Discordance of two interferon-γ release assays and tuberculin skin test in patients with uveitis

Role of Interferon-Gamma Release Assay for the Diagnosis and Clinical Follow up in Ocular Tuberculosis

PURPOSE

To assess the performance of interferon-gamma release assay (IGRA) associated with tuberculosis skin test (TST) for ocular tuberculosis (OTB) diagnosis and therapeutic decision making.

METHOD

One hundred and ninety-one patients with ocular inflammation were prospectively followed-up. Patients with clinical signs highly suspected of OTB, TST≥10 mm, and/or IGRA≥0.35 IU/mL received antitubercular therapy (ATT). Sensitivity (Se), specificity (Sp), and area under the curve (AUC) were assessed.

RESULTS

Seventy-two (37.7%) patients received ATT for presumed OTB. Combining TST and IGRA had Se=89.6%, Sp=99.2%, and AUC (0.98) significantly higher compared to TST (0.85, Z=6.3, p<.001) or IGRA (0.95, Z=2.5, p=.01). Prior history of corticosteroids or immunosuppressant with concomitantly oral prednisone and baseline IGRA> 2.0 IU/mL was associated significantly with more recurrences in ATT patients (p=.01)      .

CONCLUSION

Considering TST and IGRA together was more effective in assessing OTB diagnosis. The real value of the IGRA test to predict recurrences needs further studies.

Absence of Evidence as The Evidence Of Absence: The Curious Case of Latent Infection Causing Ocular Tuberculosis

Ocular tuberculosis (TB) is frequently considered as intraocular inflammation in the setting of latent TB, owing mainly to the absence of microbiological evidence of Mycobacterium tuberculosis in ocular fluid samples. Even though such lack of microbiological evidence, and of systemic signs of active TB disease, are suggestive of latent TB infection, molecular and rare histopathologic evidence of mycobacteria in the eye, and favourable response of ocular inflammation to anti-TB therapy point to the presence of active infection in ocular TB. Here, we discuss how intraocular inflammation in ocular TB is not merely an immunologic response to bacilli, but an active tuberculosis infection. We will discuss the reason for the frequent absence of microbiological evidence of TB in the eye in ocular TB and the diagnostic hierarchy to arrive at the diagnosis of this infectious uveitis entity.

Global prevalence and clinical outcomes of tubercular uveitis: a systematic review and meta-analysis

Tubercular uveitis (TBU) is an inflammation/infection of the eye secondary to Mycobacterium tuberculosis infection. The difficulty in making the diagnosis has resulted in variable prevalence and clinical response rates. We aimed to determine the global prevalence of TBU in uveitis patients stratified by TB high-burden countries (HBCs) and non-HBCs and by geographic regions and the clinical response of TBU to antitubercular treatment We performed a systematic review and meta-analysis of TBU studies published in PubMed, Scopus and EMBASE, up to June 30, 2020. A random effects model was used for all meta-analyses. Of 5,018 articles identified, 70 prevalence studies (65,607 uveitis and 3,166 TBU cases) and 18 clinical outcome studies (1,570 TBU cases; 1,304 responded to anti-tubercular therapy [ATT]) were analyzed. The overall weighted prevalence of TBU was 4.0% (95% CI, 3-5); in TB HBCs it was 7.0% (95% CI, 5-11), non-HBCs 3.0% (95% CI, 2-4), and sub-Saharan Africa 11.0% (95% CI, 8-15). The overall weighted clinical response was 82.0% (95% CI, 75-89). Despite the difficulty in diagnosing TBU, the prevalence is expectantly higher in HBCs, and sub-Saharan Africa and the clinical outcome is poor. Standardization of diagnostic criteria and ATT is warranted in future cohort studies.

[Observational study of QuantiFERON® management for ocular tuberculosis diagnosis: Analysis of 244 consecutive tests]

INTRODUCTION

Ocular tuberculosis (TB) diagnosisremains difficult and quantiferon (QFT) contribution needs still yet to be specified, despite its generalization in France. The purpose of this observational study is to assess in which ocular inflammation (OI) presentation QFT is prescribed and to evaluate the added value of new QuantiFERON®-TB Gold Plus (QFT-Plus) test for diagnosis ocular TB diagnosis.

