Pathophysiology of cutaneous lupus erythematosus -- novel aspects

In silico Analyses of Skin and Peripheral Blood Transcriptional Data in Cutaneous Lupus Reveals CCR2-A Novel Potential Therapeutic Target

Cutaneous lesions feature prominently in lupus erythematosus (LE). Yet lupus and its cutaneous manifestations exhibit extraordinary clinical heterogeneity, making it imperative to stratify patients with varying organ involvement based on molecular criteria that may be of clinical value. We conducted several in silico bioinformatics-based analyses integrating chronic cutaneous lupus erythematosus (CCLE)-skin and blood expression profiles to provide novel insights into disease mechanisms and potential future therapy. In addition to substantiating well-known prominent apoptosis and interferon related response in both tissue environments, the overrepresentation of GO categories in the datasets, in the context of existing literature, led us to model a “disease road-map” demonstrating a coordinated orchestration of the autoimmune response in CCLE reflected in three phases: (1) initiation, (2) amplification, and (3) target damage in skin. Within this framework, we undertook in silico interactome analyses to identify significantly “over-connected” genes that are potential key functional players in the metabolic reprogramming associated with skin pathology in CCLE. Furthermore, overlapping and distinct transcriptional “hot spots” within CCLE skin and blood expression profiles mapping to specified chromosomal locations offer selected targets for identifying disease-risk genes. Lastly, we used a novel in silico approach to prioritize the receptor protein CCR2, whose expression level in CCLE tissues was validated by qPCR analysis, and suggest it as a drug target for use in future potential CCLE therapy.

Mucocutaneous manifestations in a UK national cohort of juvenile-onset systemic lupus erythematosus patients

OBJECTIVE

To determine whether mucocutaneous manifestations are associated with major organ involvement in a UK national cohort of juvenile-onset SLE (JSLE) patients.

METHODS

JSLE patients (n = 241) from 15 different centres whose diagnosis fulfilled four or more of the ACR criteria were divided into two groups: those with at least one ACR mucocutaneous criterion (ACR skin feature positive) and those without (ACR skin feature negative) at diagnosis. The relative frequency of skin involvement was described by the paediatric adaptation of the 2004 British Isles Lupus Assessment Group (pBILAG-2004) index.

RESULTS

One hundred and seventy-nine patients (74%) had ACR-defined skin involvement with no significant demographic differences compared with those without. ACR skin feature negative patients showed greater haematological (84% vs 67%), renal (43% vs 26%) (P < 0.05) and neurological (16% vs 4%) involvement (P = 0.001). Forty-two per cent of ACR skin feature negative patients had skin involvement using pBILAG-2004, which included maculopapular rash (17%), non-scaring alopecia (15%), cutaneous vasculitis (12%) and RP (12%). ACR skin feature negative patients with moderate to severe skin involvement by pBILAG-2004 showed greater renal and haematological involvement at diagnosis and over the follow-up period (P < 0.05). Higher immunosuppressive drug use in the skin feature negative group was demonstrated.

CONCLUSION

Patients who fulfil the ACR criteria but without any of the mucocutaneous criteria at diagnosis have an increased risk of major organ involvement. The pBILAG-2004 index has shown that other skin lesions may go undetected using the ACR criteria alone, and these lesions show a strong correlation with disease severity and major organ involvement.

Visualization of epidermal and dermal alteration in papulonodular mucinosis by multiphoton microscopy

Papulonodular mucinosis (PM) is a cutaneous clue to the presence and activity of silent lupus erythematosus (LE), but the exact pathogenesis is still under secret. Moreover, the currently available treatments for PM are not satisfactory. To demonstrate the possibility of multiphoton microscopy (MPM) to trace the pathological state of PM and evaluate the treatment efficacy, epidermal and dermal alteration in skin lesion with PM before and after treatment was examined using MPM. Microstructure of epidermis as well as content and distribution of collagen and elastin in dermis were quantified to characterize the pathological states of PM. The results showed significant morphological difference between skin lesion before and after treatment, indicating the possibility of MPM to assess the therapeutic efficacy. With the advancement on MPM miniaturization and enhancement of contrast and depth of imaging, the MPM technique can be applied in in vivo tracking PM formation and progression, and leading the better understanding the PM pathogenesis and mechanism of response to any treatment, helping to establish novel effective therapies for PM.

Cutaneous manifestations of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease of unknown etiology with many clinical manifestations. The skin is one of the target organs most variably affected by the disease. The American College of Rheumatology (ACR) established 11 criteria as a classificatory instrument to operationalise the definition of SLE in clinical trials. They were not intended to be used to diagnose individuals and do not do well in that capacity. Cutaneous lesions account for four of these 11 revised criteria of SLE. Skin lesions in patients with lupus may be specific or nonspecific. This paper covers the SLE-specific cutaneous changes: malar rash, discoid rash, photosensitivity, and oral mucosal lesions as well as SLE nonspecific skin manifestations, their pathophysiology, and management. A deeper thorough understanding of the cutaneous manifestations of SLE is essential for diagnosis, prognosis, and efficient management. Thus, dermatologists should cooperate with other specialties to provide optimal care of SLE patient.

