Nontuberculous mycobacteria infections and anti-tumor necrosis factor-alpha therapy

Disseminated Mycobacterium haemophilum infection in a 72-year-old patient with rheumatoid arthritis on infliximab

Mycobacterium haemophilum is a slow growing, aerobic, fastidious mycobacterium requiring hemin and a temperature of 30-32° C for optimal growth that is ubiquitous in nature. Disease in immunocompromised adults typically manifests as skin lesions such as papules, pustules and ulcerations. This organism also causes lymphadenitis in immunocompetent children. Antitumour necrosis factor-α (anti-TNF-α) therapy with agents such as infliximab, etanercept and adalimumab is increasingly being used for immunosuppression in patients with various autoimmune conditions. These agents are known to place patients at increased risk for tuberculosis and other granulomatous diseases. However, little is known about illness caused by M haemophilum in patients on immunosuppression with anti-TNF-α therapy. We describe a case of disseminated M haemophilum manifesting as skin lesions in a 72-year-old man with rheumatoid arthritis on infliximab and methotrexate.

Application of a stochastic modeling to assess the evolution of tuberculous and non-tuberculous mycobacterial infection in patients treated with tumor necrosis factor inhibitors

In this manuscript we apply stochastic modeling to investigate the risk of reactivation of latent mycobacterial infections in patients undergoing treatment with tumor necrosis factor inhibitors. First, we review the perspective proposed by one of the authors in a previous work and which consists in predicting the occurrence of reactivation of latent tuberculosis infection or newly acquired tuberculosis during treatment; this is based on variational procedures on a simple set of parameters (e.g. rate of reactivation of a latent infection). Then, we develop a full analytical study of this approach through a Markov chain analysis and we find an exact solution for the temporal evolution of the number of cases of tuberculosis infection (re)activation. The analytical solution is compared with Monte Carlo simulations and with experimental data, showing overall excellent agreement. The generality of this theoretical framework allows to investigate also the case of non-tuberculous mycobacteria infections; in particular, we show that reactivation in that context plays a minor role. This may suggest that, while the screening for tuberculous is necessary prior to initiating biologics, when considering non-tuberculous mycobacteria only a watchful monitoring during the treatment is recommended. The framework outlined in this paper is quite general and could be extremely promising in further researches on drug-related adverse events.

Prognostic value of American Thoracic Society criteria for non-tuberculous mycobacterial disease: a retrospective analysis of 120 cases with four years of follow-up

BACKGROUND

Non-tuberculous mycobacteria (NTM) cause disease in healthy and immunocompromised patients. The American Thoracic Society (ATS) 2007 diagnostic criteria were devised to distinguish NTM disease from airway colonization. The aim of this study was to evaluate the prognostic value of the ATS criteria.

METHODS

In a 4-y follow-up study that ended on 8 June 2006, we retrospectively analyzed the symptoms, underlying diseases, and mortality of 120 adult non-HIV patients with NTM culture findings obtained between 1990 and 1998. We categorized the patients according to the 2007 ATS NTM case definition into positive and negative groups.

RESULTS

Only 61/120 patients (51%) fulfilled the ATS criteria for NTM disease. As compared to ATS-negative subjects, the ATS-positive group showed lower age, a higher proportion of females, and fewer fatal underlying diseases. Among ATS-negative subjects, 46/59 (78%) did not fulfil the microbiological criteria and 43/59 (73%) did not fulfil the radiological criteria. Mycobacterium avium complex (MAC) comprised 61% of isolations in the ATS-positive and 47% in the ATS-negative group (p = 0.15). No significant difference in median survival time was found between the groups: ATS-positive 7.4 y (95% confidence interval (CI) 0.2-14.6) and ATS-negative 5.3 y (95% CI 3.0-7.6). No significant difference was found in symptoms except fatigue, which was more common in the ATS-positive (56% vs 37%, p = 0.04). Symptoms lasted for less than a year in 48%, which suggests a more rapid disease progression than has previously been reported.

CONCLUSIONS

The fulfillment of ATS criteria was poorly associated with any difference in prognosis, and based on our findings would be a poor prognostic marker.

