[Anti-TNF alpha monoclonal antibodies (infliximab) and tuberculosis: apropos of 3 cases]

Features of the pathogenetic mechanisms of tuberculous peritonitis in an experiment

The prevalence of tuberculous peritonitis that has been observed in the recent decades is the result of lymphohematogenous spread of Mycobacterium tuberculosis (MBT) from lungs and other extrapulmonary sources. It is still unclear why certain organs and anatomical regions get involved in the inflammatory process during generalization of the tuberculosis infection. Why do some cases develop into peritoneal tuberculosis and other into kidney tuberculosis? Thus study aimed to investigate the pathogenesis of tuberculous peritonitis in a reproducible biological model. Tuberculous peritonitis was modeled in 18 rabbits (10 in the test group, 8 in control) by intraperitoneal inoculation of the MBT suspension. In order to suppress peritoneal macrophages and major cytokines, test group rabbits were injected with the TNFα inhibitor and iron (III) hydroxide sucrose complex before being infected, while control group rabbits received no immunosuppressive drugs. Autopsy of the control group animals revealed changes characteristic of pulmonary tuberculosis in 37.5% of cases, with no damage to other organs and systems registered. Conversely, test group rabbits had the signs of tuberculous peritonitis in their abdominal cavities. The results of this study suggest that it is the local immunity of an anatomical area that largely determines whether a secondary focus of extrapulmonary tuberculosis infection will develop there or not. For the peritoneum, a smaller pool of peritoneal macrophages and weaker cytokine production is a necessary and sufficient condition to have tuberculous peritonitis developing therein.

Diagnostic and Therapeutic Strategies for Peritoneal Tuberculosis: A Review

Peritoneal tuberculosis (PTB), although rarer than its pulmonary counterpart, is a serious health concern in regions of the world with high tuberculosis prevalence. Individuals with baseline immunocompromise condition, whether acquired or medically induced, are at greatest risk for experiencing PTB. While medical treatment of the condition is similar to that of the pulmonary disease, the generally immunocompromised state of those infected with PTB, along with a lack of highly sensitive and specific testing methods make early diagnosis difficult. This review discusses the risks factors, clinical features, diagnostic methods, and treatment options for PTB.

Mycobacteria and autoimmunity

Mycobacterial infections can cause a variety of different manifestations. The increasing incidence of these infections worldwide brought another medical dilemma: immunological manifestations characterized by the presence of many autoantibodies and concomitant presence of autoimmune diseases. The burden of tuberculosis reactivation that emerged with immunosuppressive therapy worsened with the growing use of biological disease-modifying antirheumatic drugs (DMARDs). This review will address the relationship between the immune system and mycobacteria.

Primary tuberculous peritonitis during infliximab therapy for Crohn's disease

A 64 year old male patient suffering from Crohn's disease received infliximab therapy for a period of 5 months prior to presentation to our hospital. Due to the symptoms fever, ascites, and diffuse abdominal tenderness on palpation of unknown origin, a CT scan of the abdomen was performed and led to the suspected diagnosis of a peritoneal carcinomatosis. QuantiFERON™ test revealed a tuberculosis infection and molecular analyses of a peritoneal specimen obtained by laparoscopy clearly identified Mycobacterium tuberculosis DNA. Quadruple tuberculostatic therapy was initiated and the patient's condition continuously improved thereafter.

La tuberculose péritonéale : une entité toujours présente. À propos de quatre observations

INTRODUCTION

Tuberculous peritonitis, a major problem in developing country, occurs preferentially in immigrant population and in patients with acquired immune deficiency syndrome (AIDS). Although rare in France, it did not disappear and epidemiological, clinical and therapeutic approach deserve to be reminded.

EXEGESIS

We reported 4 patients (immigrants in two cases), occurred in caucasian and African persons (one with AIDS). Disease was characterized by fever, abdominal pain, anorexia, weight loss and ascites. Biological and radiological were unconclusive. Cell count analysis from ascitic fluid show a lymphocytic predominance with negative direct smear for Ziehl-Neelsen strain. Tuberculous peritonitis was established with combined visual and histological diagnosic laparoscopic examination.

CONCLUSION

These observations have the interest to underline that tuberculous peritonitis must be evoked in case of lymphocytic ascitis. We believe an aggressive diagnostic approach, particulary with peritoneal biopsy, is warranted for the diagnosis of tuberculous peritonitis. Validity of PCR amplification is ascitic fluid still needs to be established.