PATIENTS AND METHODS

Monocentric, observational study, carried out in an ophthalmology department over a period of 5 months. Inclusion criteria were defined as an existence of an OI for which a QFT-Plus test was part of the etiological investigations. Of the 316 consecutive files, 72 were excluded (indeterminate test, prescription before anti-TNFα or immunosuppressant initiation, missing data, wrong indication) and 244 were selected and divided into two groups: group one (anterior uveitis/episcleritis, n=129) and group two (intermediate/posterior uveitis/optic neuritis/ocular myositis, n=115). All positive QFT patients underwent an etiological investigation including thoracic imaging.

RESULTS

Forty-five patients, aged 52±12 years, had positive QFT (18.5%), including 18 patients for group 1 and 27 for group 2. Living in TB-endemic area, TB exposure and chest imaging abnormalities were identified in 70%, 27% and 22% of cases, respectively. OI was chronic in 36% of cases (group one, 4/18; group two, 12/27). None of the 18 patients, in group 1, received anti-tuberculosis treatment (ATT) or experienced a relapse during one-year follow-up. Four QFT+ patients, from group 2 (15%) had another associated disease explaining their uveitis. Among the 23 other patients without identified etiology, 13 had at least one relevant ophthalmological signs predictive of TB uveitis (posterior synechiae, retinal vasculitis and/or choroidal granuloma) (59%). Eleven patients received a 6-month ATT trial. Radiological abnormalities and granulomas at angiography were significantly more frequent among treated patients (p=0.03 and 0.001, respectively). A full OI recovery was observed for 8 patients (73%), considered ex-post as ocular TB. Nine patients in group 2 received rifampicin/isoniazid dual therapy for 3 months, but no conclusion could be drawn as to the benefit of such prescription on OI. QFT rate comparison, according to CD4 stimulation by ESAT-6/CFP-10 peptides or by CD4/CD8 co-stimulation, was comparable and found only 4 cases of discrepancy (1.6%). None of these 4 cases had ocular TB diagnosis.

CONCLUSION

Positive QFT frequency among patients consulting for posterior OI remains high. In this study, radiological abnormalities and granulomas at angiography seemed to be more closely related to clinician decision for starting ATT trial in QFT+ patients, which was effective in 73% of cases. QFT-Plus does not seem more relevant than QFT-TB in exploring an OI. Prospective studies are necessary to codify QFT management in the etiological assessment of OI and clearly define ATT trial indications as well as their modalities.

[Ocular tuberculosis]

Despite extensive investigations, including the use of Interferon-gamma release assays (IGRA), the diagnosis of intraocular tuberculosis (TB) remains challenging. Ocular evidence of Mycobacterium tuberculosis in low endemic countries for TB is extremely rare, leading mostly to a TB-related ocular inflammation presumptive diagnosis. This present work aims: to highlights the main clinical patterns suggestive of ocular TB; and the latest recommended guidelines for diagnosing ocular TB to clarify interferon-gamma release assay (IGRA) contribution and accuracy to the management of intraocular TB and its diagnosis, in addition to other available diagnostic tools, such as tuberculin skin test, bacteriologic and histologic analysis from intra/extra ocular sample and radiographic investigations; to define the accuracy of these diagnostic tools according to the endemic TB prevalence; and finally to identify therapeutic strategies adapted to the main clinical presentations of ocular TB. Our review of the literature shows that management of suspected ocular TB differs significantly based on whether patients are from high or low TB prevalence countries since accuracy of chest X-ray, tuberculin skin test and IGRA is significantly different. Taking into account these discrepancies, distinct guidelines should be determined for managing patients with suspected ocular TB, taking into consideration home prevalence of TB-patients.

The efficacy of latent tuberculosis treatment for immunocompetent uveitis patients with a positive T-SPOT.TB test: 6-year experience in a tuberculosis endemic region

PURPOSE

To assess the efficacy of latent tuberculosis (TB) treatment for immunocompetent uveitis patients with a positive T-SPOT.TB test.

