Pneumonitis Caused by Legionella pneumoniae in a Patient With Rheumatoid Arthritis Treated With Anti-TNF-?? Therapy (Infliximab)

5′ Untranslated mRNA Regions Allow Bypass of Host Cell Translation Inhibition by Legionella pneumophila

Legionella pneumophila grows within membrane-bound vacuoles in alveolar macrophages during human disease. Pathogen manipulation of the host cell is driven by bacterial proteins translocated through a type IV secretion system (T4SS).

Fatal complication of Legionella pneumophila pneumonia in a tocilizumab-treated rheumatoid arthritis patient

We herein report a fatal case of Legionella pneumophila pneumonia in a tocilizumab-treated rheumatoid arthritis patient who was in a state of shock on admission but remained afebrile even during severe pneumonia. Legionella antigen was detected in the urine and neutrophil CD64 expression was highly elevated. Despite undergoing intensive treatment, the patient developed sepsis and died 12 days after admission. An autopsy indicated that while the Legionella infection had almost been controlled, a subarachnoid hemorrhage was the ultimate cause of death.

TNF and TNF-receptors: From mediators of cell death and inflammation to therapeutic giants - past, present and future

Tumor Necrosis Factor (TNF), initially known for its tumor cytotoxicity, is a potent mediator of inflammation, as well as many normal physiological functions in homeostasis and health, and anti-microbial immunity. It also appears to have a central role in neurobiology, although this area of TNF biology is only recently emerging. Here, we review the basic biology of TNF and its normal effector functions, and discuss the advantages and disadvantages of therapeutic neutralization of TNF - now a commonplace practice in the treatment of a wide range of human inflammatory diseases. With over ten years of experience, and an emerging range of anti-TNF biologics now available, we also review their modes of action, which appear to be far more complex than had originally been anticipated. Finally, we highlight the current challenges for therapeutic intervention of TNF: (i) to discover and produce orally delivered small molecule TNF-inhibitors, (ii) to specifically target selected TNF producing cells or individual (diseased) tissue targets, and (iii) to pre-identify anti-TNF treatment responders. Although the future looks bright, the therapeutic modulation of TNF now moves into the era of personalized medicine with society's challenging expectations of durable treatment success and of achieving long-term disease remission.

The frustrated host response to Legionella pneumophila is bypassed by MyD88-dependent translation of pro-inflammatory cytokines

Many pathogens, particularly those that require their host for survival, have devised mechanisms to subvert the host immune response in order to survive and replicate intracellularly. Legionella pneumophila, the causative agent of Legionnaires' disease, promotes intracellular growth by translocating proteins into its host cytosol through its type IV protein secretion machinery. At least 5 of the bacterial translocated effectors interfere with the function of host cell elongation factors, blocking translation and causing the induction of a unique host cell transcriptional profile. In addition, L. pneumophila also interferes with translation initiation, by preventing cap-dependent translation in host cells. We demonstrate here that protein translation inhibition by L. pneumophila leads to a frustrated host MAP kinase response, where genes involved in the pathway are transcribed but fail to be translated due to the bacterium-induced protein synthesis inhibition. Surprisingly, few pro-inflammatory cytokines, such as IL-1α and IL-1β, bypass this inhibition and get synthesized in the presence of Legionella effectors. We show that the selective synthesis of these genes requires MyD88 signaling and takes place in both infected cells that harbor bacteria and neighboring bystander cells. Our findings offer a perspective of how host cells are able to cope with pathogen-encoded activities that disrupt normal cellular process and initiate a successful inflammatory response.

Translation inhibition is a common virulence mechanism used by a number of pathogens (e.g. Diphtheria Toxin, Shiga Toxin and Pseudomonas Exotoxin A). It has been a mystery how host cells mount a pathogen-specific response and clear infection under conditions where protein synthesis is blocked by pathogens. Using Legionella pneumophila as a model, a bacterium that efficiently blocks the host protein translation machinery, we show here that the innate immune system has devised a mechanism to cope with translation inhibition by selectively synthesizing proteins that are required for inflammation.

Environmental factors associated with nosocomial legionellosis after anti-tumor necrosis factor therapy: case study

In response to 2 reported cases of nosocomial legionellosis after anti-tumor necrosis factor (TNF) treatment, the environmental controls and testing facilities in a 221-bed acute care hospital were investigated. This investigation led to the implementation of a series of specific preventive measures adapted from protocols used to protect immunosuppressed patients. These 2 cases of legionellosis might be related to 2 concurrent events: treatment of hospitalized patients with anti-TNF drugs and secondary environmental changes related to major construction work. Patients undergoing anti-TNF treatment may be at increased risk for developing opportunistic infections during construction work, renovations, or water supply perturbations and require specific preventive measures.

Fulminant legionellosis in two patients treated with infliximab for Crohn's disease: case series and literature review

Two cases of fulminant pulmonary legionellosis, complicated by prolonged intensive care unit stays and acute respiratory distress syndrome, and who were recently treated with infliximab for Crohn's disease, are described. A review of the literature revealed three additional cases in patients with inflammatory bowel disease, and a total of 22 cases of Legionella pneumophila pneumonia in the context of treatment with antitumour necrosis (TNF)-alpha medications. The median age of the patients was 49 years, and men and women were affected equally. The case fatality rate was 14% (three of 22). Early recognition and treatment of this anti-TNF-alpha-related complication would likely result in reduced mortality and morbidity. Physicians prescribing anti-TNF-alpha drugs should be aware of this association.

