between these conditions is important for the management of psoriasis and the associated comorbidities. This review will focus on the range of comorbidities associated with psoriasis, with emphasis on cardiometabolic conditions and the aim of encouraging primary care physicians to screen psoriatic patients for cardiometabolic disorders and risk factors.

Cellular pharmacodynamics of immunosuppressive drugs for individualized medicine

The therapeutic effects of immunosuppressive drugs are known to deviate largely between patients, but efficient strategies for the differentiation of patients who show clinical resistance to immunosuppressive therapies have not been established. Accordingly, a considerable number of patients receive treatment with immunosuppressive drugs despite the onset of serious side effects and poor responses. Cellular pharmacodynamics of immunosuppressive drugs in vitro using peripheral lymphocytes derived from each patient, an attractive way to distinguish resistant patients, is respected and has been applied to the carrying out of individualized immunosuppressive therapy. In this article, I summarize experimental procedures for assaying immune cell responses to immunosuppressive drugs in vitro, and highlight the relationship between cellular sensitivity to immunosuppressive drugs and the therapeutic efficacy of drugs in organ transplantation and several immunological disorders. I will also overview the molecular mechanisms and genetic bases for cellular and clinical resistance to immunosuppressive drugs. Lastly, the future clinical prospects for the application of in vitro drug sensitivity tests for "patient-tailored" immunosuppressive therapies are discussed.

The Risk of Lymphoma in Patients with Psoriasis

Psoriasis is a common, chronic, inflammatory disease. Psoriasis has been hypothesized to be associated with an increased risk of lymphoma due to its pathophysiology, its treatments, or a combination of these factors. We performed a large population-based cohort study of the risk of lymphoma in psoriasis patients using the General Practice Research Database. We identified 153,197 patients with psoriasis and 765,950 corresponding subjects without psoriasis. Psoriasis patients who received a systemic treatment consistent with extensive disease were classified as severe (N=3,994) and those who did not receive systemic therapies were classified as mild (N=149,203). The analyses were adjusted for age, gender, and person-time using a Cox proportional hazards model. For mild and severe psoriasis patients, the respective adjusted relative risks for lymphoma and its subtypes were as follows: all lymphoma 1.34 (1.16, 1.54) and 1.59 (0.88, 2.89); non-Hodgkin's lymphoma 1.15 (0.97, 1.37) and 0.73 (0.28, 1.96); Hodgkin's lymphoma (HL) 1.42 (1.00, 2.02) and 3.18 (1.01, 9.97); cutaneous T-cell lymphoma (TCL) 4.10 (2.70, 6.23) and 10.75 (3.89, 29.76). Psoriasis is associated with an increased risk of lymphoma. The association is strongest for HL and CTCL. The excess risk of lymphoma attributed to psoriasis was 7.9/100,000 psoriasis patients per year. Although patients with psoriasis have an increased relative risk of lymphoma, the absolute risk attributable to psoriasis is low given that lymphoma is a rare disease and the magnitude of association is modest.

Alefacept: a review of the literature and practical guidelines for management

Alefacept is the first biologic agent approved for the treatment of chronic, moderate to severe plaque-type psoriasis. It is a fully human fusion toxin, which binds to CD2, blocks costimulatory signaling, and selectively induces apoptosis of activated memory T cells involved in the pathogenesis of psoriasis. Alefacept has a slow onset of action, peaking approximately 18 weeks after the first injection of a 12-week course. However, it has several important advantages over the existing conventional immunosuppressive therapies for psoriasis: it is associated with long remissions without the need for maintenance therapy; its efficacy improves with subsequent courses; and it has a high safety profile. This review summarizes the mechanism of action of alefacept and the results of the clinical trials, with special emphasis on efficacy, pharmacodynamic effects on circulating lymphocytes, and safety and tolerability. Current guidelines based on the best available data to date are also presented.

