Skewing of the CD8+ T-cell repertoire in the lungs of patients with systemic sclerosis

Serum Immunoglobulin G (IgG) Subclasses in a Cohort of Systemic Sclerosis Patients

OBJECTIVES

To assess serum immunoglobulin G (IgG) subclasses in a cohort of systemic sclerosis (SSc) patients and to evaluate the influence of IgG subclasses in the main complications of the disease.

METHODS

The serum level of IgG subclasses was evaluated in 67 SSc patients and 48 healthy controls (HC), matched for sex and age. Serum samples were collected and measured IgG1-4 subclasses by turbidimetry.

RESULTS

SSc patients had lower median total IgG [9.88 g/l (IQR 8.18-11.42 g/l) vs. 12.09 g/l (IQR 10.24-13.54 g/l), p < 0.001], IgG1 [5.09 g/l (IQR 4.25-6.38 g/l) vs. 6.03 g/l (IQR 5.39-7.90 g/l), p < 0.001], and IgG3 [0.59 g/l (IQR 0.40-0.77 g/l) vs. 0.80 g/l (IQR 0.46-1 g/l), p < 0.05] serum levels compared to HC. The logistic regression analysis showed IgG3 as the only variable associated with the diffusing capacity of the lung for carbon monoxide (DLco) ≤60% of the predicted [OR 9.734 (CI 95%: 1.312-72.221), p < 0.05] and modified Rodnan skin score (mRSS) [OR 1.124 (CI 95%: 1.019-1.240), p < 0.05], anti-topoisomerase I [OR 0.060 (CI 95%: 0.007-0.535), p < 0.05], and IgG3 [OR 14.062 (CI 95%: 1.352-146.229), p < 0.05] as variables associated with radiological interstitial lung disease (ILD).

CONCLUSION

SSc patients have reduced levels of total IgG and an altered IgG subclass distribution compared to HC. Moreover, SSc patients show different serum IgG subclasses profiles according to the main involvement of the disease.

Contribution of HLA and KIR Alleles to Systemic Sclerosis Susceptibility and Immunological and Clinical Disease Subtypes

Systemic sclerosis (SSc) is an autoinflammatory, fibrotic condition of unknown aetiology. The presence of detectable autoantibodies against diverse nuclear antigens, as well as strong HLA associations with disease, suggest autoimmune involvement, however the links between endogenous and exogenous risk factors and SSc pathology remain undetermined. We have conducted a genetic analysis of HLA inheritance in two independent and meta-analysed cohorts of 1,465 SSc cases and 13,273 controls, including stratified association analyses in clinical and autoantibody positive subgroups of disease. Additionally, we have used patient genotypes to impute gene dosages across the KIR locus, encoding paired activating and inhibitory lymphocyte receptors for Class I HLA ligands, to conduct the largest analysis of KIR-HLA epistatic interactions in SSc to date. We confirm previous Class II HLA associations with SSc risk and report a new Class I association with haplotype HLA-B*44:03-HLA-C*16:01 at genome-wide significance (GWS). We further report statistically significant HLA associations with clinical and serological subtypes of disease through direct case-case comparison, and report a new association of HLA-DRB1*15:01, previously shown to bind topoisomerase-1 derived peptides, with anti-topoisomerase (ATA) positive disease. Finally, we identify genetic epistasis between KIRs and HLA class I ligands, suggesting genetic modulation of lymphocyte activation may further contribute to an individual’s underlying disease risk. Taken together, these findings support future functional investigation into endogenous immunological and environmental stimuli for disrupted immune tolerance in SSc.

Determination of T Cell Responses in Thai Systemic Sclerosis Patients

Objectives

This study is aimed at determining the role of T cells by assessing the numbers of IFN-γ- and IL-2-secreting T cells following stimulation with peptides derived from DNA topoisomerase-I protein in Thai SSc patients.

Methods

Fifty Thai SSc patients and 50 healthy controls (HC) joined this study. IFN-γ and IL-2 levels upon stimulation of T cells with 6 peptides derived from DNA topoisomerase-I protein were determined. Anti-nuclear antibodies (ANA) and anti-Scl-70 antibodies were determined by using the ELISA method.

Results

In SSc patients, we detected a significantly higher number of IFN-γ- and IL-2-secreting CD8⁺ T cells than IFN-γ- and IL-2-secreting CD4⁺ T cells after stimulation with pooled peptides derived from DNA topoisomerase-I protein. A similar percentage of CD4⁺IL-2⁺, CD4⁺IFN-γ⁺, and CD8⁺IL-2⁺ were detected following stimulation with DNA topoisomerase-I protein -in SSc patients with anti-Scl-70 antibody (SSc/anti-Scl-70⁺) and those without. In contrast, the amount of CD8⁺IFN-γ⁺ cells was significantly higher in SSc/anti-Scl-70⁺ than those without. Stimulation with individual peptides showed that CSLRVEHINLHPELD (sPep3; 15 amino acids; position 505-519 of DNA topoisomerase-I protein) was the optimal epitope that induced T cells secreting the highest levels of IFN-γ and IL-2. A higher percentage of IFN-γ⁺CD4⁺ T cells was detected in SSc/anti-Scl-70⁺ than those without the following stimulation with peptides 2 (amino acid position 475-486 [RAVALYFIDKLA] of protein DNA topoisomerase).

Conclusion

The results from this study emphasize the critical role of DNA topoisomerase-I peptides on the activation of T cells in SSc patients. The findings provide a better understanding of SSc's immunopathogenesis and may lead to the development of diagnostic tools and specific treatments for SSc in the future.

Contributions of Immune Cells and Stromal Cells to the Pathogenesis of Systemic Sclerosis: Recent Insights

Systemic sclerosis (SSc) is a multisystem rheumatic disease characterized by vascular dysfunction, autoimmune abnormalities, and progressive organ fibrosis. A series of studies in SSc patients and fibrotic models suggest that immune cells, fibroblasts, and endothelial cells participate in inflammation and aberrant tissue repair. Furthermore, the growing number of studies on single-cell RNA sequencing (scRNA-seq) technology in SSc elaborate on the transcriptomics and heterogeneities of these cell subsets significantly. In this review, we summarize the current knowledge regarding immune cells and stromal cells in SSc patients and discuss their potential roles in SSc pathogenesis, focusing on recent advances in the new subtypes by scRNA-seq.

Longitudinal analysis of T-cell receptor repertoires reveals persistence of antigen-driven CD4+ and CD8+ T-cell clusters in systemic sclerosis

