Brief report: Responses to rituximab suggest B cell-independent inflammation in cutaneous systemic lupus erythematosus

Objective The immunopathogenesis of systemic lupus erythematosus (SLE) is heterogeneous, and responses of skin to rituximab are variable. This study was undertaken to determine the phenotype of rituximab-responsive disease. Methods Eighty-two patients with SLE who were receiving rituximab were prospectively studied. Of these patients, 32 had significant skin involvement before or after treatment. Disease activity was assessed using the British Isles Lupus Assessment Group (BILAG) index 2004. Cutaneous lupus subtype was classified by a dermatologist as acute cutaneous lupus erythematosus (ACLE), subacute cutaneous lupus erythematosus (SCLE), chronic cutaneous lupus erythematosus (CCLE), or other skin diseases, with supportive photographs or biopsies where necessary. Results Of 26 patients with skin disease at baseline, 9 (35%) had a beneficial mucocutaneous response to rituximab at 6 months, with good responses in ACLE (6 of 14 patients [43%]), and poor responses in CCLE (0 of 8 patients) (P=0.034). Clinical response was associated with anti-RNP negativity (P=0.024) and anti-Ro negativity (P=0.031). Flares of SCLE and CCLE occurred in 12 patients who either had no skin disease or had ACLE at baseline (i.e., a switch in subtype). Concomitant antimalarials or conventional immunosuppressants were not associated with response or flare rate. Posttreatment biopsies confirmed typical active SLE histology in lesions occurring during B cell depletion. Conclusion Our findings indicate that the clinical response to rituximab in cutaneous manifestations of SLE depends on subtype. None of the CCLE patients responded, and new CCLE lesions were observed during B cell depletion, suggesting that initiation and activity of these lesions is not B cell dependent. Flares of a range of skin diseases after B cell depletion may indicate a change in immune regulation following B cell-targeted therapy

Development of outcome measures for autoimmune dermatoses

Validated outcome measures are essential in monitoring disease severity. Specifically in dermatology, which relies heavily on the clinical evaluation of the patient and not on laboratory values and radiographic tests, outcome measures help standardize patient care. Validated cutaneous scoring systems, much like standardized laboratory values, facilitate disease management and follow therapeutic response. Several cutaneous autoimmune dermatoses, specifically cutaneous lupus erythematosus (CLE), dermatomyositis (DM), and pemphigus vulgaris (PV), lack such outcome measures. As a result, evaluation of disease severity and patients’ response to therapy over time is less reliable. Ultimately, patient care is compromised. These diseases, which are often chronic and relapsing and remitting, are also often refractory to treatment. Without outcome measures, new therapies cannot be systematically assessed in these diseases. Clinical trials that are completed without standardized outcome measures produce less reliable results. Therefore, the development of validated outcome measures in these autoimmune dermatoses is critical. However, the process of developing these tools is as important, if not more so, than their availability. This review examines the steps that should be considered when developing outcome measures, while further examining their importance in clinical practice and trials. Finally, this review more closely looks at CLE, DM, and PV and addresses the recent and ongoing progress that has been made in the development of their outcome measures

Molecular Characterization of the Ro/SS-A Autoantigens

AbstractMolecular techniques have recently revealed that there are several immunologically distinct Ro/SS-A antigens. Three genes encoding putative Ro/SS-A protein antigens with calculated masses of 46, 52, and 60 kD have been isolated. The encoded amino acid sequence of each is quite dissimilar. The 46-kD antigen is calreticulin (CR), a highly conserved calcium-binding protein that resides predominately in the endoplasmic reticulum where it may be involved in protein assembly. Although CR has recently been confirmed to be a new human rheumatic disease-associated autoantigen, its relationship to the other components of the Ro/SS-A ribonucleoprotein has become somewhat controversial owing predominately to the fact that recombinant forms of calreticulin have not displayed the same pattern of autoantibody reactivity possesse by the native form of this protein.The 52-kD antigen most likely resides in the nucleus and may be involved in the regulation of gene expression. The cellular location and function of the 60-kD antigen is uncertain but studies indicate that it is a RNA-binding protein.The 46- and 60-kD antigens share homology with foreign polypeptides, suggesting that an immune response initially directed against a foreign protein may give rise to the autoimmune response directed at cross-reacting self proteins

