Incidence of hepatitis C virus infection in Italian patients with idiopathic pulmonary fibrosis

What Do We Need to Know About Rising Rates of Idiopathic Pulmonary Fibrosis? A Narrative Review and Update

The most common type of idiopathic interstitial pneumonia is idiopathic pulmonary fibrosis (IPF), an irreversible, progressive disorder that has lately come into question for possible associations with COVID-19. With few geographical exceptions, IPF is a rare disease but its prevalence has been increasing markedly since before the pandemic. Environmental exposures are frequently implicated in IPF although genetic factors play a role as well. In IPF, healthy lung tissue is progressively replaced with an abnormal extracellular matrix that impedes normal alveolar function while, at the same time, natural repair mechanisms become dysregulated. While chronic viral infections are known risk factors for IPF, acute infections are not and the link to COVID-19 has not been established. Macrophagy may be a frontline defense against any number of inflammatory pulmonary diseases, and the inflammatory cascade that may occur in patients with COVID-19 may disrupt the activity of monocytes and macrophages in clearing up fibrosis and remodeling lung tissue. It is unclear if COVID-19 infection is a risk factor for IPF, but the two can occur in the same patient with complicating effects. In light of its increasing prevalence, further study of IPF and its diagnosis and treatment is warranted.

Idiopathic pulmonary fibrosis therapy development: a clinical pharmacology perspective

Drug development for idiopathic pulmonary fibrosis (IPF) has been challenging due to poorly understood disease etiology, unpredictable disease progression, highly heterogeneous patient populations, and a lack of robust pharmacodynamic biomarkers. Moreover, because lung biopsy is invasive and dangerous, making the extent of fibrosis as a direct longitudinal measurement of IPF disease progression unfeasible, most clinical trials studying IPF can only assess progression of fibrosis indirectly through surrogate measures. This review discusses current state-of-art practices, identifies knowledge gaps, and brainstorms development opportunities for preclinical to clinical translation, clinical populations, pharmacodynamic endpoints, and dose optimization strategies. This article highlights clinical pharmacology perspectives in leveraging real-world data as well as modeling and simulation, special population considerations, and patient-centric approaches for designing future studies.

The role of viral and bacterial infections in the pathogenesis of IPF: a systematic review and meta-analysis

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease. Several risk factors such as smoking, air pollution, inhaled toxins, high body mass index and infectious agents are involved in the pathogenesis of IPF. In the present study, this meta-analysis study investigates the prevalence of viral and bacterial infections in the IPF patients and any possible association between these infections with pathogenesis of IPF.

Methods

The authors carried out this systematic literature review from different reliable databases such as PubMed, ISI Web of Science, Scopus and Google Scholar to December 2020.Keywords used were the following “Idiopathic pulmonary fibrosis”, “Infection”, “Bacterial Infection” and “Viral Infection”, alone or combined together with the Boolean operators "OR”, “AND” and “NOT” in the Title/Abstract/Keywords field. Pooled proportion and its 95% CI were used to assess the prevalence of viral and bacterial infections in the IPF patients.

Results

In this systematic review and meta-analyses, 32 studies were selected based on the exclusion/inclusion criteria. Geographical distribution of included studies was: eight studies in American people, 8; in European people, 15 in Asians, and one in Africans. The pooled prevalence for viral and bacterial infections w ere 53.72% (95% CI 38.1–69.1%) and 31.21% (95% CI 19.9–43.7%), respectively. The highest and lowest prevalence of viral infections was HSV (77.7% 95% CI 38.48–99.32%), EBV (72.02%, 95% CI 44.65–90.79%) and Influenza A (7.3%, 95% CI 2.66–42.45%), respectively. Whereas the highest and lowest prevalence in bacterial infections were related to Streptococcus sp. (99.49%, 95% CI 96.44–99.9%) and Raoultella (1.2%, 95% CI 0.2–3.08%), respectively.

Conclusions

The results of this review were confirmed that the presence of viral and bacterial infections are the risk factors in the pathogenesis of IPF. In further analyses, which have never been shown in the previous studies, we revealed the geographic variations in the association strengths and emphasized other methodological parameters (e.g., detection method). Also, our study supports the hypothesis that respiratory infection could play a key role in the pathogenesis of IP.

Association of COVID-19 and other viral infections with interstitial lung diseases, pulmonary fibrosis, and pulmonary hypertension: A narrative review

Background

Interstitial lung diseases (ILDs) include a broad range of diffuse parenchymal lung disorders and are characterized by diffuse parenchymal lung abnormalities leading to irreversible fibrosis. ILDs are correlated with the occurrence of pulmonary fibrosis (PF), which generally also results in pulmonary hypertension (PH). Interferons, secreted in larger amounts during viral infections, are an important possible risk factor contributing to this outcome.

Aims

In this narrative review, the role of 10 different viral infections on the generation/development of ILDs and their outcomes are described in detail. The aim of this review is to determine the probable risk that COVID-19 and other viral infections pose in the post-infection development of ILDs, PF, and PH.

Methods

Searches in PubMed (Medline), Google Scholar, Web of Science (ISI, Researcher ID, Publons), ResearchGate, Scopus, and secondary sources yielded 134 studies. After exclusion criteria, 92 studies containing the terms “Coronavirus” (COVID-19), “Interstitial Lung Diseases,” “Pulmonary Fibrosis,” “Pulmonary Hypertension” and “viral infections” were selected for inclusion. Selected articles were read with a focus on the roles of the 10 commonly studied viral infections on generation/intensification of ILDs and classified according to their dominant effect on the respiratory system, with a focus on each infection’s effects on parenchyma of the lungs and generation and/or intensification of ILDs.

Results

This review found that ILDs, PF, and PH can occur after a COVID-19 viral infection. Similar results are also seen in post-infection cases of other viral infections, including Epstein–Barr virus, Cytomegalovirus, Human herpesvirus-8, adenovirus, Hepatitis C, Torque-Teno (Transfusion-Transmitted) Virus, Human Immunodeficiency Virus, Severe Acute Respiratory Syndrome, and Middle East Respiratory Syndrome.