The T-cell receptor (TCR) is a highly polymorphic surface receptor that allows T-cells to recognize antigenic peptides presented on the major histocompatibility complex (MHC). Changes in the TCR repertoire have been observed in several autoimmune conditions, and these changes are suggested to predispose autoimmunity. Multiple lines of evidence have implied an important role for T-cells in the pathogenesis of Systemic Sclerosis (SSc), a complex autoimmune disease. One of the major questions regarding the roles of T-cells is whether expansion and activation of T-cells observed in the diseases pathogenesis is antigen driven. To investigate the temporal TCR repertoire dynamics in SSc, we performed high-throughput sequencing of CD4⁺ and CD8⁺ TCRβ chains on longitudinal samples obtained from four SSc patients collected over a minimum of two years. Repertoire overlap analysis revealed that samples taken from the same individual over time shared a high number of TCRβ sequences, indicating a clear temporal persistence of the TCRβ repertoire in CD4⁺ as well as CD8⁺ T-cells. Moreover, the TCRβs that were found with a high frequency at one time point were also found with a high frequency at the other time points (even after almost four years), showing that frequencies of dominant TCRβs are largely consistent over time. We also show that TCRβ generation probability and observed TCR frequency are not related in SSc samples, showing that clonal expansion and persistence of TCRβs is caused by antigenic selection rather than convergent recombination. Moreover, we demonstrate that TCRβ diversity is lower in CD4⁺ and CD8⁺ T-cells from SSc patients compared with memory T-cells from healthy individuals, as SSc TCRβ repertoires are largely dominated by clonally expanded persistent TCRβ sequences. Lastly, using "Grouping of Lymphocyte Interactions by Paratope Hotspots" (GLIPH2), we identify clusters of TCRβ sequences with homologous sequences that potentially recognize the same antigens and contain TCRβs that are persist in SSc patients. In conclusion, our results show that CD4⁺ and CD8⁺ T-cells are highly persistent in SSc patients over time, and this persistence is likely a result from antigenic selection. Moreover, persistent TCRs form high similarity clusters with other (non-)persistent sequences that potentially recognize the same epitopes. These data provide evidence for an antigen driven expansion of CD4⁺/CD8⁺ T-cells in SSc.

Current perspectives on the role of CD8+ T cells in systemic sclerosis

Despite long-standing recognition of the importance of T cells in systemic sclerosis (SSc; scleroderma), the role of CD8⁺ T cells in disease pathogenesis has not been well studied. Our work has shown that over-production of the pro-fibrotic cytokine IL-13 by peripheral blood effector/memory CD8⁺ T cells is critical for predisposing patients to more severe forms of cutaneous fibrosis. Moreover, IL-13-producing CD8⁺ T cells induce a pro-fibrotic phenotype in normal and SSc dermal fibroblasts, and exhibit a strong cytotoxic activity ex vivo. We also found that CD8⁺ T cells are predominantly abundant in the skin lesions of patients in the early stages of diffuse cutaneous (dc)SSc compare to late-stage disease patients. Isolation of CD8⁺ T cells from the lesional skin of early active dcSSc patients, established that they are skin-resident, express cytolytic molecules and co-express extremely high levels of IL-13 and IFNγ. Other recent studies corroborate these findings and together strongly suggest that CD8⁺ T cells contribute to SSc pathogenesis through the production of high levels of cytokines with pro-inflammatory and pro-fibrotic function as well as by exhibiting a cytotoxic activity.

T and NK Cell Phenotypic Abnormalities in Systemic Sclerosis: a Cohort Study and a Comprehensive Literature Review

Scleroderma (SSc) is a rare and heterogeneous immune-mediated disease involving the connective tissue and microvasculature whose pathogenesis remains unclear. Data concerning T and natural killer (NK) cell abnormalities and cytokine levels in the peripheral blood (PB) from patients with SSc are scarce, and the results are contradictory. The present study aimed to analyze the changes of T lymphocytes, NK cells, and T helper (Th)-related cytokines in the PB of patients with SSc in comparison to healthy individuals and its relation to disease subtype and stage, organ involvement, and nailfold capillaroscopic changes. A non-random convenience sample of 57 scleroderma patients was utilized. Fifty-five out of the 57 patients studied were women (97 %); 10 patients presented pre-scleroderma (pre-SSc) and 47 SSc: 34 limited cutaneous SSc (lcSSc) and 13 diffuse cutaneous SSc (dcSSc). Patients with SSc were classified in early (n = 7), intermediate (n = 10), and late (n = 30) disease. Blood samples were analyzed by flow cytometry for total T cells, CD4+ and CD8+ T cell subsets, total NK cells, and CD56+low and CD56+high NK cell subsets. T cells were further analyzed for the expression of the CD56 adhesion molecule and activation-related markers (HLA-DR, CD45RO). In addition, the serum levels of Th1-, Th2-, and Th17-related cytokines were measured by flow cytometry. Twenty-five healthy individuals recruited from the blood bank were used as controls. Patients had lower numbers of total lymphocytes and T cells comparing to healthy controls. Both CD4+ and CD8+ T cells were decreased, but differences were statistically significant only for CD8+ and CD8+ CD45RO+ T cells. These alterations were seen in patients with SSc but not in patients with pre-SSc, and, in general, they were more pronounced in patients with dcSSc than in patients with lcSSc, in patients with vascular involvement than in those without, as well as in patients having active and late nailfold capillaroscopic patterns. CD56+ T cells were also decreased in SSc patients, especially in those with active/late capillaroscopic patterns or with severe lung disease. Diminished numbers of circulating NK cells were also observed in patients with lcSSc and in those with early disease. No statistically significant changes were found in serum cytokine levels, as compared with controls. Patients with SSc had major alterations in circulating CD8+ and CD56+ T cells, as well as in NK cells, suggesting that these cells may play a relevant role in SSc pathogenesis, probably operating at different phases and/or at different organs. In addition, the serum levels of Th1, Th2, and Th17 cytokines did not provide useful information for evaluating T cell polarization in SSc.

The role of the acquired immune response in systemic sclerosis

Profound alterations characterize the adaptive immune response in systemic sclerosis, and several layers of evidence support a prominent role exerted by immune cellular effectors and humoral mediators in the pathogenesis of this disease. These include (i) the presence of oligoclonal T cells in tissues undergoing fibrosis consistent with (auto)antigen-specific recruitment, (ii) the preferential expansion of polarized CD4+ and CD8+ T cells producing pro-fibrotic cytokines such as IL-4 and IL-13, (iii) the presence of increased number of cells producing mediators belonging to the IL-17 family, including IL-22, which may drive and participate in inflammatory pathways involving epithelial cells as well as fibroblasts, (iv) the deficient or redirected function of T regulatory cells favoring fibrosis, and (v) the enhanced expression of CD19 and CD21 on naïve B cells, and the upregulation of co-stimulatory molecules in mature B cells, which together with the increased levels of B cell activating factor (BAFF) underlie the propensity to an exaggerated humoral response possibly favoring fibrogenesis. Despite all the progress made in understanding the features of the aberrant immune response in scleroderma, it remains unclear whether the activation of immune effector pathways ultimately drives the disease pathogenesis or rather represents a defective attempt to limit or even reverse excessive extracellular matrix deposition and progressive vasculopathy, the main hallmarks of this disease.

Successful treatment of long-term severe progressive interstitial pneumonia with low-dose corticosteroid and azathioprine in a patient with diffuse systemic sclerosis

For progressive interstitial pneumonia (progressive IP) that accompanies diffuse systemic sclerosis (diffuse SSc), no treatment guidelines have yet been established, and it is a complication with a poor prognosis. We herein report a case in which combination therapy of a low-dose corticosteroid and low-dose azathioprine was performed for progressive SSc-IP in a 64-year-old female whose respiratory function was severely damaged for a long period of time and for whom improvement was achieved. The beneficial effect has continued for 3 years with no side effects being observed during the course.

CD8+ T cells in systemic sclerosis

Systemic sclerosis (SSc) is a progressive and highly debilitating autoimmune disorder characterized by inflammation, fibrosis, and vascular damage of the connective tissue. T cell-derived cytokines have been implicated in the induction of fibrosis. We found that high levels of the profibrotic type-2 cytokine IL-13 are produced by peripheral blood effector CD8(+) T cells from SSc patients compared to normal controls. This abnormality correlates with increased expression of the transcription factor GATA-3 and the extent of skin fibrosis. Together, the data provide new insights into SSc pathogenesis and identify a specific T cell phenotype that can be used as a biomarker of immune dysfunction in patients with SSc and as a novel therapeutic target for this currently incurable disease.