Severe pyogenic infections in patients taking infliximab

OBJECTIVE

To evaluate the prevalence and risk factors of severe pyogenic infections in rheumatology patients taking infliximab in everyday practice.

METHODS

Regional prospective cohort study of patients taking infliximab for rheumatoid arthritis or ankylosing spondylitis with data collection on standardized forms. The medical records of patients with severe pyogenic infections were subjected to a detailed retrospective review. Patients with and without severe pyogenic infections were compared.

RESULTS

The cohort included 83 patients (55 women and 28 men). Severe pyogenic infections occurred in five (6%) patients (three women and two men), all of whom had acute or underlying risk factors. Higher values were found in these five patients for mean age (65.8 +/- 12 vs. 53.9 +/- 13 years, P = 0.04) and mean daily glucocorticoid dosage (15.5 +/- 9 vs. 6.9 +/- 7 mg/day prednisone-equivalent, P = 0.036), as compared to the other patients.

CONCLUSION

Older age and high-dose glucocorticoid therapy are associated with an increased risk of severe pyogenic infection during infliximab therapy. Caution is in order when starting and monitoring infliximab therapy in patients with risk factors. Our data also emphasize the need for a careful search for risk factors before each infliximab infusion.

The use of TNF-α blocking agents in rheumatoid arthritis: an overview

TNF-alpha has been found to play a pivotal role in the pathogenic mechanisms of rheumatoid arthritis (RA). The overexpression of TNF-alpha in RA synovium, the data from in vitro synovial cell cultures with the use of anti-TNF-alpha antibody and the results from TNF-alpha blockade in animal models of arthritis argued for the importance of this cytokine in RA. Drugs targeting TNF-alpha have been developed to neutralise the deleterious effects of this inflammatory cytokine. There are currently three drugs available in the treatment of RA patients with active disease, which was refractory to conventional treatments including methotrexate, infliximab (a chimeric mouse/human monoclonal antibody), etanercept (a fusion protein combining 2 p75 TNF receptors with a Fc fragment of human IgG (1)) and adalimumab (a fully human monoclonal antibody). These three drugs have proved to be effective and safe in appropriate and well conducted clinical trials and showed effectiveness in slowing and even arresting the progression of radiographic damage. With the long-term surveillance of these drugs serious adverse events were described, particularly intracellular organism infections such as tuberculosis. Other drugs targeting TNF-alpha are in development and include monoclonal antibody (CDP571), pegylated molecules (CDP870 and PEG-r-Hu-sTNF-RI) or soluble p55 TNF receptor construct (lenercept). These new biological therapies blocking TNF-alpha undoubtedly constitute a considerable advance in the management of RA, but careful evaluation at the initiation of the treatment and long-term surveillance of the patients receiving such drugs remains necessary.

Tuberculoses lors de traitements par l’infliximab

OBJECTIVES

Analysis of the tuberculosis cases reported in France in patients treated with infliximab since its marketing approval, assessment of the effect of changes in the summary of product characteristics and national guidelines.

METHODS

Based on tuberculosis reports from the national post-marketing adverse drug reaction databank of the manufacturer from January 1, 2000 through June 30, 2003, and records from the national multicenter retrospective survey on opportunistic infections with anti-TNFalpha, we analyzed all cases of tuberculosis and the impact of the changes made in December 2000 in the summary of product characteristics and the guidelines on the prevention and management of tuberculosis in patients treated with infliximab published in February 2002.

RESULTS

56 cases of tuberculosis were reported: the median interval before diagnosis was 12 weeks with a median of 3 infusions. The presence of Koch bacilli was confirmed in 32 patients; 29 patients had extrapulmonary or disseminated forms of tuberculosis. The tuberculosis rate among patients treated with infliximab was greater than among the general population and differed significantly by period (p < 0.005).

CONCLUSION

Tuberculosis can occur within the first 12 weeks of treatment with infliximab. Information for practitioners must be continued, together with surveillance of the tuberculosis cases in France.

Disseminated tuberculosis complicating anti-TNF-alpha treatment

An unusually large number of cases of tuberculosis, often of miliary or disseminated form, have been reported in patients receiving infliximab therapy for rheumatoid arthritis or Crohn's disease. We describe a patient with rheumatoid arthritis who was treated with infliximab and became systemically ill with Mycobacterium tuberculosis-disseminated infection. Patients who are candidates for treatment with tumour necrosis factor-alfa inhibitors should be evaluated for the presence of latent or active

Gene therapy for autoimmune diseases: quo vadis?

