Immunotherapy with Mycobacterium vaccae in the treatment of tuberculosis in Romania. 1. Newly-diagnosed pulmonary disease

Rapidly Growing Mycobacterium Species: The Long and Winding Road from Tuberculosis Vaccines to Potent Stress-Resilience Agents

Inflammatory diseases and stressor-related psychiatric disorders, for which inflammation is a risk factor, are increasing in modern Western societies. Recent studies suggest that immunoregulatory approaches are a promising tool in reducing the risk of suffering from such disorders. Specifically, the environmental saprophyte Mycobacterium vaccae National Collection of Type Cultures (NCTC) 11659 has recently gained attention for the prevention and treatment of stress-related psychiatric disorders. However, effective use requires a sophisticated understanding of the effects of M. vaccae NCTC 11659 and related rapidly growing mycobacteria (RGMs) on microbiome–gut–immune–brain interactions. This historical narrative review is intended as a first step in exploring these mechanisms and provides an overview of preclinical and clinical studies on M. vaccae NCTC 11659 and related RGMs. The overall objective of this review article is to increase the comprehension of, and interest in, the mechanisms through which M. vaccae NCTC 11659 and related RGMs promote stress resilience, with the intention of fostering novel clinical strategies for the prevention and treatment of stressor-related disorders.

Efficacy of Mycobacterium vaccae immunotherapy for patients with tuberculosis: A systematic review and meta-analysis

Tuberculosis (TB) is a significant cause of illness and death worldwide. Immunotherapy has been investigated in the treatment of TB. The purpose of this study was to perform a meta-analysis investigating the effectiveness of the M. vaccae vaccine. Medline, Cochrane, EMBASE, and Google Scholar were searched until November 5, 2015 using the keywords: tuberculosis, pulmonary TB, therapeutic vaccines, immunotherapy, M. vaccae, sputum smear. Randomized controlled trials (RCTs) or 2-arm prospective studies were included. The primary outcome was the sputum smear clearance rate at 1 or 2 months and 6 months after treatment. Secondary outcomes were improvement of chest X-ray findings, sputum culture negative rate at 1 or 2 months and 6 months, erythrocyte sedimentation rate (ESR), hemoglobin, and leukocyte count, weight gain, and mortality. Of 89 records identified, 13 RCTs were included in the meta-analysis. The number of patients ranged from 22 to 1337, and the mean age ranged from 26.4 to 44.3 y. Patients treated with M. vaccae were more likely to have negative sputum smear results at 1-2 months (pooled OR = 2.642, 95% CI: 1.623-4.301, P < .001) and at 6 months (pooled OR = 2.111, 95% CI: 1.141-3.908, P = .017), and have a negative sputum culture at 1 or 2 months (pooled OR = 2.660, 95% CI: 1.978-3.578, P < .001). The results of this meta-analysis suggest that M. vaccae immunotherapy may be effective in the treatment of pulmonary TB.

Levamisole as an Adjuvant to Short-Course Therapy in Newly Diagnosed Pulmonary Tuberculosis Patients

BACKGROUND

The estimated incidence and prevalence of tuberculosis in India are 2.1 and 2.6 million cases respectively. Immunotherapy may shorten tuberculosis treatments and improve the immunity of individuals as well. Hence we study the efficacy of levamisole (LVM) (immunomodulator) as an adjuvant to chemotherapy of pulmonary tuberculosis patients.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled clinical trial was conducted for 21 months in newly diagnosed sputum positive pulmonary tuberculosis patients. Patients were subjected initially to clinical examination, sputum acid-fast bacilli smear and culture, tuberculin skin test and weight record. During follow-up, above investigations were repeated. Sixty-five patients were randomly assigned into two groups to receive either tab LVM 100 mg once in a day or matching placebo, orally as a single dose, thrice a week, for 2 months with short-course antituberculosis chemotherapy.

