Clinical and diagnostic features of central nervous system tuberculosis in Indian children - a descriptive study.

Background: Children with tuberculous meningitis (TBM) present with diagnostic challenges as they often have atypical clinical features. Objective: To describe the baseline characteristic features of children diagnosed with central nervous system (CNS) TB (TBM and tuberculoma). Design: Retrospective descriptive study. Methods: Children less than 12 years presenting with neurological signs and symptoms were assessed for a therapeutic TBM trial eligibility. The results of their clinical, laboratory, neuroimaging, cerebrospinal fluid evaluations were analysed for TBM diagnosis. Results: Of 600 children evaluated, 61(10%) had CNS tuberculosis; TBM 47, tuberculoma 14. 20(33%) had definite TBM. Mean age of children with TBM was 5 ± 3.4 years. Of 47, 13(28%), 21(45%) and 13(28%) had grade I, II, and III disease respectively. Abnormalities suggestive of TBM in MRI and computed tomography brain were observed in 76% (26/34) and 77% (24/31) respectively. Abnormal cerebrospinal fluid white blood cell count, protein and glucose were observed in 56% (24/43), 49% (22/45), 47% (21/45) respectively. Among 41 patients with TBM followed up until discharge, five died. Conclusion: Younger children with TBM have severe forms. Confirmatory results may not be available in all. A holistic approach to care including addressing complications of hydrocephalus and strokes is needed.

Clinical features, results of brain imaging and other tests in the cerebrospinal fluid among children diagnosed with tuberculous meningitis ­ descriptive study Why was the study done? What did the researchers do? Records of children aged between 6 months and 12 years who presented to the health care centre with signs and symptoms of central nervous system (CNS) disease and assessed for tuberculous meningitis (TBM) clinical trial eligibility were reviewed. The research team studied the signs and symptoms of the TBM, results of the CT/MRI brain scan and tests which were done in the cerebrospinal fluid (CSF) during hospitalization. What did the researchers find? Total number of children who presented to the health centre during the study period with CNS complaints and underwent lumbar puncture were 600. Among them 61 were diagnosed with CNS TB (47 had TBM and 14 had tuberculoma). Half of them were less than five years of age. Ten had neurological dysfunction. Fever, vomiting were the common complaints. Almost half of the children had vomiting, altered level of consciousness and seizures. Tests done in the CSF detected the bacteria causing TBM in half of the children. Abnormal cell counts or biochemical changes in the CSF specific to TBM were observed in half of the children. Abnormalities in CT/MRI imaging with features specific to the disease were observed in closer to three fourth of the children. What do the findings mean? Children with TBM often present late for care with severe forms and its complications. There would be diagnostic challenges as the symptoms were vague and might not present in a specific manner, specific tests in the CSF could be negative and if undiagnosed could lead to severe morbidity impacting the quality of life or death. Taking the overall picture of presenting complaints, results of CSF test and brain scan and with high degree of suspicion, TBM should be diagnosed early and managed appropriately.

Comparison of two mycobacterial strains in performance of the whole blood mycobacterial growth inhibition assay in Indian children.

A major challenge in tuberculosis is identifying correlates of a protective immune response. The Mycobacterial Growth Inhibition Assay (MGIA) is a functional assay providing an integrated measure of the host immune response to mycobacteria. However, its feasibility is limited by reliance on biosafety level 3 facilities, and its performance has not been widely evaluated in TB-endemic settings. Here, we compared two mycobacterial strains (M. tuberculosis H37Rv versus attenuated M. bovis BCG) in the performance of whole-blood MGIA in 30 TB-exposed children (median age 2 years) in Chennai, India. The time-to-positivity in both assays was similar (5.7 days vs 6 days) and the mycobacterial growth of M. tuberculosis H37Rv and M. bovis BCG were correlated (r = 0.64, p<0.0001). In Bland-Altman analysis, the bias was -0.54 days (95% limit of agreement -2.08, 0.99). Collectively, our results indicate that M. tuberculosis H37Rv can be substituted with the less virulent M. bovis BCG strain to improve feasibility of the MGIA assay, particularly in low-income settings.

Pooled Testing Strategies for SARS-CoV-2 diagnosis: A comprehensive review.

SARS-CoV-2 has surged across the globe causing the ongoing COVID-19 pandemic. Systematic testing to facilitate index case isolation and contact tracing is needed for efficient containment of viral spread. The major bottleneck in leveraging testing capacity has been the lack of diagnostic resources. Pooled testing is a potential approach that could reduce cost and usage of test kits. This method involves pooling individual samples and testing them 'en bloc'. Only if the pool tests positive, retesting of individual samples is performed. Upon reviewing recent articles on this strategy employed in various SARS-CoV-2 testing scenarios, we found substantial diversity emphasizing the requirement of a common protocol. In this article, we review various theoretically simulated and clinically validated pooled testing models and propose practical guidelines on applying this strategy for large scale screening. If implemented properly, the proposed approach could contribute to proper utilization of testing resources and flattening of infection curve.

Evolution of Neutralization Response in HIV-1 Subtype C-Infected Individuals Exhibiting Broad Cross-Clade Neutralization of HIV-1 Strains.

Strain-specific neutralizing antibodies develop in all human immunodeficiency virus type 1 (HIV-1)-infected individuals. However, only 10-30% of infected individuals produce broadly neutralizing antibodies (bNAbs). Identification and characterization of these bNAbs and understanding their evolution dynamics are critical for obtaining useful clues for the development of an effective HIV vaccine. Very recently, we published a study in which we identified 12 HIV-1 subtype C-infected individuals from India whose plasma showed potent and broad cross-clade neutralization (BCN) ability (1). In the present study, we report our findings on the evolution of host bNAb response over a period of 4 years in a subset of these individuals. Three of the five individuals (NAB033, NAB059, and NAB065) demonstrated a significant increase (p < 0.05) in potency. Interestingly, two of the three samples also showed a significant increase in CD4 binding site-specific antibody response, maintained stable CD4+ T cell counts (>350 cells/mm3) and continued to remain ART-naïve for more than 10 years after initial diagnosis, implying a strong clinical correlation with the development and evolution of broadly neutralizing antibody response against HIV-1.