Infections and biologic therapy in rheumatoid arthritis: our changing understanding of risk and prevention

Patients with rheumatoid arthritis are at higher risk for serious infections and death from infection than the general public. Prednisone and biologic agents increase this risk, although the risk associated with biologics can be mitigated when such agents act as prednisone-sparing therapies. Some of the important causes of infectious morbidity in this setting are preventable with screening (eg, tuberculosis) or vaccination (eg, herpes zoster).

Modulation of innate host factors by Mycobacterium avium complex in human macrophages includes interleukin 17

BACKGROUND

Although opportunistic infections due to Mycobacterium avium complex (MAC) have been less common since the introduction of highly active antiretroviral therapy, globally, human immunodeficiency virus-1 (HIV-1)-positive patients remain predisposed to these infections. Absence of a properly functioning acquired immune response allows MAC persistence within macrophages localized in lymph nodes coinfected with HIV and MAC. Although a deficiency in interferon γ appears to play a part in the ability of MAC to deflect the macrophage-associated antimicrobial attack, questions about this process remain. Our study examines the ability of MAC to regulate interleukin 17 (IL-17), a proinflammatory cytokine involved in host cell recruitment.

METHODS

Coinfected lymph nodes were examined for IL-17 by immunohistochemical analysis. In vitro, macrophages exposed to mycobacteria were evaluated for transcription activities, proteins, and signaling pathways responsible for IL-17 expression. Infected macrophages were also analyzed for expression of interleukin 21 (IL-21) and negative regulators of immune responses.

RESULTS

Infection of macrophages triggered synthesis of IL-17, correlating with IL-17 expression by macrophages in coinfected lymph nodes. Infected macrophages exposed to exogenous IL-17 expressed CXCL10, which favors recruitment of new macrophages as targets for infection. Blockade of nuclear factor κ-light-chain-enhancer of activated B cells and mitogen-activated protein kinase pathways suppressed mycobacteria-induced IL-17 expression. MAC triggered expression of IL-21, IRF4, and STAT3 genes related to IL-17 regulation, as well as expression of the negative immunoregulators CD274(PD-L1) and suppressors of cytokine signaling.

CONCLUSIONS

MAC-infected macrophages can provide an alternative source for IL-17 that favors accumulation of new targets for perpetuating bacterial and viral infection while suppressing host antimicrobial immune responses.

Antimicrobial susceptibility testing, drug resistance mechanisms, and therapy of infections with nontuberculous mycobacteria

Within the past 10 years, treatment and diagnostic guidelines for nontuberculous mycobacteria have been recommended by the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Moreover, the Clinical and Laboratory Standards Institute (CLSI) has published and recently (in 2011) updated recommendations including suggested antimicrobial and susceptibility breakpoints. The CLSI has also recommended the broth microdilution method as the gold standard for laboratories performing antimicrobial susceptibility testing of nontuberculous mycobacteria. This article reviews the laboratory, diagnostic, and treatment guidelines together with established and probable drug resistance mechanisms of the nontuberculous mycobacteria.

JAK inhibition for the treatment of rheumatoid arthritis: a new era in oral DMARD therapy

INTRODUCTION

In rheumatoid arthritis (RA) there is a significant medical need for safe and effective oral disease-modifying anti-rheumatic drugs (DMARDs) for patients who respond inadequately to methotrexate, the first-line therapy in RA. Oral agents targeting Janus-associated kinases (JAKs) are the most promising new agents in clinical development. This review describes the preclinical and clinical activities of the most advanced JAK inhibitors with different JAK selectivity profiles.

AREAS COVERED

This review first describes the current treatment landscape and the pathophysiology of RA. Role for cytokines in the disease pathogenesis followed by significance of JAK/STAT pathway in cytokine signaling are discussed. Available chemical description and enzymatic data on the most advanced JAK inhibitors in clinical development are provided. Preclinical and clinical results that are publicly available are summarized. Review of literature was conducted using National Library of Medicine (NLM) database, 'PubMed'. In addition, all publicly disclosed data from companies that are developing the JAK inhibitors was researched to obtain the most up-to-date information of the compounds discussed in this report.

