Abstract Number: PB1053
Meeting: ISTH 2021 Congress
Background: Given the high risk of thrombosis in primary antiphospholipid syndrome (PAPS), additional therapies, complementary to anticoagulation, are required.
Aims: To investigate whether hydroxychloroquine (HCQ) affects the inflammatory and coagulation parameters in PAPS with thrombosis (t-PAPS).
Methods: HCQ at 400mg/day was given to anticoagulated t-PAPS patients for 6 months. After HCQ withdrawal, the same patients were followed for further 12 months. Blood samples were drawn at baseline, 6 months of HCQ use, 6 and 12 months after the end of HCQ use. Levels of tumor necrosis factor–alpha (TNF-α), interleukin 6 (IL-6), and tissue factor (TF) were quantified by ELISA.
Results: 
Demographic and clinical characteristics of the patients at baseline
| Table. 1 | Participants (n=27) |
| Age, years, mean (SD) | 44 (12) |
| Antiphospholipid antibodies profile Triple positivity, n (%) |
10 (37) |
| Time since the first thrombosis , mean (SD ) years | 8 (9) |
| Time since the last thrombosis , mean (SD) years | 4 (6) |
| Obstetric complications, n (%) | 5 (33) |
| Site of the first thrombotic episode | |
| Venous thrombosis, n (%) | 22 (77) |
| Arterial thrombosis, n (%) | 8 (30) |
| Recurrent thrombosis, n (%) | 9 (33) |
The figure illustrates the changes in the levels of TF (mean: 653.5pg/mL vs 559.55pg/mL vs 442.35pg/mL vs 685.65pg/mL), TNF-ɑ (mean: 1.795pg/mL vs 1.57pg/mL vs 1.14pg/mL vs 1.14pg/mL) and IL-6 (mean: 1.55pg/mL vs 1.48pg/mL vs 3.46pg/mL vs 3.30pg/mL) during the study period. Box plots represent means and SD. P value was calculated using paired t test. Legend: HCQ=Hydroxychloroquine; P= P-value; NS= not significant.
Twenty-seven patients completed the study. The mean age was 44 years, 78% were females and 44% had hypertension or dyslipidemia. Venous thrombosis was the index event in 77% of patients, 33% had recurrent thrombosis and 37% were triple positive for antiphospholipid antibodies (table 1). During HCQ treatment, TF and TNF-α levels decreased by 14.4 % and 12.4%, respectively. FT and TNF-α levels remained decreasing until up to six months after HCQ withdrawal. From the beginning of HCQ use to 6 months after HCQ was interrupted, TF levels decreased by 32.3% and those of TNF-α by 36.4% (P=0.01 and 0.0009, respectively). Conversely, IL-6 levels did not change with HCQ use and further increased 6 months after HCQ withdrawal. Twelve months after HCQ with drawal, the levels of IL-6 and TNF- α remained stable, while TF levels significantly increased.
Conclusions: HCQ use reducedTF and TNF-α levels in t-PAPS. This reduction was observed until up to six months after HCQ with drawal possibly due to a long-term effect of the drug. A possible rebound effect on the levels of TF was also seen 12 months after HCQ withdrawal. These findings support the hypothesis that HCQ may contribute to reduce the thrombotic risk in t-PAPS.
To cite this abstract in AMA style:
Mazetto B, Saraiva S, Jacintho B, Vieira-Damiani G, Vaz C, Oliveira JD, dos Santos AP, Mesquita G, Annichino-Bizzacchi J, Orsi F. Effect of Hydroxychloroquine on the Levels of Inflammatory Cytokines and Tissue Factor in Patients with Primary Antiphospholipid Syndrome [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/effect-of-hydroxychloroquine-on-the-levels-of-inflammatory-cytokines-and-tissue-factor-in-patients-with-primary-antiphospholipid-syndrome/. Accessed November 29, 2023.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/effect-of-hydroxychloroquine-on-the-levels-of-inflammatory-cytokines-and-tissue-factor-in-patients-with-primary-antiphospholipid-syndrome/