Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort

Abstract

PurposeTo investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status.MethodsRetrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences.ResultsOne hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007).ConclusionsThis study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

An Infant with Toxoplasmosis Retinochoroiditis: A Case Report from the Philippines

“…It should be highlighted that the group Academic Journal of Pediatrics & Neonatology that tested positive for IgM at presentation had bigger lesions, a higher incidence of macular involvement, and higher levels of intraocular inflammation. In contrast to this study, the patient had a normal or borderline high IgM titer and no additional inflammatory signs [18].…”

Screening for common eye diseases in the elderly with Optos ultra-wide-field scanning laser ophthalmoscopy: a pilot study with focus on ocular toxoplasmosis

“…A retrospective study in Germany reported that 4.2% of all the uveitis cases in their referral center were attributed to infection by T. gondii [15]. A study in Great Britain [16] describing phenotypical differences in cases of OT reported that patients with a positive IgM test were on average much older (51.1 ± 15.3 years) than those with a negative IgM serology (34.1 ± 11.8 years).…”

Bilateral ocular toxoplasmosis in a returning traveller: age and route of infection as potential risk factors

“… 14–16 A recent study in the UK has shown that the majority of patients above the age of 60 with OT had a recent acquired infection with positive IgM rather than a reactivation from congenital infection. 17 Increased susceptibility to parasitic infections in the elderly may be due to the progressive dysfunction of innate and acquired immunity (ie, immunosenescence). 18 Cellular immunity, mediated by T Iymphocytes and macrophages, plays a critical role in the normal host defences against intracellular pathogens like T. gondii .…”