The Koch phenomenon and delayed hypersensitivity: 1891-1991

Epidemiology of the koch phenomenon of infants after bacillus calmette-Guerin vaccination by interferon-γ release assay status, Japan, 2013-2019

Background

The epidemiology of infants who exhibited the Koch-like phenomenon after Bacillus Calmette-Guérin vaccination and who subsequently tested positive in interferon-γ release assay (IGRA) was compared to that of those who tested negative. The reports of pediatricians on the phenomenon to the health authorities of Japan were retrieved and analyzed.

Methods

In 2013-2019, 790 infants with such events were reported with IGRA test results available, of whom 81 (10.3%) tested positive and 709 (89.7%) negative.

Results

The infants who were IGRA positive did not show an increasing trend (P = 0.06, P = 0.60), whereas those who were IGRA negative showed a significantly increasing trend (P = 0.42, P = 0.0002). The infants who were IGRA positive did not exhibit seasonality, whereas those who were IGRA negative had a higher number of cases in winter than in summer. The rates of infants who were IGRA positive per 10 million live births showed a significant correlation with the tuberculosis (TB) notification rates by prefecture (P = 0.41, P = 0.004), whereas those who were IGRA negative did not (P = 0.04, P = 0.78).

Conclusion

The IGRA-positive infants were distributed quite differently from those who were IGRA negative and appeared more likely to be infected with TB. Reports of pediatricians on the Koch-like phenomenon should continuously be collected as the reports reflect a risk of TB infection including TB outbreaks among infants in Japan. The reports should include IGRA test results as IGRA is more specific than tuberculin skin testing. Infants with IGRA-positive results should be followed up for 2-3 years to determine their final outcomes.

The Pathogenesis of Tuberculosis-The Koch Phenomenon Reinstated

Research on the pathogenesis of tuberculosis (TB) has been hamstrung for half a century by the paradigm that granulomas are the hallmark of active disease. Human TB, in fact, produces two types of granulomas, neither of which is involved in the development of adult type or post-primary TB. This disease begins as the early lesion; a prolonged subclinical stockpiling of secreted mycobacterial antigens in foamy alveolar macrophages and nearby highly sensitized T cells in preparation for a massive necrotizing hypersensitivity reaction, the Koch Phenomenon, that produces caseous pneumonia that is either coughed out to form cavities or retained to become the focus of post-primary granulomas and fibrocaseous disease. Post-primary TB progresses if the antigens are continuously released and regresses when they are depleted. This revised paradigm is supported by nearly 200 years of research and suggests new approaches and animal models to investigate long standing mysteries of human TB and vaccines that inhibit the early lesion to finally end its transmission.

Intragranulomatous necrosis in lungs of mice infected by aerosol with Mycobacterium tuberculosis is related to bacterial load rather than to any one cytokine or T cell type

Low dose aerosol infection of C57BL/6 mice with a clinical strain of Mycobacterium tuberculosis (UTE 0335 R) induced intragranulomatous necrosis in pulmonary granulomas (INPG) at week 9 postinfection. Infection of different knockout (KO) mouse strains with UTE 0335 R induced INPG in all strains and established two histopathological patterns. The first pattern was seen in SCID mice and in mice with deleted alpha/beta T receptor, TNF R1, IL-12, IFN-gamma, or iNOS genes, and showed a massive INPG with a high granulomatous infiltration of the lung, a large and homogeneous eosinophilic necrosis full of acid-fast bacilli, with marked karyorrhexis, coarse basophilic necrosis, and surrounded by patches delimited by partially conserved alveolar septum full of PMNs. The second pattern was seen in mice with deleted IL-1 R1, IL-6, IL-10, CD4, CD8 or gamma/delta T cell receptor genes, and showed more discrete lesions with predominant homogeneous eosinophilic necrosis with few bacilli and surrounded by a well-defined lymphocyte-based ring. Local expression of IFN-gamma, iNOS, TNF and RANTES showed no significant differences between these mouse strains generating a discrete INPG. Mouse strains showing a massive INPG showed higher, lower or equal expression values compared to the control strain. In conclusion, the severity of the INPG pattern correlated with pulmonary CFU counts, irrespective of the genetic absence or the infection-induced levels of cytokine mediators.

