The Presence of HLA-A Bw4-80I KIR Ligands Could Predict “Difficult-to-Treat” Psoriasis and Poor Response to Etanercept

Clinical pharmacokinetics and pharmacodynamics of oral systemic nonbiologic therapies for psoriasis patients

INTRODUCTION

Psoriasis is a chronic inflammatory immune condition. Treatments for psoriasis vary with disease severity, ranging from topicals to systemic biologic agents. The pharmacokinetic (PK) and pharmacodynamic (PD) properties of these therapies establish drug efficacy, toxicity, and optimal dosing to ensure therapeutic drug levels are sustained and adverse effects are minimized.

AREAS COVERED

A literature search was performed on PubMed, Google Scholar, and Ovid MEDLINE for PK and PD, efficacy, and safety data regarding oral systemic nonbiologic therapies utilized for moderate-to-severe plaque psoriasis. The findings were organized into sections for each drug: oral acitretin, methotrexate, cyclosporine, apremilast, tofacitinib, and deucravacitinib.

EXPERT OPINION

Some psoriasis patients may not respond to initial therapy. Ongoing research is evaluating genetic polymorphisms that may predict an improved response to specific medications. However, financial and insurance barriers, as well as limited genetic polymorphisms correlated with treatment response, may restrict the implementation of genetic testing necessary to personalize treatments. How well psoriasis patients adhere to treatment may contribute greatly to variation in response. Therapeutic drug monitoring may help patients adhere to treatment, improve clinical response, and sustain disease control.

Genetic Influence on Treatment Response in Psoriasis: New Insights into Personalized Medicine

Psoriasis is a chronic inflammatory disease with an established genetic background. The HLA-Cw*06 allele and different polymorphisms in genes involved in inflammatory responses and keratinocyte proliferation have been associated with the development of the disease. Despite the effectiveness and safety of psoriasis treatment, a significant percentage of patients still do not achieve adequate disease control. Pharmacogenetic and pharmacogenomic studies on how genetic variations affect drug efficacy and toxicity could provide important clues in this respect. This comprehensive review assessed the available evidence for the role that those different genetic variations may play in the response to psoriasis treatment. One hundred fourteen articles were included in this qualitative synthesis. VDR gene polymorphisms may influence the response to topical vitamin D analogs and phototherapy. Variations affecting the ABC transporter seem to play a role in methotrexate and cyclosporine outcomes. Several single-nucleotide polymorphisms affecting different genes are involved with anti-TNF-α response modulation (TNF-α, TNFRSF1A, TNFRSF1B, TNFAIP3, FCGR2A, FCGR3A, IL-17F, IL-17R, and IL-23R, among others) with conflicting results. HLA-Cw*06 has been the most extensively studied allele, although it has only been robustly related to the response to ustekinumab. However, further research is needed to firmly establish the usefulness of these genetic biomarkers in clinical practice.

Infliximab modifies regulatory T cells and co-inhibitory receptor expression on circulating T cells in psoriasis

BACKGROUND

Psoriasis is a T cell-mediated autoimmune skin disease. Accumulating evidence has demonstrated that co-inhibitory receptors (CIRs) play a vital role in regulating T cell-mediated immune response, especially in neoplasm and autoimmunity. However, the immuno-function of CIRs in the development of psoriasis remains unclear.

OBJECTIVE

We investigated the expression of CIRs on the circulating T lymphocytes of psoriasis patients before and after anti-tumor necrosis factor-α (TNF-α) therapy.

METHODS

We enrolled 17 patients with moderate-to-severe plaque psoriasis, 17 patients with mild plaque psoriasis, and 18 healthy controls in this study. Fourteen of the moderate-to-severe psoriasis patients were treated with infliximab, a monoclonal antibody against TNF-α. Peripheral blood was collected, and peripheral blood mononuclear cells were extracted. The proportion of T cell subsets along with their expression of CIRs, namely T cell immunoreceptor with Ig and ITIM domains (TIGIT), lymphocyte activating gene 3 (LAG-3), cytotoxic T-lymphocyte associated protein 4 (CTLA-4), B and T lymphocyte-associated protein (BTLA), endothelial protein C receptor (PROCR), podoplanin (PDPN), programmed cell death 1 (PD-1), and T cell immunoglobulin mucin family containing molecule 3 (TIM-3), were determined by flow cytometric assay.

RESULTS

The moderate-to-severe plaque psoriasis patients had less circulating Tregs, which increased after infliximab treatment. They also had decreased TIGIT, LAG-3 but increased PDPN expression on peripheral CD4⁺ T cells. Infliximab enhanced TIGIT, LAG-3, CTLA-4 but reduced PROCR expression on circulating CD4⁺ T cells. Remarkably, both the frequency of circulating Tregs and the expression level of TIGIT on CD4⁺ T cells at baseline (pre-treatment) negatively correlated with the extent of PASI score reduction benefited from infliximab therapy.