Conclusion

Results of current studies show probable possibility for generation and/or intensification of ILDs in COVID-19 infected patients like other studied viruses. Studies on determination of the actual prevalence of ILD, PF and PH in post-COVID-19 infected patients, follow-up studies on the prevention of ILDs in recovered COVID-19 patients, and meta-analyzed studies on pulmonary outcomes of pandemic corona viruses are strongly recommended as topics for future studies.

Assessment of viral RNA in idiopathic pulmonary fibrosis using RNA-seq

Background

Numerous publications suggest an association between herpes virus infection and idiopathic pulmonary fibrosis (IPF). These reports have employed immunohistochemistry, in situ hybridization and/or PCR, which are susceptible to specificity artifacts.

Methods

We investigated the possible association between IPF and viral RNA expression using next-generation sequencing, which has the potential to provide a high degree of both sensitivity and specificity. We quantified viral RNA expression for 740 viruses in 28 IPF patient lung biopsy samples and 20 controls. Key RNA-seq results were confirmed using Real-time RT-PCR for select viruses (EBV, HCV, herpesvirus saimiri and HERV-K).

Results

We identified sporadic low-level evidence of viral infections in our lung tissue specimens, but did not find a statistical difference for expression of any virus, including EBV, herpesvirus saimiri and HERV-K, between IPF and control lungs.

Conclusions

To the best of our knowledge, this is the first publication that employs RNA-seq to assess whether viral infections are linked to the pathogenesis of IPF. Our results do not address the role of viral infection in acute exacerbations of IPF, however, this analysis patently did not support an association between herpes virus detection and IPF.

Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

BACKGROUND

This document provides clinical recommendations for the diagnosis of idiopathic pulmonary fibrosis (IPF). It represents a collaborative effort between the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society.

METHODS

The evidence syntheses were discussed and recommendations formulated by a multidisciplinary committee of IPF experts. The evidence was appraised and recommendations were formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

The guideline panel updated the diagnostic criteria for IPF. Previously defined patterns of usual interstitial pneumonia (UIP) were refined to patterns of UIP, probable UIP, indeterminate, and alternate diagnosis. For patients with newly detected interstitial lung disease (ILD) who have a high-resolution computed tomography scan pattern of probable UIP, indeterminate, or an alternative diagnosis, conditional recommendations were made for performing BAL and surgical lung biopsy; because of lack of evidence, no recommendation was made for or against performing transbronchial lung biopsy or lung cryobiopsy. In contrast, for patients with newly detected ILD who have a high-resolution computed tomography scan pattern of UIP, strong recommendations were made against performing surgical lung biopsy, transbronchial lung biopsy, and lung cryobiopsy, and a conditional recommendation was made against performing BAL. Additional recommendations included a conditional recommendation for multidisciplinary discussion and a strong recommendation against measurement of serum biomarkers for the sole purpose of distinguishing IPF from other ILDs.

CONCLUSIONS

The guideline panel provided recommendations related to the diagnosis of IPF.

Risk factors for interstitial lung disease: a 9-year Nationwide population-based study

Background

Understanding the risk factors that are associated with the development of interstitial lung disease might have an important role in understanding the pathogenetic mechanism of interstitial lung disease as well as prevention. We aimed to determine independent risk factors of interstitial lung disease development.

Methods

This was a retrospective cohort study with nationwide population-based 9-year longitudinal data. We selected subjects who were aged > 40 years at cohort entry and with a self-reported history of cigarette smoking. Cases were selected based on International Classification of Diseases codes. A cohort of 312,519 subjects were followed until December 2013. We used Cox regression analysis to calculate the hazard ratios (HRs) for interstitial lung disease development.

Results

Interstitial lung disease developed in 1972 of the 312,519 subjects during the 9-year period. Smoking (HR: 1.2; 95% confidence interval [CI]: 1.1–1.4), hepatitis C (HR: 1.6; 95% CI: 1.1–2.3), history of tuberculosis (HR: 1.5; 95% CI: 1.1–1.9), history of pneumonia (HR: 1.6; 95% CI: 1.3–2.0), and chronic obstructive pulmonary disease (HR: 1.8; 95% CI: 1.6–2.1), men (HR: 1.9; 95% CI: 1.7–2.1) were significantly associated with the development of interstitial lung disease. The risk of interstitial lung disease development increases with age, and the risk was 6.9 times higher (95% CI: 5.9–8.0) in those aged over 70 than in their forties.

Conclusions

Smoking, hepatitis C, history of tuberculosis, history of pneumonia, chronic obstructive pulmonary disease, male sex, and older age were significantly associated with interstitial lung disease development.

The renin angiotensin system in liver and lung: impact and therapeutic potential in organ fibrosis

Liver and lung fibrosis are two main organ diseases that are of particular importance in both Egypt and the US. Hepatitis C Virus "HCV" infection and idiopathic pulmonary fibrosis (IPF) are fibrotic diseases of the liver and lung respectively. The liver and lung are reported in literature to share many immune/inflammatory responses to damage through the lung-liver axis. Most importantly, HCV was shown to enhance the development of IPF and is considered one of the risk factors for IPF. The renin angiotensin system (RAS) plays a critical role in the fibrogenesis and inflammation damage of many organs including liver and lung. The relatively recently identified component of RAS, angiotensin converting enzyme-2 (ACE-2), has shown a promising therapeutic potential in models of liver and pulmonary fibrosis. This article reviews the role of RAS in organ fibrosis with focus on role of ACE-2 in fibrotic diseases of the liver and the lung.

Role of Microbial Agents in Pulmonary Fibrosis

Pulmonary fibrosis is a form of lung disease that develops due to aberrant wound-healing following repeated alveoli injury in genetically susceptible individuals, resulting in chronic inflammation, excess deposition of the extracellular matrix components, mainly collagen, and scarring of lung tissue. In addition to irradiation, environmental agents such occupational inhalants, and chemotherapeutic agents, microbial agents also play a role in the etiology of the disease. While viruses have received the most attention, emerging evidence suggest that bacteria and fungi also play a part in the etiology of pulmonary fibrosis. Furthermore, successful use of antibiotics, antiviral and antifungal drugs in several studies to attenuate fibrosis progression is also an indication of microbial involvement in the pathogenesis of the disease and could be a promising therapeutic modality for treating pulmonary fibrosis initiated or exacerbated by infectious agents.