Tuberculosis vaccine development: research, regulatory and clinical strategies

In the past decade, while the global tuberculosis (TB) epidemic has continued to devastate mankind, considerable progress has nevertheless been made in the development of new and improved vaccines for this ancient disease. Recombinant bacillus Calmette-Guerin strains, DNA-based vaccines, live attenuated Mycobacterium tuberculosis vaccines and subunit vaccines formulated with novel adjuvants have shown promise in preclinical animal challenge models. Three of these vaccines are being evaluated at present in human clinical studies, and several other vaccine preparations are being targeted for clinical trials in the near future. Although the preclinical characterisation and testing of new TB vaccines has clearly led to exciting new findings, complex regulatory and clinical trial design issues remain as a challenge to TB vaccine development. This report reviews some of the exciting advances in TB research that have led to the development of new TB vaccines, and addresses the unique regulatory and clinical issues associated with the testing of novel anti-TB preparations in human populations.

Cytokine mRNA expressed in tuberculin skin test biopsies from BCG-vaccinated and Mycobacterium bovis inoculated cattle

To obtain a better understanding of the delayed-type hypersensitivity reaction to Mycobacterium bovis, we measured the expression of cytokine mRNA from tuberculin skin test biopsies of cattle. Non-vaccinated and BCG-vaccinated cattle were inoculated intratracheally with a low dose of virulent M. bovis or sham-inoculated and 20 weeks later were skin tested with tuberculin. At necropsy 1-2 weeks later, tuberculous lesions were found in six of the nine non-vaccinated and three of the nine BCG-vaccinated animals. All of the lesioned and the majority of the non-lesioned M. bovis inoculated cattle showed a distinct skin swelling response to tuberculin, irrespective of vaccination. However, cattle with tuberculous lesions displayed larger skin swelling responses than non-lesioned cattle. Tuberculin-induced expression of IFN-gamma, IL2, IL4, IL10 and TNF-alpha mRNA occurred in the skin biopsies of all of the lesioned, M. bovis inoculated animals except for an absence of tuberculin-induced TNF-alpha mRNA expression in two animals. A lower proportion of the non-lesioned M. bovis inoculated cattle displayed tuberculin-induced expression of the five cytokine mRNA. There was no evidence of a unique pattern of cytokine expression which could be used to distinguish between diseased and protected animals. By 28 weeks after vaccination, the three BCG-vaccinated, sham-inoculated cattle displayed minimal skin swelling response to tuberculin, but tuberculin-induced expression of IFN-gamma, IL2, IL4, IL10 and TNF-alpha mRNA was observed in skin biopsies of all of these animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberculosis and cancer: parallels in host responses and therapeutic approaches?

Mycobacteria elicit two quite different immune responses. One is protective and is partly based on recognition and lysis of stressed, bacilli-laden cells expressing heat-shock proteins. The other suppresses this recognition and instead leads to indiscriminate necrosis of tissues containing mycobacteria (the Koch phenomenon). The type of response depends on the predominant T-cell maturation pathway, Th1 or Th2, which in turn is determined by priming by prior contact with environmental mycobacteria. Vaccination by BCG induces whichever response the recipient is primed to make, and this is a likely explanation of the variable efficacy of this vaccine in prevention of tuberculosis and therapy of cancer. Thus; BCG is a two-edged sword. We postulate that by using other mycobacterial preparations, such as killed Mycobacterium vaccae, it might be possible to suppress the indiscriminate necrosis and enhance Th1-regulated selective destruction of tumour cells.

Preventive medicine for HIV-infected patients: an analysis of isoniazid prophylaxis for tuberculin reactors and for anergic patients

OBJECTIVE

To analyze the policies of isoniazid prophylaxis for human immunodeficiency virus (HIV)-infected tuberculin reactors and for HIV-infected anergic patients with unknown tuberculin status.

METHODS

Transition-state model of clinical immune deterioration of HIV-infection over ten years, review of published data, and a survey of AIDS experts. Outcome measures are the numbers of tuberculosis cases and deaths prevented and isoniazid toxicity cases and deaths occurring with prophylaxis.

PATIENTS

Hypothetical cohorts of HIV-infected 40-year-olds.

