High Dimensional Immune Profiling Reveals Different Response Patterns in Active and Latent Tuberculosis Following Stimulation With Mycobacterial Glycolipids.

Upon infection with Mycobacterium tuberculosis (Mtb) the host immune response might clear the bacteria, control its growth leading to latent tuberculosis (LTB), or fail to control its growth resulting in active TB (ATB). There is however no clear understanding of the features underlying a more or less effective response. Mtb glycolipids are abundant in the bacterial cell envelope and modulate the immune response to Mtb, but the patterns of response to glycolipids are still underexplored. To identify the CD45+ leukocyte activation landscape induced by Mtb glycolipids in peripheral blood of ATB and LTB, we performed a detailed assessment of the immune response of PBMCs to the Mtb glycolipids lipoarabinomannan (LAM) and its biosynthetic precursor phosphatidyl-inositol mannoside (PIM), and purified-protein derivate (PPD). At 24 h of stimulation, cell profiling and secretome analysis was done using mass cytometry and high-multiplex immunoassay. PIM induced a diverse cytokine response, mainly affecting antigen-presenting cells to produce both pro-inflammatory and anti-inflammatory cytokines, but not IFN-γ, contrasting with PPD that was a strong inducer of IFN-γ. The effect of PIM on the antigen-presenting cells was partly TLR2-dependent. Expansion of monocyte subsets in response to PIM or LAM was reduced primarily in LTB as compared to healthy controls, suggesting a hyporesponsive/tolerance pattern derived from Mtb infection.

Characterization of the Infant Immune System and the Influence and Immunogenicity of BCG Vaccination in Infant and Adult Rhesus Macaques.

In many countries where tuberculosis (TB) is endemic, the Bacillus Calmette-Guérin (BCG) vaccine is given as close to birth as possible to protect infants and children from severe forms of TB. However, BCG has variable efficacy and is not as effective against adult pulmonary TB. At present, most animal models used to study novel TB vaccine candidates rely on the use of adult animals. Human studies show that the infant immune system is different to that of an adult. Understanding how the phenotypic profile and functional ability of the immature host immune system compares to that of a mature adult, together with the subsequent BCG immune response, is critical to ensuring that new TB vaccines are tested in the most appropriate models. BCG-specific immune responses were detected in macaques vaccinated within a week of birth from six weeks after immunization indicating that neonatal macaques are able to generate a functional cellular response to the vaccine. However, the responses measured were significantly lower than those typically observed following BCG vaccination in adult rhesus macaques and infant profiles were skewed towards the activation and attraction of macrophages and monocytes and the synthesis in addition to release of pro-inflammatory cytokines such as IL-1, IL-6 and TNF-α. The frequency of specific immune cell populations changed significantly through the first three years of life as the infants developed into young adult macaques. Notably, the CD4:CD8 ratio significantly declined as the macaques aged due to a significant decrease in the proportion of CD4+ T-cells relative to a significant increase in CD8+ T-cells. Also, the frequency of both CD4+ and CD8+ T-cells expressing the memory marker CD95, and memory subset populations including effector memory, central memory and stem cell memory, increased significantly as animals matured. Infant macaques, vaccinated with BCG within a week of birth, possessed a significantly higher frequency of CD14+ classical monocytes and granulocytes which remained different throughout the first three years of life compared to unvaccinated age matched animals. These findings, along with the increase in monokines following vaccination in infants, may provide an insight into the mechanism by which vaccination with BCG is able to provide non-specific immunity against non-mycobacterial organisms.

Immune Responses Following BCG Immunization of Infants in Uganda and United Kingdom Are Similar for Purified Protein Derivative but Differ for Secretory Proteins of Mycobacterium tuberculosis.