Subclinical activation of latent cytomegalovirus (CMV) infection and anti-CMV immune response in patients with atopic dermatitis

BACKGROUND

Microbiological infections are considered to be of pathophysiological importance in atopic dermatitis (AD). As yet, no information is available regarding cytomegalovirus (CMV) infection in this disease. This, however, is of interest because of the high prevalence of latent infections in the general population, the frequent reactivation in inflammatory diseases, and the immunomodulating capacity of CMV.

OBJECTIVES

To investigate the prevalence of latent CMV infection, the frequency of active CMV infection, and the immune response to CMV in patients with moderate to severe AD. Methods To detect active infection we analysed CMV antigen expression by peripheral blood mononuclear cells (PBMC) from 27 patients with moderate to severe AD in comparison with 53 healthy volunteers. We used three monoclonal antibodies recognizing different CMV-encoded antigens and immunocytological staining (alkaline phosphatase-antialkaline phosphatase technique).

RESULTS

Patients with AD had a higher mean frequency of CMV-positive PBMC: 2.25 per 10 000 vs. 0.74 per 10 000 in controls (P = 0.001) as well as a higher incidence of CMV antigenaemia: 29.6% vs. 7.5% (P < 0.01). Seropositivity for anti-CMV IgG antibodies indicated subclinical activation of latent infection. Remarkably, a clearance of CMV antigenaemia was observed during anti-eczematous treatment. Significantly higher plasma levels of tumour necrosis factor-alpha, which is involved in CMV reactivation, and interleukin-12, which is crucial for an antiviral cellular immune response, were observed in AD patients in comparison with healthy volunteers. Furthermore, a significantly enhanced frequency of circulating activated HLA-DR+ T cells especially in CMV-seropositive AD patients (19.3% vs. 13.5% in seronegative AD patients vs. 10.2% in controls) suggested that the active CMV infection triggers a cellular immune response. This was also supported by a high frequency of CMV-specific interferon-gamma-producing T cells in CMV-seropositive patients with AD.

CONCLUSIONS

Our data suggest that active, subclinical CMV infection is more frequent in patients with moderate to severe AD and may have immunopathophysiological relevance.

Comparison of antiproliferative effects of experimental and established antipsoriatic drugs on human keratinocytes, using a simple 96-well-plate assay

Pharmacological treatments for psoriasis are generally based on antiproliferative, anti-inflammatory, or differentiation-modifying activity, or a combination of two or more of these actions. Potentially new drugs for treatment of psoriasis, which act on proliferation, can be identified by screening large compound libraries in a cell proliferation model that allows for characterization of drug effects on in vitro growth of normal human keratinocytes. High-throughput programs based on biological testing of diverse collections of compounds can rapidly identify leads for potential drug candidates in the treatment of psoriasis. In this study, we describe nonradioactive measurement of keratinocyte proliferation in the exponential growth phase in a 96-well format, using a sensitive deoxyribonucleic acid-binding dye to analyze drugs that are pharmacologically active in growth inhibition. Release of lactate dehydrogenase was used to exclude cytotoxic effects. We examined a number of compounds in a test range of 10(-7) to 10(-5) M, including known antipsoriatic drugs, and experimental drugs that are potentially useful in the treatment of psoriasis. We found strong concentration-dependent growth inhibition by dithranol, an antipsoriatic compound that is presumed to target the epidermal compartment. Methotrexate, cyclosporin A, and all-trans retinoic acid did not significantly affect proliferation at therapeutically relevant concentrations. The p38 mitogen-activated protein kinase inhibitor, SB220025, and curcumin, a natural phytochemical, inhibited keratinocyte proliferation at 10(-5) M. We conclude that this assay, in combination with the previously developed assays for psoriatic differentiation, provides a useful tool for identification of antipsoriatic drugs.

