Background: Although progress has been made in recent years in characterizing the phenotype of paediatric-onset Sjögren’s disease (SjD) [1], there are still numerous unresolved gaps also in terms of classification criteria or specific recommendations.

Objectives: We decided to examine clinical and laboratory characteristics within a multicentre cohort of paediatric patients with SjD and to make comparisons with data obtained from a cohort of adult patients with SjD.

Methods: We included 47 patients diagnosed with paediatric-SjD from 6 different Paediatric Rheumatology centres and 47 adult SjD patients consecutively recruited from a single adult Rheumatologic centre. All patients fulfilled the ACR/EULAR 2016 classification criteria for SjD. Salivary gland biopsies resulted positive for all patients. We collected demographic, clinical and laboratory data at the time of diagnosis and at 1-year follow-up.

Results: The paediatric cohort was composed of 47 patients (n. female 42=89.4 %), median age 12.5 (10.5 - 14.8) years, 42 (89.4 %) of Caucasian ethnicity, while the adult cohort was composed of 47 patients (n. female 44=93.6 %), median age 55.6 (51 - 64.8) years, 46 (97.9 %) of Caucasian ethnicity. The predominant symptoms at baseline were represented by recurrent glandular swelling (53.2 %) and xerostomia (46.8 %) in the paediatric group, and by xerostomia (89.4 %), xerophthalmia (72.3%) and arthralgia (68.1%) in the adult group. Significant differences were found between the two groups: glandular swelling recurrence (p= 0.012), skin involvement (p=0.028) and overlap with other autoimmune diseases (p=0.007) were more frequent in children; xerostomia (p< 0.0001), xerophthalmia (p< 0.0001) and arthralgia (p< 0.0001) were more frequent in adults. Schirmer’s test was more frequently positive in adults (p<0.0001). Median positive values of ESR (p=0.035), serum ϒ-globulin (p=0.006) and IgG levels (p=0.0001) were significantly higher in children. The percentage of patients with ANA (p=0.006), anti-SSA/Ro 52 antibodies (p=0.005) and anti-SSA/Ro 60 antibodies (p=0.001) positivity was significantly higher in adult SjD (Table 1). Rheumatoid factor (RF) positivity percentage did not differ between the two cohorts, but a trend in higher levels was observed among RF positive children. C3 and C4 levels, blood cell count, CRP values and anti-SSB/La antibodies positivity did not differ. No significant differences were found about the average dosage of steroid/kg (p=0.49), hydroxychloroquine (p=0.68) or methotrexate intake (p=0.16). Rituximab, azathioprine, mycophenolate mofetil, tear or salivary substitutes were significantly more prescribed in adults. ESSDAI values were markedly higher in the paediatric group (p=0.0001), while ESSPRI values were significantly lower (p<0.0001). This difference persisted after a 1-year follow-up, with ESSDAI remaining elevated in children.

Conclusion: Our study confirms significant differences in clinical and laboratory features between children and adults. Higher disease activity is observed in paediatric-SjD, mainly expressed by glandular swelling and hypergammaglobulinemia also during follow-up. The evidence of a lower ESSPRI is unlikely to reflect less symptom burden in children. Instead, it might suggest that patient reported indexes used for adults are not suitable for children. Our results support the need to develop specific recommendations and outcome measures for the management of the paediatric SjD.

REFERENCES: [1] Rheumatology (Oxford).2021 Oct 2;60(10):4558-4567.

Acknowledgements: NIL.

Disclosure of Interests: None declared.