Delayed response to anti-tuberculosis treatment in a patient on infliximab

Immunoadjuvant Therapy and Noninvasive Ventilation for Acute Respiratory Failure in Lung Tuberculosis: A Case Study

Acute respiratory failure caused by pulmonary tuberculosis is a rare event but with a high mortality even while receiving mechanical ventilatory support. We report the case of a young man with severe pulmonary tuberculosis refractory to conventional therapy who successfully overcame the critical period of his condition using noninvasive ventilation and immunoadjuvant therapy that included three doses of etanercept 25 mg subcutaneously. We conclude that the use of etanercept along with antituberculosis treatment appears to be safe and effective in patients with pulmonary tuberculosis presenting with acute respiratory failure.

Tumor necrosis factor signaling mediates resistance to mycobacteria by inhibiting bacterial growth and macrophage death

Tumor necrosis factor (TNF), a key effector in controlling tuberculosis, is thought to exert protection by directing formation of granulomas, organized aggregates of macrophages and other immune cells. Loss of TNF signaling causes progression of tuberculosis in humans, and the increased mortality of Mycobacterium tuberculosis-infected mice is associated with disorganized necrotic granulomas, although the precise roles of TNF signaling preceding this endpoint remain undefined. We monitored transparent Mycobacterium marinum-infected zebrafish live to conduct a stepwise dissection of how TNF signaling operates in mycobacterial pathogenesis. We found that loss of TNF signaling caused increased mortality even when only innate immunity was operant. In the absence of TNF, intracellular bacterial growth and granuloma formation were accelerated and was followed by necrotic death of overladen macrophages and granuloma breakdown. Thus, TNF is not required for tuberculous granuloma formation, but maintains granuloma integrity indirectly by restricting mycobacterial growth within macrophages and preventing their necrosis.

Review article: minimizing tuberculosis during anti-tumour necrosis factor-alpha treatment of inflammatory bowel disease

BACKGROUND

Tumour necrosis factor (TNF)-alpha inhibitors are a major advance in the management of inflammatory bowel disease but increase the risk for tuberculosis (TB).

AIM

To examine the reasons for the increase in the risk for TB and the strategies to reduce it.

METHODS

PubMed searches were performed using search terms that included TB and each of the current anti-TNF-alpha biological agents and also TB and Crohn's disease.

RESULTS

Increased susceptibility to TB, often with extrapulmonary or disseminated disease, occurs following treatment with all anti-TNF-alpha biological agents and amounts to a four- to 20-fold increased risk with infliximab. TB usually occurs shortly after anti-TNF-alpha initiation suggesting reactivation of latent infection. Animal studies show that TNF-alpha inhibition impairs inflammatory cell trafficking and granuloma formation. Currently recommended screening for latent TB typically, risk assessment, tuberculin skin testing and chest radiograph used prior to anti-TNF-alpha treatment can reduce TB rates by up to 90% but newer screening interferon gamma assays may enhance screening efficacy. Patients positive on screening who are treated with isoniazid and subsequently receive anti-TNF-alpha treatment still have approximately 19% risk for TB.

CONCLUSIONS

Tuberculosis following treatment with TNF-alpha inhibitors usually results from reactivation of latent disease. Screening reduces the risk substantially but does not completely eliminate it.

The TB pandemic: an old problem seeking new solutions

Tuberculosis (TB) continues to kill more than 2 million people globally each year. Annual TB case notification rates have risen up to fourfold since the mid-1980s, with the highest rate of 1000/100,000 around Cape Town, South Africa. There is an urgent need for novel diagnostic methods and preventive vaccines to control this epidemic. The rising incidence of TB has been attributed to HIV co-infection especially in developing countries. The threat of drug resistance arising from ineffective TB treatment programmes is looming and could potentially lead to loss of any gains made in controlling the disease globally.

Pulmonary involvement in ankylosing spondylitis

PURPOSE OF REVIEW

Anti-tumor necrosis factor-alpha agents have recently been approved and recommended as effective and relatively safe drug therapy for ankylosing spondylitis. In light of this major advance in the management of these patients, recent observations on the pulmonary manifestations of ankylosing spondylitis are reviewed.

RECENT FINDINGS

High-resolution computed tomography abnormalities were found to be prevalent (range 50-85%) in ankylosing spondylitis even in patients with early disease, and in those with normal chest radiographs and without respiratory symptoms. The high-resolution computed tomography changes included apical fibrosis, interstitial lung disease, emphysema, bronchietasis and pleural thickening. In general, the high-resolution computed tomography changes were of mild degree, and no correlation was observed between high-resolution computed tomography abnormalities, pulmonary function test variables and indices of ankylosing spondylitis symptoms and disease structural severity. Spontaneous pneumothorax was reported to be a rare complication, but tended to occur in those patients with fibrobullous disease.

SUMMARY

The clinical significance of the high-resolution computed tomography abnormalities remains to be determined. Most of the published studies are cross-sectional, and are limited by lack of control subjects matched for age, gender and tobacco use. Studies to correlate high-resolution computed tomography changes with bronchoalveolar lavage and lung biopsies as well as prospective studies on long-term evolution of these findings including those patients receiving anti-tumor necrosis factor-alpha agents are needed.

[Risk of infection during treatment with tumor necrosis factor-alpha inhibitors]

Tumor necrosis factor-alpha (TNF) is essential for immune defense. TNF plays a major role in the recruitment of inflammatory cells to the site of infection and in the formation and maintenance of granulomas. In addition, it plays a primary and detrimental role in chronic autoimmune diseases. Drugs that inhibit TNF are effective in the treatment of inflammatory rheumatic and autoimmune diseases. However, the three currently available TNF antagonists (etanercept, infliximab and adalimumab) decrease host resistance to granulomatous diseases such as tuberculosis. The incidence of tuberculosis in patients treated with TNF antagonists is higher than in the general population. There are a number of case reports describing the association of TNF-antagonists and the presentation of other infectious diseases such as histoplasmosis, listeriosis, coccidioidomycosis, candidiasis and aspergillosis. These case reports, however, are anecdotal. Nonetheless, patients treated with TNF antagonists are immunocompromised and infectious diseases are most likely more frequent and may present differently than expected. In this review, we describe the role of TNF in constraining infectious diseases, the difference between the three available TNF antagonists, and we discuss the relevant clinical data published in the literature as related to the risk of anti-TNF therapy for infectious diseases.

Immunological control of tuberculosis: role of tumour necrosis factor and more

Therapy of autoimmune diseases with tumour necrosis factor (TNF) neutralising agents has provided a unique opportunity to learn about the significance of TNF in the maintenance of latent bacterial infections in humans. The remarkably high incidence of tuberculosis in patients treated with TNF antagonists raises the intriguing question about the physiological role of TNF in maintaining the lifelong latency of tubercle bacilli in granulomas in infected patients. Basic research during the past decade(s) combined with thoughtful observations in human subjects with tuberculosis and autoimmune diseases has provided several potential explanations for the recurrence of tuberculosis if TNF supply is withdrawn. TNF is involved in at least four key functions that contribute towards beneficial effects on the symptoms of autoimmune disorders on the one hand, and the attenuation of immune responses against Mycobacterium tuberculosis on the other hand. These are outlined in this review: induction of apoptosis, maturation of dendritic cells, activation of antimicrobial activity in macrophages, and orchestration of leucocyte movement.