Towards Early Diagnosis of Mixed Connective Tissue Disease: Updated Perspectives

Autoantibodies in systemic sclerosis: From disease bystanders to pathogenic players

Autoantibodies (Aab) are recognized as key indicators in the diagnosis, classification, and monitoring of systemic autoimmune diseases (AID). Recent studies have expanded knowledge through the discovery of new antigenic targets, advanced methods for measuring Aab levels, and understanding their possible pathogenic roles in AID. This narrative review uses systemic sclerosis (SSc) as an example to highlight the importance of Aab associated with HEp-2 immunofluorescence assay positivity (traditionally referred as antinuclear antibodies [ANA]), exploring recent developments in the field. Firstly, we outline the various types of ANA found in SSc and their links with specific disease features. Newly discovered antibodies shed light on SSc cases where Aab had previously gone unidentified. Secondly, we emphasize the necessity for novel quantitative techniques to track Aab levels over time by gathering data regarding the timing of Aab occurrence relative to SSc symptoms and the relationships between Aab concentrations and disease severity. Finally, we discuss the experimental findings suggesting a potential direct role of Aab in the development of SSc. The advancements surrounding Aab provide insights into new disease mechanisms and may lead to innovative diagnostic and treatment approaches.

Prognostic insights from symptom clustering analysis in systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE), a systemic autoimmune disease with heterogeneous severity, poses a challenge in classifying patients due to its dynamic phenotype. We therefore aimed to identify clinical clusters at diagnosis and at the last available visit to define subgroups with different disease trajectories.

METHODS

This retrospective study included 278 SLE patients fulfilling the 2019 EULAR/American College of Rheumatology classification criteria. Data were extracted from the patient's medical record, encompassing demographic, clinical and immunological features. Two hierarchical clustering analyses were performed: one at diagnosis and the other at the last available visit based on 23 clinical manifestations. We assessed the distribution of autoantibodies among clusters, and survival analyses compared prognosis using the Cox regression model.

RESULTS

Three symptom clusters were identified at diagnosis and confirmed at the last available visit, with consistent clinical profiles. The largest, clusters 1/1', exhibited early articular (95.3%; p=0.0043) and mucocutaneous (58.7%; p=0.0031) symptoms with the best survival rate. Clusters 2/2' displayed the most severe phenotype, including renal involvement (62.2%; p<0.0001), positivity for anti-DNA (90.0%; p=0.0151) and anti-Sm (34.4%; p<0.0001) autoantibodies, and worse prognosis. Clusters 3/3' exhibited a high proportion of SLE patients fulfilling the definition of mixed connective tissue disease (MCTD) (50.0%; p<0.0001) with anti-U1-RNP 70 kDa autoantibodies (87.5%; p<0.0001). Clusters 1 and 2 remained stable during follow-up, cluster 2 even expanding over time, while over half of cluster 3 patients transitioned to a different subgroup.

CONCLUSION

We identified a distinct MCTD phenotype within SLE patients, a severe SLE phenotype with poor prognosis, and a third group of SLE patients with lower visceral involvement. Clusters remained stable over time, providing insights into disease progression.

Clinicopathological characteristics and prognosis of lupus nephritis patients with positive anti-ribonucleoprotein antibodies

BACKGROUND

Positive anti-ribonucleoprotein antibodies may characterize a subgroup of patients affected by lupus nephritis with mild kidney damage, but little is known about their clinical features and long-term prognosis.

METHODS

Patients were retrospectively selected from the lupus nephritis database ( http://ln.medidata.cn ) of the First Affiliated Hospital of Sun Yat-sen University between 2006 and 2011. Logistic regression analysis identified the clinicopathological indicators related to positive anti-ribonucleoprotein antibodies. Additionally, the Cox proportional hazard regression model was used to assess the association of baseline variables with clinical outcomes.

RESULTS

Of the 485 enrolled patients, 184 (37.9%) tested positive for anti-ribonucleoprotein antibodies. The group with positive anti-ribonucleoprotein antibodies exhibited a higher prevalence of rash, photosensitivity, and Raynaud's phenomenon, and lower scores on the systemic lupus erythematosus disease activity index (SLEDAI) and the Activity Index scores in kidney biopsies. It is important to note that, although proteinuria did not differ, patients with anti-ribonucleoprotein positivity had a lower prevalence of hematuria and cylindruria, and a higher estimated glomerular filtration rate than patients without anti-ribonucleoprotein antibodies. After a median follow-up of approximately 170 months, no significant differences were observed in kidney or patient survival between groups.

CONCLUSIONS

Lupus nephritis patients with anti-ribonucleoprotein antibodies present milder kidney damage and more dermatological manifestations. Despite the negative correlation between anti-ribonucleoprotein antibodies and both SLEDAI and activity index scores, these antibodies may not be predictive of better kidney outcomes.

Recognition of Idiopathic Inflammatory Myopathies Underlying Interstitial Lung Diseases

Interstitial Lung Disease (ILD) is one of the most common causes of mortality in idiopathic Inflammatory Myopathies (IIM). Despite these conditions being commonly associated with proximal weakness, skin rashes and arthritis, ILD can be the first or the sole clinical feature in up to 60% of patients, potentially leading to incorrect diagnosis. The early recognition of an underlying IIM in ILD patients can allow for prompt treatment, which could potentially stabilize or even improve the lung disease, also avoiding the development of other clinical features associated with the condition. The objective of this review is to describe the clinical, serological and radiological features associated with IIM-ILD, mainly focusing on dermatomyositis and antisynthetase syndrome.

Comprehensive Exploration of Antinuclear Antibodies (ANAs): Unveiling Clinical Significance, Associations with Cancer, and the Nuances of Differential Diagnosis in Positive ANA Patients

This comprehensive review delves into the complex realm of antinuclear antibodies (ANAs), expanding beyond their traditional involvement in autoimmune rheumatic disorders. By digging into historical changes, diagnostic complexity, and clinical significance, the debate reveals the shifting relationships between ANAs, particularly with cancer. Specialized studies provide practical insights on ANA testing processes, standardization, and upcoming challenges. Examining prevalence trends in the United States provides a time dimension to ANA dynamics, linking autoimmune and oncological considerations. The debate delves into the complexity of lupus erythematosus, emphasizing ANAs' diverse presentations and their potential as flexible diagnostic and prognostic indicators. The complex relationship between ANAs and cancer is highlighted, demonstrating their potential as early markers or indicators of malignancies. Looking ahead, this synthesis anticipates advances in personalized medicine and collaborative research, putting ANAs at the forefront of advanced diagnostics and treatments for autoimmune disorders and cancer. This synthesis envisions a future for ANA research in which these antibodies play a critical role in promoting personalized treatment, enhancing diagnostics, and fostering collaborative initiatives that cross traditional boundaries. As ANAs grow more prominent at the junction of autoimmune illnesses and cancer, this synthesis lays the path for further research and novel advances in understanding, diagnosing, and treating complicated medical conditions.