Introduction: The immunogenicity of BCG vaccination in infants differs between populations. We hypothesized that prenatal exposure to mycobacterial antigens might explain the differences in immune responses to BCG seen in other studies of infants in Africa and the United Kingdom (UK) and we explored this in birth cohorts in Uganda and the UK. Materials and Methods: Blood samples were obtained from BCG-immunized infants of mothers with (n = 110) and without (n = 121) latent Mycobacterium tuberculosis infection (LTBI) in Uganda and BCG-immunized infants of mothers without LTBI (n = 25) in the UK at 10 and 52 weeks after birth. Cytokine and chemokine responses to PPD were measured to assess responses to BCG immunization, and to ESAT6/CFP10 to assess exposure to or infection with M. tuberculosis or non-tuberculous mycobacteria (NTM) in 6-day whole blood culture supernatants by a 17-plex Luminex assay. Median responses were compared between Ugandan infants (together, and separated by maternal LTBI status) and UK infants. Results: The IFN-γ response to BCG vaccination was similar between Ugandan and UK infants at 10 and 52 weeks. At week 52, TNF production was marginally higher in Ugandan infants, but after adjusting for multiple comparisons this difference was not significant. At weeks 10 and 52, stimulation of blood with ESAT6/CFP10 produced significantly higher IFN-γ, TNF, IL-12p40, IL-1α, IL-1ß, IL-1Ra, IP-10, MIP-1α, MIP-1ß, and GM-CSF in Ugandan compared to UK infants. Stimulation of blood with ESAT6/CFP10 produced significantly higher amounts of IL-8 (p = 0.0001), IL-10 (p = 0.0022), and IL-13 (p = 0.0020) in the UK than in Ugandan infants of mothers without LTBI at week 10, but not at week 52. Conclusions: Immune responses to mycobacterial antigens following BCG immunization are similar for PPD, but differ for ESAT6/CFP10, between infants in Uganda and the UK. Neither maternal LTBI nor infant exposure to or infection with mycobacteria impacts the response to BCG. The observed global differences in immune response to BCG immunization are likely to be due to other causes.

A molecularly defined skin test reagent for the diagnosis of bovine tuberculosis compatible with vaccination against Johne's Disease.

Tuberculin Purified Protein Derivatives (PPDs) exhibit multiple limitations: they are crude extracts from mycobacterial cultures with largely unknown active components; their production depends on culture of mycobacteria requiring expensive BCL3 production facilities; and their potency depends on the technically demanding guinea pig assay. To overcome these limitations, we developed a molecularly defined tuberculin (MDT) by adding further antigens to our prototype reagent composed of ESAT-6, CFP-10 and Rv3615c (DIVA skin test, DST). In vitro screening using PBMC from infected and uninfected cattle shortlisted four antigens from a literature-based list of 18 to formulate the MDT. These four antigens plus the previously identified Rv3020c protein, produced as recombinant proteins or overlapping synthetic peptides, were formulated together with the three DST antigens into the MDT to test cattle experimentally and naturally infected with M. bovis, uninfected cattle and MAP vaccinated calves. We demonstrated significant increases in MDT-induced skin responses compared to DST in infected animals, whilst maintaining high specificity in unvaccinated or MAP vaccinated calves. Further, MDT can also be applied in in vitro blood-based interferon-gamma release assays. Thus, MDT promises to be a robust diagnostic skin and blood test reagent overcoming some of the limitations of PPDs and warrants full validation.

Different PPD-stimulated cytokine responses from patients infected with genetically distinct Mycobacterium tuberculosis complex lineages.

OBJECTIVES: The genetic diversity of Mycobacterium tuberculosis complex (MTBC) influences the immune response of the host, which may affect the immunodiagnostic tests and biomarker assessment studies used for tuberculosis (TB). This study aimed to determine whether the mycobacterial-antigen-stimulated cytokine responses vary with the genotype of the MTBC infecting the patient. METHODS: Eighty-one patients with confirmed active pulmonary TB were recruited, and MTBC clinical strains were isolated from their sputum for bacterial lineage single-nucleotide polymorphism typing. Whole blood was drawn from the patients to measure the purified protein derivative (PPD)-stimulated cytokine responses (GM-CSF, IFN-γ, IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, TNF-α, IFN-α, IL-12, eotaxin, IL-13, IL-15, IL-17, MIP1-α, MIP1-ß, MCP1, IL1RA, IP10, IL2R, MIG) with the Luminex multiplex immunoassay. RESULTS: Of the 24 cytokines studied, three were produced differentially in whole blood dependent on the infecting lineage of MTBC. Decreased production of IL-17 was observed in patients infected with modern lineages compared with patients infected with ancestral lineages (P < 0.01), and production of IFN-γ and IL-2 was significantly decreased in patients infected with lineage 4 strains compared with patients infected with lineage 3 strains (P < 0.05). CONCLUSION: MTBC strains belonging to lineage 4 induced a decreased whole-blood PPD-stimulated pro-inflammatory cytokine response.