EXPERT OPINION

Emerging clinical results demonstrate that JAK inhibition is a validated new mechanism for the development of oral DMARD agents that is likely to join the armamentarium against RA in the near future.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Mycobacterium genavense in the Netherlands: an opportunistic pathogen in HIV and non-HIV immunocompromised patients. An observational study in 14 cases

Mycobacterium genavense is an opportunistic non-tuberculous mycobacterium previously mostly associated with HIV-infected patients with CD4 counts below 100/μL. In this retrospective observational study of medical charts we studied all Dutch patients in whom M. genavense was detected between January 2002 and January 2010. Of the 14 patients identified, 13 (93%) showed clinically relevant M. genavense disease. All patients with M. genavense disease were severely immunocompromised, including HIV-infected patients, solid organ transplant recipients, those with chronic steroid use in combination with other immune modulating drugs, recipients of chemotherapy for non-Hodgkin lymphoma, and those with immunodeficiency syndromes. Two patients had non-disseminated pulmonary M. genavense disease. Of the 12 patients treated, eight (75%) showed a favourable outcome. Four patients died in this study, three despite treatment for M. genavense disease. We conclude that M. genavense is a clinically relevant pathogen in severely immunocompromised patients that causes predominantly disseminated disease with serious morbidity and mortality. M. genavense is increasingly seen among non-HIV immunocompromised patients.

Clinical significance and antibiotic susceptibilities of nontuberculous mycobacteria from patients in Crete, Greece

AIM

To describe the clinical significance and antibiotic susceptibilities of nontuberculous mycobacteria (NTM) isolated from patients in Crete, Greece between January 2000 and December 2009.

PATIENTS & METHODS

NTM identification was performed using conventional bacteriological methods and confirmed by molecular characterization with commercially available assays. Rare and novel species were identified by sequencing of the 16SrRNA and of the hsp65 genes. Antibiotic susceptibility testing was performed by E-test. Rapidly growing (RGM) and slowly growing (SGM) NTM were tested against 14 antimicrobials, including nine common ones, except for Mycobacterium avium and Mycobacterium intracellulare (MAC) complex isolates that were tested only against azithromycin, clarithromycin, linezolid and moxifloxacin.

RESULTS

During the study period, 290 positive samples for NTM were recovered from 207 patients. Among the positive samples, 150 were identified as SGM and 57 as RGM. Overall, 50 patients met American Thoracic Society criteria for disease due to NTM, 42 by SGM and eight by RGM. Risk factors in patients with NTM disease were underlying lung diseases, mainly chronic obstructive pulmonary disease and asthma, smoking, rheumatoid arthritis, AIDS, alcohol or drug abuse, malignancies and bronchiectasis. The most common disease-causing species were the MAC complex (n = 25) followed by Mycobacterium kansasii (n = 10). Amikacin was the most active drug for RGM with 100% susceptibility. Macrolides were very active against isolates of the MAC complex, while tigecycline had excellent activity in vitro against RGM. M. kansasii was the most susceptible NTM species in vitro.

CONCLUSION

Our study is the first to describe the clinical significance, risk factors and susceptibility patterns of NTM isolates in a Greek population.

Prevalence of nontuberculous mycobacterial lung disease in U.S. Medicare beneficiaries

RATIONALE

Pulmonary nontuberculous mycobacteria (PNTM) are an important cause of morbidity among older adults in the United States, but national prevalence estimates are lacking.

OBJECTIVES

To describe the prevalence and trends of PNTM disease among adults aged 65 years or older throughout the United States.

METHODS

A nationally representative 5% sample of Medicare Part B beneficiaries was analyzed from 1997 to 2007. Demographic and medical claims data were compiled and prevalence estimates for PNTM and selected comorbidities were calculated and trends over time evaluated. Logistic regression was used to identify demographic and geographic factors associated with PNTM.

MEASUREMENTS AND MAIN RESULTS

From 1997 to 2007, the annual prevalence significantly increased from 20 to 47 cases/100,000 persons, or 8.2% per year. The period prevalence was 112 cases/100,000 persons, although prevalence was twofold higher among Asians/Pacific Islanders than among whites (228 vs. 116 cases/100,000 persons). Western states had the highest period prevalence at 149 cases/100,000 persons, with Hawaii having the highest prevalence at 396 cases/100,000 persons, followed by southeastern states, which had a period prevalence of 131 cases/100,000 persons. PNTM cases had more comorbid conditions than noncases and were 40% more likely to die than noncases. Women were 1.4 times more likely to be a PNTM case than men. Relative to whites, Asians/Pacific Islanders were twice as likely to be a case, whereas blacks were half as likely.