Th17 peripheral cells are increased in diffuse cutaneous systemic sclerosis compared with limited illness: a cross-sectional study

Systemic Sclerosis (SSc) is an autoimmune disease characterized by fibrosis and vasculopathy. A key feature is the presence of T cells in inflammatory lesions. To establish the differences in peripheral blood T helper (Th) subpopulations in diffuse cutaneous (dc) and limited cutaneous (lc) SSc patients, blood samples from 57 dcSSc and 78 lcSSc patients were obtained. Controls were collected from healthy volunteers (n = 16), active systemic lupus erythematosus (aSLE) patients (n = 13), and active rheumatoid arthritis (aRA) patients (n = 12). Mononuclear cells were analyzed by flow cytometry to determine Th1 (CD4+/IFN-γ+), Th2 (CD4+/IL-4+), Th17 (CD4+/IL-17+), and regulatory T cells (Tregs; CD4+/CD25+/Foxp3+) subsets. Th17 and Th1 subsets were increased in SSc groups versus healthy controls (P < 0.001) and aSLE patients (P < 0.001 for Th17 and P < 0.008 for Th1). Th2 cells were higher in dcSSc patients than in the healthy and aSLE groups (P = 0.03 and P = 0.009, respectively). Tregs were increased in the aRA group when compared with SSc patients and healthy controls (P ≤ 0.003). Patients with immunosuppressive treatment had lower numbers of Th17 and Th2 cells (P = 0.02). Our results shed further light into the preponderant role of Th17 and Th1 in patients with SSc. However, these findings certainly deserve to be studied in depth.

The pathogenesis of systemic sclerosis

Systemic sclerosis (SSc), also known as scleroderma, is a rare connective tissue disease characterized by vascular and immune dysfunction, leading to fibrosis that can damage multiple organs. Its pathogenesis is complex and poorly understood. Two major clinical subtypes are the limited and diffuse forms. Research into SSc has been hampered by its rarity, its clinical heterogeneity, and the lack of mouse models that accurately recapitulate the disease. Clinical and basic studies have yielded some mechanistic clues regarding pathogenesis. Recent insights gained through the use of microarrays have revealed distinctive subsets of SSc within and beyond the limited and diffuse subsets. In this review, we discuss potential mechanisms underlying the vascular, autoimmune, and fibrotic points of dysregulation. Proper categorization of SSc patients for research studies by use of microarrays or other biomarkers is critical, as disease heterogeneity may explain some of the inconsistencies of prior studies.

Fibrosis and immune dysregulation in systemic sclerosis

Autoimmune and inflammatory phenomena are characteristically present in systemic sclerosis (SSc) and impact on dysregulated fibroblast extracellular matrix deposition, hallmark of the disease in conjunction with fibroproliferative vasculopathy. Oligoclonal T helper 2-like cells are present in the skin and peripheral blood in early diffuse disease. Type 2 cytokines synergize with profibrotic cytokines including transforming growth factor beta, favoring collagen deposition and metalloproteinase inhibition by fibroblasts. Furthermore, chemokine with pro-fibrotic and pro-angiogenic properties are preferentially produced by fibroblasts under the influence of Th2-like cells. The profibrotic monocyte chemotactic protein 1 is also produced by fibroblasts, partially in response to Toll-like receptor 4 (TLR4) recognition, when autoantibodies (autoAb) bind to fibroblast surface. In addition, immune-complex formed by autoAb and ubiquitous antigens including topoisomerase-1 favor the production of interferon-alpha (IFN-α) possibly by interacting with intravesicular TLRs. Consistent with this findings, unbiased gene screening has revealed that SSc peripheral blood cells express genes induced by IFN-α, a characteristic shared with systemic lupus erythematosus and other autoimmune disorders. These findings highlight the complex relationship between adaptive and acquired immune responses, which may participate to the pathogenesis of SSc in manners until now unsuspected, which may help in identifying novel therapeutic targets.

Polymyositis/dermatomyositis and interstitial lung disease: A new therapeutic approach with T-cell-specific immunosuppressants

Interstitial lung disease (ILD) is a common complication of polymyositis (PM) and dermatomyositis (DM), and accounts for a significant proportion of their morbidity and mortality because of the resistance to therapeutic agents including corticosteroids. Its pathogenic mechanism is not known, but several studies have provided findings implicating that T-cells, especially activated CD8+ cells, may play essential roles, and thus could be therapeutic targets in this disease. To test this hypothesis, we began clinical investigation of the efficacy of T-cell-specific immunosuppressants, cyclosporine (CsA) and FK506, in PM/DM patients with ILD. In our retrospective nationwide multi-center study compiling a total of 53 patients, a combination of CsA and corticosteroids resulted in favorable early and long-term outcome in the majority of patients except for DM patients with acute ILD. In this subset, those who received the combination as an initial therapy had better survival than those who initially received corticosteroids alone. FK506 has a similar mode of action but is up to 100-fold more potent than CsA in vitro, and has been used in more refractory ILD cases. We next reviewed 5 PM/DM patients with ILD who failed on various immunosuppressants including CsA and were subsequently treated with FK506 in our hospital, and found that 3 improved promptly, 1 gradually and steadily, and another case responded slowly after prednisolone dose was increased. None developed adverse effects. In summary, these T-cell targeted therapies have a potential to be the cornerstone of the treatment for ILD in PM/DM patients. The combination therapy with CsA and corticosteroids may be efficacious especially when used early. FK506 may be advantageous even in refractory cases to CsA. These findings indicate that further investigation is warranted. Currently, prospective investigation of FK506 is underway.

T cells, B cells, and polarized immune response in the pathogenesis of fibrosis and systemic sclerosis

PURPOSE OF REVIEW

A better comprehension of the interactions between cells of the adaptive immune system with fibroblasts and endothelial cells is required to understand abnormal extracellular matrix deposition, development of pathologic fibrosis, and vasculopathy.

RECENT FINDINGS

Skin T cells with high IL-4 production potential and peripheral blood T cells preferentially expressing chemokine receptors associated with Th2 functions are found in individuals with active systemic sclerosis. Animal models indicate that Th2 cells and IL-13 can induce muscular hypertrophy in pulmonary arterial vasculature. In bleomycin-induced fibrosis, B cells produce fibrogenic cytokines upon interaction of an endogenous ligand (hyaluronan) with toll-like receptor-4. In the sclerodermatous graft versus host model, the lack of tumor necrosis factor-production by CD4+ T cells is permissive for fibrosis development. Dermal fibrosis and capillary loss typical of systemic sclerosis can be reversible after high-dose immunosuppression and hematopoietic stem cell transplantation.

SUMMARY

Although immunosuppressive strategies to treat patients with systemic sclerosis and allied conditions are largely disappointing, thus indicating a permissive rather than causative role of immunoinflammatory events characteristic of the disease, new findings stress that cells of the adaptive immune system play important roles in assisting fibrogenesis and vascular abnormalities. This may help in identifying efficacious strategies aimed at their control.

Scleroderma gene expression and pathway signatures

Gene expression studies in scleroderma have shown large and consistent changes in the gene expression of end-target tissues. These changes reflect the lymphocyte infiltration and pathway deregulation potentially linked to disease pathogenesis. Gene expression in scleroderma also reflects the clinical heterogeneity in the disease and can be used to categorize patients. Contained within these gene expression signatures are groups of genes that could serve as biomarkers for clinical end points and disease activity. The use of mechanism-derived gene expression signatures in scleroderma will provide a better understanding of the deregulated pathways contributing to disease pathogenesis.

