Identification of Recent Tuberculosis Exposure Using QuantiFERON-TB Gold Plus, a Multicenter Study.

We investigated whether the difference of antigen tube 2 (TB2) minus antigen tube 1 (TB1) (TB2-TB1) of the QuantiFERON-TB gold plus test, which has been postulated as a surrogate for the CD8+ T-cell response, could be useful in identifying recent tuberculosis (TB) exposure. We looked at the interferon gamma (IFN-γ) responses and differences in TB2 and TB1 tubes for 686 adults with QFT-plus positive test results. These results were compared among groups with high (368 TB contacts), low (229 patients with immune-mediated inflammatory diseases [IMID]), and indeterminate (89 asylum seekers or people from abroad [ASPFA]) risks of recent TB exposure. A TB2-TB1 value >0.6 IU·ml-1 was deemed to indicate a true difference between tubes. In the whole cohort, 13.6%, 10.9%, and 11.2% of cases had a TB2>TB1 result in the contact, IMID, and ASPFA groups, respectively (P = 0.591). The adjusted odds ratios (aORs) for an association between a TB2-TB1 result of >0.6 IU·ml-1 and risk of recent exposure versus contacts were 0.71 (95% confidence interval [CI], 0.31 to 1.61) for the IMID group and 0.86 (95% CI, 0.49 to 1.52) for the ASPFA group. In TB contact subgroups, 11.4%, 15.4%, and 17.7% with close, frequent, and sporadic contact had a TB2>TB1 result (P = 0.362). The aORs versus the close subgroup were 1.29 (95% CI, 0.63 to 2.62) for the frequent subgroup and 1.55 (95% CI, 0.67 to 3.60) for the sporadic subgroup. A TB2-TB1 difference of >0.6 IU·ml-1 was not associated with increased risk of recent TB exposure, which puts into question the clinical potential as a proxy marker for recently acquired TB infection. IMPORTANCE Contact tuberculosis tracing is essential to identify recently infected people, who therefore merit preventive treatment. However, there are no diagnostic tests that can determine whether the infection is a result of a recent exposure or not. It has been suggested that by using the QuantiFERON-TB gold plus, an interferon gamma (IFN-γ) release assay, a difference in IFN-γ production between the two antigen tubes (TB2 minus TB1) of >0.6 IU·ml-1 could serve as a proxy marker for recent infection. In this large multinational study, infected individuals could not be classified according to the risk of recent exposure based on differences in IFN-γ in TB1 and TB2 tubes that were higher than 0.6 IU·ml-1. QuantiFERON-TB gold plus is not able to distinguish between recent and remotely acquired tuberculosis infection, and it should not be used for that purpose in contact tuberculosis tracing.

Neuroretinitis caused by Bartonella henselae in Gipuzkoa, 2014-2019.

INTRODUCTION: Bartonella henselae causes cat scratch disease (CSD), spread by a cat scratch or bite. Cats are its main reservoir. This sometimes results in optic neuritis or neuroretinitis. OBJECTIVE: To review these conditions in Gipuzkoa (Spain), 2014-2019. METHODS: A retrospective review of serology registries and clinical registries, selecting those with consistent clinical signs, contact with cats and positive serology for B. henselae (IgG-IFA ≥1/256). RESULTS: Sixty-four patients had CSD. Of these, one had optic neuritis and 3 had neuroretinitis (4/64; 6.3%). In 3 patients, flu-like symptoms preceded eye symptoms. Two suffered from loss of visual acuity at discharge, despite prolonged treatment with antibiotics and corticosteroids. CONCLUSION: Optic neuritis and neuroretinitis caused by B. henselae are severe complications with a non-negligible incidence among patients with CSD in Gipuzkoa. We recommend ruling out CSD in patients with symptoms of optic neuritis or neuroretinitis (sudden vision loss, etc.) and contact with cats.

Neuroretinitis caused by Bartonella henselae in Gipuzkoa, 2014-2019. / Neurorretinitis por Bartonella henselae en Gipuzkoa, 2014-2019.

INTRODUCTION: Bartonella henselae causes cat scratch disease (CSD), spread by a cat scratch or bite. Cats are its main reservoir. This sometimes results in optic neuritis or neuroretinitis. OBJECTIVE: To review these conditions in Gipuzkoa (Spain), 2014-2019. METHODS: A retrospective review of serology and clinical records, selecting those with consistent clinical signs, contact with cats and positive serology for B. henselae (IgG-IFA≥1/256). RESULTS: Sixty-four patients had CSD. Of these, one had optic neuritis and 3 had neuroretinitis (4/64; 6.3%). In 3 patients, flu-like symptoms preceded eye symptoms. Two suffered from loss of visual acuity at discharge, despite prolonged treatment with antibiotics and corticosteroids. CONCLUSION: Optic neuritis and neuroretinitis caused by B. henselae are severe complications with a non-negligible incidence among patients with CSD in Gipuzkoa. We recommend ruling out CSD in patients with symptoms of optic neuritis or neuroretinitis (sudden vision loss, etc.) and contact with cats.