Viruses in Idiopathic Pulmonary Fibrosis. Etiology and Exacerbation

Viral infections are important contributors to exacerbation of asthma and chronic obstructive pulmonary disease; however, the role of viruses in the pathogenesis of idiopathic pulmonary fibrosis (IPF) is less clear. This likely reflects that fact that IPF acute exacerbations are defined clinically as "noninfectious," and little attention has been paid to the outcomes of patients with IPF with diagnosed infections. However, accumulating evidence suggests that infections (both bacterial and viral) may influence disease outcomes either as exacerbating agents or initiators of disease. Support for a viral role in disease initiation comes from studies demonstrating the presence of herpesviral DNA and epithelial cell stress in the lungs of asymptomatic relatives at risk for developing familial IPF. In addition, the number of studies that can associate viral (especially herpesviral) signatures in the lung with the development of IPF is steadily growing, and activated leukocyte signatures in patients with IPF provide further support for infectious processes driving IPF progression. Animal modeling has been used to better understand how a gamma herpesvirus infection can modulate the pathogenesis of lung fibrosis and has demonstrated that preceding infections appear to reprogram lung epithelial cells during latency to produce profibrotic factors, making the lung more susceptible to subsequent fibrotic insult, whereas exacerbations of existing fibrosis, or infections in susceptible hosts, involve active viral replication and are influenced by antiviral therapy. In addition, there is new evidence that bacterial burden in the lungs of patients with IPF may predict a poor prognosis.

Hepatitis C virus as a systemic disease: reaching beyond the liver

Chronic hepatitis C (CHC) is associated with multiple extrahepatic manifestations that may impact infected patients. The mechanisms through which these develop include those which are immunological, in which the chronic persistence of virus leads to the circulation of immune complexes (mixed cryoglobulinemia) and other autoimmune phenomena, and those which are virological and related to the extrahepatic tropism of the virus to other tissues. It is estimated that 40-74 % of patients with CHC may develop at least one extrahepatic manifestation during the course of the disease. Extrahepatic syndromes may represent the first signal of hepatitis C infection in some patients. CHC is associated with a four-fold increased risk of insulin resistance and type 2 diabetes mellitus; with cardiovascular disease in 17-37 % of patients; and with increased risk for cerebrovascular deaths, with a biological gradient of cerebrovascular mortality correlating with an increasing serum viral load. CHC is also associated with lymphoproliferative disorders, particularly non-Hodgkin B-cell lymphoma. The kidney is involved in 35-60 % of patients with CHC-associated mixed cryoglobulinemia. The prevalent type of glomerulonephritis associated with mixed cryoglobulinemia is membranoproliferative glomerulonephritis. In 30 % of cases, renal involvement begins with a nephritis syndrome and acute renal failure, while in 55 % there is only mild hematuria, microalbuminuria, proteinuria and renal insufficiency. CHC is also associated with cognitive impairment, especially in memory and concentration. Thus, extrahepatic CHC manifestations involve multiple organ systems outside the liver linked to a variety of comorbidities which may lead to significantly increased mortality from non-liver-related events.

Recent Evidence for Pharmacological Treatment of Idiopathic Pulmonary Fibrosis

Objective: To describe emerging evidence for the pharmacological treatment of idiopathic pulmonary fibrosis (IPF). Data Sources: A search of PubMed (1966 to July 2014) was performed using the terms idiopathic pulmonary fibrosis and treatment. Study Selection and Data Extraction: Review of articles was restricted to articles in English and relating to placebo-controlled or comparative clinical trial data of recent significance. Evidence statements from the most recent international guidelines and some historical trial data were also included for context. Data Synthesis: Numerous treatment options have been evaluated for IPF. Therapies evaluated in large trials have either resulted in increased mortality (anticoagulation, triple-therapy with N-acetylcysteine [NAC], azathioprine, and prednisone) or demonstrated a lack of efficacy (endothelin receptor antagonists, single-agent NAC). Pirfenidone, a novel antifibrotic and anti-inflammatory agent, has demonstrated efficacy in several recent analyses and is the only approved medication for the treatment of IPF in more than 30 countries outside of the United States, with resubmission to the Food and Drug Administration (FDA) recently made. Nintedanib, a tyrosine kinase inhibitor, has demonstrated encouraging results in phase III studies and has also recently been submitted for FDA approval. Conclusions: Limited options have existed for the treatment of IPF. New evidence suggests that safe and efficacious treatment options for IPF are on the horizon in the form of pirfenidone and nintedanib, although both agents await FDA decisions.

Immunohistochemical detection of virus through its nuclear cytopathic effect in idiopathic interstitial pneumonia other than acute exacerbation

Idiopathic interstitial pneumonias include complex diseases that have a strong interaction between genetic makeup and environmental factors. However, in many cases, no infectious agent can be demonstrated, and these clinical diseases rapidly progress to death. Theoretically, idiopathic interstitial pneumonias could be caused by the Epstein-Barr virus, cytomegalovirus, adenovirus, hepatitis C virus, respiratory syncytial virus, and herpesvirus, which may be present in such small amounts or such configuration that routine histopathological analysis or viral culture techniques cannot detect them. To test the hypothesis that immunohistochemistry provides more accurate results than the mere histological demonstration of viral inclusions, this method was applied to 37 open lung biopsies obtained from patients with idiopathic interstitial pneumonias. As a result, immunohistochemistry detected measles virus and cytomegalovirus in diffuse alveolar damage-related histological patterns of acute exacerbation of idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia in 38 and 10% of the cases, respectively. Alveolar epithelium infection by cytomegalovirus was observed in 25% of organizing pneumonia patterns. These findings were coincident with nuclear cytopathic effects but without demonstration of cytomegalovirus inclusions. These data indicate that diffuse alveolar damage-related cytomegalovirus or measles virus infections enhance lung injury, and a direct involvement of these viruses in diffuse alveolar damage-related histological patterns is likely. Immunohistochemistry was more sensitive than the histological demonstration of cytomegalovirus or measles virus inclusions. We concluded that all patients with diffuse alveolar damage-related histological patterns should be investigated for cytomegalovirus and measles virus using sensitive immunohistochemistry in conjunction with routine procedures.