Infliximab in severe ulcerative colitis: short-term results of different infusion regimens and long-term follow-up

BACKGROUND

Severe ulcerative colitis is a life-threatening disorder, despite i.v. glucocorticoids treatment. Infliximab has been proposed as a safe rescue therapy.

AIM

To evaluate short- and long-term effectiveness and safety of infliximab in severe refractory ulcerative colitis.

METHODS

Eighty-three patients with severe ulcerative colitis (i.v. glucocorticoids treatment-refractory) were treated with infliximab in 10 Italian Gastroenterology Units. Patients underwent one or more infusions according to the choice of treating physicians. Short-term outcome was colectomy/death 2 months after the first infusion. Long-term outcome was survival free from colectomy. Safety data were recorded.

RESULTS

Twelve patients (15%) underwent colectomy within 2 months. One died of Legionella pneumophila infection 12 days after infliximab. Early colectomy rates were higher in patients receiving one infusion (9/26), compared with those receiving two/more infusions (3/57, P = 0.001, OR = 9.53). Seventy patients who survived colectomy and did not experience any fatal complications were followed-up for a median time of 23 months; 58 patients avoided colectomy during the follow-up. Forty-two patients were maintained on immunosuppressive drugs. No clinical features were associated with outcomes.

CONCLUSIONS

Infliximab is an effective and relatively safe therapy to avoid colectomy and maintain long-term remission for patients with severe refractory ulcerative colitis. In the short term, two or more infusions seem to be more effective than one single infusion.

Légionellose

Legionnaires disease, more formally known as legionellosis, is a relatively common form of severe pneumonia caused by Legionella, a genus of waterborne bacteria. Legionellosis is acquired by inhalation of legionellae from contaminated environmental sources. Legionella pneumophila serogroup 1 is responsible for more than 80% of cases in most countries. More than 1500 cases were reported in France in 2005. Initial diagnosis is based on tests for urinary antigens. The mortality rate for legionellosis depends on the promptness of appropriate antibiotic therapy. Macrolides (erythromycin or intravenous azithromycin, which is preferred to erythromycin for its better pharmacodynamic properties) and fluoroquinolones (levofloxacin) are the antibiotics of choice for severe legionellosis.

Legionnaires’ Disease

The incidence of legionnaires’ disease (LD) seems to increase with age, particularly in males [36]. It was considered an infrequent cause of pneumonia in the past, but it currently ranks second to pneumococcus in the list of etiologic agents of severe community-acquired pneumonia (CAP) of bacterial origin [2, 24, 60, 89]. Considering less severe cases, in a series of 145 pneumonias in which BCYE culture, serology and the Legionella urinary antigen (LUA) test were systematically applied, Vergis et al. [91] reported a prevalence of LD of 13.7%. In another series of 392 adult patients with CAP treated in a university hospital, Sopena et al. found a prevalence of 12.5%, and LD was the second cause of pneumonia [83].

Impact of Biologic Agents on Infectious Diseases

Until recently, inflammatory diseases, collagen vascular diseases, inflammatory bowel diseases, and multiple sclerosis were met with a limited offering for treatment. The introduction of biologic agents has revolutionized the approach to these diseases, offering many patients freedom from disease activity staving off resultant destruction to organs and joints with marked improvement in quality of life and disability. This article focuses on the development of serious infections associated with the use of biologic agents. Presented is a synthesis of case series, reports, and systematic reviews to elucidate implicated pathogens and clinical presentations in patients being treated with biologic agents and to form a cursory backbone for prevention and treatment strategies to which clinicians prescribing these agents or encountering patients already on these agents can readily refer. Maintenance of a high index of suspicion is imperative for the prevention and appropriate treatment of serious life-threatening infections in these patients.

Emergence of Legionella pneumophila Pneumonia in Patients Receiving Tumor Necrosis Factor- Antagonists

BACKGROUND

Patients treated with tumor necrosis factor-alpha (TNF-alpha) antagonists have an increased risk of infection, but infection due to Legionella pneumophila has rarely been described in patients receiving such therapy.

METHODS

A registry involving 486 clinical departments in France was designed by a multidisciplinary group (Recherche Axée sur la Tolérance des Biothérapies [RATIO]) to collect data on opportunistic and severe infections occurring in patients treated with TNF-alpha antagonists. All cases are reported to RATIO in accordance with national health authorities and validated by infectious disease experts. The legionellosis rate among patients treated with TNF-alpha antagonists was compared with the rate in France overall.

RESULTS

We report a 1-year consecutive series of 10 cases of L. pneumophila pneumonia in France in 2004, including 6 cases treated with adalimumab, 2 treated with etanercept, and 2 treated with infliximab. The median patient age was 51 years (range, 40-69 years). Eight patients were treated for rheumatoid arthritis, 1 was treated for cutaneous psoriasis, and 1 was treated for pyoderma gangrenosum. The median duration of TNF-alpha antagonist treatment at onset of infection was 38.5 weeks (range, 3-73 weeks). Eight patients were receiving concomitant treatment with corticosteroids, and 6 were receiving treatment with methotrexate. The relative risk of legionellosis when receiving treatment with a TNF-alpha antagonist, compared with the relative risk in France overall, was estimated to be between 16.5 and 21.0. We also report a second episode of confirmed legionellosis following the reintroduction of infliximab therapy.

CONCLUSIONS

L. pneumophila pneumonia is a potentially severe but curable infection that might complicate anti-TNF-alpha therapy. In patients receiving anti-TNF-alpha who develop pneumonia, legionellosis should be systematically investigated, and first-line antibiotic therapy should be efficient against L. pneumophila.