Monica L. Brown

Pathogenesis of systemic sclerosis

Systemic scleroderma (SSc) is one of the most complex systemic autoimmune diseases. It targets the vasculature, connective tissue-producing cells (namely fibroblasts/myofibroblasts), and components of the innate and adaptive immune systems. Clinical and pathologic manifestations of SSc are the result of: (1) innate/adaptive immune system abnormalities leading to production of autoantibodies and cell-mediated autoimmunity, (2) microvascular endothelial cell/small vessel fibroproliferative vasculopathy, and (3) fibroblast dysfunction generating excessive accumulation of collagen and other matrix components in skin and internal organs. All three of these processes interact and affect each other. The disease is heterogeneous in its clinical presentation that likely reflects different genetic or triggering factor (i.e., infection or environmental toxin) influences on the immune system, vasculature, and connective tissue cells. The roles played by other ubiquitous molecular entities (such as lysophospholipids, endocannabinoids, and their diverse receptors and vitamin D) in influencing the immune system, vasculature, and connective tissue cells are just beginning to be realized and studied and may provide insights into new therapeutic approaches to treat SSc.

Vascular involvement in systemic sclerosis (scleroderma)

Systemic sclerosis (SSc) is an acquired multiorgan connective tissue disease with variable mortality and morbidity dictated by clinical subset type. The etiology of the basic disease and pathogenesis of the systemic autoimmunity, fibrosis, and fibroproliferative vasculopathy are unknown and debated. In this review, the spectrum of vascular abnormalities and the options currently available to treat the vascular manifestations of SSc are discussed. Also discussed is how the hallmark pathologies (ie, how autoimmunity, vasculopathy, and fibrosis of the disease) might be effected and interconnected with modulatory input from lysophospholipids, sphingosine 1-phosphate, and lysophosphatidic acid.

20S-Hydroxyvitamin D3, Noncalcemic Product of CYP11A1 Action on Vitamin D3, Exhibits Potent Antifibrogenic Activity in Vivo

CONTEXT There is no effective treatment for systemic sclerosis and related fibrosing diseases. Recently the action of CYP11A1 on vitamin D(3) was shown to produce biologically active 20S-hydroxyvitamin D [20(OH)D(3)] and 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3). OBJECTIVES Because 20(OH)D(3) is noncalcemic (nontoxic) in vivo at very high doses, we evaluated its antifibrogenic activities both in vitro and in vivo. Because it is further metabolized by CYP11A1, we also tested preclinical utilities of its hydroxyderivatives, especially 20,23(OH)(2)D(3). DESIGN Human dermal fibroblasts from scleroderma and normal donors were used to test the efficiency of hydroxyvitamin D derivatives in inhibiting TGF-β1-induced collagen and hyaluronan synthesis and inhibiting cell proliferation. The in vivo activity of 20(OH)D(3) was tested using bleomycin-induced sclerosis in C57BL/6 mice. RESULTS 20(OH)D(3) and 20,23(OH)(2)D(3) inhibited TGF-β1-induced collagen and hyaluronan synthesis similarly to 1,25(OH)(2)D(3) in cultured human fibroblasts. Also, 20(OH)D(3), 20,23(OH)(2)D(3), and 1,25(OH)(2)D(3) suppressed TGF-β1-induced expression of COL1A2, COL3A1, and hyaluronan synthase-2 mRNA, indicating that they regulate these matrix components at the transcriptional level. 20(OH)D(3), 20,23(OH)(2)D(3), 20,22(OH)(2)D(3), and 17,20,23(OH)(3)D(3) inhibited proliferation of dermal fibroblasts with comparable potency with 1,25(OH)(2)D(3), with 20(OH)D(2) being less active and 1α(OH)D(3) being almost inactive. 20,23(OH)(2)D(3) at 3 μg/kg had no effect on serum Ca(++) or fibroblast growth factor-23 levels and did not cause any noticeable signs of morbidity. 20(OH)D(3) markedly suppressed fibrogenesis in mice given sc bleomycin as demonstrated by total collagen content and hematoxylin and eosin staining of skin biopsies. CONCLUSIONS 20(OH)D(3) is an excellent candidate for preclinical studies on scleroderma, with other CYP11A1-derived products of its metabolism deserving further testing for antibrogenic activity.

Supernatants from culture of type I collagen-stimulated PBMC from patients with cutaneous systemic sclerosis versus localized scleroderma demonstrate suppression of MMP-1 by fibroblasts.

Systemic sclerosis (SSc) is a chronic fibrosing disease characterized by vasculopathy, autoimmunity, and an accumulation of collagen in tissues. Numerous studies have shown that compared to healthy or diseased controls, the peripheral blood mononuclear cells (PBMC) from patients with SSc produce a variety of cytokines or proliferate when cultured with solubilized type I collagen (CI) or constituent α1(II) and α2(I) polypeptide chains. The purpose of this study was to determine whether PBMC isolated from patients with SSc and cultured in vitro with soluble CI elaborated soluble mediators that inhibit the production of collagenase (i.e., matrix metalloproteinase, MMP-1) by fibroblasts. Supernatants of CI-stimulated PBMC from juvenile and adult diffuse cutaneous (dc)SSc patients significantly reduced MMP-1 production by SSc dermal fibroblasts, while supernatants of CI-stimulated PBMC from patients with localized scleroderma (LS) did not. CI-stimulated PBMC culture supernatants from patients with dcSSc in contrast to patients with LS exhibited increased levels of platelet-derived growth factor (PDGF)-AA, PDGF-BB, TNF-α, IL-13, and EGF. Prolonged culture of SSc dermal fibroblasts with recombinant PDGF-BB or IL-13 inhibited the induction of MMP-1 in response to subsequent TNF-α stimulation. These data suggest that therapies aimed at reducing these cytokines may decrease collagen accumulation in SSc, preventing the development of chronic fibrosis.