RESULTS

Sputum negativity at 1 week was observed in 11 (44%) patients in LVM group whereas only 3 (12%) in placebo group. All the patients 25 (100%) in LVM group were sputum negative compared to 14 (56%) in placebo group by the end of 3 weeks. In LVM group, 24 (96%) and 11 (44%) patients in placebo group show radiological improvement at 2 months. A direct correlation existed between quantum of immune response and weight gain with LVM. LVM rendered all anergic patients to positive tuberculin reactors. In LVM group, patients with initial Mantoux ≥20 mm and advanced cavitary disease, there was decrease in tuberculin reaction size.

CONCLUSION

Adjuvant immunomodulation with levamisole has the potential of shortening the total duration of antitubercular therapy.

Role of immunotherapy in the treatment of tuberculosis

Tuberculosis is caused byMycobacterium tuberculosis, an intracellular pathogen residing in macrophages. Cell mediated immune (CMI) and delayed type of hypersensitive (DTH) responses play a pivotal role in providing protection to the host. The most important cell is the CD4 T lymphocyte, which is divided into TH1 and TH2 subsets depending on the type of cytokines produced. TH1 cells produce the cytokines interferon-gamma and interleukin-2, which are important for activation of antimycobacterial activities and essential for the DTH response. Grange opines that the immune response in an individual with tuberculous infection gets 'locked in' to one or other pattern of response viz. TH1 or TH2 response, the latter response leading to tissue damage and progression of disease.Stanford and co-workers conducted several studies on the effectiveness ofMycobacterium vaccae, as an immunotherapeutic agent for tuberculosis. It is non-pathogenic in humans and is thought to be a powerful TH1 adjuvant. A series of small studies pointed thatM. vaccae has a beneficial effect and there is enough evidence now to show that its use as an immunotherapeutic agent, as an adjunct to chemotherapy in the treatment of tuberculosis especially at a time when drug resistance is rampant, appears promising.

Mycobacterium vaccae as adjuvant therapy to anti-tuberculosis chemotherapy in never-treated tuberculosis patients: a meta-analysis

Objective

To evaluate the effectiveness and safety of heat-killed M.vaccae added to chemotherapy of never-treated tuberculosis (TB) patients.

Methods

The databases of Medline, Embase, Biosis, Cochrane Central Register of Controlled Trials, SCI, CBM, VIP and CNKI were searched. Randomized controlled trials (RCT) and Controlled clinical trials (CCT) comparing M.vaccae with or without a placebo-control injection as adjuvant therapy in the chemotherapy of never-treated TB patients were included. Two reviewers independently performed data extraction and quality assessment. Data were analyzed using RevMan 5.0 software by The Cochrane Collaboration.

Results

Fifty four studies were included. At the end of the follow-up period, Pooled RR (Risk Ratio) and its 95% CI of sputum smear conversion rate were 1.07 (1.04, 1.10) in TB patients without complications, 1.17 (0.92, 1.49) in TB patients with diabetes mellitus, 1.02 (0.94, 1.10) in TB patients with hepatitis B, and 1.46 (0.21, 10.06) in TB patients with pneumosilicosis. In elderly TB patients the RR was 1.22 (1.13, 1.32). Analysis of each time point during the follow-up period showed that M.vaccae could help to improve the removal of acid-fast bacilli from the sputum, and promote improvement of radiological focal lesions and cavity closure. Compared with the control group, the differences in levels of immunological indicators of Th1 such as IL-2 and TNF-α were not statistical significant (P = 0.65 and 0.31 respectively), and neither was that of IL-6 produced by Th2 (P = 0.52). An effect of M.vaccae of prevention of liver damage was found in TB patients with hepatitis B (RR 0.20 and 95% CI (0.12, 0.33). No systemic adverse events were reported.

Conclusion

Added to chemotherapy, M.vaccae is helpful in the treatment of never-treated TB patients in terms of improving both sputum conversion and X-ray appearances.