The immunobiology of systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by vascular damage, autoimmunity, and excessive collagen deposition. Despite advances in disease-specific treatment of other rheumatologic diseases, disease-targeted treatment in SSc continues to be elusive. In this review, our goal was to place the contemporary immunobiology of SSc in the perspective of clinical medicine.

METHODS

We performed a PubMed search for the period from 1989 to 2007, using the keyword, "systemic sclerosis," resulting in a total of 9099 publications, including 1252 reviews. Articles were then selected based on their discussion of recent advances in the elusive pathogenesis of SSc. A final total of 259 articles were chosen for the review.

RESULTS

The SSc hallmarks of vascular damage, immunologic activation, and collagen deposition can be traced to 4 major factors: T-cells, fibroblasts, B-cells, and cytokines/chemokines. T-cells are a major component of the infiltrate in skin and lung, exhibiting increased expression of activation markers and showing signs of antigen-driven expansion. Preliminary data indicate that induction of oral tolerance with collagen, a target of SSc T-cell responses, is associated with clinical benefits. Although this suggests that T-cells participate in the pathogenesis of SSc, their precise role and antigen specificity largely remain to be elucidated. Defective numbers and functions of certain T-cell subsets, such as natural killer and gammadelta T-cells, may be involved in the failure to maintain tolerance. Other data suggest that gammadelta T-cells may themselves be effector cells in endothelial cell cytotoxicity. There are several lines of evidence for a pathogenic role of B-cells in SSc, in particular, through the production of autoantibodies. Antibody-dependent cell-mediated cytotoxicity is a primary pathogenic event in an animal model of SSc and is likely to be involved in human SSc. Nonetheless, there is as yet no convincing evidence for the pathogenicity of SSc-specific antibodies. SSc fibroblasts exhibit a specific phenotype characterized not only by excessive collagen production but also by increased responsiveness to and production of cytokines and chemokines. This phenotype is induced by a complex network of cytokines and chemokines but appears to be maintained in the absence of exogenous stimuli via the autocrine production of some of these factors by SSc fibroblasts themselves, particularly transforming growth factor, platelet-derived growth factor, monocyte chemoattractant protein 1, and interleukin-1.

CONCLUSIONS

Significant variations in laboratory data among patients suggest that the pathology reflects a heterogeneous disease. Nonetheless, the possibility of achieving clinical benefits by inducing oral tolerance highlights the importance of characterizing SSc T-cell antigens. It is hoped that the identification of some of the key players in the induction and maintenance of the SSc fibroblast phenotype may yield new disease-targeted treatment regimens for patients with SSc.

Autoimmunity in systemic sclerosis: current concepts

Systemic sclerosis (SSc) is characterized by tissue fibrosis, obliterative microangiopathy, and immune abnormalities. The role of autoimmunity in generating the clinical and pathologic phenotype in SSc remains uncertain. Distinct subsets of antinuclear antibodies are selectively associated with unique disease manifestations but do not have a proven pathogenic role. A new class of autoantibodies recognizing cellular or extracellular matrix antigens has been recognized in SSc patients. They seem to directly activate pathways that may contribute to SSc-specific tissue and vascular damage. Data confirms that activation and polarization of T cells can contribute to a profibrotic environment. Also, activated immune effector cells can promote vascular obliterative damage through direct cytotoxic pathways targeting the endothelium or by inducing proinflammatory molecules. Technologies are emerging to accurately measure the autoantigen-specific T-cell response in SSc patients. Perturbed B-cell homeostasis has been reported in SSc. If confirmed in-vivo, these advances could lead to new disease-modifying therapeutic strategies directed at SSc-specific immune effector pathways.

Update on pathophysiology of scleroderma with special reference to immunoinflammatory events

Scleroderma or systemic sclerosis (SSc) is a complex disease in which the vasculopathy and the activation of the immune system with production of inflammatory mediators lead to dysregulated fibroblast activation. The resulting excessive deposition of collagens and other extracellular matrix proteins ends in fibrosis and organ dysfunction. The cause is unknown, but environmental factors are thought to play a role by triggering abnormal responses in genetically susceptible hosts. The recent past has witnessed important advances in the definition of mechanisms that underlie the persistent activation in fibroblasts of genes involved in uncontrolled fibrosis, a hallmark of SSc. These include the preferential production of type 2 T cell cytokines in target organs, the presence of autoantibodies with fibroblast-activating capacities, the production of vasoconstrictive mediators that impact on fibroblast biosynthetic properties, the transforming growth factor-beta-related metabolic signature, and the presence of altered signaling pathways in fibroblasts. Furthermore, while no animal models recapitulate all the features of SSc, they have been instrumental for assessing the relevance of specific processes to the development of fibrosis. More importantly, some of the research findings are leading to therapies that target altered processes with the potential of changing the prognosis of some dismal aspects of the disease.

Scleroderma Lung

The lungs are frequently involved in systemic sclerosis ('scleroderma'), a rare, disabling disease of unknown origin, characterised by skin thickening and Raynaud's phenomenon. The pathogenesis of scleroderma is complex, but signs and symptoms of excessive fibrosis, vasculopathy and inflammation are almost universally present. Dyspnoea in scleroderma patients can be due to chest wall tightening from skin thickening, pleural disease, cardiac involvement, myositis of intercostal muscles, or so-called scleroderma lung disease. Scleroderma lung disease encompasses vascular (pulmonary artery hypertension) or interstitial lung disease, or both. A comprehensive work-up is required to delineate the underlying cause of dyspnoea in a scleroderma patient, and to establish the contribution of each component to the symptoms. This should include a 6-minute walk test, pulmonary function testing, high-resolution thoracic CT scanning, ECG, echocardiography and, if pulmonary artery hypertension is suspected, right-heart catheterisation; bronchoalveolar lavage is optional. Lung disease in scleroderma contributes significantly to excess morbidity and early mortality, especially when diffusion capacity drops below 40% and/or forced vital capacity below 50%. However, recent clinical studies have unequivocally demonstrated that scleroderma lung disease is amenable to treatment with new vasodilatory drugs that target specific pathways involved in vasoconstriction, or with cyclophosphamide for interstitial lung disease. Uncontrolled studies have suggested that these therapies also have an impact on survival, but controlled studies with a long follow-up are needed to corroborate this point.

Peripheral T lymphocytes from patients with early systemic sclerosis co-cultured with autologous fibroblasts undergo an oligoclonal expansion similar to that occurring in the skin

In recent years several reports have suggested that T cells may have a role in systemic sclerosis (SSc). The aim of our study was to investigate the dynamics of T cell repertoire in early SSc disease analysing a target organ, the skin, and the peripheral blood. To date, indeed, it is not clear if T cell expansions found in SSc reflect a general activation or result from specific antigen stimulation in the target organs. This is an important point to assess in order to characterize the role of T cells in the development of SSc. To address these questions we studied T cell repertoire by CDR3 length analysis in skin biopsies and peripheral blood obtained from patients affected by SSc and we found that a skewed T cell repertoire was present only in the biopsies. In order to characterize more effectively the meaning of these data, we performed co-cultures using fibroblasts and peripheral blood mononuclear cells (PBMCs) obtained from SSc patients. These experiments showed that same T cell expansions were detectable in the skin of SSc patients and in the cultures of PBMCs and autologous fibroblasts of the patients but not in their peripheral blood. Taken together, these data suggest that fibroblasts trigger specific T cell expansions in the early phase of SSc.