A fatal presentation of dermatomyositis with facial swelling

Juvenile dermatomyositis (JDM) is the most common inflammatory autoimmune myopathy in children. Most common presentations consist of heliotrophic rash and/or gottrons papules in addition to proximal muscle weakness. A typical presentations have been reported. We present a 13-year-old African American male who presented with a two-week history of bilateral periorbital edema that was unresponsive to glucocorticoids. He had elevated transaminases but no detectable muscle weakness. A muscle biopsy was consistent with juvenile dermatomyositis. This case highlights the need to consider dermatomyositis in cases of facial swelling and the use of aggressive immunosuppressive therapies due to its associated vasculopathies.

Characterization of inhibitory T cells induced by an analog of type II collagen in an HLA-DR1 humanized mouse model of autoimmune arthritis

IntroductionWe used DR1 transgenic mice and covalently linked DR1 multimers to characterize analog-specific inhibitory T cells in collagen-induced arthritis (CIA). Because of the low numbers of antigen-specific T cells in wild-type mice, functional T-cell studies in autoimmune arthritis have been challenging. The use of T-cell receptor (TCR) transgenic mice has provided useful information, but such T cells may not represent the heterogeneous T-cell response that occurs in natural settings. Our focus was to develop tools to identify and characterize the population of immunoregulatory T cells induced in wild-type mice by an analog peptide of CII259-273, which contains amino acid substitutions at positions 263 (N) and 266 (D) (analog peptide A12).MethodsDR1 multimers, developed by loading empty class II molecules with exogenous peptide, provide a method for visualizing antigen-specific T cells with flow cytometry. However, the low binding avidity of A12 for the major histocompatibility complex (MHC) made this strategy untenable. To overcome this problem, we generated DR1 multimers in which the analog peptide A12 was covalently linked, hoping that the low-avidity analog would occupy enough binding clefts to allow detection of the responsive T cells.ResultsStaining with the tetramer revealed that A12-specific T cells were readily detectable at 10 days after immunization. These CD4(+) T cells are a highly selective subset of the TCR repertoire and have a limited clonality. Analysis of cytokine expression showed that cells detected by tetramer (A12) expressed primarily suppressive cytokines (interleukin-4 (IL-4) and IL-10) in response to collagen, compared with control cells. Although they did not express Fox-p3, they were extremely effective in preventing and suppressing inflammatory arthritis.ConclusionsIn summary, our studies showed that the use of covalently linked multimers allows characterization of analog-specific T cells that are otherwise difficult to detect. The suppressive character of the analog-specific T-cell response suggests that these cells attenuate autoimmunity and differ significantly in phenotype from the inflammatory T cells predominantly found in arthritic joints. Such reagents will become powerful tools to study T-cell responses in RA patients in upcoming clinical trials.

A 9-year-old boy with chronic urticaria and progressive spondyloarthritis.

A 9-year-old African American boy presented with chronic urticaria and progressive spondyloarthritis. Laboratory tests were abnormal for persistently positive antinuclear antibodies and undetectable total hemolytic complement (CH50) despite normal levels of complement C2, C3, and C4. Ultimately, further testing revealed an underlying deficiency in the immune system that may be associated with autoimmune disease and thus have a bearing on the patients urticaria and spondyloarthritis. This is a unique presentation of a rare disease and underscores the importance of evaluating for systemic disease in the workup of chronic urticaria.

Autoimmune Features of Wiskott-Aldrich Syndrome: A Case Report

Diffuse alveolar hemorrhage in a pediatric patient requires urgent and aggressive therapy. Here we report a young child with Wiskott-Aldrich syndrome and antiplatelet antibody manifesting as recurrent pulmonary hemorrhage due to pauci-immune capillaritis that was successfully treated with rituximab.

Fever and Rash

revealed a left pleural effusion and left lower lobe atelectasis/consolidation. Fluid obtained from ultrasound-guided thoracentesis had 930 white blood cells/mm with 39% neutrophils, 3% bands, 38% lymphocytes, lactate dehydrogenase 196 IU/L, total protein 2.5 g/dL, pH 8.0, and cultures negative for bacteria. Because of persistent symptoms despite parental doxycycline, ceftriaxone (1 g daily) was added. After 10 days of doxycycline and 7 days of ceftriaxone, his skin rash resolved but he remained febrile (38-40°C) and continued to have generalized fatigue and bilateral lower extremity edema. Serum titers for tick-borne illnesses (Table 1) drawn after 2 weeks of illness were positive for Ehrlichia chaffeensis (immunoglobulin G of 1:512 and immunoglobulin M of 1:80). As no other titers for infectious entities were positive, rifampin was added to treat a possible resistant infection. When fever and proteinuria (4+ proteinuria) persisted despite treatment, the possibility of an underlying systemic illness was entertained. A 24-hour urine specimen was collected that contained 7700 mg (194.2 mg/m/h) protein (Table 1). A renal biopsy was performed, which confirmed the diagnosis of membranous lupus nephritis (International Society of Nephrology/Renal Pathology Society class V) (Figure 3). Other laboratory parameters that supported the diagnosis of systemic lupus erythematosus (SLE) included a positive antinuclear antibody (ANA) titer of 4.79 with a homogenous pattern together with a positive antibody to double-stranded DNA and low serum complement levels (C3 and C4). Taken together, his clinical symptoms and laboratory parameters confirmed the diagnosis of SLE. He was started on prednisone 40 mg twice daily with immediate resolution of his fatigue and fever and a more gradual resolution of the proteinuria and peripheral edema. Case Report