Peripheral CD4+ cell prevalence and pleuropulmonary manifestations in systemic lupus erythematosus patients

The interplay between rheumatic diseases and pulmonary health

Patients with rheumatic diseases (RDs) are prone to a number of comorbidities, particularly those affecting the respiratory system due to inflammatory and autoimmune mechanisms. Rheumatoid arthritis (RA), systemic sclerosis (SSc), and inflammatory idiopathic myopathies (IIMs) often present with progressive interstitial lung disease (ILD). The prevalence of ILD varies among patients with RDs, with 11% in RA, 47% in SSc, and 41% in IIMs. Some diagnostic markers, including KL-6, cytokines TNF-α and IL-6, and autoantibodies (anti-CCP), play a crucial role in assessing and predicting the course of pulmonary involvement in RDs. Lung fibrosis is a progressive disorder in SSc and RA, limiting the effiency of therapeutic interventions. Re-evaluating treatment approaches with disease-modifying anti-rheumatic drugs (DMARDs) is crucial for understanding their impact on the risk of lung affections. Despite initial concerns surrounding methotrexate, recent evidence points to its benefits in RA-associated interstitial lung disease (RA-ILD). Recognizing the intricate relationship between autoimmune RDs and lung affections is crucial for formulating effective treatment strategies. Emphasis is placed on collaborative efforts of rheumatologists and pulmonologists for early diagnosis, comprehensive care, and optimal patient outcomes in RA-ILD.

Why is a paediatric respiratory specialist integral to the paediatric rheumatology clinic?

Systemic connective tissue diseases (CTDs) are characterised by the presence of autoantibodies and multiorgan involvement. Although CTDs are rare in children, they are associated with pulmonary complications, which have a high morbidity and mortality rate. The exact pathophysiology remains unclear. The pleuropulmonary complications in CTD are diverse in their manifestations and are often complex to diagnose and manage. The most common CTDs are discussed. These include juvenile systemic lupus erythematosus, juvenile dermatomyositis, juvenile systemic sclerosis, Sjögren's syndrome and mixed connective tissue disease. We describe the clinical features of the pleuropulmonary complications, focusing on their screening, diagnosis and monitoring. Treatment strategies are also discussed, highlighting the factors and interventions that influence the outcome of lung disease in CTD and pulmonary complications of treatment. Early detection and prompt treatment in a multidisciplinary team setting, including respiratory and rheumatology paediatricians and radiologists, is paramount in achieving the best possible outcomes for these patients.

Correlation of the levels of DNA-binding inhibitor Id3 and regulatory T cells with SLE disease severity

E proteins, a subset of basic helix-loop-helix (bHLH) proteins, are transcription activators and their functions are inhibited by DNA-binding inhibitor (Id) 1-4. Studies have shown that Treg levels are decreased in Id3 knockout mice. Mice over-expressing Id1 in CD4 T cells possessed a greater number of regulatory T cells (Treg) and exhibited attenuated experimental autoimmune encephalomyelitis (EAE). The significance of Id proteins in human systemic lupus erythematosus (SLE) remains unclear. In this study, we systematically analyzed Id transcription in naïve, memory CD4 cells and regulatory T cells in peripheral blood mononuclear cells (PBMCs) in patients with active or inactive SLE. In parallel, Treg subsets in PBMCs were analyzed using different strategies. Id expression levels were correlated with Treg numbers as well as clinical indicators. We found that Id genes expressed in human peripheral CD4 cells were mainly Id2 and Id3. Id3 levels were significantly elevated in CD4⁺CD25^hi T cells of patients with active SLE. Likewise, Id3 levels were positively correlated with increased CD4⁺FoxP3⁺ and CD4⁺Helios⁺FoxP3⁺ Treg cells in these patients. Id3 levels were found to be positively correlated with erythrocyte sedimentation rate (ESR), lupus anticoagulant (LAC), ribosomal antibody and SLE Disease Activity Index (SLEDAI) in patients with active SLE. Mice overexpressing Id1 in CD4⁺ T cells possessed significantly higher Treg levels in spleen and lower autoantibody concentrations in serum. Our results suggest that during the pathogenesis of SLE, up-regulation of Id3 can promote Treg differentiation to play an inhibitory effect on autoimmune responses.