CONCLUSIONS

The prevalence of PNTM is increasing across all regions of the United States and among both men and women. Significant racial/ethnic and geographic differences suggest important gene-environment interactions.

Mycobacteria and biological response modifiers: two sides of the relationship

With increasing use of biological response modifiers (BRMs) for various systemic inflammatory diseases there is a need to be vigilant about complications with the use of these therapies. It is important to have appropriate screening for the infections in patients requiring BRMs. However, many studies have reported benefits of certain BRMs in the treatment of infections such as tuberculosis as adjuncts. Continued research and technical advances in immunogenetics helps understand complex mechanisms in the usage of the BRMs. This article summarizes the different aspects of the relationship between mycobacterial infections and the use of various BRMs for inflammatory conditions.

Radiological features and therapeutic responses of pulmonary nontuberculous mycobacterial disease in rheumatoid arthritis patients receiving biological agents: a retrospective multicenter study in Japan

Objective

This study was performed to evaluate the radiological features of and therapeutic responses to pulmonary disease caused by nontuberculous mycobacteria (NTM) in the setting of biological therapy for rheumatoid arthritis (RA).

Methods

We conducted a retrospective chart review of 13 patients from multiple centers who had developed pulmonary NTM disease during biological therapy for RA, including infliximab, etanercept, adalimumab, and tocilizumab.

Results

Most cases were asymptomatic or resulted in only common-cold-like symptoms. Abnormalities in computed tomography (CT) imaging were protean and frequently overlapped. The most predominant pattern was nodular/bronchiectatic disease (six cases), followed by alveolar infiltrate (three cases), cavitary disease (two cases), and pulmonary nodules (two cases). In most cases, pulmonary NTM disease had spread from a preexisting lesion; in particular, bronchial/bronchiolar abnormalities. In three cases, one or more nodular lesions with or without calcification were a focus of disease. Following the discontinuation of biological agents, most patients responded to anti-NTM therapy. Two patients showed no exacerbation in the absence of any anti-NTM therapy. In one patient, restarting tocilizumab therapy while continuing to receive adequate anti-NTM therapy produced a favorable outcome. In two other patients with a previous history of pulmonary NTM disease, introducing biological therapy led to recurrence, but anti-NTM therapy was effective in these patients.

Conclusion

CT abnormalities of pulmonary NTM disease in RA patients receiving biological therapy were variable, but were not unique to this clinical setting. NTM disease can spread from preexisting structural abnormalities, even if they are minute. Contrary to our expectations, the therapeutic outcomes of pulmonary NTM disease were favorable in these patients.

Is continuation of anti-tumor necrosis factor-α therapy a safe option for patients who have developed pulmonary mycobacterial infection? : Case presentation and literature review

Continuation of anti-tumor necrosis factor-α (TNFα) therapy generally has not been recommended for patients who have developed nontuberculous mycobacterial (NTM) diseases; in daily practice, however, we often encounter patients with refractory rheumatoid arthritis (RA) who experience uncontrollable flares following withdrawal of anti-TNFα agents. Here, we report a case of pulmonary NTM disease caused by Mycobacterium intracellulare occurring in a patient with refractory RA undergoing etanercept therapy. Since there was the concern of an exacerbation of RA symptoms, etanercept was continued during anti-NTM therapy. The patient's pulmonary symptoms and radiological abnormalities were found to have markedly improved in a relatively short time period after beginning the anti-NTM therapy. Additionally, her RA symptoms were adequately controlled without the occurrence of any unexpected adverse events. The continuation of etanercept therapy may be a safe option during anti-NTM therapy if patients' underlying diseases would otherwise be difficult to control. Strictly supervised anti-NTM therapy and patients' informed consent are mandatory. We review the medical literature on NTM disease associated with anti-TNFα therapy for rheumatic diseases and discuss the safety of simultaneous use of anti-TNFα agents in patients during anti-NTM therapy.

Each type of cause that initiates rheumatoid arthritis or RA flares differentially affects the response to therapy

The autoimmune disease rheumatoid arthritis (RA) presents difficulty in diagnosis, commonly observed flare ups, polycyclical nature of RA progression, and variable response to therapies. Congruent with multiple causes, literature has documented various infectious agents, environmental factors, physical trauma, silica and food sensitivities as potential causes of RA or RA flares in different populations. We propose that these>36 events can initiate RA or RA flares which complicates treatment decisions. Each pharmaceutical medicine benefits 15-82% of RA patients. Predictive factors are needed. Because the initiating cause of RA or RA flare affects the type of joint damage, initial inflammatory response, adaptive immune response, and potential molecular mimicry, we propose the "RA cause affects response to therapy" (RACART) theory. The potential cause combined with confounding factors such as genetic risk factors, nutritional status, epigenetic status, inflammatory levels, and detoxification ability may help predict responses to various therapies.

