Clinical and laboratory features of childhood-onset primary Sjögren's syndrome: A retrospective study from China

Kidney manifestations of pediatric Sjögren's syndrome

Approximately 1% of all patients with Sjögren's syndrome (SS) are children. Unlike the adult form, in which sicca syndrome is the main presentation, in children, the most common clinical finding is recurrent enlargement of the salivary glands. In pediatric SS, extraglandular manifestations represent a significant feature and, among these, kidney manifestations are relevant. Kidney involvement is observed in 5-20.5% of children with SS, most frequently tubulointerstitial nephritis. This injury can lead to serious phenotypes, including distal kidney tubular acidosis with the development of severe hypokalemia, which can lead to ECG abnormalities, weakness, and hypokalemic periodic paralysis. Kidney implications in pediatric SS also include nephrolithiasis, nephrocalcinosis, and various types of glomerular damage, which often require immunosuppressive therapies. Laboratory findings are usually comparable to adults, including hyperglobulinemia and high rates of antinuclear antibodies (ANA, 63.6-96.2%), and anti-Ro/SSA (36.4-84.6%). The current classification criteria for SS are inaccurate for the pediatric population, and more specific criteria are needed to improve the diagnostic rate. Due to the rarity of the disease, strong recommendations for treatment are lacking, and several therapeutic strategies have been reported, mostly based on glucocorticoids and disease-modifying antirheumatic drugs, with different outcomes. The aim of this paper is to provide an overview of the kidney implications of pediatric SS based on the latest evidence of the medical literature.

Microvascular status in juvenile Sjögren's disease: the first nailfold videocapillaroscopy investigation

INTRODUCTION

Juvenile Sjögren's disease (jSjD) is a rare autoimmune disease characterized by exocrine gland involvement and systemic manifestations, including small vessel vasculitis and Raynaud's phenomenon (RP). We aimed to investigate the microvascular status in jSjD patients by nailfold videocapillaroscopy (NVC) and the potential correlations with clinical and serological features.

METHODS

Clinical data from thirteen consecutive jSjD patients (11 females and 2 males), with a mean age of 16 ± 4 years, diagnosed before 16 years of age (mean age at diagnosis 12 ± 3) according to the 2016 American College of Rheumatology/EULAR criteria for adult SjD, were collected including age- and sex-matched healthy controls (HCs). Clinical, laboratory, and instrumental data were collected, together with NVC examination. Non-specific and specific NVC parameters were investigated, such as capillary density, capillary dilations, giant capillaries, microhaemorrhages and abnormal shapes. Associations between NVC findings and clinical/serological features were explored and analysed using parametrical and non-parametrical tests.

RESULTS

Capillary density reduction correlated significantly with articular involvement (arthralgias) (p = 0.024). Microhaemorrhages correlated with lower C3 levels (p = 0.034). No specific NVC pattern for jSjD was identified, whereas abnormal capillary shapes were significantly higher in jSjD patients than HCs (p = 0.005). NVC abnormalities were not associated with SjD-specific instrumental tests (biopsy, imaging, Schirmer's test). RP was present in 8% of jSjD patients.

CONCLUSIONS

The reduction of capillary density, as well as microhaemorrhages at NVC analysis, are significantly associated with some clinical aspects like articular involvement and serum biomarkers (C3 reduction). The NVC is suggested as safe and further analysis in jSjD patients.

Ro52/TRIM21 - From host defense to autoimmunity

Ro52 (TRIM21) belongs to the ubiquitin ligase family. This protein plays a crucial role in many immunological processes, including antibody-dependent intracellular neutralization, synergy with the complement system, antiviral response, death mediation, oxidative stress response, and protein ubiquitination. Abnormal expression of TRIM21 can break immunological tolerance and lead to the production of autoantibodies against TRIM21. Antibodies against TRIM21 are detected in various autoimmune diseases, including Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), or myositis. However, anti-TRIM21 presence is not limited to autoimmune connective tissue disorders. It was observed in patients with malignancies, various cancerous processes, infectious diseases, and idiopathic interstitial pneumonia. The occurrence of TRIM21 autoantibodies is also associated with clinical features, such as the prevalence of interstitial lung diseases and cardiac or haematological involvement in connective tissue disorders. The purpose of this review was to summarize current knowledge of the immunological functions of TRIM21 and analyze the clinical implications of anti-TRIM21 antibodies in the disease course.

A single-center study of clinical features of pediatric Sjögren's syndrome

OBJECTIVE

Sjögren's syndrome (SS) is a rare disease with unclear diagnostic criteria among the children and adolescents. The purpose of this study is to describe the clinical features of pediatric Sjögren's syndrome and validate with Japanese diagnostic guidelines criteria of 2018.

METHODS

We conducted a retrospective analysis of the clinical data of a cohort of 54 patients with pediatric Sjögren's syndrome admitted to our hospital over a total of 10 years from September 2013 to September 2022.

RESULTS

The ratio of females to males was 49:5 among the 54 children (34 cases of primary SS and 20 cases of secondary SS), the average age of onset of symptoms for the first time was 9.9 years, and the average age at diagnosis was 10.2 years. In terms of subjective symptoms, 7 cases (13.0%) presented with dry mouth and 5 cases (9.3%) reported dry eyes. The positive rates were 9.3% for Schirmer I test, 70.4% for salivary gland function test, and 55.6% for salivary gland ultrasonography. The positive rates were 94.4% for Anti-Ro/SSA antibodies, 66.7% for Anti-La/SSB antibodies, 88.9% for ANA, 59.3% for RF, and the elevation rate of IgG was 63.0%. Among the EULAR Sjögren's syndrome disease activity index (ESSDAI) domains, the biological, constitutional, glandular, cutaneous, and lymphadenopathy domains were most involved. Treatment consisted of glucocorticoids in 88.9% of the patients in our study and hydroxychloroquine in 92.6%. As per the Japanese version of the clinical practice guidance for Sjögren's Syndrome in pediatric patients (2018), 5 cases were identified as Definite SS, 35 cases as Probable SS, and 14 cases as Possible SS. With respect to primary and secondary SS, there was essentially no significant difference between the groups in any of the above aspects.

CONCLUSIONS

Patients with pediatric SS presented with a wide spectrum of clinical features, a low prevalence of reported symptoms of dry mouth and dry eyes, and various clinical manifestations with multi-system involvement. These are similar to other pediatric study cohorts in terms of epidemiology, auxiliary investigation results, disease activity scores, and treatment. The coincidence between our study and the Japanese version of the clinical practice guidance for Sjögren's Syndrome in pediatric patients (2018) is good for the diagnosis of pediatric SS.