Increased microorganisms DNA levels in peripheral blood monocytes from psoriatic patients using PCR with universal ribosomal RNA primers

It has long been suspected that systemic and focal infections cause or exacerbate psoriatic lesions. We previously showed that peripheral blood monocytes in psoriatic patients are activated and overproduce inflammatory cytokines. In addition, it has been reported that macrophages activated by ingesting microorganisms release tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Therefore we hypothesized that the monocytes in psoriatic patients may be activated by ingesting microorganisms and overproduce inflammatory cytokines. We examined the detection of microorganism DNA in monocytes from 15 patients with psoriasis vulgaris and from 12 healthy controls. DNA was extracted from monocytes, and a polymerase chain reaction (PCR) assay was performed for the detection using universal primers from conserved regions of the bacterial 16S ribosomal RNA gene or the fungal 18S rRNA gene. At the same time, we calculated the psoriasis area and severity index (PASI) scores and analyzed their correlations with the microorganisms DNA levels. The results showed that bacterial 16S DNA levels in monocytes were significantly higher in psoriatic patients than in controls. The fungal 18S DNA levels were also higher in psoriatic patients than in controls, but the differences were not significant. Although the microorganisms DNA levels in monocytes of psoriatic patients were high, there was no correlation between the bacterial DNA levels in monocytes of the psoriatics and PASI scores. Our study suggests that monocytes in psoriatic patients engulf more bacteria than there in controls, causing an activation of monocytes and triggering the formation of new lesions in the initial stages of psoriasis.

Profiles of activated T lymphocytes in peripheral blood of Kuwaiti psoriasis vulgaris patients

We have previously reported unexpected immunological features of psoriasis among Kuwaitis, suggesting novel patterns of immune reactivity contributing to the disease. To better define this phenomenon, we herein describe profiles of major populations and immunologically activated subsets of peripheral blood lymphocytes in a cohort of Kuwaiti psoriasis vulgaris patients. Whole venous blood from fifteen psoriatic and twenty eight normal, healthy subjects was analyzed by 2-color flow cytometry for levels of major lymphocyte species and their immunologically activated subsets. When compared to normal subjects, psoriatic blood contained lower cell densities of CD2+, CD8+ (p=0.002 respectively) and B lymphocytes (CD19+) (p=0.003), with a trend toward a lower CD4+ density (p=0.072). Within each major lymphocyte population, activated lymphocytes were present at higher percentages in psoriatic than in healthy blood. These included CD4+ HLA-DR+ (p=0.002), CD4+CD25+ (p=0.043), CD4+CD54+ (p=0.005), CD8+CD25+ (p=0.015), CD8+ HLA-DR+ (p=0.046) and CD3+CD16+CD56+ (p=0.023) Additionally, psoriatic patients were found to have an expanded ratio of memory to naive T cells (CD45RO+CD45RA+) relative to control subjects; this was expected on the basis of increased immune activation. Our findings are consistent with a picture of psoriasis as a disease mediated by activated lymphocytes.

Promoter region polymorphism of the CD14 gene (C-159T) is not associated with psoriasis vulgaris

Keratinocytes of psoriatic skin show aberrant expression of membrane-bound CD14 (mCD14). In addition, soluble CD14 (sCD14) is elevated in the sera of psoriatic patients. The mechanisms leading to increased CD14 expression and secretion in psoriasis are poorly understood. A bi-allelic polymorphism in the promoter region of the CD14 gene controls CD14 expression on monocytes and sCD14 levels in the sera of healthy subjects. In this context, we explored the CD14 promoter region genotypes of 63 Finnish patients with psoriasis and 126 non-psoriatic controls using a new ARMS-PCR method. No differences in the CD14 genotype frequencies were found between the groups. Thus, our results suggest that the enhanced CD14 expression in psoriasis is not attributable to functional variants of CD14 (-159C/T).