A novel screening method detects herpesviral DNA in the idiopathic pulmonary fibrosis lung

BACKGROUND

Herpesviruses could contribute to the lung epithelial injury that initiates profibrotic responses in idiopathic pulmonary fibrosis (IPF).

METHODS

We identified herpesviral DNA from IPF and control lung tissue using a multiplex PCR-and microarray-based method. Active herpesviral infection was detected by standard methods, and inflammatory cell subtypes were identified with specific antibodies. Patients that underwent lung transplantation were monitored for signs of herpesviral infection.

RESULTS

A total of 11/12 IPF samples were positive for Epstein-Barr virus (EBV) and 10/12 for human herpesvirus 6B (HHV-6B) DNA. Control lung samples (n = 10) were negative for EBV DNA, whereas three samples were positive for HHV-6B. EBV-encoded RNA (EBER) was identified in nine IPF samples and localized mainly to lymphocytic aggregates. HHV-6B antigens were detected in mononuclear cells in IPF lung tissue. CD20+ B lymphocytic aggregates that were surrounded by CD3+ T cells were abundant in IPF lungs. CD23+ cells (activated B cells, EBV-transformed lymphoblasts, and dendritic cells) were observed in the aggregates. IPF patients had no signs of increased herpesviral activation after lung transplantation.

CONCLUSIONS

Inflammatory cells are the main source of herpesviral DNA in the human IPF lung. Diagnostic tools should be actively used to elucidate whether herpesviral infection affects the pathogenesis, progression, and/or exacerbation of IPF.

Idiopathic pulmonary fibrosis-an epidemiological and pathological review

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease (ILD) affecting the pulmonary interstitium. Other forms of interstitial lung disease exist, and in some cases, an environmental etiology can be delineated. The diagnosis of IPF is typically established by high-resolution CT scan. IPF tends to have a worse prognosis than other forms of ILD. Familial cases of IPF also exist, suggesting a genetic predisposition; telomerase mutations have been observed to occur in familial IPF, which may also explain the increase in IPF with advancing age. Alveolar epithelial cells are believed to be the primary target of environmental agents that have been putatively associated with IPF. These agents may include toxins, viruses, or the autoantibodies found in collagen vascular diseases. The mechanism of disease is still unclear in IPF, but aberrations in fibroblast differentiation, activation, and proliferation may play a role. Epithelial-mesenchymal transition may also be an important factor in the pathogenesis, as it may lead to accumulation of fibroblasts in the lung and a disruption of normal tissue structure. Abnormalities in other components of the immune system, including T cells, B cells, and dendritic cells, as well as the development of ectopic lymphoid tissue, have also been observed to occur in IPF and may play a role in the stimulation of fibrosis that is a hallmark of the disease. It is becoming increasingly clear that the pathogenesis of IPF is indeed a complex and convoluted process that involves numerous cell types and humoral factors.

Viral infection and aging as cofactors for the development of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease of unknown origin and progression that primarily affects older adults. Accumulating clinical and experimental evidence suggests that viral infections may play a role, either as agents that predispose the lung to fibrosis or exacerbate existing fibrosis. In particular, herpesviruses have been linked with IPF. This article summarizes the evidence for and against viral cofactors in IPF pathogenesis. In addition, we review mechanistic studies in animal models that highlight the fibrotic potential of viral infection, and explore the different mechanisms that might be responsible. We also review early evidence to suggest that the aged lung may be particularly susceptible to viral-induced fibrosis and make recommendations for future research directions.

An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management

This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.

Hepatitis C and pulmonary fibrosis: Hepatitis C and pulmonary fibrosis

BACKGROUND

Hepatitis C virus (HCV) is a hepatotropic and lymphotropic virus that causes hepatic and extrahepatic disease. Emerging clinical data suggest that chronic HCV infection can lead to many direct and indirect effects on the lung.

OBJECTIVES

This article discusses evidence on the relationship between HCV infection and pulmonary fibrosis to increase knowledge on this topic among clinicians and scientists and highlights the need for further study.

METHODS

We searched the MEDLINE, ISI WEB OF KNOWLEDGE, OVID, ELSEVIER, and MDCONSULT databases and top respiratory journals, such as the American Journal of Respiratory and Critical Care, Chest, and Thorax for articles in English using the following keywords: hepatitis C, HCV infection, IPF, pulmonary fibrosis, and interstitial pneumonitis. We reviewed the reference lists of all identified studies.

RESULTS

The evidence for a pathogenetic link between pulmonary fibrosis and HCV is: the higher frequency of HCV markers in IPF patients, an increase in lymphocyte and neutrophil numbers in bronchoalveolar lavage of chronic HCV infection patients, and the development of IPF in HCV-related chronic hepatitis that is treated with interferon. There is a discrepancy between studies on the frequency of HCV in IPF patients, which might be attributed to geographical differences of in the prevalence of HCV infection, selection bias in choosing the control group, and the HCV genome.

CONCLUSIONS

BAL studies in HCV infection are associated with increased counts of lymphocytes and neutrophils in BAL fluid. These studies show that HCV infection is associated with nonspecific pulmonary inflammatory reactions that are not compatible with IPF but that it can lead to pulmonary fibrosis. The other factor is interferon therapy. Interstitial pneumonia and sarcoidosis are well-documented complications of IFN therapy. More extensive cohort studies should be conducted to confirm an actual causal relationship between HCV infection and pulmonary fibrosis.

Non-steroid agents for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis is a chronic progressive lung disease with poor outcome and no effective treatment to date. This is an update of a Cochrane Review first published in 2003.

OBJECTIVES

To assess the efficacy of non-steroid agents in adults with idiopathic pulmonary fibrosis.