RESULTS

Because the tuberculosis activation rate is so high in HIV-infected patients, the benefits of prophylaxis far outweigh the risks of isoniazid toxicity for tuberculin reactors with HIV infection at any stage of immune function: 1,469-2,868 tuberculosis cases and 170-274 deaths are prevented per 10,000 cohort over ten years, depending upon the cohort's initial immune state. The benefits of prophylaxis outweigh the risks of isoniazid toxicity for anergic HIV-infected patients if they come from a community with a 2% to 3% or greater prevalence of Mycobacterium tuberculosis infection.

CONCLUSIONS

Isoniazid prophylaxis is a reasonable prevention measure for HIV-infected tuberculin reactors and for many HIV-infected anergic patients.

Nucleotide sequence analysis and serologic characterization of the Mycobacterium intracellulare homologue of the Mycobacterium tuberculosis 19 kDa antigen

Disseminated Mycobacterium avium/Mycobacterium intracellulare complex (MAC) disease is a frequent complication in patients with the acquired immune deficiency syndrome (AIDS). In this report, we present the nucleotide sequence of the M. intracellulare MI22 gene. Computer sequence comparisons reveal that the MI22 gene, which encodes a serologically active protein, has 78% DNA sequence identity and 77% protein sequence identity with the seroreactive 19 kDa Mycobacterium tuberculosis lipoprotein antigen. Southern blot hybridizations indicate that an MI22 gene probe binds similar-sized restriction fragments in M. tuberculosis and M. intracellular genomic DNA. In addition, immunoblot analyses demonstrate that MI22 is recognized by sera from tuberculosis patients. These data further support the existence of 19 kDa MAC and M. tuberculosis protein homologues. Phase partitioning experiments and the presence of a consensus lipid modification site in the deduced MI22 protein sequence strongly suggest that M122 is also a lipoprotein. Comparative analyses of these mycobacterial antigenic homologues may provide the basis for the design of species-specific diagnostic reagents.

Skin changes in the tuberculin test

This review describes the recent advances in knowledge of the nature and range of physiological changes that occur in the skin at the site of a positive tuberculin reaction. The infiltration of T-cells and monocyte/macrophages shows a marked compartmentalisation suggesting that the functions of particular cell types depend on their localisation. The extent of cutaneous oedema (detectable as induration) is not closely related to other features of the reaction or to systemic indicators of cell mediated immunity. The intensity of hyperaemia is maximal at the centre of the reaction and is correlated in most cases with the density of cellular infiltration in the dermis suggesting a functional coordination. Despite this correlation between cell numbers and velocity of blood flow, the reaction normally shows hypoxia, hypercapnia and local acidosis, but this metabolic modification may not be a wholly disadvantageous effect since these conditions appear to facilitate the growth and metabolism of activated lymphocytes and macrophages. In very strong reactions, there is central relative slowing of the circulation and this may lead to necrosis in extreme cases. There are however a minority of cases where cell infiltration occurs but induration is not palpable: this situation has been named pseudoanergy, and its pathogenesis has not yet been established. The occurrence of pseudoanergy must throw some doubt on the conventional criteria for positivity in the reading of tuberculin skin tests (induration greater than 5 mm) and this may have relevance to future strategies for assessment of new vaccines.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytokines and the Koch phenomenon

We outline the mechanisms contributing to the human form of the Koch phenomenon, which we define as necrosis occurring within 24-48 h of injection of mycobacterial antigen into the skin of past or present tuberculosis patients. It is probable that tissue damage mediated in the same way occurs in the lesions themselves. We suggest that the necrosis is mediated in part by cytokines, particularly Tumour Necrosis Factor (TNF), and that this occurs for three reasons. First, Mycobacterium tuberculosis evokes an immunoregulatory abnormality characterised by raised agalactosyl IgG. This abnormality, also found in rheumatoid arthritis, Crohn's disease, and Erythema Nodosum Leprosum, seems to be associated with dysregulation of cytokine release. Secondly, M. tuberculosis itself triggers further cytokine release. Thirdly, the normally protective role of TNF is distorted by several interacting properties of components of M. tuberculosis, which render the cytokine toxic to the host tissues. The immunoregulatory abnormality may be susceptible to correction by immunotherapy.