Immunological basis for the introduction of immunotherapy with Mycobacterium vaccae into the routine treatment of TB

An account is given of the immunological investigations carried out in Rosario (Argentina) to identify suitable methods for the assessment of the efficacy of immunotherapy for TB. Some of these were then applied to three small studies: one of a single injected dose of heat-killed, borate-buffered Mycobacterium vaccae administered early in treatment, another of three such doses administered at monthly intervals from the start of treatment, and the third of ten oral doses at frequent intervals throughout short-course chemotherapy. All three displayed better clearance of bacilli from the sputum, faster improvement in clinical symptoms, better radiological resolution of lesions and a return of most immunological parameters towards those of healthy persons. In principle, the immune change achieved is an increase in Th1 mechanisms, notably IL-2 and -12 with downregulation of the tissue damaging aspects of Th2. As an addition to chemotherapy for drug-susceptible or drug-resistant TB, with or without concomitant HIV infection, this immunotherapy offers a safe and effective improvement.

Potential for immunotherapy with heat-killed Mycobacterium vaccae in respiratory medicine

Immunotherapy with Mycobacterium vaccae has been shown to be beneficial as part of the treatment for a wide range of diseases. In the respiratory system, the late airway response in bronchial asthma is modified by a single dose and bronchial aspects of hayfever are reduced allowing a major reduction in the use of bronchial dilators. In studies of advanced adenocarcinoma of the lung survival is increased by an average of 4 months when up to five doses of M. vaccae are added to the course of chemotherapy. The quality of life of cancer patients receiving immunotherapy with M. vaccae is improved, even if survival is not increased. It is suggested that the mechanism of action of immunotherapy with heat-killed, borate-buffered M. vaccae is likely to be very similar in all these diseases for which human pulmonary tuberculosis provides a model. In this study, additional immunological data are reported from material stored from an earlier study of immunotherapy for pulmonary tuberculosis to help complete the information on the way that treatment with three monthly injections of heat-killed, borate-buffered M. vaccae (SRL172) may act.

Immunotherapy with oral, heat-killed, Mycobacterium vaccae in patients with moderate to advanced pulmonary tuberculosis

A research investigation to evaluate the potential of an oral preparation of Mycobacterium vaccae SRL172 (NCTC 11659) as an immunotherapeutic has been carried out in ten patients with moderate to advanced pulmonary tuberculosis at Carrasco Hospital, Argentina. Comparison was made between oral and injected M.vaccae sharing a mutual control group. Clinical, bacteriological, hematological, radiological and immunological assessments all showed comparable benefits for both injected and oral treatment over those achieved with chemotherapy alone. The only significant difference between results of injected and oral M.vaccae was the failure of the latter to reduce TNF-α production by cultured mononuclear cells. A more intensive regime for the oral preparation was used, which as an addition to the directly observed therapy, short-course, treatment should improve results in both drug susceptible and drug-resistant cases. A Phase II Good Clinical Practice trial is now required.

Immunological consequences of three doses of heat-killed Mycobacterium vaccae in the immunotherapy of tuberculosis

We report the first study of triple-dose immunotherapy with heat-killed Mycobacterium vaccae (SRL 172) combined with short-course, directly observed chemotherapy in newly diagnosed pulmonary tuberculosis patients. The study was carried out in Rosario, Argentina, where single-dose immunotherapy with M. vaccae has previously been shown effective. Twenty-two HIV seronegative patients, sputum-positive for tubercle bacilli, entered a randomised and partly blinded trial. Twelve patients received injections of SRL 172 and 10 patients received placebo on days 1, 30 and 60 of chemotherapy. All patients were followed up clinically, by sputum bacteriology, chest radiography and haematology. Patients receiving SRL 172 showed faster and more complete clinical improvement, accelerated disappearance of bacilli from sputum, better radiological clearance and a more rapid fall in ESR, than did those receiving placebo. Follow-up continued for a year after therapy and no patient failed treatment or relapsed. Special investigations included longitudinal assessments of respiratory bursts and expression of CD11b on separated polymorphonuclear and mononuclear leukocytes. Tumour necrosis factor alpha (TNF-alpha) was measured in the supernates of cultured cells and both TNF-alpha and interleukin-4 (IL-4) were measured in serum samples. Immunotherapy recipients showed a significantly faster return towards normal values in all the immunological parameters, than did placebo recipients. The results are consistent with a regulatory activity on cellular immunity, reducing the influence of Th2 and enhancing Th1 to the benefit of the patients. This could allow a reduced period of chemotherapy without loss of efficacy and help to prevent the development of multi-drug resistance.