T cells and B cells in the pathogenesis of systemic sclerosis: recent insights and therapeutic opportunities

Among the earliest pathologic events in systemic sclerosis (SSc) is the infiltration of mononuclear cells into the skin lesion. This inflammatory cell infiltration precedes the development of fibrosis, suggesting an integral role for the presence of these cells in the fibrotic events observed in the lesion. However, immunosuppressive therapies that are effective in other autoimmune disease have not been successful in the treatment of SSc, making the clinical management of this disease very difficult. The aim of this paper is to review the latest findings regarding the activation and the functional polarization of T cells and their role in the pathogenesis of SSc. Furthermore, the potential role of B cells, a hitherto scantily investigated inflammatory cell in SSc, is discussed. Understanding the interplay between T and B cells, and the processes that promote the fibrotic cytokine pattern seen in these patients is of utmost importance for the development of effective therapies to treat the clinical complications.

Signatures of differentially regulated interferon gene expression and vasculotrophism in the peripheral blood cells of systemic sclerosis patients

OBJECTIVE

To obtain a global view of the immunological alterations occurring in early systemic sclerosis (SSc) by transcriptional profiling of peripheral blood cells (PBCs).

METHODS

Oligonucleotide microarrays were used to compare PBC gene expression profiles in 18 SSc cases (<2 yr duration) and 18 controls matched for race, gender and ethnicity. SSc cases had no prior or current exposure to cytotoxic drugs. PAXgene tubes were used to stabilize RNA during phlebotomy. Changes in gene expression were independently validated by real-time polymerase chain reaction.

RESULTS

SSc PBCs demonstrated differential expression of 18 interferon-inducible genes. Six of these genes were identical to the interferon signature genes in lupus peripheral blood mononuclear cells. Notably, SSc PBCs also had increased expression of allograft inflammatory factor (AIF1) and several selectins and integrins involved in cellular adhesion to the endothelium. Global analysis of 284 known biological pathways revealed that 13 were differentially regulated in SSc PBCs, including two pathways (IL2RB and GATA3) that lead to T(H)2 polarization.

CONCLUSIONS

Transcriptional profiling reliably discriminates between PBCs from SSc and normal donors despite the fact that they represent a heterogeneous cell population. Multiple biological pathways were differentially regulated in SSc PBCs, but a common thread across these pathways was alterations in protein tyrosine kinase 2beta and mitogen-activated protein kinase signalling. Although the SSc PBC gene expression profile demonstrated some parallels with the lupus interferon gene signature, there was also increased expression of transcripts encoding proteins that target PBCs to the endothelium, which might be relevant to the vasculopathy of SSc.

T cell repertoire in patients with stable scleroderma

At onset of systemic sclerosis (SSc), T cells have been found to oligoclonally expand in the skin, presumably in response to auto-antigens, but the T cell repertoire has not been evaluated at a later stage. To determine whether a perpetuating immune response contributes to the pathogenesis of stable SSc, the T cell repertoire was analysed in patients with diffuse (d) or limited (l) SSc, and compared to patients with primary Raynaud's phenomenon (RP) or healthy volunteers (Ctrl). The T cell repertoire (total, CD4 or CD8 sorted blood T cells) was analysed by qualitative and quantitative immunoscope (14 BV families analysed) in 11 untreated dSSc and 11 untreated lSSc, 10 RP and 11 Ctrl. To better detect in vivo activated cells, repertoire analysis was also performed on sorted CD4 T cells after in vitro culture with IL-2. In parallel, 6 skin biopsies from SSc patients were analysed. After 7-8 years of disease evolution, SSc patients did not show detectable clonal T cell expansions in the skin, even after tentative expansion from the biopsy with IL-2. Total T cell, sorted CD4 and CD8 T cell repertoires from the blood of patients with SSc did not show significant perturbation as compared to patients with RP and Ctrl. After IL-2 culture for 7 days, blood CD4 T cells from the patients did not preferentially expand as compared to RP and Ctrl. These findings suggest that antigen-driven immune responses may play a lesser role in established SSc than at disease onset.

Increased CD8+ T cell apoptosis in scleroderma is associated with low levels of NF-kappa B

Our objectives were (1) to compare lymphocyte subpopulation apoptosis rates in SSc patients versus healthy controls and (2) to compare Bcl-2 and NF-kappa B expression in cultured CD8 lymphocytes of SSc patients versus controls. Peripheral blood samples were obtained from 27 SSc patients meeting the American College of Rheumatology criteria for SSc and 28 healthy individuals. Mononuclear cells were isolated by Ficoll-Hypaque density gradient separation and cultured for 48 hr. For determination of apoptosis within specific cell populations, samples were labeled with PE-conjugated monoclonal antibody to CD8, CD4, and a FITC-conjugated monoclonal antibody to Annexin V. Flow cytometry was carried out with a FACS operating with Cellquest software. CD8+ lymphocytes were positively selected with magnetic microbeads conjugated to antihuman CD8. CD8 T cells were separated, then incubated with activation for 48 hr, and NF-kappa B and Bcl-2 analysis was carried out using Western immunoblotting. The CD4:CD8 ratio was increased in SSc compared to controls (2.6 +/- 1.13 vs.1.87 +/- 0.76; P = 0.018). The spontaneous apoptosis rate of SSc CD8 lymphocytes was increased compared to that of controls of (21.9 +/- 13.7 vs. 13.3 +/- 9.9; P = 0.019). No difference was found in the rate of CD4 apoptosis of SSc patients versus controls (9.8 +/- 5.2 vs. 7.18 +/- 4.89%; P = ns). The expression of NF-kappa B in SSc CD8 lymphocytes was decreased compared with that of CD8 lymphocytes from healthy controls (144 +/- 13 vs. 188 +/- 11; P = 0.018). Whereas expression of Bcl-2 was similar in activated CD8+ T cells of SSc patients and healthy controls, CD8+ T cell apoptosis rate was found to be in reverse correlation with expression of NF-kappa B in these cells ( r = - 0.53, P = 0.029). The increased CD4:CD8 ratio in SSC may result from increased CD8+ T cell apoptosis. Increased SSc CD8 T cell apoptosis is associated with low levels of NF-kappa B.

Autologous stem cell transplantation in the treatment of systemic sclerosis: report from the EBMT/EULAR Registry

OBJECTIVE

To analyse the durability of the responses after haematopoietic stem cell transplantation (HSCT) for severe systemic sclerosis (SSc) and determine whether the high transplant related mortality (TRM) improved with experience. This EBMT/EULAR report describes the longer outcome of patients originally described in addition to newly recruited cases.

METHODS

Only patients with SSc, treated by HSCT in European phase I-II studies from 1996 up to 2002, with more than 6 months of follow up were included. Transplant regimens were according to the international consensus statements. Repeated evaluations analysed complete, partial, or non-response and the probability of disease progression and survival after HSCT (Kaplan-Meier).

RESULTS

Given as median (range). Among 57 patients aged 40 (9.1-68.7) years the skin scores improved at 6 (n = 37 patients), 12 (n = 30), 24 (n = 19), and 36 (n = 10) months after HSCT (p<0.005). After 22.9 (4.5-81.1) months, partial (n = 32) or complete response (n = 14) was seen in 92% and non-response in 8% (n = 4) of 50 observed cases. 35% of the patients with initial partial (n = 13/32) or complete response (n = 3/14) relapsed within 10 (2.2-48.7) months after HSCT. The TRM was 8.7% (n = 5/57). Deaths related to progression accounted for 14% (n = 8/57) of the 23% (n = 13/57) total mortality rate. At 5 years, progression probability was 48% (95% CI 28 to 68) and the projected survival was 72% (95% CI 59 to 75).