IL-32 expression in the airway epithelial cells of patients with Mycobacterium avium complex lung disease

Lung disease due to Mycobacterium avium complex (MAC) organisms is increasing. A greater understanding of the host immune response to MAC organisms will provide a foundation to develop novel therapies for these recalcitrant infections. IL-32 is a newly described pro-inflammatory cytokine that enhances host immunity against various microbial pathogens. Cytokines that induce IL-32 such as interferon-gamma, IL-18, IL-12 and tumor necrosis factor-alpha are of considerable importance to mycobacterial immunity. We performed immunohistochemistry and morphometric analysis to quantify IL-32 expression in the lungs of 11 patients with MAC lung disease and 10 controls with normal lung tissues. After normalizing for basement membrane length, there was a profound increase in IL-32 expression in the airway epithelial cells of the MAC-infected lungs compared with controls. Following normalization for alveolar surface area, there was a trend toward increased IL-32 expression in type II alveolar cells and alveolar macrophages in the lungs of MAC patients. Human airway epithelial cells (BEAS-2B) infected with M. avium produced IL-32 by a nuclear factor-kappa B-dependent mechanism. In both BEAS-2B cells and human monocyte-derived macrophages, exogenous IL-32γ significantly reduced the growth of intracellular M. avium. This finding was corroborated by an increase in the number of intracellular M. avium recovered from THP-1 monocytes silenced for endogenous IL-32 expression. The anti-mycobacterial effect of IL-32 may be due, in part, to increased apoptosis of infected cells. These findings indicate that IL-32 facilitates host defense against MAC organisms but may also contribute to the airway inflammation associated with MAC pulmonary disease.

Atypical mycobacterial infection presenting as persistent skin lesion in a patient with ulcerative colitis

Immunosuppressive drugs are commonly used for the treatment of inflammatory bowel disease. Patients receiving immunosuppressants are susceptible to a variety of infections with opportunistic pathogens. We present a case of skin infection with Mycobacterium chelonae in a 60-year-old Caucasian woman with ulcerative colitis who had been treated with corticosteroids and azathioprine. The disease manifested with fever and rash involving the right leg. Infliximab was administered due to a presumptive diagnosis of pyoderma gangrenosum, leading to worsening of the clinical syndrome and admission to our hospital. Routine cultures from various sites were all negative. However, Ziehl-Neelsen staining of pus from the lesions revealed acid-fast bacilli, and culture yielded a rapidly growing mycobacterium further identified as M. chelonae. The patient responded to a clarithromycin-based regimen. Clinicians should be aware of skin lesions caused by atypical mycobacteria in immunocompromised patients with inflammatory bowel disease. Furthermore, they should be able to thoroughly investigate and promptly treat these conditions.

Infections associated with monoclonal antibody and fusion protein therapy in humans

Monoclonal antibodies (mAbs), especially those that interact with immune or hematologic leukocyte membrane targets, have changed the outcome of numerous diseases. However, mAbs can block or reduce immune cells and cytokines, and can lead to increased risk of infection. Some of these risks are predictable and can be explained by their mechanisms of action. Others have been observed only after the mAbs were licensed and used extensively in patients. In this review, we focus on infectious complications that occur upon treatment with mAbs or Fc-containing fusion proteins targeting leukocyte membrane proteins, including CD52, CD20, tumor necrosis factor, VLA4, CD11a and CTLA4. We report their known infectious risks and the recommendations for their use. Although most of these drugs are clinically safe when the indications are respected, we emphasize the need for regular updating of pharmacovigilance data.

Defective innate immunity in inflammatory bowel disease: a Crohn's disease exclusivity?

PURPOSE OF REVIEW

This review summarizes the recent developments in support of the immunodeficiency model of Crohn's disease.