Influence of vaccination against paratuberculosis on the diagnosis of caprine tuberculosis during official eradication programmes in Castilla y León (Spain).

The information generated from the official eradication programmes of caprine tuberculosis (TB) in Castilla y León, Spain, during 2018, has been used to assess the effect of vaccination against paratuberculosis (PTB) and the presence of this infection, on the single intradermal tuberculin (SIT) test results. Data from 121,665 goats belonging to 1936 different herds were analysed using generalized linear models. An epidemiological survey was conducted to know the herd immunization status against PTB and the date of last vaccination. All SIT test-positive animals were further investigated in order to confirm the diagnosis of TB, through bacterial culture, and PTB, by histopathological and qPCR analyses. SIT positivity was found in 39 (2.01%) herds and 507 (0.41%) goats. TB was confirmed by M. caprae or M. bovis isolation in 10 (0.51%) herds and 46 (0.038%) goats. PTB was diagnosed in 13 (33.33%) and 55 (10.84%) of the SIT test-positive herds and goats, respectively. Vaccination against PTB showed a significant influence on the results of the SIT test at herd level, with higher positivity detected among those herds vaccinated. However, this effect was not observed when the total number of animals was considered, where the highest positivity was found in unvaccinated goats. The time elapsed between vaccination and SIT test performance also influenced the results. The strongest effect was found when less than eight months elapsed between performing both activities, and to a lesser extent between 8 and 12 months. Conversely, no positive herds or animals were found when the time elapsed was higher than one year. No significant effect of the presence of PTB was observed. These findings demonstrate that the use of PTB vaccine does not result in false positives to a SIT test at individual level, provided that the time elapsed between the performance of both practices is higher than 12 months.

CD4+ T cell proliferative responses to PPD and CFP-10 associate with recent M. tuberculosis infection.

Interferon-γ release assays cannot differentiate latent from active tuberculosis (TB), nor identify the recently infected with increased risk of active disease. The objective of this study was to identify biomarkers of recent infection following exposure to tuberculosis, to increase the positive predictive value for incipient TB. Contacts to patients with pulmonary TB were tested repeatedly with interferon-γ release assays and flow-cytometry. Proliferative CD4+ T cell responses to purified protein derivative (PPD) and 11 M. tuberculosis antigens were analysed. The individual probability of recent and remote infection was estimated using clinical data in a novel mathematical model and compared with CD4+ responses in a prediction model. The most specific prediction of recent infection was high CD4+ proliferative responses to CFP-10 and PPD and a low CD4+ response to ESAT-6. CD4+ proliferative responses to Rec85a, Rec85b and Rv1284 were also observed in recent infection, but did not reach significance in the prediction model. CONCLUSIONS: High CD4+ proliferative responses to CFP-10 and PPD and a low response to ESAT-6 may be used as biomarkers to improve positive predictive values for recent LTBI and thus, increased risk of incipient TB. Rec85a, Rec85b and Rv1284 are also of interest to study further in this context.

Development of a diagnostic compatible BCG vaccine against Bovine tuberculosis.