Effect of IL-21 on the Balance of Th17 Cells/Treg Cells in the Pathogenesis of Graves' Disease

Graves' disease (GD) is a common organ-specific autoimmune disease, and its pathogenesis is still unclear. The aim of this study is to investigate the role of interleukin (IL)-21 in the regulation of Th17/Treg cells in GD. We recruited 28 newly diagnosed GD patients, 27 GD patients in remission (eGD), and 24 normal controls (NC). Thyroid function and autoantibodies were evaluated by electrochemical luminescence. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured with or without recombinant human interleukin-21 (rhIL-21), and mRNA and protein levels were quantified by real-time PCR and ELISA, respectively. Compared with those in the eGD and control groups, the thyroid function indexes and autoantibodies levels were significantly different in the GD group (P < 0.05). Without rhIL-21 stimulation, the expression levels of retinoid-related orphan gamma t (RORγt), IL-17, IL-22, forkhead box protein P3 (Foxp3) and IL-10 mRNA and the IL-10 and IL-22 proteins were significantly higher in the GD group than those in the eGD and control groups (P < 0.05). rhIL-21 stimulation increased the RORγt, IL-17, and IL-22 mRNA levels and IL-22 protein levels and decreased the Foxp3 and IL-10 mRNA levels and IL-10 protein levels (P < 0.05) in the GD group. In conclusion, our analyses demonstrated that IL-21 might induce the differentiation of CD4⁺ T cells to Th17 cells and reduce Treg cell differentiation, which could contribute to activation of the downstream immune response and the pathogenesis of GD.

Peripheral CD4+ T-cell changes in connective tissue diseases

Connective tissue diseases (CTDs) are all characterized by changes in the adaptive immune system. In the last few decades several CD4 + T lymphocytes and their products have been associated with the development, progression, organ involvement, or therapeutic response of different CTDs. The T helper (Th) T-cell subsets are easy to measure in the peripheral blood, however changes are difficult to interpret. This review summarizes data about Th1/Th2/Th17 and regulatory T-cell (Treg) changes in the most common CTDs. Concordance and divergence of data might help in the better understanding of the common processes of these different systemic autoimmune disorders and might give future clues for differences in disease behavior and treatment response.

Pulmonary manifestations of rheumatologic diseases

PURPOSE OF REVIEW

The present review intends to provide an overview of the diversity and complexity of pulmonary manifestations of rheumatologic diseases and gaps in knowledge to effectively manage them.

RECENT FINDINGS

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of autoimmune disorders. Despite their significant morbidity and mortality, we have limited understanding about their pathogenesis. Here, we provide an overview of the pathophysiology and current management approach of these disorders, highlighting tools which assist with diagnosis, risk stratification and therapy. In this context, we address the need to develop a standardized approach to diagnose at-risk patients with rheumatologic disease and to predict their progression and the need to develop robust studies which evaluate the factors and interventions that influence pulmonary disease outcome.

SUMMARY

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of severe autoimmune disorders. By adopting a collaborative research approach among multicenters to help diagnose, risk stratify, and understand disease progression, effective management decisions can be optimized to improve clinical outcome.