Biological therapies using antibodies and cytokines are becoming widespread for the treatment of chronic inflammatory autoimmune diseases. However, these treatments have several limitations - such as expense, the need for repeated injections and unwanted side-effects - that can be overcome by genetic delivery. This review summarizes the ingenuity, sophistication and variety of gene-therapy approaches that have been taken in the design of therapeutic molecules and vectors, the engineering of cells and the regulation of gene expression for the targeting of disease outcome. We focus our attention on multiple sclerosis, type 1 diabetes and rheumatoid arthritis.

T cell-derived tumour necrosis factor is essential, but not sufficient, for protection against Mycobacterium tuberculosis infection

Tumour necrosis factor (TNF) is critical for sustained protective immunity against Mycobacterium tuberculosis infection. To investigate the relative contributions of macrophage- and T cell-derived TNF towards this immunity T cells from wild-type (WT) or TNF-/- mice were transferred into RAG-/- or TNF-/- mice which were then infected with M. tuberculosis. Infected RAG-/- mice and RAG-/- recipients of TNF deficient T cells developed overwhelming infection, with extensive pulmonary and hepatic necrosis and succumbed with a median of only 16 days infection. By contrast, RAG-/- recipients of WT T cells showed a significant increase in survival with a median of 32 days. Although initial bacterial growth was similar in all groups of RAG-/- mice, the transfer of WT, but not TNF-/-, T cells led to the formation of discrete foci of leucocytes and macrophages and delayed the development of necrotizing pathology. To determine requirements for macrophage-derived TNF, WT or TNF-/- T cells were transferred into TNF-/- mice at the time of M. tuberculosis infection. Transfer of WT T cells significantly prolonged survival and reduced the early tissue necrosis evident in the TNF-/- mice, however, these mice eventually succumbed indicating that T cell-derived TNF alone is insufficient to control the infection. Therefore, both T cell- and macrophage-derived TNF play distinct roles in orchestrating the protective inflammatory response and enhancing survival during M. tuberculosis infection.

An inflammation-inducible adenoviral expression system for local treatment of the arthritic joint

To achieve a disease-regulated transgene expression for physiologically responsive gene therapy of arthritis, a hybrid promoter was constructed. The human IL-1 beta enhancer region (-3690 to -2720) upstream of the human IL-6 promoter region (-163 to +12) was essential in mounting a robust response in HIG-82 synovial fibroblasts and in RAW 264,7 macrophages. A replication-deficient adenovirus was engineered with luciferase (Luc) controlled by the IL-1/IL-6 promoter (Ad5.IL-1/IL-6-Luc). LPS caused a 23- and 4.6-fold induction of Luc. activity in RAW cells infected with Ad5.IL-1/IL-6-Luc or the conventional Ad5.CMV-Luc construct, respectively. Next, adenoviruses (10(6) ffu) were injected into the knees of C57Bl/6 mice. An intra-articular injection of zymosan, 3 days after Ad5.IL-1/IL-6-Luc, increased Luc. activity by 39-fold but had no effect in the Ad5.CMV-Luc joints. The constitutive CMV promoter was rapidly silenced and could not be reactivated in vivo. In contrast, the IL-1/IL-6 promoter could be reactivated by Streptococcal cell wall (SCW)-induced arthritis up to 21 days after infection. Next the IL-1/IL-6 promoter was compared to the C3-Tat/HIV-LTR two-component system in wild-type, IL-6(-/-) and IL-1(-/-) gene knockout mice. Both systems responded well to LPS-, zymosan- and SCW-induced arthritis. However, the basal activity of the IL-1/IL-6 promoter was lower and IL-6 independent. This study showed that the IL-1/IL-6 promoter is feasible to achieve disease-regulated transgene expression for treatment of arthritis.

