Objective

To investigate the clinical manifestations and early renal involvement in pediatric patients with primary Sjögren's syndrome （pSS）.

Methods

A total of 30 pediatric patients with pSS who were hospitalized in the Department of Rheumatology and Immunology，Capital Center for Children's Health，Capital Medical University，between January 2017 and January 2023 were included in this study.A retrospective analysis was conducted on their general clinical data，laboratory test results，renal involvement，and prognosis.This study followed the procedures in accordance with the DeclarationofHelsinkioftheWorldMedicalAssociation revised in 2013.

Results

①Among the 30 children with pSS，the male-to-female ratio was 1∶5.The age of onset and the age at diagnosis were （8.9±3.8）years and （10.3±3.4）years respectively.The predominant systemic manifestations included recurrent glandular swelling or parotitis （23/30，76.7%），hematologic involvement（17/30，56.7%），localized cutaneous vasculitis （12/30，40.0%），erythema multiforme （2/30，6.7%），and diffuse cutaneous vasculitis （1/30，3.3%）.②Laboratory examinations revealed that among 30 cases，14 cases（46.7%）showed labial salivary gland atrophy with multifocal lymphocytic infiltration in the interstitium，and the number of lymphocytes in each focus exceeded 50.Additionally，3 cases（10.0%）underwent sialography，which demonstrated punctate to small saccular dilation of the terminal ducts with incomplete emptying.③Among the 30 children with pSS，the mean European League Against Rheumatism （ESSDAI）score was 14.7±7.8，indicating moderate to severe disease activity.None of the children had neurological involvement.Serum abnormalities were present in 24 cases （80.0%），glandular involvement in 23 cases （76.7%），and hematologic involvement in 17 cases （56.7%），with thrombocytopenia being the predominant manifestation.Skin lesions of varying degrees were observed in 15 cases （50.0%）.Among the 30 children with pSS，5 cases（16.7%）exhibited trace to mild proteinuria（±to+），and 4 cases （13.3%）had abnormal elevation in 24 h urinary protein excretion （153.7～787.8 mg/d）.The prevalence of early renal involvement in children with pSS was relatively high （90.9%，20/22），with a higher incidence of early tubular injury（86.4%，19/22），although the severity was mild.The incidence of early glomerular injury was 31.8%（7/22）.The treatment for the 30 children with pSS primarily consisted of oral corticosteroids，immunosuppressive agents，and hydroxychloroquine sulfate （HCQ）.Among them，23 children were followed up for a median duration of 17 months （ranging from 7 to 38 months）.During this period，21 patients achieved stable clinical symptoms，normalized inflammatory markers，and no disease relapse was observed during the gradual tapering of corticosteroids.

Conclusions

The primary clinical manifestations and affected systems in pediatric pSS include recurrent glandular swelling/repeated parotitis，followed by hematologic involvement.Recurrent parotitis should be considered as one of the diagnostic criteria for pediatric pSS.With active treatment，most children with pSS achieve stable clinical symptoms during follow-up.The incidence of early renal involvement in pediatric pSS is relatively high，especially the rate of renal tubular injury.Renal biopsy should be actively performed in children with pSS.