Urine Lipoarabinomannan Testing in Adults With Advanced Human Immunodeficiency Virus in a Trial of Empiric Tuberculosis Therapy

BACKGROUND

The urine lipoarabinomannan (LAM) antigen test is a tuberculosis (TB) diagnostic test with highest sensitivity in individuals with advanced human immunodeficiency virus (HIV). Its role in TB diagnostic algorithms for HIV-positive outpatients remains unclear.

METHODS

The AIDS Clinical Trials Group (ACTG) A5274 trial demonstrated that empiric TB therapy did not improve 24-week survival compared to isoniazid preventive therapy (IPT) in TB screen-negative HIV-positive adults initiating antiretroviral therapy with CD4 counts <50 cells/µL. Retrospective LAM testing was performed on stored urine obtained at baseline. We determined the proportion of LAM-positive participants and conducted modified intent-to-treat analysis excluding LAM-positive participants to determine the effect on 24-week survival, TB incidence, and time to TB using Kaplan-Meier method.

RESULTS

A5274 enrolled 850 participants; 53% were male and the median CD4 count was 18 (interquartile range, 9-32) cells/µL. Of the 850, 566 (67%) had LAM testing (283 per arm); 28 (5%) were positive (21 [7%] and 7 [2%] in the empiric and IPT arms, respectively). Of those LAM-positive, 1 participant in each arm died and 5 of 21 and 0 of 7 in empiric and IPT arms, respectively, developed TB. After excluding these 28 cases, there were 19 and 21 deaths in the empiric and IPT arms, respectively (P = .88). TB incidence remained higher (4.6% vs 2%, P = .04) and time to TB remained faster in the empiric arm (P = .04).

CONCLUSIONS

Among outpatients with advanced HIV who screened negative for TB by clinical symptoms, microscopy, and Xpert testing, LAM testing identified an additional 5% of individuals with TB. Positive LAM results did not change mortality or TB incidence.

Clinical value of cerebrospinal fluid neurofilament light chain in semantic dementia

BACKGROUND

Semantic dementia (SD) is a neurodegenerative disorder characterised by progressive language problems falling within the clinicopathological spectrum of frontotemporal lobar degeneration (FTLD). The development of disease-modifying agents may be facilitated by the relative clinical and pathological homogeneity of SD, but we need robust monitoring biomarkers to measure their efficacy. In different FTLD subtypes, neurofilament light chain (NfL) is a promising marker, therefore we investigated the utility of cerebrospinal fluid (CSF) NfL in SD.

METHODS

This large retrospective multicentre study compared cross-sectional CSF NfL levels of 162 patients with SD with 65 controls. CSF NfL levels of patients were correlated with clinical parameters (including survival), neuropsychological test scores and regional grey matter atrophy (including longitudinal data in a subset).

RESULTS

CSF NfL levels were significantly higher in patients with SD (median: 2326 pg/mL, IQR: 1628-3593) than in controls (577 (446-766), p<0.001). Higher CSF NfL levels were moderately associated with naming impairment as measured by the Boston Naming Test (rs =-0.32, p=0.002) and with smaller grey matter volume of the parahippocampal gyri (rs =-0.31, p=0.004). However, cross-sectional CSF NfL levels were not associated with progression of grey matter atrophy and did not predict survival.

CONCLUSION

CSF NfL is a promising biomarker in the diagnostic process of SD, although it has limited cross-sectional monitoring or prognostic abilities.

Few eligible for the newly recommended short course MDR-TB regimen at a large Mumbai private clinic

BACKGROUND

India has the world's highest tuberculosis burden, and Mumbai is particularly affected by multidrug resistant tuberculosis (MDR-TB). WHO recommends short, intensive treatment ("Short Course") for previously untreated pulmonary MDR-TB patients but does not require universal drug susceptibility testing (DST) before Short Course. DST would likely screen out many MDR-TB patients in places like Mumbai with significant drug resistance.

METHODS

MDR-TB patients at a private clinic were recruited for a prospective observational cohort. Short Course eligibility was evaluated by clinical criteria and DST results. Eligibility by DST was classified as rifampin monoresistance (as tested by Xpert MTB/RIF), rifampin, fluoroquinolones, and 2nd-line injectable drugs resistance (as tested by line probe assays) and resistance to other drugs.

RESULTS

Of 559 participants with MDR-TB, 33% met clinical eligibility for Short Course. DST for rifampin, fluoroquinolones, and 2nd-line injectable drugs excluded 74.7% of participants. Complete phenotypic DST excluded 96.6% of participants. Prior treatment with either 1st or 2nd-line drugs did not significantly affect eligibility.

CONCLUSIONS

In a global MDR-TB hotspot, < 5% of participants with MDR-TB were appropriate for Short Course by clinical characteristics and DST results. Rapid molecular testing would not sufficiently identify drug resistance in this population. Eligibility rates were not significantly reduced by prior TB treatment.