{
  "abstract": "Objectives The aim of this study was to evaluate the change in aPL titers over time, thrombotic recurrence and mortality rates, and treatment-related adverse events in APS patients treated with rituximab.Methods This retrospective single center study included 43 patients with thrombotic APS (11 PAPS, 32 SLE+APS) who received at least 1 cycle of rituximab (1000 mg on days 0 and 15). Baseline demographic, clinical, and serologic characteristics, anticardiolipin (aCL) IgG/IgM and anti-beta2-glycoprotein-I (aB2GPI) IgG/IgM titers at 6 to 12 months of rituximab treatment were reviewed. The positivity threshold for aCL and aB2GPI IgG/IgM was accepted as >40 GPL/MPL units or >99th percentile.Results Baseline characteristics are summarized in table 1. The median follow-up after rituximab was 3.5 (IQR: 5.8) years. Whilst the majority of patients were treated with rituximab for thrombotic APS, some were treated for lupus nephritis or non-renal SLE activity (table 1). At 6–12 months post-rituximab, aPL positivity declined: aCL IgG from 29 (67.4%) to 13 (30.2%), aCL IgM from 9 (20.9%) to 2 (4.7%), aB2GPI IgG from 22 (51.2%) to 9 (20.9%), and aB2GPI IgM from 9 (20.9%) to 2 (4.7%). There was also a statistically significant decrease in aPL antibody titers (figure 1). Five patients developed new events after rituximab and details are shown in table 2. Five deaths occurred during follow-up: sepsis (n=1), traumatic intracranial hemorrhage (n=1), lupus nephritis (n=1), recurrent pulmonary hemorrhage 38 months post-rituximab (n=1), and treatment-refractory CAPS 6 months after rituximab (n=1). Bacterial infections were observed in 15 patients (4 required hospitalization and 1 lost after ICU admission), COVID infections in 7 (2 required hospitalization), herpes zoster in 3. Finally, 2 patients developed allergic reactions, none were anaphylaxis.Abstract PO:01:012 Table 1Baseline demographic, clinical, and laboratory characteristics and rituximab indications of the cohort (n=43)Abstract PO:01:012 Table 2Details of aPL-related events after rituximabAbstract PO:01:012 Figure 1Change in aPL titers 6-12 months after rituximabConclusions In patients with thrombotic APS, rituximab treatment may prevent thrombotic recurrence with a significant decrease in aPL titers. It is noteworthy that 4 of 5 patients who developed recurrence after rituximab were not receiving effective anticoagulant therapy. These data suggest that under consideration of infectious complications, rituximab may be an effective alternative in high-risk APS patients with recurrent thrombosis.",
  "authors": [
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Division of Rheumatology, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Omer Uludag"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Soner Altin"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Gamze Kemec"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Division of Rheumatology, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Yasemin Yalcinkaya"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Division of Rheumatology, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Ahmet Gul"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Division of Rheumatology, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Murat Inanc"
    },
    {
      "affiliations": [
        "Istanbul University, Istanbul Faculty of Medicine, Division of Rheumatology, Department of Internal Medicine, Istanbul, Turkey"
      ],
      "name": "Bahar Artim Esen"
    }
  ],
  "title": "PO:01:012 Rituximab in antiphospholipid syndrome: aPL titer decline and clinical outcomes",
  "uid": "fd42f73d-8933-5232-bbdf-303b478f6ec8"
}