CCL21 and IP-10 as blood biomarkers for pulmonary involvement in systemic lupus erythematosus patients

Biomarkers for pulmonary manifestations in systemic lupus erythematosus (SLE) are missing. Plasma samples of nine SLE patients with known pulmonary involvement (SLEpulm) and nine SLE patients without pulmonary involvement (SLE) were tested by multiplex microarray analysis for various cyto- and chemokines. Significantly decreased lung function paramters for forced vital capacity (FVC), total lung capacity (TLC), diffusion capacity for carbon monoxide (DLCO) and diffusion of CO corrected on lung volume (KLCO) were observed in SLEpulm as compared to SLE patients. CC chemokine ligand 21 (CCL21) and interferon gamma-induced protein 10 (IP-10) levels were significantly higher in SLEpulm, than in patients without pulmonary manifestations. CCL21 correlated negatively with DLCO ( r = −0.73; p < 0.01) and KLCO ( r = −0.62; p < 0.01), while IP-10 with FVC and forced expiratory volume one second. Receiver Operating Characteristics (ROC) analysis confirmed high sensitivity and specificity for the separation of SLE patients with and without pulmonary involvement for the chemokines CCL21 (Area Under Curve (AUC): 0.85; sensitivity%: 88.90; specificity%: 75.00; p < 0.01) and IP-10 (AUC: 0.82; sensitivity%: 66.67, specificity%: 100; p < 0.01). Pleuropulmonary manifestations in SLE patients associated with lung functional and DLCO/KLCO changes and were associated with significant increase in CCL21 and IP-10. These chemokines might serve as potential biomarkers of lung involvement in SLE patients.

Long time enzyme replacement therapy stabilizes obstructive lung disease and alters peripheral immune cell subsets in Fabry patients

BACKGROUND

Fabry disease is an X-linked lysosomal storage disorder, causing accumulation of globotriaosylceramid in different organs. Glycolipids are activators of different immune cell subsets the resulting inflammation is responsible for organ damage. Pulmonary involvement leads to airway inflammation; however, data on severity, as well as the effect of enzyme replacement therapy on lung function parameters and changes in peripheral immune cell subsets on lung involvement are sparse.

METHODS

Seven Fabry patients and four carriers underwent detailed clinical examinations screening for pulmonary manifestations. Repetitive measurements were performed on five patients on ERT (average follow-up 5 years). Patients with Fabry disease and control volunteers were included into peripheral blood cell measurements.

RESULTS

Lung involvement was present in all patients. Symptoms suggestive for lung disease were mild, however, obstructive ventilatory disorder, dominantly affecting small airways accompanied by hyperinflation was demonstrated in all affected patients. ERT resulted in small improvement of FEV1 in most treated patients. Decreased ratio of myeloid DC, Th17 cells while increase in T helper (Th)1 cells, and no change in Th2 and regulatory T (Treg) cells were detected in Fabry patients.

CONCLUSIONS

Fabry disease results mainly in mild symptoms related to lung involvement, characterized by moderate non-reversible obstructive ventilatory disorder. Stabilization of airway obstruction during follow-up was observed using ERT in most patients, emphasizing the importance of this treatment in respect of pulmonary manifestations. Changes of immune cell subsets in the peripheral blood might play a role in inflammatory process, including small airways in Fabry patient's lung.

Th17 cells in autoimmune and infectious diseases

The view of CD4 T-cell-mediated immunity as a balance between distinct lineages of Th1 and Th2 cells has changed dramatically. Identification of the IL-17 family of cytokines and of the fact that IL-23 mediates the expansion of IL-17-producing T cells uncovered a new subset of Th cells designated Th17 cells, which have emerged as a third independent T-cell subset that may play an essential role in protection against certain extracellular pathogens. Moreover, Th17 cells have been extensively analyzed because of their strong association with inflammatory disorders and autoimmune diseases. Also, they appear to be critical for controlling these disorders. Similar to Th1 and Th2 cells, Th17 cells require specific cytokines and transcription factors for their differentiation. Th17 cells have been characterized as one of the major pathogenic Th cell populations underlying the development of many autoimmune diseases, and they are enhanced and stabilized by IL-23. The characteristics of Th17 cells, cytokines, and their sources, as well as their role in infectious and autoimmune diseases, are discussed in this review.