Mycobacterium vaccae (SRL172) immunotherapy as an adjunct to standard antituberculosis treatment in HIV-infected adults with pulmonary tuberculosis: a randomised placebo-controlled trial

BACKGROUND

Mortality rates of HIV-infected patients treated for tuberculosis remain high. This study aimed to assess the effect on mortality of immunotherapy with single-dose SRL172 added to standard antituberculosis chemotherapy in such patients.

METHODS

The double-blind trial enrolled 1229 patients aged 18-60 years, who had never received antiretroviral treatment and who presented with newly diagnosed, sputum-smear-positive pulmonary tuberculosis to referral centres in Lusaka, Zambia, and Karonga, Malawi. Both HIV-positive and HIV-negative patients were enrolled, to avoid stigmatisation. Participants were randomly assigned a single injection of SRL172 or matching placebo within 2 weeks of starting 8 months of antituberculosis chemotherapy and followed up for at least 12 months. The primary endpoint was time to death in the HIV-infected population. Analyses were based on 760 HIV-positive patients after exclusion of 84 patients with errors in storage of the injection, no bacteriological confirmation, or no HIV result.

FINDINGS

Of 760 HIV-infected patients, 374 received SRL172 and 386 received placebo. SRL172 did not cause any serious adverse events. The follow-up rate was 88% at 12 months in both groups. Of the HIV-positive patients, 109 (19.5 per 100 person-years) of 372 assigned SRL172 and 107 (19.3 per 100 person-years) of 386 assigned placebo died. In the Cox's regression analysis, stratified by centre, the hazard ratio of deaths (SRL172/placebo) was 1.03 (95% CI 0.79-1.35). There was no evidence of benefit to the group assigned SRL172.

INTERPRETATION

Immunotherapy with single-dose SRL172 as an adjunct to standard antituberculosis treatment in HIV-positive adults with pulmonary tuberculosis had no significant effect on survival or bacteriological outcome, though the treatment was safe and well tolerated.

A double-blind, placebo-controlled study of vitamin A and zinc supplementation in persons with tuberculosis in Indonesia: effects on clinical response and nutritional status

BACKGROUND

The results of cross-sectional studies indicate that micronutrient deficiencies are common in patients with tuberculosis. No published data exist on the effect of vitamin A and zinc supplementation on antituberculosis treatment.

OBJECTIVE

Our goal was to investigate whether vitamin A and zinc supplementation increases the efficacy of antituberculosis treatment with respect to clinical response and nutritional status.

DESIGN

In this double-blind, placebo-controlled trial, patients with newly diagnosed tuberculosis were divided into 2 groups. One group (n = 40) received 1500 retinol equivalents (5000 IU) vitamin A (as retinyl acetate) and 15 mg Zn (as zinc sulfate) daily for 6 mo (micronutrient group). The second group (n = 40) received a placebo. Both groups received the same antituberculosis treatment recommended by the World Health Organization. Clinical examinations, assessments of micronutrient status, and anthropometric measurements were carried out before and after 2 and 6 mo of antituberculosis treatment.

RESULTS

At baseline, 64% of patients had a body mass index (in kg/m(2)) < 18.5, 32% had plasma retinol concentrations < 0.70 micromol/L, and 30% had plasma zinc concentrations < 10.7 micromol/L. After antituberculosis treatment, plasma zinc concentrations were not significantly different between groups. Plasma retinol concentrations were significantly higher in the micronutrient group than in the placebo group after 6 mo (P < 0.05). Sputum conversion (P < 0.05) and resolution of X-ray lesion area (P < 0.01) occurred earlier in the micronutrient group.

CONCLUSION

Vitamin A and zinc supplementation improves the effect of tuberculosis medication after 2 mo of antituberculosis treatment and results in earlier sputum smear conversion.

