D2.383 - Ocular Cicatricial Pemphigoid: Experience with Methotrexate immunosuppression in a case series from Mar del Plata, Argentina

Ocular Cicatricial Pemphigoid (OCP) is a chronic, rare autoimmune disease affecting ocular mucosal surfaces, characterized by autoantibody deposition in the conjunctival basement membrane, triggering recurrent inflammation that progresses to subepithelial fibrosis, symblepharon formation, and irreversible blindness. With an estimated incidence of 0.24-2 cases per million inhabitants/year, it is considered a very low prevalence disease. Diagnosis is confirmed by direct immunofluorescence (DIF) on conjunctival biopsy, but its sensitivity is limited (30-80%); therefore, a negative result does not exclude diagnosis in cases with high clinical suspicion. Early immunosuppressive treatment is crucial, requiring interdisciplinary management between ophthalmology and allergy/immunology.

Observational, descriptive, cross-sectional study. Patients diagnosed with OCP who started immunosuppressive treatment at Centro de Alergia Mar del Plata between January 2022 and December 2025 were included. All were jointly evaluated with ophthalmology (Foster staging). Baseline laboratory tests (complete blood count, liver function, albumin, renal function) were performed, and folic acid supplementation was indicated. Subcutaneous Methotrexate 15 mg/week was the first-line treatment, adjusted according to response and tolerance.

Ten female patients were included (mean age 65.5 years, range 50-80). Diagnosis was confirmed by DIF-positive biopsy in 5 cases (50%). Five patients (50%) had negative DIF but compatible histology (squamous metaplasia, goblet cell loss, chronic inflammation) and highly suggestive clinical features. All patients (100%) had clinically compatible features. At referral, 90% (9/10) were on topical corticosteroids and 60% (6/10) on systemic corticosteroids. Laboratory findings revealed mild hypoalbuminemia (3.65-3.99 g/dL) in 5 patients (50%), positive ANA (low titers) in 3 (30%), positive RF in 1, and anemia in 2 (20%). Methotrexate was initiated in 9 patients (90%): 7 (70%) continued on monotherapy with good response, 1 patient (10%) non-responder to MTX was switched to oral cyclosporine achieving stability, and 1 patient (10%) died from causes unrelated to immunosuppressive treatment. Two patients (20%) developed MTX-related pneumopathy (one switched to rituximab, one to azathioprine). Currently, 9 patients are stable and 1 deceased.

OCP prevalence may be underestimated; our experience as a referral center in Mar del Plata (10 cases/600,000 inhabitants) suggests a higher frequency than reported. DIF has limited sensitivity (50%); a negative result does not exclude diagnosis in compatible and progressive cases. Hypoalbuminemia was a frequent finding (50%), possibly a marker of chronic inflammation. Methotrexate demonstrated efficacy in 80% of cases, but alternatives such as oral cyclosporine should be considered in non-responders. Close monitoring for pulmonary toxicity is required (20% in our series). Interdisciplinary management and timely referral are essential for therapeutic success.