RECENT FINDINGS

The demonstration of impaired acute inflammation in Crohn's disease provides a novel mechanism for its pathogenesis, with diminished macrophage cytokine production and neutrophil recruitment leading to reduced bacterial clearance. The innate immune response may be further overwhelmed by other factors. The mucosal barrier in Crohn's patients is disrupted, with abnormal ultrastructure as well as antibacterial defensin deficiency. Specific bacterial agents may contribute and one promising candidate, adherent-invasive Escherichia coli, has recently been described. An interaction between Nod2 and the autophagy system has been elucidated, with direct consequences for bacterial clearance, and the most recent genome-wide association study meta-analysis has extended the number of Crohn's disease susceptibility loci to 71. The spectrum of congenital immunodeficiency disorders recognized to develop Crohn's-like inflammatory bowel disease is also expanding. Conversely, no specific immunodeficiency has so far been observed in ulcerative colitis, in which the defect appears to be failure of inflammation termination and resolution.

SUMMARY

Recent advances continue to highlight defects in innate immunity in Crohn's patients. Similar abnormalities may extend to other granulomatous disorders, but not diseases such as ulcerative colitis.

Mycobacterial infections in the era of modern biologic agents

Patients with rheumatologic disease are at increased risk for mycobacterial infections because of both immunocompromising therapy and preexisting lung damage from the disease itself. Tuberculosis is uncommon in the United States; however, it is relatively more prevalent in immigrants, minorities, elderly, persons with acquired immune deficiency syndrome and among healthcare workers. In the United States, the nontuberculous mycobacteria (NTM) are now more prevalent than tuberculosis. Although initially noted in men with chronic obstructive pulmonary disease, recent observations indicate increasing numbers of NTM cases in slender white women. Because of the often atypical presentation of NTM lung disease, diagnosis is commonly delayed. Because there is solid evidence that tumor necrosis factor-alpha-modifying agents are associated with serious NTM disease, it is important that specific screening tests (eg, chest x-ray, computed tomographic lung scans, sputum cultures or referral to pulmonary or infectious disease specialists) be used before initiating anti-tumor necrosis factor therapy.

Identification of loci associated with tolerance to Johne's disease in Holstein cattle

Johne's disease, caused by Mycobacterium avium subspecies paratuberculosis (Map), is a fatal disease in cattle. The objective of this study was to identify loci associated with tolerance in cows infected with Map. Tolerance was defined as a cow's fitness at a given level of Map infection intensity. Fitness was measured by Map faecal cultures, and Map infection intensity was measured by culturing four gut tissues. The quantitative phenotype of tolerance was defined by numerical indexes of cultures of peak (peak tolerance, PT) and average (average tolerance, AT) faecal and tissue Map from 245 Holstein cows. The categorical phenotype was defined as: ≥ 100 cfu Map tissue infection, and faecal shedding ≥ 75 cfu (intolerant) or <10 cfu (tolerant cows). In 94 cows, Map was identified in ≥ 1 tissue, including 44 cows with ≥ 100 Map tissue cfu and 36 with ≥ 1 faecal cfu. A genome-wide association analysis was performed after filtering, leaving genotypes for 45,789 SNPs in 90 animals for the quantitative phenotype and 16 cases and 25 controls for the categorical analysis of tolerance. rs41748405:A>C (BTA15) was associated with PT (P = 1.12 × 10(-7)) and AT (P = 2.17 × 10(-6)). Associations were identified with PT and adjacent SNPs ss61512613:A>G and ss61530518:A>G (BTA6) (P < 3.0 × 10(-5)), and with AT for ss61469568:A>G (BTA 2) (P = 3.3 × 10(-5)) and ss86284768:A>G (BTA1) (P = 3.31 × 10(-5)). For the categorical phenotype, an association was found with ss8632653:A>G (BTA6) (P < 5.0 × 10(-5)). This is the first study to identify loci associated with tolerance to Johne's disease.

The reliability of diagnostic coding and laboratory data to identify tuberculosis and nontuberculous mycobacterial disease among rheumatoid arthritis patients using anti-tumor necrosis factor therapy

PURPOSE

Anti-tumor necrosis factor-alpha (anti-TNF) therapies are associated with severe mycobacterial infections in rheumatoid arthritis patients. We developed and validated electronic record search algorithms for these serious infections.