Bovine tuberculosis (BTB) caused by Mycobacterium bovis remains a major problem in both the developed and developing countries. Control of BTB in the UK is carried out by test and slaughter of infected animals, based primarily on the tuberculin skin test (PPD). Vaccination with the attenuated strain of the M. bovis pathogen, BCG, is not used to control bovine tuberculosis in cattle at present, due to its variable efficacy and because it interferes with the PPD test. Diagnostic tests capable of Differentiating Infected from Vaccinated Animals (DIVA) have been developed that detect immune responses to M. bovis antigens absent in BCG; but these are too expensive and insufficiently sensitive to be used for BTB control worldwide. To address these problems we aimed to generate a synergistic vaccine and diagnostic approach that would permit the vaccination of cattle without interfering with the conventional PPD-based surveillance. The approach was to widen the pool of M. bovis antigens that could be used as DIVA targets, by identifying antigenic proteins that could be deleted from BCG without affecting the persistence and protective efficacy of the vaccine in cattle. Using transposon mutagenesis we identified genes that were essential and those that were non-essential for persistence in bovine lymph nodes. We then inactivated selected immunogenic, but non-essential genes in BCG Danish to create a diagnostic-compatible triple knock-out ΔBCG TK strain. The protective efficacy of the ΔBCG TK was tested in guinea pigs experimentally infected with M. bovis by aerosol and found to be equivalent to wild-type BCG. A complementary diagnostic skin test was developed with the antigenic proteins encoded by the deleted genes which did not cross-react in vaccinated or in uninfected guinea pigs. This study demonstrates the functionality of a new and improved BCG strain which retains its protective efficacy but is diagnostically compatible with a novel DIVA skin test that could be implemented in control programmes.

Enzyme-linked immunosorbent assay as complement of intradermal skin test for the detection of mycobacterium bovis infection in cattle.

Diagnostic tests based on cell-mediated immunity are used in programs for the control and eradication of bovine tuberculosis (bTB), which is mainly caused by Mycobacterium bovis. Additional serological assays could be performed as an ancillary method to detect an infected animal that fails to produce an immune response against the intradermal reaction (IDR), the official bTB test. In this study, we evaluated the effectiveness of an enzyme-linked immunosorbent assay (ELISA) that uses bovine PPD as a capture antigen as a complement to the IDR in herds with confirmed cases of bTB. The study was conducted in two stages. First, a panel of 200 serum samples was analyzed by ELISA. The sensitivity and specificity obtained were 60% and 99%, respectively. The subsequent stage consisted of evaluating 7,494 bovines from 14 selected dairy farms. The number of animals yielding a IDR negative/ELISA positive result were 200. A necropsy analysis of 33 of these IDR negative/ELISA positive animals revealed that 30 (91%) presented granulomatous lesions and positive M. bovis isolation. This finding confirmed bTB in most cases. Altogether, the results obtained in the present study suggest that the combined use of IDR and ELISA is an effective strategy to improve the control of bTB in endemic herds.

Characteristic profile of antibody responses to PPD, ESAT-6, and CFP-10 of Mycobacterium tuberculosis in pulmonary tuberculosis suspected cases in Surabaya, Indonesia.

Accurate and rapid diagnostic tools are important aspects of managing tuberculosis (TB) cases appropriately. However, the sensitivity and specificity of diagnostic kits based on immune response such as the tuberculin skin test (TST) and interferon gamma release assay (IGRA) are still debated. Thus, the exploration and assessment of specific biomarker-targeted antibodies are needed for the development of an accurate and rapid diagnostic tool. The present study was conducted in patients with a respiratory problem suspected to be TB at Dr. Soetomo Hospital, Surabaya, Indonesia. Among 102 patients tested by GeneXpert and AFB, 59 serum samples were from cases retrospectively determined to have active TB. A total of 102 serum of healthy controls (HC) was also collected. The PPD antigen and the recombinant CFP-10 and ESAT-6 proteins were prepared. Antibody responses against these proteins were evaluated by ELISA. All samples were also screened for the possibility of Mycobacterium avium-intracellulare complex (MAC) infection using Capilla MaC kit. The results showed that TB patients had a significantly higher concentration of IgG antibody in response to PPD than the HC. In addition, the receiver operating characteristic (ROC) curve analysis showed that PPD was acceptable for diagnostic purposes with an AUC value of 0.835 (95% CI 0.770-0.900, p < 0.0001). However, ESAT-6 and CFP-10 had low AUCs, and 32 samples from both groups showed a low concentration of IgA antibody against all antigens. The MAC detection results also showed that the concentration of IgA in the HC group was the highest. The current results indicate that PPD is a better antigen for antibody-based detection of TB than ESAT-6 and CFP-10. Based on the MAC detection assay, 53 people in the HC group were probably infected with rapidly growing nontuberculous mycobacteria (NTM), although antibody response to PPD was low.