SEARCH STRATEGY

We searched the Cochrane Airways Group Register (30 March 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1, 2010), Ovid MEDLINE to March week 5, 2010, EMBASE to week 13, 2010 and PubMed to April 2010, with additional handsearching, including abstracts of international conferences. We also contacted pharmaceutical companies and researchers in the field.

SELECTION CRITERIA

Randomised studies comparing non-steroid drugs with placebo or steroids in adults with idiopathic pulmonary fibrosis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and assessed risk of bias. We contacted pharmaceutical companies to obtain missing information, if any. We combined survival outcomes using Peto odds ratios or hazard ratios (HR).

MAIN RESULTS

Fifteen trials involving 10 different drugs were included. Two trials enrolling 1156 patients compared interferon gamma-1beta with placebo: interferon gamma-1beta did not significantly improve survival (HR 0.88, 95% CI 0.47 to 1.64; P = 0.68). Four trials involving 1155 patients compared pirfenidone with placebo. Three trials, conducted in 1046 patients, provided data on progression-free survival: pirfenidone significantly reduced the risk of disease progression by 30% (HR 0.70, 95% CI 0.56 to 0.88, P = 0.002). Data on the effect of pirfenidone on pulmonary function could only be assessed for two studies analysing 314 patients. Forced vital capacity or vital capacity was significantly improved by pirfenidone (mean difference 0.08 L, 95% CI 0.03 to 0.13, P = 0.0006).

AUTHORS' CONCLUSIONS

Based on available data, partly still unpublished, pirfenidone appears to improve progression-free survival and, to a lesser extent, pulmonary function in patients with idiopathic pulmonary fibrosis. More data are needed on overall survival and quality of life on treatment. From the studies in this review, interferon gamma-1beta has not been shown to affect survival. Other agents evaluated in single studies either failed to provide evidence for a benefit or need to be assessed in larger randomised controlled trials.

Relationship between hepatitis C virus infection and pulmonary disorders: potential mechanisms of interaction

Recently, an increasing number of reports have suggested that chronic hepatitis C virus (HCV) infection is associated with pulmonary disorders. The effects of HCV on the lung may present as worsening of lung function and impaired responses to therapy in patients with chronic obstructive pulmonary disease and asthma. Moreover, chronic HCV infection may be associated with the pathogenesis of interstitial lung disease. It is believed that chronic HCV infection may contribute to the immune responses modulating the pathogenic processes underlying pulmonary disorders and, therefore, may lead to a wide spectrum of clinical presentations. Potential candidates for a role in these immune responses are the CD8(+) T lymphocytes and inflammatory cytokines. In this review, the effects of HCV on the lung and the potential mechanisms of interaction between chronic HCV infection and pulmonary disorders will be discussed.

Hepatitis C virus and autoimmunity

Hepatitis C virus infection is associated with several extrahepatic manifestations. About 60% of patients infected with HCV develop at least one extrahepatic manifestation. The majority of these diseases seem to be triggered through autoimmune mechanisms, such as autoantibody production, autoreactive T cells and complex autoimmune mechanisms leading to systemic autoimmune disorders. In this review we categorize these diseases into three groups according to the main pathogenetic process involved, in particular B-cell-mediated, T-cell-mediated and complex autoimmune systemic diseases.

Determinants of initiation and progression of idiopathic pulmonary fibrosis

IPF is a devastating disease with few therapeutic options. The precise aetiology of IPF remains elusive. However, our understanding of the pathologic processes involved in the initiation and progression of this disease is improving. Data on the mechanisms underlying IPF have been generated from epidemiologic investigations as well as cellular and molecular studies of human tissues. Although no perfect animal model of human IPF exists, pre-clinical animal studies have helped define pathways which are likely important in human disease. Epithelial injury, fibroblast activation and repetitive cycles of injury and abnormal repair are almost certainly key events. Factors which have been associated with initiation and/or progression of IPF include viral infections, abnormal cytokine, chemokine and growth factor production, oxidant stress, autoimmunity, inhalational of toxicants and gastro-oesophageal reflux disease. Furthermore, recent evidence identifies a role for a variety of genetic and epigenetic abnormalities ranging from mutations in surfactant protein C to abnormalities in telomere length and telomerase activity. The challenge remains to identify additional inciting agents and key dysregulated pathways that lead to disease progression so that we can develop targeted therapies to treat or prevent this serious disease.

ELMOD2, a candidate gene for idiopathic pulmonary fibrosis, regulates antiviral responses

Viral infections and abnormal host response are thought to cause epithelial injury in idiopathic pulmonary fibrosis (IPF). To understand IPF pathogenesis, we have used overexpression cell models and expression microarrays to discover genes networked with ELMO domain containing 2 (ELMOD2) gene genetically implicated in IPF. The identified pathways were confirmed in vitro, and ELMOD2 protein expression was characterized in tissue samples. Here 303 genes were significantly altered after ELMOD2 transfection of human alveolar epithelial A549 cell line. The enriched pathways were interferon induction, viral response, antigen processing and presentation, and I-/nuclear factor-kappaB signaling. ELMOD2 showed immunoreactivity in macrophages and type II alveolar epithelial cells in normal human lung. In A549 cells, forced expression of ELMOD2 increased type I and type III interferon mRNA expression, and ELMOD2-specific siRNA molecules inhibited expression of these antiviral cytokines in response to Toll-like receptor three (TLR3) activation. In human macrophages silencing of ELMOD2 inhibited TLR3-dependent expression of type I and type III interferon genes. Influenza A virus infection decreased ELMOD2 mRNA expression in A549 cells and macrophages suggesting negative regulation in viral infections. In summary, our results show that TLR3 pathway is dependent on ELMOD2.-Pulkkinen, V., Bruce, S., Rintahaka, J., Hodgson, U., Laitinen, T., Alenius, H., Kinnula, V. L., Myllärniemi, M., Matikainen, S., Kere, J. ELMOD2, a candidate gene for idiopathic pulmonary fibrosis, regulates antiviral responses.

Systemic abnormalities in liver disease

Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases.

