{
  "abstract": "Introduction Systemic Lupus Erythematosus (SLE) and Systemic Sclerosis (SSc) are distinct connective tissue disorders with characteristic clinical and serological profiles. Overlap syndromes represent a diagnostic and therapeutic challenge, with an estimated prevalence of 6.8%. These cases may evolve over several years, with some disease-specific antibodies testing positive later on the course of the disease, complicating early recognition and management.Material and Methods This is a clinical case report.Results We report the case of a 48-year-old female who, in 2012, presented to the Rheumatology appointment with Raynaud’s phenomenon, inflammatory polyarthralgias affecting the small joints of the hands and photosensitivity. Physical examination revealed sclerodermoid facies and sclerodactyly. Laboratory evaluation showed an erythrocyte sedimentation rate (ESR) of 9 mm/h, C-reactive protein (CRP) of 1.9 mg/L, antinuclear antibodies (ANA) at a titer of 1:1000 with homogeneous pattern, and positive anti-double-stranded DNA (anti-dsDNA) antibodies. Complement levels were normal, and the extractable nuclear antigen (ENA) panel (including anti-Ro/SSA, anti-La/SSB, anti-Sm, anti-RNP, anti-Scl70, anti-Jo1, and anti-centromere antibodies) was negative, as well as anticardiolipin and antiphospholipid antibodies. Nailfold videocapillaroscopy was unremarkable at presentation. The patient was diagnosed with SLE and started on hydroxychloroquine 400 mg/day, pentoxifylline 400 mg three times daily, and nifedipine 30 mg/day, achieving partial symptomatic improvement. Repeated videocapillaroscopy in 2017 revealed an active scleroderma pattern, and in 2018, six years after the initial diagnosis, anti-Scl70 antibodies were found strongly positive, confirming the diagnosis of SLE-SSc overlap syndrome. Simultaneously, the patient had reported exertional dyspnea since 2014. Pulmonary function tests remained stable until 2022, when persistent respiratory complaints prompted a repetition of the previous normal thorax CT, which now demonstrated fibrotic non-specific interstitial pneumonia (NSIP). Immunosuppressive therapy was initiated with mycophenolate mofetil, titrated to 1000 mg twice daily, alongside with nintedanib 100 mg twice daily, maintaining clinical stability.Conclusions This case illustrates the diagnostic challenges of overlap syndromes. The delayed seropositivity of anti-Scl70 antibodies emphasizes that serology alone may underestimate disease evolution. Anti-Scl70 positivity is known to correlate with a higher risk of interstitial lung disease in SSc, consistent with this patient’s pulmonary involvement. A high index of suspicion is warranted in patients with clinical features suggestive of SLE-ES overlap syndrome, even in the absence of early serological confirmation. Longitudinal monitoring, including serial autoantibody testing, capillaroscopy, and pulmonary evaluation is essential for timely recognition and management of organ involvement.",
  "authors": [
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Ana Da Rocha Sá"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Carlos Marques Gomes"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Mariana Diz Lopes"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Bárbara Esteves"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal",
        "Hospital Divino Espírito Santo - Rheumatology Department, Ponta Delgada, Portugal"
      ],
      "name": "Marina Oliveira"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Miguel Natal"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Sara Helena Amaro Lopes"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Salomé Garcia"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Raquel Miriam Ferreira"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Lúcia Costa"
    },
    {
      "affiliations": [
        "ULS São João - Rheumatology Department, Porto, Portugal"
      ],
      "name": "Georgina Terroso"
    }
  ],
  "title": "P.348 Delayed seroconversion and pulmonary involvement in SLE-systemic sclerosis overlap syndrome: a case report",
  "uid": "616eaa45-b8ce-5b45-a4bf-ea5f4cae03ac"
}