CD69, HLA-DR and the IL-2R identify persistently activated T cells in psoriasis vulgaris lesional skin: blood and skin comparisons by flow cytometry

Many lymphocyte-activation-associated molecules are observed by immunohistochemistry in psoriasis vulgaris lesional skin. Non-T cells in lesional skin also express these molecules. We quantitatively measured the number of T cells expressing cell surface activation-associated molecules (CD69, CD25, CD122, HLA-DR) and co-stimulatory molecules (CD28, CTLA-4, CD80, CD86), including a Type 2 T cell marker (CD30) and CD11b, by flow cytometry of skin and peripheral blood. T cells in single cell suspensions of psoriatic lesional-epidermis-expressed HLA-DR (86%), CD69 (59%), CD25 (55%), CD122 (44%), and CD28 (91%). Dermal T cells showed similar percentages except for CD69 (17%). CD69 was found directly in lesional skin biopsies by immunohistochemistry. Both CD4 and CD8 subsets from lesional skin contained large populations of CD25+ cells with a bias towards CD8 activation in the epidermis and towards CD4 activation in the dermis. CD86, CD80, CTLA-4, CD30 and CD11b were expressed by less than 23% of the T cell populations from both the epidermis and dermis. CD30+CD4+ cells were found two-fold over CD8+ T cells. These results show that the majority of lesional lymphocytes are persistently activated. We also found the majority of Type 2 associated markers primarily on the CD4+ epidermal T cell population. Psoriatic blood contained elevated levels of T cells expressing CD25, primarily within the CD8+ subset. Thus the majority of lesional T cells expressed the three primary activation markers, while psoriatic blood T cells were distinguished by an increase in CD25, specifically within the CTL population.

Epidermal HLA-DR and the enhancement of cutaneous reactivity to superantigenic toxins in psoriasis

Streptococcal and staphylococcal superantigens (SAg's) have been implicated in the pathogenesis of inflammatory skin diseases, but the mechanisms by which these toxins act are unknown. The present study assessed the ability of nanogram quantities of topically applied purified toxic shock syndrome toxin-1 (TSST-1), staphylococcal enterotoxin type B, and streptococcal pyrogenic enterotoxin types A and C to induce inflammatory reactions in clinically uninvolved skin of normal controls and subjects with psoriasis, atopic dermatitis, and lichen planus. These SAg's triggered a significantly greater inflammatory skin response in psoriatics than in normal control subjects or in subjects with atopic dermatitis or lichen planus. Surprisingly, skin biopsies did not exhibit the T-cell receptor Vbeta stimulatory properties predicted for SAg-induced skin reactions. By 6 hours after patch testing with SAg's, TNF-alpha mRNA had increased in the epidermis (but not the dermis) in biopsies from psoriatics, compared with controls. Immunohistochemical studies revealed significantly higher HLA-DR expression in keratinocytes from psoriatics than from controls. However, a mutant TSST-1 protein that fails to bind HLA-DR did not elicit an inflammatory skin reaction. These results indicate that keratinocyte expression of HLA-DR enhances inflammatory skin responses to SAg's. They may also account for previous studies failing to demonstrate selective expansion of T-cell receptor Vbetas in psoriatics colonized with SAg-producing Staphylococcus aureus, and they identify a novel T cell-independent mechanism by which SAg's contribute to the pathogenesis of inflammatory skin diseases.

Presence of activated lymphocytes in the peripheral blood of patients with halo nevi

BACKGROUND

The involution of the central pigmented lesion in halo nevus (HN) seems to be mediated by an immune response against self antigens expressed by melanocytes.

OBJECTIVE

We assessed the presence of activated lymphocytes in the peripheral blood lymphocytes from patients with HN.

METHODS

Peripheral blood was obtained from patients with HN associated with benign pigmented lesions (5) or melanoma (2) as well as from patients with melanoma without HN (5) and healthy subjects (10). Activated lymphocytes were detected by flow cytometry analysis using monoclonal antibodies (mAb) against CD69, CD71, CD98, HLA-DR, and activated beta(1) integrins (HUTS-21 mAb).

