The Role of Age in Ocular Toxoplasmosis: Clinical Signs of Immunosenescence and Inflammageing – a perspective study

Purpose: To investigate the association between age, immune response, and the clinical presentation in ocular toxoplasmosis (OT).

Design: Retrospective, observational cohort study.

Methods: A review of medical records of patients with active OT at the Uveitis Center, Charité Universitätsmedizin was conducted. Baseline parameters included age at presentation, primary manifestation or recurrence, visual acuity, intraocular pressure (IOP), size and location of active lesions, inflammatory activity, antibody index (AI), and complications of intraocular inflammation. The data are presented as mean ± standard deviation (SD).

Results: Between 1998 and 2019, 290 patients with active OT were diagnosed at our tertiary reference center. The mean age was 37.7 ± 17.1 years, 53.8% were females, and 195 patients (70.9%) showed recurrent disease. Older age was associated with lower-baseline visual acuity (p = 0.043), poor visual outcome (p = 0.019), increased inflammatory activity (p < 0.005), and larger retinal lesions (p < 0.005). Older patients presented a lower AI (<35 years: 45.1 ± 82.7, median: 12.1; ≥35 years: 18.6 ± 50.5, median: 5.8; p = 0.046), confirmed by a decrease of AI with increasing age (R² = 0.045; p = 0.024). Complications were observed more frequently in patients with primary ocular toxoplasmosis (p = 0.046) and were mostly accompanied by panuveitis (p = 0.018) and a longer duration of illness (p = 0.037). Furthermore, panuveitis (p = 0.025), ocular hypertension (p = 0.037), and improved visual acuity development (p = 0.035) were associated with the presence of primary ocular toxoplasmosis. Macular involvement (24.3% of patients) was positively correlated with complications (macular/peripapillary edema and retinal detachment, p < 0.005) and poor visual outcome (p < 0.005) and was negatively correlated with inflammatory activity (p < 0.005).

Conclusions: We found a strong and clinically-relevant impact of age on the clinical presentation and course of OT. While an unspecific inflammatory response increased with age, the specific, local humoral immune response declined. These findings are well in line with the concept of immunosenescence and inflammageing in uveitis. In addition, alongside patient age, the primary manifestation and the retinal lesion location were identified factors contributing to the severity of intraocular inflammation and the occurrence of ocular complications.