High levels of anti-tuberculin (IgG) antibodies correlate with the blocking of T-cell proliferation in individuals with high exposure to Mycobacterium tuberculosis

SummaryObjectivesTo determine the effect of anti-tuberculin antibodies in the T-cell proliferation in response to tuberculin and Candida antigens in individuals with different levels of tuberculosis (TB) risk.MethodsSixteen high-risk TB individuals, 30 with an intermediate TB risk (group A), and 45 with a low TB risk (group B), as well as 49 control individuals, were studied. Tuberculin skin test (TST) results were analyzed and serum levels of antibodies (IgG and IgM) against purified protein derivative (PPD) were measured by ELISA. Tuberculin and Candida antigens were used to stimulate T-cell proliferation in the presence of human AB serum or autologous serum.ResultsHigh levels of anti-tuberculin IgG antibodies were found to be significantly associated with the blocking of T-cell proliferation responses in cultures stimulated with tuberculin but not with Candida antigens in the presence of autologous serum. This phenomenon was particularly frequent in high-risk individuals with high levels of anti-tuberculin IgG antibodies in the autologous serum when compared to the other risk groups, which exhibited lower levels of anti-tuberculin antibodies.ConclusionsAlthough cellular immunity plays a central role in the protection against TB, humoral immunity is critical in the control of Mycobacterium tuberculosis infection in high-risk individuals with latent TB infection

COVID-19 Transmission in Children: Implications for Schools

The COVID-19 pandemic poses multiple issues of importance to child health including threats to physical health and disruption of in-school learning. This chapter reviews what is currently known about COVID-19 epidemiology, presentation, pathophysiology, case definitions, therapies, and in-school transmission in children. COVID-19 has some unique characteristics in children including the rare yet severe Multisystem Inflammatory Syndrome in Children (MIS-C) that may be related to acquired immune responses. There are limited studies to date to define therapeutic guidelines in children, however consensus recommendations from multiple organizations are summarized including the use of immunomodulatory therapies (intravenous immunoglobulin, steroids, anakinra and tocilizumab), antiplatelet (aspirin) and anti-coagulant (low molecular weight heparin) therapies. Finally, considerations for safe return to the classroom are discussed including strategies for optimized student to teacher ratios, hand washing, social distancing, sibling pairing and staged re-opening strategies

Characterization of the Memory Antibody Response to Zika in a Flavivirus-Endemic Region of Colombia

(Title) Characterization of the Memory Antibody Response to Zika in a Flavivirus-Endemic Region of Colombia. (Primary Presenter) Grace Mantus (Co-Authors) Grace Mantus, Liliana Encinales, Andres Angelo Cadena Bonfanti, Nelly Pacheco, Aileen Chang, Rebecca Lynch (Abstract) With an increasing number of Zika vaccines moving through clinical trials, there is a need to better understand the antibody response caused by Zika infection in flavivirus endemic areas. In this study, we sought to determine the longevity and characteristics of the memory antibody response to Zika infection in 40 Colombian individuals infected during the 2016 epidemic. Luciferase-based neutralization assays using a recombinant viral particle (RVP) system were performed to determine individual’s neutralizing antibody titers against dengue serotypes 1 and 2 and Zika. Based on the results of the Zika RVP assay, individuals were classified as positive (ID50\u3e500; n=20) or negative (ID50\u3c500; n=20) for previous Zika infection. Within the Zika+ group, neutralization was further tested for sensitivity to a mutation in the lateral ridge (LR) of the Zika domain III E protein (K394A). Zika+ individuals had significantly higher neutralizing titers against dengue-1 and dengue-2 than Zika- individuals. There was no significant difference observed in the overall ability of the Zika+ group to neutralize the K394A mutant as compared to wildtype, but rare individuals demonstrated a reduction in neutralization of the mutant virus. Overall, we observed that the effects of Zika infection on an individual’s antibody response are long-lasting. Elevated titers of dengue neutralizing antibodies appear to persist at least 8 months post infection. This observation suggests that Zika infection triggers a boost in neutralizing antibody responses across dengue serotypes in flavi-immune individuals. Despite the isolation of potent neutralizing antibodies against the LR in both humans and mice challenged with Zika, we did not detect significant titers of Zika neutralizing antibodies targeting the LR. While these antibodies might be present, they do not appear to be the immunodominant response in the majority of persons infected with Zika in Colombia

Stiffness, pain, and joint counts in chronic chikungunya disease: relevance to disability and quality of life.

Introduction/Objectives: To characterize the importance of musculoskeletal stiffness in a cohort of chikungunya patients with chronic joint symptoms. Method: Eighty-two patients were followed up 3 years after chikungunya infection. Tender and swollen joint counts, a pain intensity scale, Health Assessment Questionnaire-Disability Index (HAQ-DI), and the EuroQol EQ-5D quality of life instrument were completed. A musculoskeletal stiffness questionnaire provided scores for overall stiffness and its components: stiffness severity, physical impact, and psychosocial impact. Results: Patients had a mean age 51 ± 14 years. Sixty-seven patients were still experiencing chronic arthralgia. Musculoskeletal stiffness was reported by 43/67 patients with arthralgia and 3/15 patients without arthralgia. A physical impact of stiffness was reported by 87% patients and psychosocial impact by 71% patients. Mean tender joint count in patients reporting arthralgia was 6 ± 7, mean pain intensity 65 ± 20 out of 100, mean HAQ-DI was 0.54 ± 0.52, and mean EQ-VAS global health perception was 68 ± 62 out of 100. Stiffness severity was correlated with tender joint counts (ρ = 0.46) and pain intensity (ρ = 0.40). All three measures were equally well correlated with the EuroQol-VAS global health perception. Pain and tender joints were better correlated with the HAQ-DI (ρ = 0.68 and ρ = 0.63), but stiffness was more strongly correlated with several quality of life domains, including mobility. Swollen joints were a poor predictor of outcomes. Conclusions: Musculoskeletal stiffness following chikungunya infection is distinct from arthralgia. It does not always occur in the same patients or with a corresponding intensity. Joint pain and stiffness may be independently associated with disability and quality of life assessments