Characteristic profile of antibody responses to PPD, ESAT-6, and CFP-10 of Mycobacterium tuberculosis in pulmonary tuberculosis suspected cases in Surabaya, Indonesia

Abstract Accurate and rapid diagnostic tools are important aspects of managing tuberculosis (TB) cases appropriately. However, the sensitivity and specificity of diagnostic kits based on immune response such as the tuberculin skin test (TST) and interferon gamma release assay (IGRA) are still debated. Thus, the exploration and assessment of specific biomarker-targeted antibodies are needed for the development of an accurate and rapid diagnostic tool. The present study was conducted in patients with a respiratory problem suspected to be TB at Dr. Soetomo Hospital, Surabaya, Indonesia. Among 102 patients tested by GeneXpert and AFB, 59 serum samples were from cases retrospectively determined to have active TB. A total of 102 serum of healthy controls (HC) was also collected. The PPD antigen and the recombinant CFP-10 and ESAT-6 proteins were prepared. Antibody responses against these proteins were evaluated by ELISA. All samples were also screened for the possibility of Mycobacterium avium-intracellulare complex (MAC) infection using Capilla MaC kit. The results showed that TB patients had a significantly higher concentration of IgG antibody in response to PPD than the HC. In addition, the receiver operating characteristic (ROC) curve analysis showed that PPD was acceptable for diagnostic purposes with an AUC value of 0.835 (95% CI 0.770-0.900, p < 0.0001). However, ESAT-6 and CFP-10 had low AUCs, and 32 samples from both groups showed a low concentration of IgA antibody against all antigens. The MAC detection results also showed that the concentration of IgA in the HC group was the highest. The current results indicate that PPD is a better antigen for antibody-based detection of TB than ESAT-6 and CFP-10. Based on the MAC detection assay, 53 people in the HC group were probably infected with rapidly growing nontuberculous mycobacteria (NTM), although antibody response to PPD was low.

Application of transdermal patches with new skin test reagents for detection of latent tuberculosis.

Introduction. Current intradermal tuberculin skin tests for latent tuberculosis infection (LTBI) based on purified protein derivative (PPD) have poor specificity.Aims. Developing a better skin test antigen as well as a simple skin patch test may improve and facilitate diagnostic performance.Methodology. Defined recombinant antigens that were unique to Mycobacterium tuberculosis (MTB), including two potential latency-associated antigens (ESAT-6 and Rv2653c) and five DosR-encoded latency proteins (Rv1996, Rv2031c, Rv2032, DevR and Rv3716c), were used as diagnostic skin test reagents in comparison with a standard PPD. The performance of the skin tests based on the detection of delayed-type hypersensitivity (DTH) reaction in guinea pigs sensitized to MTB and M. bovis bacille Calmette-Guérin (BCG) vaccine was evaluated.Results. The latency antigens Rv1996, Rv2031c, Rv2032 and Rv2653c and the ESAT-6 protein elicited less reactive DTH skin responses in MTB-sensitized guinea pigs than those resulting from PPD, but elicited no response in BCG-vaccinated guinea pigs. The remaining two latency antigens (DevR and Rv3716c) elicited DTH responses in both groups of animals, as did PPD. The reactivity of PPD in BCG-vaccinated guinea pigs was greater than that of any of the selected skin test reagents. Using stronger concentrations of selected skin test reagents in the patch test led to increased DTH responses that were comparable to those elicited by PPD in guinea pigs sensitized with MTB.Conclusion. Transdermal application of defined purified antigens might be a promising method for LTBI screening.

Proportions of interferon-γ-producing ascites lymphocytes in response to mycobacterial antigens: A help for early diagnosis of peritoneal tuberculosis in a low TB incidence country.