CONCLUSION

This EBMT/EULAR report showed that response in two thirds of the patients after HSCT was durable with an acceptable TRM. Based on these results prospective, randomised trials are proceeding.

Cytokine regulation of pulmonary fibrosis in scleroderma

Pulmonary fibrosis occurs in up to 70% of scleroderma patients and progresses to cause severe restrictive lung disease in about 15% of patients. The mechanisms that cause pulmonary fibrosis in scleroderma remain incompletely understood. Increased amounts of mRNA or protein for multiple profibrotic cytokines and chemokines have been identified in lung tissue or broncholveolar lavage samples from scleroderma patients, when compared to healthy controls. These cytokines include transforming growth factor (TGF)-beta, connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), oncostatin M (OSM), monocyte chemotactic factor-1 and pulmonary and activation-regulated chemokine (PARC). Potential cellular sources of these profibrotic cytokines and chemokines in scleroderma lung disease include alternatively activated macrophages, activated CD8+ T cells, eosinophils, mast cells, epithelial cells and fibroblasts themselves. This review summarizes the literature on involvement of cytokines and chemokines in the development of pulmonary fibrosis in scleroderma.

High-dose immunosuppressive therapy and autologous progenitor cell transplantation for systemic sclerosis

High-dose immunosuppressive therapy aimed at immunoablation, given together with autologous stem cell transplantation, has resulted in prolonged (>3 years) improvements of skin thickening and functional ability, together with a stabilization of pulmonary function in two-thirds of treated patients with severe systemic sclerosis. Transplant-related mortality occurred in 17% of the first cohort of 41 patients reported to the European Group for Blood and Marrow Transplantation, which included cases from the United States, but this figure has dropped to 8.7% in a recent retrospective analysis of 57 transplants performed in Europe. Similar outcomes were reported in multicentre studies from the United States of 19 patients, and from France of 12 patients, with improvements in skin scores and functional assessments, together with a stabilization of internal organ dysfunction. Based on the results of these phase I/II studies, multicentre prospective randomized trials are being planned or are in progress in Europe and the United States employing uniform patient entry criteria and outcome parameters. The aim of these studies is to compare the clinical benefits and safety of transplant regimens versus conventional chemotherapy in patients with severe systemic sclerosis who are at risk of life-threatening organ failure and premature mortality. Eligibility criteria include a diagnosis of diffuse systemic sclerosis of recent onset and major organ (heart, kidney, lungs) involvement according to predefined criteria. The prospective randomized trials address two issues related to the treatment of severe systemic sclerosis: is intensive immunosuppressive therapy superior to conventional therapy, and can self-tolerance be re-established?

Occurrence of an activated, profibrotic pattern of gene expression in lung CD8+ T cells from scleroderma patients

OBJECTIVE

Pulmonary fibrosis is a major cause of death in scleroderma patients. Previous studies have shown an increase in CD8+ T cells in the lungs of scleroderma patients. In the present study, we sought to determine whether activated CD8+ T cells contribute to pulmonary fibrosis in scleroderma patients through the production and activation of profibrotic mediators.

METHODS

CD8+ cells were isolated from bronchoalveolar lavage fluid obtained from 19 scleroderma patients and 7 healthy subjects. The phenotype of these cells was determined using DNA array technology. Expression of selected genes was confirmed in real-time polymerase chain reaction and enzyme-linked immunosorbent assay experiments.

RESULTS

Hierarchical clustering of gene expression profiles revealed 2 groups of subjects. Group 1 consisted of 11 patients (8 with and 3 without lung inflammation). Group 2 consisted of 15 subjects (7 healthy controls and 2 patients with and 6 without lung inflammation). Gene expression in group 1 indicated T cell activation, a type 2 phenotype, production of profibrotic factors and matrix metalloproteinases, and reduced activation-induced cell death. Increased expression of beta6 integrin messenger RNA by CD8+ T cells in group 1 suggested the possibility that these T cells might induce cell-contact-dependent activation of latent transforming growth factor beta (TGFbeta).

CONCLUSION

A subset of scleroderma patients at higher risk of progressive lung disease have activated, long-lived CD8+ T cells in their lungs that could promote fibrosis directly, through production of profibrotic factors such as interleukin-4 and oncostatin M, as well as indirectly, through activation of TGFbeta.

Identification of oligoclonal CD4 T cells in diffuse large B cell lymphomas

Human B cell lymphomas often contain CD4 T cells. Here we show that, in diffuse large B cell lymphomas (DLCL), such T cells are oligoclonal. The CDR3 lengths and nucleotide sequences of oligoclonal TCRBV of CD4 T cells in an original and relapsed lymphoma from one patient were compared. Three BV23 sequences were identical (12/17 and 16/16 clones in primary and relapsed lymphomas, respectively), but were absent in CD4 T cells from another patient's DLCL. Two of the repetitive BV23 sequences were found in peripheral blood CD4 T cells (5/17 clones); gamma-irradiated DLCL from this patient stimulated syngeneic BV23 response in CD4 cells (92% of BV23 had the same CDR3 length). Skew in TCRBV representation was observed in CD4 T cells from all the DLCL. One DLCL, with overrepresentation of BV13S1 in CD4 cells, stimulated the same TCR in CD4 cells from three unrelated individuals. These findings support the conclusion that there is clonal selection of CD4 T cells in DLCL.

Systemic sclerosis: current views of its pathogenesis

Systemic sclerosis (SSc) is an autoimmune disorder of unknown etiology characterized by severe and often progressive cutaneous and visceral fibrosis, pronounced alterations in the microvasculature, and numerous cellular and humoral immune abnormalities. Clinically, SSc is very heterogeneous, encompassing a spectrum ranging from mild limited forms of skin sclerosis with minimal internal organ involvement to severe skin and multiple internal organ fibrosis. Mortality and morbidity in SSc are very high and are directly related to the extent of the fibrotic and microvascular alterations. A better understanding of the pathogenesis of this incurable disorder will help to better target and design effective therapy in the future.

Epidemiology and pathogenesis of scleroderma

Scleroderma is a heterogenous connective tissue disorder characterized by fibrosis of the skin, with or without internal organ involvement. The aetiology of scleroderma may involve both environmental and genetic factors. Abnormalities involving the immune system, vascular tissue and extracellular matrix have been demonstrated. Recent research has focused on microchimerism as a risk factor for the development of scleroderma. This article reviews the epidemiology and pathogenesis of this disorder.