METHODS

The study used electronic clinical, microbiologic, and pharmacy records from Kaiser Permanente Northern California (KPNC) and the Portland Veterans Affairs Medical Center (PVAMC). We identified suspect tuberculosis and nontuberculous mycobacteria (NTM) cases using inpatient and outpatient diagnostic codes, culture results, and anti-tuberculous medication dispensing. We manually reviewed records to validate our case-finding algorithms.

RESULTS

We identified 64 tuberculosis and 367 NTM potential cases, respectively. For tuberculosis, diagnostic code positive predictive value (PPV) was 54% at KPNC and 9% at PVAMC. Adding medication dispensings improved these to 87% and 46%, respectively. Positive tuberculosis cultures had a PPV of 100% with sensitivities of 79% (KPNC) and 55% (PVAMC). For NTM, the PPV of diagnostic codes was 91% (KPNC) and 76% (PVAMC). At KPNC, ≥ 1 positive NTM culture was sensitive (100%) and specific (PPV, 74%) if non-pathogenic species were excluded; at PVAMC, ≥1 positive NTM culture identified 76% of cases with PPV of 41%. Application of the American Thoracic Society NTM microbiology criteria yielded the highest PPV (100% KPNC, 78% PVAMC).

CONCLUSIONS

The sensitivity and predictive value of electronic microbiologic data for tuberculosis and NTM infections is generally high, but varies with different facilities or models of care. Unlike NTM, tuberculosis diagnostic codes have poor PPV, and in the absence of laboratory data, should be combined with anti-tuberculous therapy dispensings for pharmacoepidemiologic research.

Choice of Biologic Therapy for Patients with Rheumatoid Arthritis: The Infection Perspective

Biologicals revolutionized the treatment of Rheumatoid Arthritis (RA). The targeted suppression of key inflammatory pathways involved in joint inflammation and destruction allows better disease control, which, however, comes at the price of an elevated infection risk due to relative immunosuppression. The disease-related infection risk and the infection risk associated with the use of TNF-α inhibitors (infliximab, adalimumab, etanercept, golimumab and certolizumab pegol), rituximab, abatacept and tocilizumab are discussed. Risk factors clinicians need to take into account when selecting the most appropriate biologic therapy for RA patients, as well as precautions and screening concerning a number of specific infections, such as tuberculosis, intracellular bacterial infections, reactivation of chronic viral infections and HIV are reviewed.

Life-Threatening Complications of Biological Therapies

The last decade was characterized by the successive introduction of several biological agents for the treatment of autoimmune rheumatic diseases (ARD). Randomized controlled trials (RCT) proved them to have globally acceptable safety and tolerability profiles. However, life-threatening complications are rare events and RCT are underpowered to detect them. As these drugs became more widely prescribed in clinical practice, and particularly, having the information from multiple national biologics registries available, serious adverse events became perceptible. Infection remains the major concern, but other serious and life-threatening complications have emerged, such as malignancies, congestive heart failure, demyelinating disorders, and drug-induced autoimmune syndromes. Several of these are correlated with either the underlying disease or concomitant immunosuppressive medication. Most of them can be avoided by the adoption of preventive measures and an early proper management might significantly change the outcome. Awareness of the possible serious side effects is of utmost importance for a safer use of biological agents.

In this chapter, we aim to describe the most commonly reported life-threatening complications of biological therapies in the literature – including those with antitumor necrosis factor agents, rituximab, abatacept, tocilizumab, and anakinra. Risk groups are identified and strategies for the prevention and initial management are included.

Serodiagnosis of Mycobacterium avium-complex pulmonary disease with an enzyme immunoassay kit that detects anti-glycopeptidolipid core antigen IgA antibodies in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) has many pulmonary manifestations, including bronchial abnormalities that can develop into Mycobacterium avium-complex (MAC) pulmonary disease (PD). MAC-PD can be lethal in patients receiving tumor necrosis factor-alpha blockers despite administration of antibiotics. Diagnosis of MAC-PD is often difficult, because MAC is an environmental organism. In this study, we investigated the usefulness of serodiagnosis of MAC-PD in RA patients by using an enzyme immunoassay (EIA) kit that detects anti-glycopeptidolipid (GPL) core antigen IgA antibodies. Antibody levels were measured in 63 patients with RA: 14 with MAC-PD plus 3 cultured nontuberculous mycobacteria (NTM) other than MAC, 16 with pulmonary abnormalities characterizing NTM but undetected in sputum culture, and 30 control subjects. RA patients with MAC-PD showed significantly higher antibody levels than controls (p = 0.02). The cutoff point was set at 0.7 IU/l, making the sensitivity and specificity of the antibody in MAC-PD and control patients 43% and 100%, respectively. The EIA kit is useful for diagnosis of MAC-PD in RA patients because of its high specificity. This test is an easier and less invasive form of examination and could therefore replace bronchoscopy as the main diagnostic procedure for RA patients with MAC-PD.