BACKGROUND: Peritoneal tuberculosis (TB) remains difficult to diagnose because of its non-specific clinical features and the lack of efficient microbiological tests. As delayed diagnosis is associated with high mortality rates, new diagnostic tools are needed. METHODS AND FINDINGS: We investigated for 24 patients prospectively enrolled with a possible diagnosis of peritoneal TB, the diagnostic value of the analysis of IFN-γ production by peritoneal fluid lymphocytes in response to a short in vitro stimulation with mycobacterial antigens. The patients were classified in two groups: non-TB and confirmed or highly probable TB. Diagnosis of TB was based on microbiological and histopathological criteria and/or a favorable response to anti-TB treatment. The IFN-γ production by peritoneal CD4+ T lymphocytes was analyzed by flow cytometry after an overnight in vitro stimulation with three different mycobacterial antigens, purified protein derivative (PPD), heparin-binding haemagglutinin (HBHA) or early-secreted-antigen-target-6 (ESAT-6). The percentages of PPD-, HBHA- or ESAT-6-induced IFN-γ-producing peritoneal fluid CD4+ T lymphocytes were higher in the TB group than in the non-TB group (p = 0.0007, p = 0.0004, and p = 0.0002 respectively). Based on cut-off values determined by ROC curve analysis of the results from TB and highly probable TB compared to those of non-TB patients, the sensitivity of these three tests was 100% with a specificity of 92%. CONCLUSIONS: The analysis of mycobacterial-induced IFN-γ production by peritoneal lymphocytes is a promising tool to reliably and rapidly diagnose peritoneal TB. Further studies should be performed on larger cohorts of patients in high-TB-incidence countries to confirm the clinical value of this new diagnostic approach for peritoneal TB.

Evaluation of tuberculin skin test (TST) in vervet monkeys (Chlorocebus pygerythrus) using experimentally tuberculin sensitized animals.

BACKGROUND: Nowadays, several test methods with different useful values are available for diagnosis of the tuberculosis (TB) in non-human primates (NHPs). Despite some limitations of tuberculin skin test (TST), it is still the most commonly used method for TB testing of NHPs. METHODS: During this investigation, TST was performed upon three groups of experimentally tuberculin sensitized and one group of non-sensitized vervet monkeys (Chlorocebus pygerythrus) by means of two types of old tuberculin (OT) and two types of purified protein derivative (PPD) tuberculin. RESULTS: The data obtained from this study revealed that PPD tuberculin prepared from both Mycobacterium tuberculosis and Mycobacterium bovis has more advantages over OT in tuberculin testing of the vervet monkeys. The potency of the PPD tuberculin prepared from M bovis was estimated almost twice as much of the M tuberculosis. CONCLUSIONS: Intrapalpebral injection of 0.1 mL of a concentration of ≥1 mg/mL of PPD tuberculin prepared from M bovis is the preferred method for TST of vervet monkeys.

Identification of bovine tuberculosis biomarkers to detect tuberculin skin test and IFNγ release assay false negative cattle.

Bovine tuberculosis (bTB) is an important animal and zoonotic disease, which causes severe economic losses. The main focus of this study was to assess the predictive power of previously identified biomarkers of bTB in infected animals that were negative to the tuberculin skin test (TST). We studied 16 animals with bTB, in which the disease was confirmed by necropsy, and 16 healthy animals. The level of expression of ten biomarkers (CXCL9, THBS1, MMP9, IL-22, CXCL10, IFNγ, IL-17, FYVE, CD14, IL-1R) was evaluated by RT-qPCR upon stimulation or not of peripheral blood mononuclear cells with PPDb (purified protein derivative of bovine tuberculin). In this assay, CXCL9, THBS1, MMP9, IL-22 and IFNγ changed their expression level depending on the bTB status. In addition, we evaluated different biomarker candidates simultaneously to infer the animal condition. By performing an analysis with classification trees, we found that the sturdiest combination was IL-22, IFNγ and IL-1R. On the other hand, CXCL10, IFNγ and IL-22's expression distinguished between bTB positive animals that were negative to TST (TST false negative animals) and the bTB negative groups. Thus, these biomarkers are promising candidates to be tested as an ancillary diagnostic assay. In addition, the expression of CXCL10 and IL-22 exhibited also significant differences between the bTB positive animals that were undetectable by IFNγ release assay (IGRA) and TST tests (TST and IGRA false negative animals) and the bTB negative groups. Therefore, CXCL10 and IL-22 constitute candidate biomarkers that could complement the two most widely used diagnostic tests.