The diagnosis and management of multiple-drug-resistant-tuberculosis at the beginning of the new millenium

Multiple-drug-resistant tuberculosis (MDRTB) is more difficult to treat and the treatment is less likely to produce favourable results compared to treatment of drug-sensitive disease. Success requires close co-operation between the laboratory, which defines a case as MDRTB, and the clinical team, who will treat it as well as the public health staff who will address aspects of contact tracing and institutional cross-infection. National surveys have indicated that MDRTB occurs at a higher rate in some countries such as Estonia and Latvia (14.1% and 9% respectively, in 1998) and Russia (although there are only limited validated data). In contrast, in Western Europe and in some countries of Eastern Europe, such as the Czech Republic, Slovenia, Slovakia and Poland with good tuberculosis (TB) prevention and treatment programmes, the combined MDRTB prevalence was 1% or less. The early diagnosis of MDRTB and case management by experienced teams from the outset remains the best hope clinically for these patients. Adequately supervised and prolonged combination chemotherapy is essential, with drug choice governed mainly by quality-controlled in vitro drug susceptibility data. There is a more limited role for surgery, and immunomodulating therapy, such as the use of gamma-interferon, may have a useful adjunct role. Clearly the most important therapeutic modality for MDRTB is to treat drug-sensitive TB correctly in the first instance and prevent the emergence of resistant TB.

Double-blind placebo-controlled trial of Mycobacterium vaccae immunotherapy for tuberculosis in KwaZulu, South Africa, 1991-97

To investigate Mycobacterium vaccae immunotherapy in the treatment of human tuberculosis and to assess longer-term outcomes following treatment for tuberculosis patients, a double-blind placebo-controlled Phase-2 clinical trial was set up in the Mseleni and Manguzi health wards in north-eastern KwaZulu, South Africa. In 1991-93, 204 patients admitted with clinical tuberculosis to the 2 hospitals were allocated to receive single intradermal doses of 0.1 mL M. vaccae NCTC 11659 or 0.1 mL tetanus toxoid alongside standard 6-months chemotherapy with rifampicin, isoniazid, pyrazinamide and ethambutol. The main outcome measures were sputum bacteriology culture conversion to negativity, clinical assessment, weight gain, erythrocyte sedimentation rate and chest radiography. Patients were followed-up after 4 years to determine their health status. M. vaccae cases gained weight more quickly during the first 8 weeks compared with 'placebo' patients. Regression analysis found a synergistic relationship between BCG positive scar status and M. vaccae-induced weight gain. No further difference was found between treatment groups. The bacterial conversion rate to negativity at 2 months was much lower than expected (44.8% active, 38.8% placebo). Mortality was considerably higher than expected after treatment (7.1% each group) and after 4 years (25.8% active, 21.0% placebo; death from tuberculosis 14.5% and 16.1%, respectively). Immune sensitization to environmental mycobacteria may explain the geographical variability of M. vaccae efficacy, as occurs with BCG vaccination and occurred with Koch's tuberculins of the late 19th century. Multiple doses of M. vaccae may be more effective. Further work is required to link the ability of M. vaccae to modulate protective cytokine profiles to favourable outcome in clinical studies. The high mortality found in this study suggests urgent reviews of chemotherapy and monitoring of patients are necessary in KwaZulu.

Safety and immunogenicity of a five-dose series of inactivated Mycobacterium vaccae vaccination for the prevention of HIV-associated tuberculosis

Five doses of inactivated Mycobacterium vaccae vaccine were administered intradermally to 22 human immunodeficiency virus (HIV)-infected patients (11 bacille Calmette-Guérin [BCG]-positive and 11 BCG-negative) in Zambia whose CD4 lymphocyte counts were >/=200 cells/mm(3). HIV viral load and lymphocyte proliferation responses were compared for vaccine recipients and 22 HIV-infected control patients (11 BCG-positive and 11 BCG-negative). Immunization was safe and well tolerated in all patients, and induration at the vaccine site decreased from dose 1 to dose 5. A transient decrease in HIV viral load was observed in BCG-positive vaccine recipients after dose 3 but not after subsequent doses. Median lymphocyte stimulation indices to M. vaccae were 6.0 in vaccine recipients and 2.3 in control patients (P<.001). Stimulation indices were >/=3.0 in 19 vaccine recipients (86%) and 7 control patients (32%; P=.001). A 5-dose series of vaccination with inactivated M. vaccae is safe in HIV-infected patients and induces lymphocyte proliferation responses to the vaccine antigen. M. vaccae vaccine is a candidate for the prevention of tuberculosis in HIV infection.