RESULTS

The peripheral blood lymphocytes from patients with HN, associated with either benign or malignant lesions, exhibited a significantly higher expression of all activation markers studied compared with patients with melanoma without HN or compared with healthy subjects. Therefore the peripheral blood of HN patients contained a significant fraction of lymphocytes with an activated (CD69(+), HLA-DR(+), CD98(bright)), cell proliferating (CD71( bright)), and high adhesive (HUTS-21(bright)) phenotype. These activated cells disappeared from peripheral blood after the surgical resection of the skin lesion.

CONCLUSION

Our findings further support the involvement of immune activation in HN phenomenon.

Overexpression of monocyte-derived cytokines in active psoriasis: a relation to coexistent arthropathy

An overexpression of inflammatory cytokines has been found in the lesional skin as well as peripheral blood in patients with psoriasis, although its etiological significance is not yet understood. In order to evaluate the cell type responsible for the elevated cytokines in the peripheral blood, we investigated cytokine profiles of the fractionated peripheral blood mononuclear cells (PBMCs) in 30 patients with psoriasis and 27 healthy controls. Without stimulation, higher levels of interleukin (IL)-1beta, IL-6, and IL-8 were produced by freshly isolated PBMCs from the patients than those from the controls. In the fractionated PBMCs, the monocyte-rich fractions were mainly responsible for the production of these cytokines and mRNA. The elevated levels of monocyte-derived cytokine mRNAs decreased following successful treatment with cyclosporin A. Although no correlation was found between the cytokine levels and the psoriasis area and severity index (PASI) scores, patients with arthropathy showed significantly high production levels of IL-1beta, IL-6, and IL-8. These findings suggest that monocytes are the major cell source producing inflammatory cytokines in the peripheral blood of psoriasis, and the increased cytokine levels are related to the coexistent arthropathy rather than the severity of cutaneous lesions.

A high prevalence of cytomegalovirus antigenaemia in patients with moderate to severe chronic plaque psoriasis: an association with systemic tumour necrosis factor alpha overexpression

Microbiological aspects are considered to be of pathophysiological importance in psoriasis, but there has so far been no information regarding cytomegalovirus (CMV) infection. This is of interest due to the high prevalence of latent infection in the general population, the frequent reactivation in inflammatory diseases, and the immunomodulating capacity of CMV. To detect active infection we analysed CMV antigen expression of peripheral blood mononuclear cells (PBMC) from psoriatic patients (n = 30) in comparison with healthy volunteers (n = 65). Using three monoclonal antibodies and immunocytological staining (alkaline phosphatase-antialkaline phosphatase technique), we frequently found CMV antigenaemia in psoriasis (43%) compared with healthy laboratory staff (12%, P < 0. 01) and blood donors (6%, P < 0.001). Clearance of CMV antigenaemia was observed with antipsoriatic treatment. CMV antigenaemia was symptomless, and was associated with seropositivity for anti-CMV IgG but not IgM antibodies, indicating subclinical activation of latent infection. Serological investigations in 85 psoriatic patients gave no evidence for a higher prevalence of latent CMV infection. In psoriatic lesions, CMV DNA was only rarely detected by polymerase chain reaction. As it has been shown that tumour necrosis factor (TNF)-alpha can induce CMV reactivation, we determined TNF-alpha plasma concentrations and mRNA expression in PBMC from psoriatic patients. Elevated TNF-alpha levels were found and correlated with the frequency of CMV antigen-expressing PBMC, suggesting a critical role of TNF-alpha in CMV activation. We speculate that active, subclinical CMV infection may be of pathophysiological importance in psoriasis.

Individual pharmacodynamics assessed by antilymphocyte action predicts clinical cyclosporine efficacy in psoriasis

BACKGROUND

Cyclosporine (INN, ciclosporin) use for psoriasis has been proposed and clinically examined. However, individual variation in cyclosporine efficacy is currently observed. To evaluate individual therapeutic potency of cyclosporine, pharmacodynamic approaches were performed with use of peripheral blood mononuclear cells (PBMCs) from patients with psoriasis.