METHODS

This is a consecutive case series of all T-SPOT.TB positive latent TB patients with presumed tuberculous uveitis managed with anti-tuberculous therapy (ATT) from 1 January 2000 to 31 December 2015. Patients with active TB or other known causes of uveitis, immunocompromised states and those followed up < 12 months were excluded. Descriptive statistics and hypothesis testing were performed, with a significance level of p < 0.05 taken.

RESULTS

Among the 75 T-SPOT.TB tests performed for uveitis, 14 cases were enrolled. Mycobacterium tuberculosis was isolated in none of the sputum and intraocular samples. Most cases had posterior uveitis (10/14 cases, 71.4%) and/or intermediate uveitis (9/14 cases, 64.3%). Vasculitis was predominantly occlusive. The mean presenting best-corrected visual acuity (BCVA) was 0.18, improving to 0.44 at 6 months (p = 0.03) and 0.40 at 12 months. (p = 0.03). At 1 year, remission of uveitis was achieved in 92.9%, in which none of them recurred at the last follow-up. High-dose systemic steroid was required in 50% of patients. Only 1 patient was steroid dependent at 18 months. The BCVA improvement in patients treated with or without steroid was comparable.

CONCLUSION

In a TB-endemic region with wide Bacille Calmette-Guerin vaccination coverage, ATT for immunocompetent uveitis patients with latent TB identified from T-SPOT.TB test can improve vision, induce long-term steroid-free remission, and prevent recurrence and systemic reactivation of TB in those who require steroid.

Retina and the tubercle Bacillus: Four decades of our journey and current understanding

Tuberculosis continues to be a major pandemic with enormous public health implication. Involvement of ocular tissues in the form of tubercles, tuberculomas, panophthalmitis, and iris granulomas are well recognized as definitive manifestations of tuberculosis. For these lesions, confirmatory evidence is available in the form of demonstration of acid-fast Bacillus on Ziehl-Neelsen staining. For other retinochoroidal disorders such as central serous chorioretinopathy, retinal vasculitis, and presumed ocular tuberculosis, hard evidence about the role of Mycobacterium tuberculosis is lacking. In this review, work done at our center over the past four decades in the form of experimental animal studies, nucleic acid amplification assays and clinical studies regarding the above retinochoroidal pathologies and the tubercle Bacillus is presented. It is possible that revisiting experimental animal studies may be a way forward in the current scenario of ambiguity about the cause-effect relationship between M. tuberculosis and few of the retinochoroidal disorders.

Presumed tuberculosis-associated uveitis: rising incidence and widening criteria for diagnosis in a non-endemic area

PurposeTo assess the incidence, clinical ocular involvement and effectiveness of anti-tuberculous treatment in patients with chronic uveitis presumed to be associated with tuberculosis in a non-endemic community.Patients and methodsRetrospective case series of patients with uveitis and evidence of tuberculosis, with no other identified cause of uveitis, who underwent a 6-month course of standard anti-tuberculosis treatment between 2008 and 2015. The response to treatment was assessed at 6 and 12 months after initiation of treatment.ResultsForty-eight patients were included of whom 36 (75%) were born outside the United Kingdom. Only five had concurrent active pulmonary or nodal tuberculosis. There were 85 affected eyes, including 25 with granulomatous anterior uveitis, 32 with retinal vasculitis (occlusive in 21), and 20 with multifocal choroiditis or serpiginous-like retinochoroiditis. Gamma-interferon testing was positive in 95%. Complete resolution at end point was seen in only 60%, but a further 19% were inflammation-free on topical steroid only. Resolution was lower (50%) in those with panuveitis compared to other anatomical types (75%). Sixty-four eyes (75%) had a LogMAR visual acuity of 0.1 or better at the end of the study.ConclusionsThe incidence of presumed tuberculosis-associated uveitis (TBU) has almost quadrupled in this region. The efficacy of treatment has not been enhanced by the introduction of gamma-interferon testing to support diagnosis. Some patients may require more prolonged antibiotic therapy to ensure quiescence, but chronic non-infective anterior uveitis may in any case follow treated TBU.