CONCLUSION

Anti-TNF-α therapy increased the frequency of Tregs and TIGIT, LAG-3, CTLA-4 expression but reduced PROCR expression on circulating CD4⁺ T cells in psoriasis patients. The baseline proportion of Tregs and the expression level of TIGIT on circulating CD4⁺ T cells might serve as predictive markers for the degree of disease remission benefited from infliximab treatment.

HLA Correlations with Clinical Phenotypes and Risk of Metabolic Comorbidities in Singapore Chinese Psoriasis Patients

INTRODUCTION

Psoriasis is a systemic, chronic inflammatory disease that not only afflicts the skin but is also associated with cardiovascular disease and metabolic syndrome. The strongest susceptibility loci for the disease is within the human leukocyte antigen (HLA) complex, though specific HLA allelic associations vary between populations.

OBJECTIVE

Our objective was to investigate HLA associations with clinical phenotypes of psoriasis and metabolic syndrome in Chinese psoriasis cases.

METHODS

We conducted an observational case-control study in Singapore with a cohort of psoriasis cases consecutively recruited from an outpatient specialist dermatological center (n = 120) compared with 130 healthy controls.

RESULTS

Significant HLA associations with psoriasis were observed with HLA-A*02:07, B*46:01, C*01:02, and C*06:02. The three-locus haplotype of A*02:07-C*01:02-B*46:01 was also significant (odds ratio [OR] 3.07; p = 9.47 × 10^-5). We also observed an association between nail psoriasis and HLA-A*02:07 carriers (OR 4.50; p = 0.002), whereas C*06:02 carriers were less prone to have nail involvement (OR 0.16; p = 0.004). HLA-A*02:07 was also identified as a possible risk allele for hypertension (OR 2.90; p < 0.05), and C*01:02 was a possible risk allele for dyslipidemia (OR 3.36; p < 0.05), both known to be common comorbidities in patients with psoriasis.

CONCLUSION

Our results demonstrate the growing importance of discerning population-specific clinical phenotypes and their association with certain HLA alleles in psoriasis.

Reduced Efficacy of Biological Drugs in Psoriatic Patients with HLA-A Bw4-80I KIR Ligands

BACKGROUND

Biological drugs (biologics) are a highly effective therapy for the moderate to severe form of psoriasis, an immune-mediated dermatosis with a strong immunogenetic component. The interaction between human leukocyte antigen (HLA) class I ligands and killer immunoglobulin-like receptors (KIR) has a functional significance in the education of natural killer (NK) cells, and can thus influence the response to biologics.

OBJECTIVE

In this study, we investigated the impact of HLA-A and -B KIR ligands in the response to biologics in a cohort of psoriatic patients.

METHODS

Eighty-five patients with moderate to severe psoriasis treated with biologics (adalimumab, etanercept, infliximab, ustekinumab and secukinumab) were enrolled in the study. Clinical response was evaluated as patients attaining 50%, 75% or 90% reduction in the Psoriasis Area and Severity Index (PASI) (PASI 50, 75 or 90, respectively) over 6 months' follow-up. Poor response was defined as PASI 50, and in this case patients shifted to treatment with a different biologic. Fifty-two patients (61.2%) showed excellent response (PASI 90) to the first biologic, while 33 patients (38.8%), needed two or more biologics before reaching an excellent response (PASI 90) and were considered difficult to treat.

RESULTS

Only HLA-A Bw4-80I ligands were associated with the response to biologics; in particular, they were linked with reduced response both at univariable analysis (odds ratio [OR] 3.11, 95% confidence interval [CI] 1.19-8.07; p = 0.019) and multivariable analysis (OR 5.02, 95% CI 1.40-17.97; p = 0.013).

CONCLUSION

We suggest that the HLA-A Bw4-80I epitope could be a marker of reduced responsiveness to biologics. The possible reason for this is an increase of tumour necrosis factor (TNF)-α and the silencing of NK cells through the predominant interaction with the KIR3DL/S pair. HLA-KIR affinities might lead to a more efficient way to prescribe biologics.