METHODS

Cyclosporine effects on PBMC-blastogenesis were examined in 33 patients with psoriasis. The drug concentration that gave 50% inhibition of mitogen-stimulated PBMC proliferation in vitro (IC50, in nanograms per milliliter) was evaluated in each patient. Cyclosporine was administered at an initial dose of 5 mg/kg/day, and the dose was tapered for 16 weeks to 3 mg/kg/day. The recovery rate in the psoriasis area and the severity index (PASI) 16 weeks after cyclosporine therapy began was measured.

RESULTS

Cyclosporine IC50 values in 33 patients deviated widely, from 0.1 to 120.6 ng/ml. We classified these patients into two groups on the basis of their PBMC sensitivity to cyclosporine with use of the median cyclosporine IC50 (3.0 ng/ml) of these patients as the cutoff point. The PASI recovery rate after cyclosporine therapy in the patients with high sensitivity was significantly higher than that in the patients with low sensitivity (p < 0.0007). Moreover, a significant negative correlation between the IC50 and the PASI recovery rate was observed in these 33 patients (r = -0.73; p < 0.0001). Blood trough levels and side effects of cyclosporine were not significantly different between the two patient groups.

CONCLUSIONS

The results showed that we could use PBMCs to pharmacodynamically predict the patients with a poor response to cyclosporine therapy. These patients may require larger doses of cyclosporine or alternative approaches to treatment. The patients with PBMCs sensitive to cyclosporine should be evaluated for treatment with smaller doses of the drug to avoid serious side effects.

IL-10 is a key cytokine in psoriasis. Proof of principle by IL-10 therapy: a new therapeutic approach

Overexpression of proinflammatory, type 1 cytokines has been demonstrated in psoriasis and is believed to be of pathophysiological importance. IL-10 is a type 2 cytokine with major impact on immunoregulation, since it inhibits type 1/proinflammatory cytokine formation. Therefore, we investigated its role in psoriasis. We found a relative deficiency in cutaneous IL-10 mRNA expression compared with other inflammatory dermatoses. Interestingly, patients during established antipsoriatic therapy showed higher IL-10 mRNA expression of peripheral blood mononuclear cells than patients before therapy. This suggested that IL-10 may have antipsoriatic capacity. Therefore, we performed a phase 2 pilot trial with subcutaneous IL-10 administration (8 microg/kg/d) over 24 d in three patients. Clinical efficiency measured by objective and subjective parameters was found. Immunosuppressive effects (depressed monocytic HLA-DR expression, TNF-alpha and IL-12 secretion capacity, IL-12 plasma levels, and responsiveness to recall antigens) as well as a shift toward a type 2 cytokine pattern (increasing proportion of IL-4, IL-5, and IL-10 producing T cells, selective increase in IgE serum levels) were observed. Remarkably, IL-10 administration also enhanced the intracutaneous IL-10 mRNA expression. Our investigations demonstrate the major importance of IL-10 in psoriasis and show that IL-10 administration represents a new therapeutic approach. This is the first report on IL-10 therapy for cutaneous disorders.

Immunotherapy of Psoriasis

Background:

Psoriasis is a common inflammatory skin disease, characterized by epidermal keratinocyte hyperproliferation and an inflammatory infiltrate. Current research indicates that epidermal hyperproliferation is, in part, dependent upon the milieu of cytokines and growth factors produced chiefly by T cells within the infiltrate and that the T cells play a central role in the pathogenesis of psoriasis.

Objective:

Recent developments in the treatment of psoriasis are discussed in the context of current understanding of the pathogenesis of this condition.

Conclusion:

Significant advances are being made in the treatment directed against these specific immunologic aberrations. Efficacy of immunosuppressive agents such as cyclosporine, FK506 (tacrolimus), anti-CD4 monoclonal antibodies, and IL-2 fusion-toxin in the treatment of psoriasis underscore its probable immune basis. Highly specific treatment directed against cytokines, angiogenesis, and adhesion molecules remains experimental, but shows promise for safer systemic treatment in the future.