Abnormal expression of intracellular cytokines and chemokine receptors in peripheral blood T lymphocytes from patients with systemic sclerosis

In patients with systemic sclerosis (SSc), there are conflicting findings regarding which is predominant between type 1 and type 2 immune responses. To determine the balance between type 1 and type 2 T lymphocytes in peripheral blood from SSc patients, we investigated the expression of intracellular cytokines, such as interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, and IL-13, and chemokine receptors such as CXCR3 and CCR4 by flow cytometry. The frequency of IFN-gamma-producing cells among CD8+ cells was significantly increased in patients with diffuse cutaneous SSc (n = 11, P < 0.0001) and limited cutaneous SSc (lSSc; n= 16, P < 0.0001) compared with normal controls (n = 17) while there was no significant difference in the frequency of IL-4- or IL-13-producing cells. In contrast, the frequency of IFN-gamma- or IL-4-producing cells among CD4+ cells was similar between the three groups. Similar results were obtained when absolute numbers were assessed. The frequency of IFN-gamma-producing cells among CD8+ cells inversely correlated with percentage DLco in SSc patients (r = - 0.650, P < 0.005). CXCR3+ CD8+ cells selectively produced IFN-gamma, and the frequency of CXCR3+ CD45RO+ cells among CD8+ cells was higher in lSSc patients (n = 14, P < 0.01) than in normal controls (n = 22). In contrast, there was no significant difference in the frequencies of CXCR3- or CCR4-expressing CD45RO+ cells among CD4+ cells. These results demonstrate the predominance of type 1 cytokine-producing cells (Tc1 cells) in peripheral blood CD8+ T cells from SSc patients, but no definite Th1/Th2 imbalance in CD4+ T cells. Tc1 cells may be associated with pulmonary vascular damage in SSc.

Gene expression in bronchoalveolar lavage cells from scleroderma patients

The hypothesis of this study is that activation of cell-mediated immunity with associated macrophage activation occurs in the lungs of scleroderma patients with lung inflammation. Gene expression profiles were determined in bronchoalveolar lavage (BAL) cells from scleroderma patients with and without lung inflammation and control subjects, using DNA array technology. Enzyme-linked immunosorbent assay was used to measure proteins in BAL fluids. Gene expression profiles were similar in BAL cells from patients without lung inflammation and control subjects. Gene expression profiles in patients with lung inflammation showed increased expression of chemokines and chemokine receptor genes, which would lead to migration of T cells, especially type 2 T cells, and phagocytic cells. Protein levels of pulmonary and activated-response chemokine and monocyte chemoattractant protein-1 were elevated. Other changes in gene expression suggested alterations in gene transcription, cell cycle control, vesicle transport, antigen-presenting function, and intracellular signaling. Two anti-inflammatory cytokines, interleukin-1 receptor antagonist and transforming growth factor-beta1, had increased expression, consistent with other human fibrotic lung diseases and animal models of lung fibrosis. These findings suggest recruitment of T cells and chronic macrophage activation in scleroderma patients at greater risk for lung fibrosis, but differ from typical delayed-type hypersensitivity responses, without prominence of type 1 T cells and inflammatory cytokines.

Oligoclonal T cell expansion in the skin of patients with systemic sclerosis

Fibrosis, microvascular fibroproliferative alterations, and autoantibody production are the main features of systemic sclerosis (SSc), and all of them can be explained by cytokine production by activated T cells. However, little is known about the role of T cells in the pathogenesis of SSc, and there is no information on the Ag(s) that elicits such activation. To determine whether T cells infiltrating the skin biopsies of patients with SSc are oligoclonal, beta-chain TCR transcripts from T cells infiltrating the skin of five patients with SSc of recent onset were amplified by either Vbeta-specific PCR or nonpalindromic adaptor PCR. The resulting PCR products were subsequently cloned and sequenced. High proportions of identical beta-chain TCR transcripts ranging from 43 to 90% of those sequenced were found in five patients, strongly suggesting the presence of oligoclonal T cells in these infiltrates. A dominant T cell clone was found to be clonally expanded in skin biopsies obtained from a single patient with SSc at three different times (0, 8, and 13 mo earlier) and from three different skin regions. beta-chain TCR transcripts from PBMC from normal donors (methodological control) were unique when compared with each other, typical for polyclonal populations of T cells. The finding of oligoclonal T cells infiltrating the skin of patients with SSc suggests that these T cells have undergone proliferation in situ in the skin and clonal expansion in response to as yet unidentified Ag(s). These results suggest that T cells are involved in the pathogenesis of the disease.

Evaluation and management of pulmonary fibrosis in scleroderma

Pulmonary fibrosis causes significant morbidity and mortality in patients with scleroderma. Lung inflammation identifies patients at greater risk for decline in forced vital capacity and diffusing capacity for carbon monoxide. Factors that are increased in patients with scleroderma with lung fibrosis include connective tissue growth factor, KL-6, pulmonary surfactant-D, tissue inhibitor of metalloproteinase 2, monocyte chemotactic protein-1, macrophage inhibitory protein-1 alpha, soluble interleukin-6 receptors, anti-endothelial cell antibodies, and anti-DNA topoisomerase I antibodies. Potential mechanisms of lung damage in scleroderma include increased production of profibrotic type 2 cytokines and abnormal signaling by thrombin of tenascin-C production by lung fibroblasts, with protein kinase C epsilon as an intermediate in the signaling pathway. Treatment of scleroderma lung disease with cyclophosphamide may have a beneficial effect on pulmonary function and survival. Lung transplantation provides a therapeutic option for patients with scleroderma with end-stage lung disease.

Phase I/II trial of autologous stem cell transplantation in systemic sclerosis: procedure related mortality and impact on skin disease

BACKGROUND

Systemic sclerosis (SSc, scleroderma) in either its diffuse or limited skin forms has a high mortality when vital organs are affected. No treatment has been shown to influence the outcome or significantly affect the skin score, though many forms of immunosuppression have been tried. Recent developments in haemopoietic stem cell transplantation (HSCT) have allowed the application of profound immunosuppression followed by HSCT, or rescue, to autoimmune diseases such as SSc.

METHODS

Results for 41 patients included in continuing multicentre open phase I/II studies using HSCT in the treatment of poor prognosis SSc are reported. Thirty seven patients had a predominantly diffuse skin form of the disease and four the limited form, with some clinical overlap. Median age was 41 years with a 5:1 female to male ratio. The skin score was >50% of maximum in 20/33 (61%) patients, with some lung disease attributable to SSc in 28/37 (76%), the forced vital capacity being <70% of the predicted value in 18/36 (50%). Pulmonary hypertension was described in 7/37 (19%) patients and renal disease in 5/37 (14%). The Scl-70 antibody was positive in 18/32 (56%) and the anticentromere antibody in 10% of evaluable patients. Peripheral blood stem cell mobilisation was performed with cyclophosphamide or granulocyte colony stimulating factor, alone or in combination. Thirty eight patients had ex vivo CD34 stem cell selection, with additional T cell depletion in seven. Seven conditioning regimens were used, but six of these used haemoimmunoablative doses of cyclophosphamide +/- anti-thymocyte globulin +/- total body irradiation. The median duration of follow up was 12 months (3-55).

RESULTS

An improvement in skin score of >25% after transplantation occurred in 20/29 (69%) evaluable patients, and deterioration in 2/29 (7%). Lung function did not change significantly after transplantation. One of five renal cases deteriorated but with no new occurrences of renal disease after HSCT, and the pulmonary hypertension did not progress in the evaluable cases. Disease progression was seen in 7/37 (19%) patients after HSCT with a median period of 67 (range 49-255) days. Eleven (27%) patients had died at census and seven (17%) deaths were considered to be related to the procedure (direct organ toxicity in four, haemorrhage in two, and infection/neutropenic fever in one). The cumulative probability of survival at one year was 73% (95% CI 58 to 88) by Kaplan-Meier analysis.

CONCLUSION

Despite a higher procedure related mortality rate from HSCT in SSc compared with patients with breast cancer and non-Hodgkin's lymphoma, the marked impact on skin score, a surrogate marker of mortality, the trend towards stabilisation of lung involvement, and lack of other treatment alternatives justify further carefully designed studies. If future trials incorporate inclusion and exclusion criteria based on this preliminary experience, the predicted procedure related mortality should be around 10%.