Reactivation of latent tuberculosis infection in TNF-deficient mice

TNF-deficient mice are highly susceptible to Mycobacterium tuberculosis H37Rv infection. Here we asked whether TNF is required for postinfectious immunity in aerosol-infected mice. Chemotherapy for 4 wk commencing 2 wk postinfection reduced CFU to undetectable levels. While wild-type mice had a slight rise in CFU, but controlled infection upon cessation of chemotherapy, TNF-deficient mice developed reactivation of infection with high bacterial loads in lungs, spleen, and liver, which was fatal within 13-18 wk. The increased susceptibility of TNF-deficient mice was accompanied by diminished recruitment and activation of T cells and macrophages into the lung, with defective granuloma formation and reduced inducible NO synthase expression. Reduced chemokine production in the lung might explain suboptimal recruitment and activation of T cells and uncontrolled infection. Therefore, despite a massive reduction of the mycobacterial load by chemotherapy, TNF-deficient mice were unable to compensate and mount a protective immune response. In conclusion, endogenous TNF is critical to maintain latent tuberculosis infection, and in its absence no specific immunity is generated.

Adenoviral delivery of IL-18 binding protein C ameliorates collagen-induced arthritis in mice

Elevated concentrations of interleukin-18 (IL-18) are found in both serum and synovial fluid of patients suffering from rheumatoid arthritis (RA) and this cytokine has recently been implicated in the development of experimental arthritis. In this present study, we developed an IL-18 neutralizing intervention and examined its efficacy for local intra-articular treatment of experimental arthritis. To this end we constructed an adenoviral vector containing the murine IL-18 binding protein isoform c gene (AdCMVIL-18BPc). The constructed adenoviral vector was validated on replication deficiency, transfection efficacy and ability to express biological functional IL-18BPc. Intra-articular overexpression of IL-18BPc significantly reduced incidence of collagen-induced arthritis (CIA) in treated kneejoints. Affected kneejoints of IL-18BPc-treated mice showed less severe arthritis, characterized by reduction of inflammation and destruction of bone and cartilage. Local intra-articular IL-1BPc treatment in both knees provided additional protection against CIA incidence and severity in distal paws. Measurement of serum levels of specific collagen type (CII) Abs revealed a moderate reduction of circulating IgG2a anti-CII Abs, while IgG1 anti-CII Abs remained at similar level. The present study underlines the involvement of IL-18 as an important proinflammatory cytokine in onset of experimental arthritis. Furthermore, it shows that endogenous IL-18 can be blocked efficiently through local adenoviral overexpression of IL-18BPc, indicating that treatment with IL-18BPc might contribute to joint protection in RA.

Infectious complications of biologic treatments of rheumatoid arthritis

Agents that block the action of tumor necrosis factor-alpha and recombinant interleukin-1 have been shown to be effective biologic treatment modalities in patients with rheumatoid arthritis. Given the immunosuppressive effects of tumor necrosis factor-alpha and interleukin-1 blockers, infections have emerged as possible complications of using these agents, an observation foreshadowed in prelicensure animal studies. At this time, hundreds of thousands of patients have received these drugs, and a wide variety of infectious complications has been reported, among which reactivation tuberculosis is most notable. Case reports alone, however, do not necessarily reflect a causal association between a therapeutic product and an adverse event. The authors review the infectious complications of the use of these agents as reported in the medical literature from November 2001 through October 2002.

In situ detection of Mycobacterium tuberculosis transcripts in human lung granulomas reveals differential gene expression in necrotic lesions

We have used RNA-RNA in situ hybridization to detect the expression of several Mycobacterium tuberculosis genes in tuberculous granulomas in lung tissue sections from tuberculosis patients. The M. tuberculosis genes chosen fall into two classes. Four genes (icl, narX, and Rv2557 and Rv2558) have been implicated in the persistence of the bacterium in the host, and two genes (iniB and kasA) are upregulated in response to isoniazid exposure. Both necrotic and nonnecrotic granulomas were identified in all of the patients. Necrotic granulomas were divided into three zones: an outer lymphocyte cuff containing lymphocytes and macrophages, a transition zone consisting of necrotic material interspersed with macrophages, and a central acellular necrotic region. Transcripts of all of the genes studied were found in nonnecrotic granulomas and in the lymphocyte cuff of necrotic granulomas. Mycobacterial gene expression was associated with CD68-positive myeloid cells. Rv2557 and/or its homologue Rv2558, kasA, and iniB were expressed within the transition zone of necrotic granulomas, whereas icl and narX transcripts were absent from this area. There was no evidence of transcription of any of the genes examined in the central necrotic region, although mycobacterial DNA was present. The differential expression of genes within granulomas demonstrates that M. tuberculosis exists in a variety of metabolic states and may be indicative of the response to different microenvironments. These observations confirm that genes identified in models of persistence or in response to drug treatment in vitro are expressed in the human host.