Pulmonary fibrosis: pathogenesis, etiology and regulation

Pulmonary fibrosis and architectural remodeling of tissues can severely disrupt lung function, often with fatal consequences. The etiology of pulmonary fibrotic diseases is varied, with an array of triggers including allergens, chemicals, radiation and environmental particles. However, the cause of one of the most common pulmonary fibrotic conditions, idiopathic pulmonary fibrosis (IPF), is still unclear. This review examines common mechanisms of pulmonary wound-healing responses following lung injury, and highlights the pathogenesis of some of the most widespread pulmonary fibrotic diseases. A three phase model of wound repair is reviewed that includes; (1) injury; (2) inflammation; and (3) repair. In most pulmonary fibrotic conditions dysregulation at one or more of these phases has been reported. Chronic inflammation can lead to an imbalance in the production of chemokines, cytokines, growth factors, and disrupt cellular recruitment. These changes coupled with excessive pro-fibrotic IL-13 and/or TGFbeta1 production can turn a well-controlled healing response into a pathogenic fibrotic response. Endogenous regulatory mechanisms are discussed including novel areas of therapeutic intervention. Restoring homeostasis to these dysregulated healing responses, or simply neutralizing the key pro-fibrotic mediators may prevent or slow the progression of pulmonary fibrosis.

Hepatitis C virus enhances incidence of idiopathic pulmonary fibrosis

AIM: To investigate the cumulative development incidence and predictive factors for idiopathic pulmonary fibrosis in hepatitis C virus (HCV) positive patients.

METHODS: We studied 6150 HCV infected patients who were between 40-70 years old (HCV-group). Another 2050 patients with hepatitis B virus (HBV) were selected as control (HBV-group). The mean observation period was 8.0 ± 5.9 years in HCV-group and 6.3 ± 5.5 years in HBV-group. The primary goal is the development of idiopathic pulmonary fibrosis (IPF) in both groups. The cumulative appearance rate of IPF and independent factors associated with the incidence rate of IPF were calculated using the Kaplan-Meier method and the Cox proportional hazard model. All of the studies were performed retrospectively by collecting and analyzing data from the patient records in our hospital.

RESULTS: Fifteen patients in HCV-group developed IPF. On the other hand, none of the patients developed IPF in HBV-group. In HCV-group, the cumulative rates of IPF development were 0.3% at 10th year and 0.9% at 20th year. The IPF development rate in HCV-group was higher than that in HBV-group (P = 0.021). The IPF development rate in patients with HCV or HBV was high with statistical significance in the following cases: (1) patients ≥ 55 years (P < 0.001); (2) patients who had smoking index (package per day × year) of ≥ 20 (P = 0.002); (3) patients with liver cirrhosis (P = 0.042).

CONCLUSION: Our results indicate that age, smoking and liver cirrhosis enhance the development of IPF in HCV positive patients.

Viruses as co-factors for the initiation or exacerbation of lung fibrosis

Idiopathic pulmonary fibrosis (IPF) remains exactly that. The disease originates from an unknown cause, and little is known about the mechanisms of pathogenesis. While the disease is likely multi-factorial, evidence is accumulating to implicate viruses as co-factors (either as initiating or exacerbating agents) of fibrotic lung disease. This review summarizes the available clinical and experimental observations that form the basis for the hypothesis that viral infections may augment fibrotic responses. We review the data suggesting a link between hepatitis C virus, adenovirus, human cytomegalovirus and, in particular, the Epstein-Barr gammaherpesvirus, in IPF. In addition, we highlight the recent associations made between gammaherpesvirus infection and lung fibrosis in horses and discuss the various murine models that have been used to investigate the contribution of gammaherpesviruses to fibrotic progression. We review the work demonstrating that gammaherpesvirus infection of Th2-biased mice leads to multi-organ fibrosis and highlight studies showing that gammaherpesviral infections of mice either pre- or post-fibrotic challenge can augment the development of fibrosis. Finally, we discuss potential mechanisms whereby viral infections may amplify the development of fibrosis. While none of these studies prove causality, we believe the evidence suggests that viral infections should be considered as potential initiators or exacerbating agents in at least some cases of IPF and thereby justify further study.

Pulmonary alterations in patients with chronic HCV infection

BACKGROUND

Chronic hepatitis C virus infection has been reported in association with several extrahepatic manifestations. Included in this list is interstitial lung involvement.

AIMS

The aim of the present study was to evaluate pulmonary alterations in patients with chronic hepatitis C virus infection.

PATIENTS

Twenty-one patients with chronic hepatitis C virus infection were enrolled into a prospective study. One patient has been excluded because of underlying tuberculosis.

METHODS

All patients underwent pulmonary function tests, diffusion capacity for carbon monoxide and high-resolution computed tomography of the chest.

RESULTS

Forced vital capacity, forced expiratory volume in first second/forced vital capacity and forced expiratory volume in first second values were reduced to less than 80% of predicted values in 3, 11 and 5 patients, respectively. Diffusion capacity for carbon monoxide was low in 12 patients (60%), 8 of whom had simultaneous decrease in diffusion capacity for carbon monoxide/VA values. Thorax high-resolution computed tomography revealed abnormal findings in eight patients (40%). Fifteen patients with chronic hepatitis C virus infection (75%) had at least one pulmonary alteration as evidenced by abnormal pulmonary function tests, diffusion capacity for carbon monoxide and/or high-resolution computed tomography results.

CONCLUSION

In spite of a limited study population, these findings may implicate that pulmonary manifestations of chronic hepatitis C virus infection are frequently underdiagnosed.

Case-control study of medical history and idiopathic pulmonary fibrosis in Japan

OBJECTIVES

A few epidemiological studies have indicated that a patient's past medical history may contribute to the risk of developing idiopathic pulmonary fibrosis (IPF). A relationship between a history of selected disorders and the risk of IPF was assessed in a multicentre hospital-based case-control study in Japan.

METHODOLOGY

Included in the study were 104 patients of IPF, aged 40 years or over, who had been diagnosed within the previous 2 years, in accordance with the most recent criteria. Control subjects, aged 40 years or over, consisted of 56 hospitalized patients diagnosed as having acute bacterial pneumonia and four outpatients with the common cold. Adjustment was made for age, gender, region, pack-years of smoking, employment status, occupational exposure and BMI.