Mycobacterium vaccae immunotherapy for treating tuberculosis

BACKGROUND

Mycobacterium vaccae has been advocated for immunotherapy in the treatment of tuberculosis and other infections caused by mycobacteria.

OBJECTIVES

The objective of this review was to assess the effects of Mycobacterium vaccae for treating tuberculosis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials register, Medline, Embase and reference lists of articles. We also contacted organisations and individuals working in the field.

SELECTION CRITERIA

Randomised and quasi-randomised trials of preparations of whole, killed Mycobacterium vaccae in patients with tuberculosis.

DATA COLLECTION AND ANALYSIS

One reviewer assessed trial quality and extracted data.

MAIN RESULTS

Four trials met the inclusion criteria. There was no effect on mortality (2 trials, RR 1.01, 95% CI 0.50 to 2.04); no consistent effect on sputum negativity or sputum culture; and a high level of adverse reactions.

REVIEWER'S CONCLUSIONS

Immunotherapy with Mycobacterium vaccae does not appear to benefit patients with tuberculosis.

Improvement in psoriasis after intradermal administration of heat-killed Mycobacterium vaccae

BACKGROUND

New treatments for psoriasis are being developed, but many are associated with limited efficacy, side-effects, or rapid recurrence after discontinuation. Thus, the aim of new agents is to induce longer term remissions with fewer side-effects. Preliminary studies have shown that Mycobacterium vaccae, a nonpathogenic organism prepared as a heat-killed suspension, may induce periods of remission in some psoriasis patients when administered intradermally.

METHODS

To further assess the efficacy and tolerability of M. vaccae in patients with moderate to severe psoriasis (psoriasis area and severity index (PASI) of 12-35), we conducted an open label study whereby 24 patients received two intradermal inoculations of M. vaccae in lesion-free deltoid skin, separated by a period of 3 weeks.

RESULTS

Twelve weeks after starting treatment, 14 of 24 patients (58%) showed marked improvement in the PASI score (greater than 50% reduction), two had moderate improvement (25-50% reduction), six were unchanged (< 25% reduction), and two had worsened (> 5% increase). By 24 weeks, 11 of 22 patients continued to show greater than 50% improvement. Five patients had complete clearance of skin lesions that lasted for at least 6 months.

CONCLUSIONS

Intradermal administration of heat-killed M. vaccae suspension was well tolerated and induced clinically significant improvement in a majority of psoriasis patients in this cohort. Placebo-controlled testing to further define the efficacy of this treatment is warranted.

Clinical and serological studies of tuberculosis patients in Argentina receiving immunotherapy with Mycobacterium vaccae (SRL 172)

Two small, placebo-controlled studies of immunotherapy with heat killed Mycobacterium vaccae added to routine chemotherapy for pulmonary tuberculosis, together involving 40 HIV seronegative patients, were carried out in Argentina. The immunotherapy was associated with reduced sputum smear positivity of AFB at 1 month and a greater reduction in ESR at 2 months. In the first study radiological improvement was better (P < 0.05) among immunotherapy recipients. In the second study, weight regain and time to become apyrexial were measured and were found to be improved amongst immunotherapy recipients (P < 0.05). In the first month of treatment the levels of IgG to the 65 kDa and 70 kDa heat-shock proteins showed greater falls following immunotherapy (P < 0.05 and P < 0.001, respectively). On admission serum cytokine levels of interleukins 4 and 10 (IL-4, IL-10), interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) were grossly raised in comparison with a matched control group (P < 0.001). After 1 month. Levels of IL-4, IL-10 and TNF-alpha fell (P < 0.001, P < 0.01 and P < 0.01, respectively) and levels of IFN-gamma rose more (P = 0.005) in immunotherapy recipients than in those receiving chemotherapy alone. The results are in accord with a switch towards a TH1 immunological status and clinical benefit for immunotherapy recipients.