Comparative sensitivity of the test with tuberculosis recombinant allergen, containing ESAT6-CFP10 protein, and Mantoux test with 2 TU PPD-L in newly diagnosed tuberculosis children and adolescents in Moscow.

BACKGROUND: A group of Russian scientists has developed Diaskintest, which comprises Mycobacterium tuberculosis-specific recombinant proteins CFP10-ESAT6, for skin testing (0.2 µg/0.1 ml). STUDY PURPOSE: To evaluate the comparative sensitivity of TST with 2 TU PPD-L and a skin test with tuberculous recombinant allergen (Diaskintest) containing the ESAT6-CFP10 protein in children and adolescents with newly diagnosed active tuberculosis during mass screening in the primary medical service in Moscow. MATERIALS AND METHODS: The trial was a comprehensive retrospective group study of children and adolescents diagnosed in Moscow with active tuberculosis in 2013-2016, aged 0 to 17 years inclusive. RESULTS: From 441 patients selected for analysis 408 patients had both tests (TST with 2 TU PPD-L and Diaskintest) performed, in 193 patients both tests were given simultaneously, of them 162 patients were BCG-vaccinated. Comparative results of both tests in 408 patients with tuberculosis: at cut-off ≥ 5 mm, both tests has similar sensitivity: Diaskintest 98.3% (95% CI 97.0-99.6%), TST 98.0% (95% CI 96.7-99.4%), at cut-off ≥10 mm, the sensitivity decreases for both tests: Diaskintest 90.0% (95% CI 87.0-93.0%), TST 88.7% (95% CI 85.6-91.9%), but at cut-off ≥ 15 mm, the decrease in sensitivity is statistically significant: for Diaskintest 61.5% (95% CI 56.7-66.3%), and for TST 46.3% (95% CI 41.4-51.3%), p <0.0001. The results of simultaneous setting of tests on different hands in 193 people (including 162 BCG-vaccinated), do not differ from the results for 408 people. The correlation between the results of Diaskintest and TST was significant in all groups. CONCLUSION: In children and adolescents with active tuberculosis, Diaskintest of 0.2 µg/ml and the Mantoux test with 2 TU PPD-L have high sensitivity (98%) at a cut-off of 5 mm; however, at cut-off ≥ 15 mm sensitivity is significantly reduced, and the decrease is more pronounced in the Mantoux test. The advantage of Diaskintest is that, unlike the Mantoux test, it has high specificity under the conditions of mass BCG vaccination. The test is simple to carry out, and can be used in mass screening.

Synergy between tuberculin skin test and proliferative T cell responses to PPD or cell-membrane antigens of Mycobacterium tuberculosis for detection of latent TB infection in a high disease-burden setting.

Tuberculin skin test (TST) is used most widely for the detection of latent tuberculosis infection (LTBI), even though evidences suggest that it could be underreporting the prevalence of LTBI particularly in high disease-burden settings. We have explored whether in vivo (TST) and in vitro (cell-proliferative) T cell responses to PPD can serve as complementary measures. In addition, we also probed whether in vitro T cell response to cell-membrane antigens (Mem) of Mycobacterium tuberculosis (MTB) can serve as a biomarker for LTBI. Study subjects comprised 43 healthcare workers (HCWs), and 9 smear-positive TB patients served as 'disease control'. To measure proliferative T cell responses, 0.1 ml blood (diluted 1:10) was incubated (5 days) with test or control antigen. Cells were stained with fluorescent antibodies to T cell (CD3+/CD4+/CD8+) surface markers and, after fixation and permeabilization, to nuclear proliferation marker Ki67. Data was acquired on a flow cytometer. HCWs who had an intimate exposure to MTB showed significantly higher TST positivity (85%) than the rest (43%), notwithstanding their BCG vaccination status. The proliferative responses of CD4+ and CD8+ subsets of T cells were comparable. Sixty seven and 100% TST-negative HCWs, respectively, were positive for proliferative T cell response to PPD and MTBMem. Cumulative positivity (TST or in vitro) was 86% with PPD and 100% with MTBMem indicating complementarity of the two responses. As standalone in vitro assay, MTBMem provided a significantly higher positivity (95%) than PPD (67%). T cell responses of TB patients were 'generally' depressed, having implications for the development of immunological assays for 'progressive' LTBI. Altogether, these results demonstrate that in vivo and in vitro T cell responses to PPD are complementary and in vitro response to MTBMem can be developed as a highly sensitive biomarker for LTBI.