Pulmonary T cell repertoire in patients with graft-versus-host disease following blood and marrow transplantation

Pulmonary inflammation is one of the risk factors associated with blood and marrow transplantation (BMT). To determine the potential role of T cells in pulmonary complications after transplantation, we analyzed the T-cell repertoire expressed in bronchoalveolar lavage fluids from eleven patients with graft-versus-host disease following BMT. A reverse transcriptase-polymerase chain reaction was used to amplify rearranged TCR transcripts in unfractionated, CD4+, and CD8+ T cells from bronchoalveolar lavage fluids. The relative expression of TCR variable (V) gene families and the diversity of junctional region lengths associated with different AV and BV gene families were analyzed. Nearly all TCR AV and BV gene families were detected in bronchoalveolar lavage cells from BMT recipients. Oligoclonal patterns of TCR junctional region lengths were observed in unfractionated, CD4+, and CD8+ bronchoalveolar T cells. The oligoclonal expansion of bronchoalveolar T cells in patients was confirmed by DNA sequencing. TCRV gene expression is almost completely restored in the lungs of BMT recipients as early as two weeks after transplantation. Increased oligoclonality among TCR gene families suggests either an incomplete restoration of TCR diversity or an antigen-driven expansion of T cells in the lungs of BMT recipients with graft-versus-host disease, not necessarily related to pulmonary infection.

Production of type 2 cytokines by CD8+ lung cells is associated with greater decline in pulmonary function in patients with systemic sclerosis

OBJECTIVE

This study addresses the hypothesis that a profibrotic pattern of cytokines is produced in the lungs of patients with systemic sclerosis (SSc) and causes fibrosis.

METHODS

Using a reverse transcriptase-polymerase chain reaction technique, interleukin-4 (IL-4), IL-5, and interferon-gamma (IFNgamma) messenger RNA (mRNA) were measured in unseparated CD8+ and CD4+ bronchoalveolar lavage (BAL) cells from SSc patients and healthy controls. To confirm the results, CD8+ T cells were cloned from BAL fluids, and the pattern of cytokine mRNA made by these cells was determined. Serial pulmonary function tests were done.

RESULTS

BAL cells from healthy controls made IFNgamma mRNA, with no or little IL-4 or IL-5 mRNA. In contrast, BAL cells from the majority of SSc patients made IL-4 and/or IL-5 mRNA, with or without approximately equal amounts of IFNgamma mRNA. This pattern of cytokines was made by CD8+ T cells, which were increased in the lungs of these SSc patients. Patients whose BAL cells made this type 2 pattern of cytokine mRNA had a significant decline in forced vital capacity over time after the BAL, whereas patients whose BAL cells made IFNgamma mRNA alone did not. Both wild-type and an alternative splice variant of IL-4 mRNA were increased in BAL cells from SSc patients. Both forms of IL-4 stimulated alpha2(I) collagen mRNA in human dermal and lung fibroblasts.

CONCLUSION

The type 2 pattern of cytokine mRNA produced by BAL cells from SSc patients differs from unopposed IFNgamma production found in healthy BAL cells. This production of type 2 cytokine mRNA by CD8+ T cells is associated with a significant decline in lung function over time, which suggests a pathologic role for these T cells in interstitial fibrosis in SSc.

T-cell receptor gene usage in patients with fibrosing alveolitis and control subjects

BACKGROUND

Fibrosing alveolitis is characterized by inflammation, fibrosis and increased numbers of activated CD4+ T-cells in the lower respiratory tract. The aims of this study were to compare the T-cell antigen receptor repertoire in the lungs of subjects with fibrosing alveolitis systemic sclerosis (FASSc) with cryptogenic fibrosing alveolitis (CFA) and normal control subjects, to determine whether FASSc is driven by a specific T-cell trigger and is determined by a T-cell driven immune response, and to assess the clonality of CD4+ and CD8+ TcR usage in subjects with FASSc.

MATERIALS AND METHODS

We used reverse transcription polymerase chain reaction with specific V alpha- and V beta-chain primers to identify the TcR gene usage in biopsy material, bronchoalveolar lavage fluid or peripheral blood from our subjects.

RESULTS

We found individual-specific restriction of V alpha- and V beta-chain usage in lung biopsies from patients and control subjects. To establish whether this was due to expression bias in the CD4+ or CD8+ T-cells and was restricted to the lung, the alpha beta-T-cell receptor chain usage was assessed in T-cell subsets separated from the lungs of patients with fibrosing alveolitis and was compared with that of the peripheral blood. There was no consistent difference in the expression of any variable family chain among the population studied, although there was a significant difference between lung and peripheral blood lymphocyte V beta-families in CD8+ T-cells (P = 0.0007).

CONCLUSION

We conclude that there is individual TcR V alpha- and V beta-expression bias in subjects with fibrosing alveolitis.

Changes in integrin/adhesion molecule expression, but not in the T-cell receptor repertoire, in old mice infected with tuberculosis

The results of this study present data in support of the hypothesis that T lymphocytes in both young and old mice infected with virulent Mycobacterium tuberculosis undergo changes in expression of cell surface integrin/adhesion molecules as determined by flow cytometric analysis. These data thus further support the hypothesis that a reduced ability of T-cells in old mice to adequately and promptly accumulate at sites of inflammation induced by bacterial implantation is a central parameter underlying the increased susceptibility of these mice to this intracellular bacterial infection. In addition, however, no changes were observed in terms of the T-cell receptor expression (repertoire) of these animals, indicating that this facet of immunity is preserved in aging.

T-Cell repertoire in the blood and lungs of atopic asthmatics before and after ragweed challenge

T cells play a pivotal role in initiating and orchestrating allergic responses in asthma. The goal of this work was to learn whether ragweed challenge in the lungs alters the T-cell repertoire expressed in the blood and lungs of atopic asthmatics. Analyses of cell numbers, differentials, and T-cell subsets in bronchoalveolar lavage (BAL) fluids showed that ragweed challenge was associated with preferential recruitment of CD4+ T cells into the lungs. A reverse transcriptase-polymerase chain reaction (RT-PCR) was used to amplify T-cell receptor (TCR) gene transcripts from unfractionated, CD4+, and CD8+ T cells in blood and BAL fluids. As judged by RT-PCR, the usage of TCR Valpha and Vbeta gene families in BAL fluids was similar to that in blood. Ragweed challenge did not change the levels of expression of these V gene families. The clonality of T cells was estimated by analyzing the diversity of TCR V-(D)-J junctional region nucleotide lengths associated with each Valpha and Vbeta gene family, using sequencing gel electrophoresis. Most V gene families in blood and BAL fluids were associated with multiple junctional region lengths before and after ragweed challenge, indicating polyclonal expression. Some V gene families were expressed in an oligoclonal manner in unfractionated, CD4+, and CD8+ T cells in BAL fluids before ragweed challenge, as indicated by a few predominant junctional region lengths. The majority of these V gene families became polyclonal after challenge, compatible with polyclonal T-cell influx during inflammation immediately after ragweed challenge. However, some V gene families became oligoclonal or developed a new oligoclonal pattern of junctional region lengths in BAL T cells after ragweed challenge. Surprisingly, this occurred in both CD4+ and CD8+ T cells. In one of these instances, DNA sequencing of Vbeta21 junctional regions in CD8+ T cells confirmed a change from polyclonal to oligoclonal expression after ragweed challenge. These findings show that ragweed challenge is associated with polyclonal influx and oligoclonal activation of both CD4+ and CD8+ T cells in the lungs.