Cutaneous manifestations of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease of unknown etiology with many clinical manifestations. The skin is one of the target organs most variably affected by the disease. The American College of Rheumatology (ACR) established 11 criteria as a classificatory instrument to operationalise the definition of SLE in clinical trials. They were not intended to be used to diagnose individuals and do not do well in that capacity. Cutaneous lesions account for four of these 11 revised criteria of SLE. Skin lesions in patients with lupus may be specific or nonspecific. This paper covers the SLE-specific cutaneous changes: malar rash, discoid rash, photosensitivity, and oral mucosal lesions as well as SLE nonspecific skin manifestations, their pathophysiology, and management. A deeper thorough understanding of the cutaneous manifestations of SLE is essential for diagnosis, prognosis, and efficient management. Thus, dermatologists should cooperate with other specialties to provide optimal care of SLE patient.

Effectiveness of topical calcineurin inhibitors as monotherapy or in combination with hydroxychloroquine in cutaneous lupus erythematosus

BACKGROUND

  Calcineurin inhibitors show potent anti-inflammatory effects and favorable safety profile when used in the treatment of cutaneous lupus erythematosus (CLE).

OBJECTIVE

  The present study investigates the change in clinical parameters of erythema, desquamation and edema, when calcineurin inhibitors are used as monotherapy or in combination with hydroxychloroquine in CLE for a period of 60 days.

METHODS

  18 patients were treated with topical tacrolimus and 20 patients with topical pimecrolimus, as monotherapy or in combination with hydroxychloroquine. Clinical parameters of erythema, desquamation and edema were assessed on a scale from 0 to 3 for erythema and edema and 0 to 2 for desquamation.

RESULTS

  Statistically significant improvement in erythema, desquamation and edema was observed in patients on monotherapy with calcineurin inhibitor and combination treatment with hydroxychloroquine, regardless of disease type. Combination treatment resulted in improvement of edema in 100% of patients, while monotherapy did so in 75% of patients.

CONCLUSIONS

  Topical calcineurin inhibitors enhance the therapeutic effect of systemic agents in cutaneous lupus erythematosus, and result in improvement of the clinical parameters studied.

Clearance deficiency and systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a fairly heterogeneous autoimmune disease. Impaired clearance functions for dying cells may explain accumulation of nuclear autoantigens in various tissues of SLE patients. Our data show that in a subgroup of patients with SLE, apoptotic cells accumulated in the germinal centres of the lymph nodes. Apoptotic material was attached to the surfaces of follicular dendritic cells. Furthermore, we found an accumulation of apoptotic cells in the skin of patients with cutaneous lupus after UV exposure. Granulocytes and monocytes in whole blood of SLE patients showed a reduced uptake of albumin- and polyglobin-coated beads. Furthermore, we analysed sera from SLE patients in migration assays and observed that the attraction signals for macrophages were reduced by sera of approximately 25% of the SLE patients. Analyses of high-affinity DNA binding IgG autoantibodies of SLE patients revealed that those antibodies had gained their DNA reactivity in a germinal centre reaction. We suggest a stepwise maturation from a non-anti-DNA reactive B cell to an anti-dsDNA autoreactive B cell. We conclude that impaired clearance in early phases of apoptosis leads to a secondary necrotic status of the cells. Danger signals are released; modified autoantigens are accessible, favouring an autoimmune reaction.

Low number of regulatory T cells in skin lesions of patients with cutaneous lupus erythematosus

OBJECTIVE

To define the phenotype and function of CD4+,CD25+ regulatory T cells (Treg) in patients with cutaneous lupus erythematosus (CLE), a heterogeneous autoimmune disease characterized primarily by inflammatory skin lesions.

METHODS

The number of Treg in skin specimens obtained from patients with various subtypes of CLE was investigated by immunohistochemical analysis, using anti-Foxp3 and anti-CD4 monoclonal antibodies. Furthermore, characterization of peripheral blood CD4+,CD25+ Treg from normal healthy donors and patients with CLE was carried out by flow cytometry, analyzing the expression of Foxp3 and Treg subpopulations. We also purified CD4+,CD25(high) Treg obtained from patients with CLE and tested the sensitivity of these cells to CD95L-mediated apoptosis.

RESULTS

Quantitative analysis of CD4+ T cells in skin lesions from patients with CLE revealed that the number was similar to that in lesions from patients with other chronic inflammatory diseases, but the number of Foxp3+ Treg in CLE was significantly reduced. There was no correlation between disease subtype and the frequency of Foxp3+ Treg in the skin of patients with CLE. In peripheral blood, no significant differences were observed in the number and phenotype of CD4+,CD25+ Treg or in the sensitivity to apoptosis of CD4+,CD25(high) Treg derived from patients with CLE and those derived from normal healthy donors.

CONCLUSION

These data suggest that an organ-specific abnormality of Treg in the skin underscores the importance of analyzing Treg in the affected tissue. Such a local process might give insight into the pathogenic mechanisms of CLE and differs from a global peripheral dysfunction as reported for patients with a systemic manifestation of the disease.