RESULTS

Medical histories of hypertension, hyperlipidaemia, coronary heart disease, diabetes mellitus, hepatitis C virus infection, tuberculosis, asthma, atopic dermatitis and allergic rhinitis were not statistically significantly associated with the risk of IPF, although cases were more likely to have suffered from allergic rhinitis and less likely to have been asthmatics than control subjects. Having a child with a history of allergic rhinitis, but not of asthma or atopic dermatitis, was significantly related to an increased risk of IPF.

CONCLUSIONS

These findings suggest that a genetic predisposition to allergic rhinitis may be associated with an increased risk of IPF.

Hepatitis C virus and the lung: implications for therapy

Hepatitis C virus (HCV) infection is a chronic blood-borne disease that affects > 4,000,000 individuals in the United States. The majority of individuals with HVC infection acquire a chronic hepatitis that predisposes them to the complications of cirrhosis and hepatoma. Chronic HCV infection is, however, associated with multiple extrahepatic manifestations as well, including recently recognized effects on the lung. These include primary effects on lung function, as well as secondary effects in the settings of progressive liver disease and drug treatment for HCV. In this article, we discuss the emerging clinical data that support a role for HCV infection in lung disease, describe the multiple pulmonary manifestations of this viral infection, and outline the therapies available for specific pulmonary complications of chronic HCV infection.

Pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing lung disease limited to the lungs and associated with the histologic appearance of usual interstitial pneumonia (UIP) on surgical lung biopsy. The estimated prevalence in the United States is between 35,000 and 55,000 cases,and evidence suggests that the prevalence is increasing for IPF. Risk factors associated with pulmonary fibrosis include smoking, environmental exposures, gastroesophageal reflux dis-ease, commonly prescribed drugs, diabetes mellitus, infectious agents, and genetic factors. The diagnosis requires a careful history and physical examination, characteristic physiological and radiological studies, and, in some cases, a surgical lung biopsy. The natural history of IPF is not known, but evidence supports the concept of a continuum of idiopathic interstitial pneumonias that may overlap in time. Most patients with IPF succumb to respiratory failure, cardiovascular disease, lung cancer, pulmonary embolism, infection, and other health problems. The median survival time for patients with IPF is less than 3 yr. Factors that predict poor outcome include older age, male gender, severe dyspnea, history of cigarette smoking, severe loss of lung function, appearance and severity of fibrosis on radiological studies, lack of response to therapy,and prominent fibroblastic foci on histopathologic evaluation. Conventional therapy (corticosteroids, azathioprine, cyclophosphamide) provides only marginal benefit. Lung transplantation should be considered for patients with IPF refractory to medical therapy. In light of the poor prognosis and lack of response to available anti-inflammatory therapy, alternative approaches to therapy are being pursued. Emerging strategies to treat patients with IPF include agents that inhibit epithelial injury or enhance repair, anti-cytokine approaches, agents that inhibit fibroblast proliferation or induce fibroblast apoptosis, and other novel approaches.

Desquamative Interstitial Pneumonia and Hepatitis C Virus Infection: A Rare Association

Extrahepatic manifestations of hepatitis C virus (HCV) infection are common. The authors report the unusual occurrence of desquamative interstitial pneumonia (DIP) in a patient with HCV. An immunologic response to HCV infection may have a role in the pathogenesis of DIP in patients with chronic HCV. Since DIP is treatable, HCV patients with pulmonary infiltrates should be thoroughly investigated for this disorder. In our experience, the use of steroids in HCV-associated DIP improved the patient's respiratory status without increasing the viral load.

Idiopathic pulmonary fibrosis: current understanding of the pathogenesis and the status of treatment

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal pulmonary fibrotic lung disease. The diagnostic histological changes are called usual interstitial pneumonia and are characterized by histological temporal heterogeneity, whereby normal lung tissue is interspersed with interstitial fibrosis, honeycomb cysts and fibroblast foci. Pulmonary functions show restricted volumes and capacities, preserved flows and evidence of decreased gas exchange. High-resolution computed axial tomography demonstrates evidence of fibrosis and lung remodelling such as honeycomb cysts and traction bronchiectasis. There is no known effective treatment for IPF, but lung transplantation improves survival.

HHV-6 and 7 DNA loads in lung tissues collected from patients with interstitial pneumonia

The aim of this study is to determine whether human herpesvirus 6 (HHV-6) and HHV-7 might play an important role in causing interstitial pneumonia in patients who have not undergone transplantation. HHV-6 and HHV-7 DNAs were quantitated by real-time polymerase chain reaction (PCR) in paraffin embedded lung tissues collected from 24 patients having the disease. Control tissues (without fibrosis) were also collected from 19 of the 24 patients. Statistical analysis was carried out by the Wilcoxon signed rank test or the Mann-Whitney U-test. HHV-6 DNA was detected in 3 (12.5%) of the 24 target tissues and 3 (15.8%) of the 19 control tissues, respectively. In contrast, HHV-7 DNA was detected in 19 (79.2%) of the 24 target tissues and 11 (57.9%) of the 19 control tissues. Neither HHV-6 DNA load (P = 0.6395) nor HHV-7 DNA load (P = 0.5966) in target tissues differed between males and females. Neither HHV-6 DNA load (P = 0.9589) nor HHV-7 DNA load (P = 0.7419) in target tissues differed between cases with and without underlying collagen disease. While HHV-6 DNA load did not differ between the target and control tissues (P > 0.9999), the HHV-7 DNA load was significantly higher in the target tissue than in the control tissue (P = 0.0298). This study suggests that HHV-7 may play an important role in causing interstitial pneumonia in patients who are not transplant recipients.