Interferon and Biologic Signatures in Dermatomyositis Skin: Specificity and Heterogeneity across Diseases

BACKGROUND: Dermatomyositis (DM) is an autoimmune disease that mainly affects the skin, muscle, and lung. The pathogenesis of skin inflammation in DM is not well understood. METHODOLOGY AND FINDINGS: We analyzed genome-wide expression data in DM skin and compared them to those from healthy controls. We observed a robust upregulation of interferon (IFN)-inducible genes in DM skin, as well as several other gene modules pertaining to inflammation, complement activation, and epidermal activation and differentiation. The interferon (IFN)-inducible genes within the DM signature were present not only in DM and lupus, but also cutaneous herpes simplex-2 infection and to a lesser degree, psoriasis. This IFN signature was absent or weakly present in atopic dermatitis, allergic contact dermatitis, acne vulgaris, systemic sclerosis, and localized scleroderma/morphea. We observed that the IFN signature in DM skin appears to be more closely related to type I than type II IFN based on in vitro IFN stimulation expression signatures. However, quantitation of IFN mRNAs in DM skin shows that the majority of known type I IFNs, as well as IFN g, are overexpressed in DM skin. In addition, both IFN-beta and IFN-gamma (but not other type I IFN) transcript levels were highly correlated with the degree of the in vivo IFN transcriptional response in DM skin. CONCLUSIONS AND SIGNIFICANCE: As in the blood and muscle, DM skin is characterized by an overwhelming presence of an IFN signature, although it is difficult to conclusively define this response as type I or type II. Understanding the significance of the IFN signature in this wide array of inflammatory diseases will be furthered by identification of the nature of the cells that both produce and respond to IFN, as well as which IFN subtype is biologically active in each diseased tissue

An Allograft Glioma Model Reveals the Dependence of Aquaporin-4 Expression on the Brain Microenvironment

Aquaporin-4 (AQP4), the main water channel of the brain, is highly expressed in animal glioma and human glioblastoma in situ. In contrast, most cultivated glioma cell lines don’t express AQP4, and primary cell cultures of human glioblastoma lose it during the first passages. Accordingly, in C6 cells and RG2 cells, two glioma cell lines of the rat, and in SMA mouse glioma cell lines, we found no AQP4 expression. We confirmed an AQP4 loss in primary human glioblastoma cell cultures after a few passages. RG-2 glioma cells if grafted into the brain developed AQP4 expression. This led us consider the possibility of AQP4 expression depends on brain microenvironment. In previous studies, we observed that the typical morphological conformation of AQP4 as orthogonal arrays of particles (OAP) depended on the extracellular matrix component agrin. In this study, we showed for the first time implanted AQP4 negative glioma cells in animal brain or flank to express AQP4 specifically in the intracerebral gliomas but neither in the extracranial nor in the flank gliomas. AQP4 expression in intracerebral gliomas went along with an OAP loss, compared to normal brain tissue. AQP4 staining in vivo normally is polarized in the astrocytic endfoot membranes at the glia limitans superficialis and perivascularis, but in C6 and RG2 tumors the AQP4 staining is redistributed over the whole glioma cell as in human glioblastoma. In contrast, primary rat or mouse astrocytes in culture did not lose their ability to express AQP4, and they were able to form few OAPs

Comparison of Pulmonary Involvement Between Patients Expressing Anti-PL-7 and Anti-Jo-1 Antibodies

Anti-PL-7 is an anti-tRNA synthetase antibody, and interstitial lung disease (ILD) is the most frequent complication of anti-PL-7-associated antisynthetase syndrome. However, the features of ILD have not been fully elucidated. The present study retrospectively compares 7 and 15 patients who were positive for anti-PL-7 and anti-Jo-1 antibodies, respectively. The features of ILD did not significantly differ between the two groups, but the ratio of lymphocytes in bronchoalveolar lavage fluid was higher in the Jo-1 than in the PL-7 group. High-resolution computed tomography revealed nonspecific interstitial pneumonia in all patients in the PL-7 group and organizing pneumonia in four of the 15 patients in the Jo-1 group. These findings suggest that pulmonary complications slightly differ between patients expressing anti-PL-7 and anti-Jo-1 antibodies. Further studies are required to clarify the features of ILD associated with PL-7