VITREOUS TREPONEMAL ANTIBODY AS A SUPPLEMENTARY TEST TO SEROLOGY FOR THE CONFIRMATION OF SYPHILITIC CHORIORETINITIS

Prognostic effect of HIV on visual acuity in ocular syphilis: a systematic review

BACKGROUND/OBJECTIVES

Ocular syphilis is a vision-threatening disease that can lead to permanent blindness if left untreated. The global re-emergence of syphilis warrants greater investigations into the visual prognosis of eyes affected by this potentially devastating disease. This systematic review investigates the impact of HIV on visual acuity (VA) outcomes in ocular syphilis.

METHODS

A literature search of Medline, PubMed, Embase, Clinicaltrials.gov and Cochrane Reviews was conducted for studies published between 01 January 2011 and 19 March 2022, reporting non-aggregate initial and post-treatment VA data of eyes with ocular syphilis and corresponding HIV status in patients ≥ 18 years.

RESULTS

A total of 95 studies, including 364 patients and 568 eyes, were evaluated. Among people living with HIV with a diagnosis of ocular syphilis, affected eyes were more likely to have optic nerve involvement and panuveitis. However, HIV status, CD4 cell count, and HIV viral load were not predictive of VA outcomes of treated ocular syphilis. Prognostic factors of final VA worse than 1.00 logMAR were female sex, the presence of macular edema, and VA ≥ 1.00 at presentation. The strongest predictor of a worse final VA was VA ≥ 1.00 at presentation.

CONCLUSIONS

This systematic review demonstrates that HIV status, CD4 cell count, and HIV viral load are not significant factors impacting VA outcomes of eyes with ocular syphilis. While visual prognosis is generally good, poor visual outcome is most strongly predicted by poor VA at presentation. This underscores the importance of early recognition and treatment prior to permanent vision loss.

Penicillin Responsive Presumed Seronegative Ocular Syphilis in a Patient with Human Immunodeficiency Virus: A Case Report and Review of the Literature

Ocular and systemic syphilis are well known to mimic other clinical entities making them challenging to diagnose in many cases. Syphilis testing plays an important role in diagnosis and timely treatment. Here we describe a patient with untreated human immunodeficiency virus (HIV) infection who presented with bilateral panuveitis with repeatedly negative syphilis serologies. In light of worsening retinitis while on aggressive anti-viral treatment and in consideration of the clinical suspicion for syphilitic uveitis, intravenous penicillin was initiated empirically. The patient demonstrated significant improvement subjectively and objectively after treatment. We also review and discuss syphilis testing reliability generally and in HIV co-infected patients in particular. Empiric intravenous penicillin should be considered in patients with clinical features of ocular syphilis despite negative serologic testing, especially in those with HIV co-infection.

Appraisal of vitreous syphilis antibody as a novel biomarker for the diagnosis of syphilitic uveitis: a prospective case-control study

PURPOSE

To determine the sensitivity and specificity of syphilis antibody tests in vitreous samples and to propose an algorithm using vitreous syphilis antibody as a supplementary test to confirm syphilitic uveitis (SU).

METHODS

A prospective case-control study was conducted at the Retina and Uveitis Clinic from May 2017 to January 2020. Initially, patients were classified based on syphilis serology into group 1 (positive testing) and group 2 (negative testing). Group 1 was further divided into 2 subgroups (group 1A and 1B) depending on their relevant clinical manifestations and clinical improvement. Group 2 served as a control group.

RESULTS

Thirty-eight patients were enrolled in the study: 14 in group 1A, 5 in group 1B, and 19 in group 2B. No patient was assigned to group 2A. All patients in group 1A, representing definite SU, completed syphilis test (rapid plasma reagin [RPR], enzyme immunoassay [EIA], and fluorescent treponemal antibody-absorption [FTA-ABS]) for vitreous, and all vitreous samples yielded positive results. Of the 5 subjects in group 1B, 3 cases were considered to be not SU with different conditions, and 2 were indeterminate for SU. They presented with different features not typical of SU, and they had variable and fewer positive syphilis antibody responses. The most sensitive test for detecting syphilis antibodies in vitreous was EIA (90.9%), followed by RPR (80.0%) and FTA-ABS IgG (78.9%). EIA and FTA-ABS had the highest specificity, detecting 100% of the syphilis antibody.

CONCLUSIONS

Vitreous analysis of syphilis antibody can serve as a supplementary test to confirm SU in selected cases as the proposed algorithm.

Immunological tests and their interpretation in uveitis

Uveitis is a complex disorder including both infectious and non-infectious etiologies. Clinical diagnosis is a challenge because many diseases share common clinical signs. Laboratory support is crucial for confirming the clinical diagnosis. Laboratory diagnosis includes direct tests and indirect tests. For example smear, culture, and molecular diagnostics demonstrate the pathogens, hence they are direct tests. Immunologic tests employ an antigen to detect presence of antibodies to a pathogen, or an antibody to detect the presence of an antigen, of the pathogen in the specimens. The immunological tests used in laboratories are made by producing artificial antibodies that exactly “match” the pathogen in question. When these antibodies come into contact with a sample they bind to the matching pathogen if found in the sample. Hence they are grouped under indirect evidence. There are several investigations in uveitis to reach the confirmed diagnosis including microbiological, immunological, imaging and molecular diagnostic testing. In this section we will discuss immunological investigations of infectious and non-infectious uveitis.