Herpesvirus DNA is consistently detected in lungs of patients with idiopathic pulmonary fibrosis

On the basis of earlier reports associating Epstein-Barr Virus (EBV) with half of the cases of idiopathic pulmonary fibrosis (IPF), we hypothesized that chronic infection with EBV or a closely related herpesvirus would be detected in all cases of IPF. We tested lung specimens from 33 IPF patients (8 patients with familial IPF and 25 patients with sporadic IPF) and 25 patients with other diseases as controls for the presence of eight herpesviruses using PCR-based techniques. One or more of four herpesviruses (cytomegalovirus [CMV], EBV, human herpesvirus 7 [HHV-7], and HHV-8) were detected in 32 of 33 (97%) subjects with IPF and in 9 of 25 (36%) controls (P < 0.0001). CMV, EBV, and HHV-8 were found more frequently in IPF patients than in controls (P < 0.05, P < 0.001, and P < 0.01 respectively). Two or more herpesviruses were detected in 19 of 33 (57%) IPF patients and in 2 of 25 (8%) controls (P < 0.001). Two or more herpesviruses and HHV-8 were found more frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05 for both comparisons), and CMV was found less frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05). Immunohistochemistry for EBV or HHV-8 antigen showed viral antigen primarily in airway epithelial cells. These data support the concept that a herpesvirus could be a source of chronic antigenic stimulation in IPF.

Impaired lung epithelial permeability in hepatitis C virus antibody positive patients detected by 99mTc-DTPA aerosol scintigraphy

Chronic hepatitis C virus (HCV) infection has been recently identified as an aetiological agent in idiopathic pulmonary fibrosis. The present study was designed to determine the pulmonary clearance rate of 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) in asymptomatic HCV antibody positive (HCV Ab+) patients and the role of 99mTc-DTPA aerosol scintigraphy in the early detection of lung involvement. Twenty-six non-smoker HCV Ab+ and HCV-RNA (+) patients (20 female, six male; aged 43+/-11 years), with no clinical pulmonary symptoms, and normal radiological findings, were studied. Thirty-one healthy non-smoker volunteers (24 female, seven male; aged 40+/-10 years) were taken as a control group. 99mTc-DTPA aerosol inhalation scintigraphy and pulmonary function tests were performed in all patients and in controls. On the basis of the scintigrams the percentage decline in activity per minute (Kep) was evaluated, which represented an accurate parameter of lung membrane permeability. The mean Kep values of healthy controls (0.78+/-0.13 for left lung, 0.79+/-0.14 for right lung) were significantly lower than HCV Ab+ patients (1.10+/-0.31 for left lung, 1.11+/-0.34 for right lung, P<0.001). But no significant change was observed in PFT (P>0.05). We conclude that subclinical alveolitis and/or interstitial lung disease may be present in patients with HCV Ab+, since it is known that an increase in the epithelial permeability of the lung is an early manifestation of interstitial disease.

Sarcoidosis in two patients with chronic hepatitis C treated with interferon, ribavirin and amantadine

We report two patients with chronic hepatitis C, both nonresponders to a previous course of interferon (IFN), who developed or suffered an exacerbation of sarcoidosis while under treatment with IFN-alpha2a, ribavirin and amantadine. Patient 1: symptoms appeared after week 4 and treatment was withdrawn at month 9 due to severe weight loss, marked dyspnea, muscular weakness, dryness of mouth and facial paralysis. Stage III pulmonary sarcoidosis and polyneuropathy were confirmed. The patient had become steroid dependent and nine months after cessation of the treatment dyspnea and muscular weakness still persisted. She achieved a complete sustained response of hepatitis C. Patient 2: presented with a previous diagnosis of granulomatous hepatitis with chronic active hepatitis C and chronic dermatitis. The treatment exacerbated a cutaneous sarcoidosis. Furthermore, hiliar adenopathies consistent with stage I sarcoidosis became evident. Sarcoidosis responded to corticosteroids, but elevated transaminases and hepatitis C viraemia resisted. Hence, the combination of amantadine with ribavirin and IFN can develop or exacerbate subclinical sarcoidosis. A synergistic effect of these three drugs is suggested.

Recent advances in the aetiology of cryptogenic fibrosing alveolitis

Crytogenic fibrosing alveolitis is the commonest intersititial lung disease but, until recently, very little has been known about its aetiology. The histopathologist usually sees this disease at transbronchial biopsy or at autopsy. This article reviews the current knowledge of the aetiology of cryptogenic fibrosing alveolitis looking at possible infective, occupational, drug-related, smoking-associated, genetic and dietary factors. Knowledge of the possible roles of these factors in the disease process informs histopathologists when they are reporting these biopsies and enables them to make a larger contribution to defining the pathogenetic mechanisms.

Increased risk of fibrosing alveolitis associated with interleukin-1 receptor antagonist and tumor necrosis factor-alpha gene polymorphisms

Fibrosing alveolitis (FA) is characterized by persistent inflammation and elevated production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), and interleukin-1 receptor antagonist (IL-1ra) in the lung. Single base variations at position +2018 in the IL-1ra gene (IL-1RN) and position -308 in the TNF-alpha gene (TNF-A) are overrepresented in other chronic inflammatory disease populations. We have tested the hypothesis that predisposition to FA may also be influenced by these polymorphisms by genotyping 88 cases and matched controls from England and 61 cases and 103 unmatched controls from Italy. The rarer allele for IL-1RN and TNF-A was designated allele 2 in each case. For IL-1RN allele 2, in the English group, the relative odds of FA were increased in homozygous subjects by an odds ratio (OR) of 10.2 (95% confidence intervals [CI], 1.26 to 81.4; p = 0.03) and for carriers by an OR of 1.85 (95% CI, 0.94 to 3.63; p = 0.075). In the Italian population, the risk of FA was increased, in IL-1RN allele 2 homozygotes (OR, 2.54; 95% CI, 0.68 to 9.50; p = 0.2) and in carriers (OR 2.40; 95% CI, 1.26 to 4.60; p = 0.008). Carriage of TNF-A allele 2 was also associated with increased risk of FA in the English (OR, 1.85; 95% CI, 0.94 to 3.63; p = 0.075) and Italian (OR, 2.50; 95% CI, 1.14 to 5.47; p = 0.022) populations. These data suggest IL-1RN (+2018) allele 2 and TNF-A (-308) allele 2 confer increased risk of developing FA and, therefore, that unopposed IL-1beta and/or excessive TNF-alpha may play a pathophysiologic role in this condition.