Reinforcing involvement of NK cells in psoriasiform dermatitis animal model

Psoriasis (Ps) is a chronic inflammatory immune-mediated disease with skin and joint manifestations, characterized by abnormal and rapid proliferation of keratinocytes and infiltration of psoriatic lesions with immune cells. Extensive literature suggests that Ps is a T-cell mediated disease its pathogenesis being highly related to innate and adaptative immune cells. Although natural killer (NK) cells are involved in the inflammatory process of Ps through pro-inflammatory cytokine secretion (tumor necrosis factor α, interferon γ), their role in this pathology is not yet fully elucidated. In order to study the involvement of NK subpopulations in the pathogenesis of Ps we used the imiquimod-based mouse model of psoriasiform dermatitis and NK cells complex phenotype patterns from peripheral blood (PB) and spleen were investigated. Skin inflammation and the disease severity were assessed using in vivo measurements (erythema, desquamation and induration parameters, PASI modified score), splenomegaly assessment and histopathological evaluation. Phenotypic characterization of NK cells in imiquimod (IMQ)-treated mice was performed by flow cytometry, for both PB and spleen cell suspension. A large panel of surface markers was used: maturation and activation markers [cluster of differentiation (CD)49b, CD11b, CD43, CD27, KLRG1, CD335, CD69, CD28, gp49R, CD45R, CD11c] and markers for cytokine receptors (CD25, CD122, CD132). Our experimental data showed important differences in IMQ-treated mouse NK cell phenotype as compared to control group. The maturation markers (CD11b, CD43, CD27, KLRG1) were found increased on NK cells, in periphery and spleen, while CD49b⁺NK1.1⁺ was significantly lower, and the alterations correlated with the severity of the disease. Our findings reflect the immune engagement toward activatory profile of NK cells and draw attention to evaluating Ps intensity correlated with the mature profile of circulating NK cells.

Relationship between human leukocyte antigen DRB1 and psoriasis in Iraqi patients

Objectives:

To investigate the role of Human leukocyte antigen (HLA) Class II DRB1 in susceptibility to psoriasis in Iraqi patients.

Methods:

A cross-sectional comparative study including 40 patients with psoriasis attending the Department of Dermatology, Al-Kindy teaching hospital in Baghdad, Iraq, between September 2013-2015. Patient selection was carried out by the dermatologists. Ninety healthy individuals were included in the study. Human leukocyte antigen genotyping was carried out by the sequence specific oligonucleotide (SSO) method using Auto LiPA 48 (Innogenetics, Belgium) in the HLA typing research unit of the Al-Kindy College of Medicine, Baghdad, Iraq.

Results:

There is an increased frequency of HLA-DRB1*0102, *0306 in psoriatic patients with psoriasis p-values=0.001, confidence interval(CI)=2.492-37.487 and odds ratio(OR)=9.666. Human leukocyte antigen-DRB1*1101 is significantly associated with plaque-type psoriasis with p=0.0434, CI=1.04-1.69, and OR=4.2. Human leukocyte antigen-DRB1*0102 is significantly associated with other types of psoriasis with p=0.018, CI=0.0223-0.701, and OR=0.125.

Conclusion:

Human leukocyte antigen-DRB1*0102 and *0306 are significantly associated with psoriasis. Human leukocyte antigen-DRB1*1101 is significantly associated with plaque-type psoriasis. Human leukocyte antigen-DRB1*0102 is significantly associated with other types of psoriasis rather than plaque-type psoriasis.

Treating a Multidrug-Resistant Psoriatic HLA-C*18:01 Allele Carrier with Combination Ustekinumab Apremilast Therapy

BACKGROUND

Nowadays, even though several biologic therapies are available to treat psoriasis, multidrug-resistant disease continues to be a therapeutic challenge. Combination therapy has therefore become increasingly important. In this context, apremilast, according to its safety profile, could easily be combined with biologics in patients with comorbidities and/or recalcitrant multidrug-resistant psoriasis.

OBJECTIVE

Our goal is to share experience from our institution in the observation of a patient with severe chronic plaque psoriasis that was unresponsive to all anti-tumor necrosis factor-α treatment and to an anti-interleukin (IL)-17A drug and only partially responsive to ustekinumab, even in combination with apremilast. The patient carried a rare allele infrequently found in Caucasian people: human leukocyte antigen (HLA)-C*18:01. This allele has been found to be positively associated with psoriasis in Brazilian patients.

METHODS

The patient was typed for the HLA-C locus at high resolution via polymerase chain reaction sequence-specific oligonucleotide probes (PCR-SSOP) using a commercial kit (LAB^®Type, One Lambda Inc., Canoga Park, CA, USA).

RESULTS

Our patient, previously described as having multidrug-resistant psoriasis, commenced ustekinumab and apremilast combination therapy. After 12 weeks, the Psoriasis Area Severity Index score had worsened, and we suspended combination therapy because the patient reported an absence of any benefit and was experiencing side effects from the induction therapy with apremilast.

CONCLUSIONS

Expanding on the previously reported experience with this patient, we conclude that HLA-C*18:01 probably indicates a severe, recalcitrant, multidrug-resistant psoriasis phenotype for which proper therapy remains to be identified.