Baseline Cytokine Profiles of Tuberculin-Specific CD4+ T Cells in Non-Muscle-Invasive Bladder Cancer May Predict Outcomes of BCG Immunotherapy.

Intravesical Bacillus Calmette-Guérin (BCG) immunotherapy preserves the bladder after resection of high-risk non-muscle-invasive bladder cancer (NMIBC). About 30% of patients experience treatment failure, which cannot be predicted a priori and carries a high risk of disease progression. We examined the in vitro tuberculin responsiveness of CD4+ T cells before BCG immunotherapy in 42 patients with high-risk NMIBC. The frequencies and functionalities of cytokine-expressing CD4+ T cells immediately before and after BCG immunotherapy induction were assessed by flow cytometry after overnight tuberculin stimulation. Tuberculin-induced secreted mediators were measured by electrochemiluminescence. We correlated the results with recurrence-free patient survival 6 months after induction. A tuberculin-induced, secreted, IL2 concentration > 250 pg/mL was the best predictor of recurrence-free survival, providing 79% sensitivity, 86% specificity (AUC = 0.852, P = 0.000), and overall correct classification in 78.6% of cases. In 50% of patients later experiencing recurrence, but not in any of the recurrence-free survivors, IL2 secretion was < 120 pg/mL. Other parameters predicting recurrence-free survival included secreted IFNγ (AUC = 0.796, P = 0.002) and the frequencies of TNF-producing (TNF+) CD4+ T cells (AUC = 0.745, P = 0.010). "Polyfunctional" CD4+ T cells (IFNγ+/IL2+/TNF+) were significantly associated with recurrence-free survival (AUC = 0.801, P = 0.002). Thus, the amount of IL2 secretion from CD4+ T cells after overnight in vitro incubation with tuberculin predicted the outcome of BCG immunotherapy. As many as half of potential BCG failures could be identified before induction therapy is begun, enabling better choices regarding treatment. Cancer Immunol Res; 6(10); 1212-9. ©2018 AACR.

Antigen-specific interferon-gamma release is decreased following the single intradermal comparative cervical skin test in African buffaloes (Syncerus caffer).

Effective disease management of wildlife relies on the strategic application of ante-mortem diagnostic tests for early identification and removal of M. bovis-infected animals. To improve diagnostic performance, interferon-gamma release assays (IGRAs) are often used in conjunction with the tuberculin skin test (TST). Since buffaloes are major maintenance hosts of M. bovis, optimal application of bovine TB diagnostic tests are especially important. We aimed to determine whether the timing of blood collection relative to the TST has an influence on IFN-γ production and diagnostic outcome in African buffaloes. Release of IFN-γ in response to bovine purified protein derivative (PPD), avian PPD and PC-HP® and PC-EC® peptides was measured by Bovigam® and an in-house IGRA in a group of Bovigam®-positive and - negative buffaloes at the time the TST was performed and three days later. There was significantly lower IFN-γ release in response to these antigens post-TST in Bovigam®-positive buffaloes, but no significant changes in Bovigam®-negative buffaloes. Also, a significantly greater proportion of buffaloes were Bovigam®-positive prior to the TST than three days later. We therefore recommend that blood samples for use in IGRAs be collected prior to or at the time the TST is performed to facilitate the correct identification of greater numbers of IGRA-positive buffaloes.