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Background: Systemic Sclerosis (SSc) is an autoimmune disorder characterized by microvascular damage and the excessive deposition of extracellular matrix in the skin and organs, contributing to the characteristic pro-fibrotic cycle. Treatment remains challenging, with limited data on the efficacy and safety of Rituximab (RTX) in SSc; however, its application is considered for severe, refractory cases. Recent studies highlight RTX´s positive impact on skin conditions and lung stabilization.
While we know that in AAV and RA, the risk of infection associated with RTX has IgG as one of its main determinants, we have little data on patients with SSc. We hypothesize that, since the disease has a different etiopathology, the profile of markers associated with infection may also be different.
Objectives: The main objective of this study is to evaluate the association of clinical and laboratory data for the incidence of infection in patients with SSc taking RTX.
Methods: This is a retrospective, observational study and the medical records of patients treated at the infusion center of a tertiary hospital were evaluated. Inclusion factors were patients over the age of 18 who met the 2013 American College of Rheumatology (ACR) and European Alliance of Rheumatology Associations (EULAR) criteria for SSc and patients who had at least one RTX application with data available 6 months after the first dose. The exclusion criteria were patients with diagnosis of other immune-mediated rheumatic diseases.
The severity of infections related to the use of RTX will be classified using the Common Terminology Criteria for Adverse Events (CTCAE).
Statistical analysis was carried out using the chi-square and Fisher methods for categorical variables and the Mann-Whitney method for continuous variables, with statistical significance considered when p <0.05
Results: Between March and December 2023, a total of 23 patients were selected for the study.
Among the patients selected, the average age was 45 ± 11 years, with a predominance of females (78.3% vs. 21.7%) and an average BMI of 23.6±5 Kg/m 2 . The diffuse form was the most prevalent and was also most associated with interstitial lung disease (ILD). The clinical manifestations most seen in the analysis were Raynaud’s phenomenon (100%), digital ulcers (73,9%), ILD (82,6%), and gastrointestinal involvement (65,2%).
There was a total of 17 infectious complications, the most common being skin infections (29.4% of infections), followed by SARS-CoV-2 infection and bacterial pneumonia (17.6% each). Among the complications observed, one was grade 1 on the CTCAE scale (mild), fifteen were grade 2 (moderate, with intervention required, but not hospitalization) and one was grade 3, requiring hospitalization.
The statistical analysis comparing the groups with infectious complications and the control group is shown in Table 1 below.
Conclusion: Unlike the data found in RA and AAV, our study found no association between IgG levels and increased infectious risk in SSc patients taking RTX. An association was found with the presence of digital ulcers. Although promising and pointing to a differentiated risk profile for the infectious risk of RTX in SSc, prospective studies with a larger sample size are needed to confirm our findings.
REFERENCES: NIL.
Statistical analysis and comparison between groups of patients with SSc taking RTX who did or did not become infected.
| Variable | ES+RTX+ Infections (n=10) | ES+RTX
| p value |
|---|---|---|---|
| Age - years | 44±12 | 46±10 | 0,7092 |
| Gender | Female (70%) | Female (84%) | 0,7395 |
| BMI - kg/m 2 | 23,6±4,2 | 22,4±6,2 | 0,4833 |
| Clinical form | Diffuse (70%) | Diffuse (69%) | 0,9706 |
| Sclerodactyly | 5 (50%) | 8 (61%) | 0,8973 |
| Calcinosis | 2 (20%) | 2 (15%) | 1 |
| Telangectasia | 2 (20%) | 5 (38%) | 0,6193 |
| Digital ulcers | 10 (100%) | 7 (53%) | 0,0433 |
| Gastrointestinal involvement | 6 (60%) | 9 (69%) | 0,9847 |
| Interstitial lung disease | 8 (80%) | 11 (84%) | 1 |
| Cumulative dose of glucocorticoid - mg | 3534 ±2563 | 6607 ± 9933 | 0,5714 |
| Mycophenolate use | 10 (100%) | 10 (76%) | 0,4805 |
| IgG at baseline - mg/dL | 1548±637 | 1606±437 | 0,5573 |
| IgG drop (%) - 2nd cycle | 18,5±13,3 | 10,8±8,4 | 0,6247 |
| IgG drop (%) - 3rd cycle | 14,2±9 | 13,7±12,3 | 0,9433 |
| IgG drop (%) - 4th cycle | 19,4±11,4 | 11,3±17,2 | 0,5476 |
| CRP at baseline - mg/L | 9±11,6 | 10,3±11,1 | 0,419 |
Acknowledgements: NIL.
Disclosure of Interests: Vitor de Castro Grotti: None declared, Alisson Pugliesi Abbvie, Janssen, Lilly, UCB, Pfizer, Boehringer, Astra Zeneca, Boehringer and UCB, Gabriela Vilaça Gutierrez: None declared, Rodrigo da Rocha Jorge: None declared, Regis Suwa Marques: None declared, Maria Fernanda Zacarin: None declared, Ana Paula del Rio: None declared, Marília Paula Souza dos Santos: None declared, Zoraida Sachetto: None declared.