Examining a paradox in the pathogenesis of human pulmonary tuberculosis: immune activation and suppression/anergy

Protective immunity against Mycobacterium tuberculosis (MTB) in animal models is based on cell-mediated immunity (CMI), involving bi-directional interactions between T cells and cells of the monocyte/macrophage (MO/MA) lineage. Key factors include MO-derived interleukin (IL)-12 and tumor necrosis factor (TNF)-alpha as well as T cell derived IL-2 and interferon (IFN)-gamma. These cytokines appear particularly crucial in the induction of MA-mediated elimination of mycobacteria. Several lines of evidence indicate that similar mechanisms are operating in humans. During active pulmonary tuberculosis (PTB), signs of both immune depression and immune activation are concomitantly present. Decreased tuberculin skin test reactivity in vivo and deficient IFN-gamma production by MTB-stimulated mononuclear cells in vitro are observed. On the other hand, the serum levels of several cytokines, including TNF, and other inflammatory mediators are increased and circulating MO and T cell show phenotypic and functional evidence of in vivo activation. In this review, we will discuss the evidence for three models, which could explain this apparent paradox: 1. Stimulation of the T cell-suppressive function from MO/MA; 2. Intrinsic T cell refractoriness, possibly associated with tendency to apoptosis (programmed cell death), and 3. Compartmentalization and redistribution of immune responses to the site of disease. The opportunistic behavior of MTB during human immunodeficiency virus (HIV) infection can be explained by suppression of type-1 responses at the level of antigen-presenting cells, CD4 T cells and effector macrophages. The ominous prognostic significance of intercurrent PTB during HIV infection seems primarily due to prolonged activation of HIV replication in macrophages. Supportive immune therapy during PTB could aim at correcting the type-1 deficiency either by IFN-gamma inducers (e.g. IL-12, IL-18) or by neutralizing the suppressive cytokines transforming growth factor beta (TGF-beta) and IL-10. Alternatively, inflammatory over-activity could be reduced by neutralizing TNF. Finally, anti-apoptotic therapies (e.g. IL-15) might be considered.

Immunotherapy with Mycobacterium vaccae in the treatment of tuberculosis in Romania. 2. Chronic or relapsed disease

In this study of 102 patients with culture-positive chronic treatment failure or repeatedly relapsed pulmonary tuberculosis receiving chemotherapy, 56 received an injection of killed Mycobacterium vaccae as immunotherapy after 1 month of treatment. At the start of treatment, there was little difference between those receiving immunotherapy and the 46 patients in the control group receiving chemotherapy alone. Thereafter, the two groups diverged so that 1 yr later, 43 of 56 (77%) patients receiving M. vaccae had a successful outcome, in comparison with 24 of 46 (52%) patients receiving chemotherapy alone (P < 0.02). Successful results were obtained from patients infected with drug-resistant bacilli, 20 of 32 (63%) patients compared with 11 of 25 (44%) patients, respectively, as well as from fully drug-sensitive cases (23 of 24 compared with 12 of 21 patients; P = 0.004). At the final follow-up after 22 months, 13 of 56 patients receiving immunotherapy had an unfavourable outcome compared with 26 of 46 members of the control group (P = 0.0006). During the study, 16 patients died of tuberculosis (six after immunotherapy), and 12 were lost to follow-up. Not only was bacteriological success improved by immunotherapy, chest X-ray showed markedly better resolution of cavities and other radiological lesions, recovery of body weight was improved, and the mean erythrocyte sedimentation rate returned almost to normal (P < 0.001) in comparison with those receiving chemotherapy alone. These changes were seen even in those failing bacteriological cure, suggesting that the immunotherapy had been effective, but that bacilli were replicating in an extracellular situation, protecting them from its effects.