Mycobacterium avium complex cervical lymphadenitis in an immunocompetent adult

Nontuberculosis mycobacterial cervical lymphadenitis is a relatively common disease in immunocompetent children but a rare disease in immunocompetent adults. We report the diagnosis and treatment of Mycobacterium avium complex cervical lymphadenitis in an adult female. Our evaluation of immune competence, including gamma interferon (IFN-gamma) and interleukin-12 (IL-12) signaling, found no evidence of deficiency.

Nontuberculous mycobacterial lung disease

PURPOSE OF REVIEW

There is increasing awareness that nontuberculous mycobacteria (NTM) lung diseases are becoming more prevalent. Nontuberculous mycobacterial diseases could legitimately be seen as an emerging public-health threat.

RECENT FINDINGS

Nontuberculous mycobacterial lung disease associated radiographically with nodules and bronchiectasis occurs primarily in women. These patients are associated with a specific morphotype, including low BMI, tall stature, scoliosis, pectus excavatum and mitral valve prolapse. The pathophysiologic link between these findings and the development of bronchiectasis and NTM disease remains unclear. As with tuberculosis, the tumor-necrosis factor alpha (TNF-alpha) blockers also predispose to NTM infection that can be severe. The most frustrating aspect of NTM therapy remains the generally poor correlation between in-vitro antibiotic susceptibility and in-vivo response to antimicrobials. A possible insight into this phenomenon is the recent discovery of an inducible macrolide resistance (erm) gene in Mycobacterium fortuitum and Mycobacterium abscessus. This gene can produce in-vivo resistance without resulting in a 'resistant' MIC for macrolides.

SUMMARY

The NTM pose an increasing problem for clinicians and are associated with significant obstacles that thwart successful treatment of NTM disease. Continued progress in the areas of disease pathogenesis and therapy will improve the outlook for these patients.

Mycobacterium marinum infection complicated by anti-tumour necrosis factor therapy

Mycobacteria other than tuberculosis infections in patients taking various tumour necrosis factor (TNF)-α inhibitors have been reported in the literature. We describe sporotrichoid spread of Mycobacterium marinum in a man with Crohn's disease treated with infliximab. After starting ethambutol and rifampicin and discontinuing infliximab, a worsening appeared. M. marinum infection may have a potential local spread and systemic dissemination in patients treated with TNF-α inhibitors.

Host immune response to rapidly growing mycobacteria, an emerging cause of chronic lung disease

Rapidly growing mycobacteria (RGM) are environmental organisms classified under the broader category of nontuberculous mycobacteria. The most common RGM to cause human diseases are Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium massiliense. Infections due to the RGM are an emerging health problem in the United States. Chronic pulmonary disease and skin/soft-tissue infections are the two most common disorders due to these organisms. Clinical outcomes in the treatment of M. abscessus infections are generally disappointing. Because less is known about the nature of the immune response to M. abscessus than for tuberculosis, we herein highlight the major clinical features associated with infections due to M. abscessus and other RGM, and review the known host immune response to RGM, drawing from experimental animal and clinical studies. Based on in vitro and in vivo murine models, Toll-like receptor 2, dectin-1, tumor necrosis factor (TNF)-α, IFN-γ, leptin, T cells, and possibly neutrophils are important components in the host defense against RGM infections. However, excessive induction of TNF-α by the R morphotype of M. abscessus may allow it to be more pathogenic than the S morphotype. Clinical observations and/or genetic studies in humans corroborate many of the findings in animals in that those with cell-mediated immunodeficiency, genetic defects in IFN-γ-IL-12 axis, and those individuals on TNF-α blockers are at increased risk for nontuberculous mycobacteria infections, including the RGM. However, much remains to be discovered on why seemingly healthy individuals, particularly slender postmenopausal women with thoracic cage anomalies, appear to be at increased risk.