Diagnosis and management of interstitial pneumonitis associated with interferon therapy for chronic hepatitis C

Pulmonary function testing in patients with liver cirrhosis (Review)

Liver cirrhosis is a common long-term outcome of chronic hepatic inflammation. Patients with liver cirrhosis may also have pulmonary complications. There are several reasons for pulmonary dysfunction in liver cirrhosis, including intrinsic cardiopulmonary dysfunction unrelated to liver disease and specific disorders related to the presence of liver cirrhosis and/or portal hypertension. The most prevalent and clinically significant pulmonary complications are hepatic hydrothorax, hepatopulmonary syndrome, spontaneous pulmonary empyema and portopulmonary hypertension. Pulmonary function tests (PFTs) have traditionally been used to assess the lung function of patients with liver cirrhosis. To the best of our knowledge, the present review is the first to detail all types of PFTs performed in patients with liver cirrhosis and discuss their clinical significance. Patients with liver cirrhosis have reduced values of spirometric parameters, diffusion capacity for carbon monoxide (DLCO), lung volumes, maximal inspiratory pressure and maximal expiratory pressure. Furthermore, they have a higher closing volume, a greater airway occlusion pressure 0.1 sec after the onset of inspiratory flow and greater exhaled nitric oxide values. In order to improve pulmonary function, patients with ascites may require therapeutic paracentesis. Such findings should be considered when evaluating individuals with liver disease, particularly those who may require surgery. Poor lung function, particularly restrictive lung disease, can have an impact on post-transplant outcomes, such as ventilator time, length of hospital duration and post-operative pulmonary complications; thus, the transplant care team needs to be aware of its prevalence and relevance.

Herbal medicine-induced multiple pulmonary pseudotumors

Japanese herbal medicines (HMs) cause adverse drug reactions (ADRs); however, solid nodule formation is uncommon. In this report, we aimed to show that ADRs with HM can mimic lung cancer. A 63-year-old man complained of back pain. His physician prescribed a traditional Japanese HM, Keishikajutsubuto, which alleviated his symptoms. After 4 weeks, a chest radiograph showed multiple lung nodules that were absent 6 months earlier; the patient did not have cough, fever, or dyspnea. Computed tomography (CT) showed multiple, bilateral lung nodules; however, blood tests and lung biopsy showed no abnormalities, ruling out interstitial pneumonia and lung cancer. Three months after the HM was discontinued, CT showed resolution of the lesions. Interstitial pneumonia was reported as a side effect of HM; however, no such side effect was reported for Keishikajutsubuto. When a patient presents with multiple lung nodules, a side effect of HM should be considered as a differential diagnosis.

Hepatitis C Virus-Associated Extrahepatic Manifestations in Lung and Heart and Antiviral Therapy-Related Cardiopulmonary Toxicity

Besides liver cirrhosis and hepatocellular carcinoma, chronic hepatitis C virus (HCV) infection is associated with many extrahepatic manifestations (EHMs). HCV exhibits lymphotropism that is responsible for various EHM. An important characteristic of HCV is escape from the immune system, which enables it to produce chronic infections and autoimmune disorders along with accumulation of circulating immune complexes. These EHMs have large spectrum, because they affect many organs such as heart, lungs, kidney, brain, thyroid, and skin. HCV-related cardiac and pulmonary manifestations include myocarditis, cardiomyopathies, cardiovascular diseases (i.e., Stroke, ischemic heart disease), chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, asthma, and interstitial lung diseases. This review discusses etiology and pathogenesis of HCV-associated cardiac and pulmonary manifestations and how different genes, immune system, indirectly linked factors (mixed cryoglobulinemia), liver cirrhosis, and antiviral treatment are involved in HCV-related heart and lung diseases, however, their exact mechanism is not clear.

Interstitial pneumonia associated to peginterferon alpha-2a: A focus on lung function

Pulmonary toxicity related to the use of pegylated interferon alpha-2a during treatment of hepatitis C infections is rare; nonetheless, some cases with fatal outcomes have been reported. Evaluating patients’ pulmonary function is a key to diagnosis, follow-up and prognosis of several respiratory diseases, but case reports of respiratory manifestations related to the use of pegylated interferon alpha-2a have limited their findings to only baseline measurements. This paper examines the case of a 65-year-old woman with chronic hepatitis C virus infection who developed interstitial pneumonitis associated with pegylated interferon alpha-2a. Initial lung function evaluation revealed a marked reduction compared to an earlier assessment; the results were consistent with a moderate restricted pattern. Fortunately, over the ensuing 8 weeks of follow-up after discontinuing the drug, the patient recovered her lung function and experienced an overall improvement in her respiratory symptoms.

Concurrent acute interstitial pneumonia and pulmonary embolism during treatment with peginterferon alpha-2a and ribavirin in a patient with hepatitis C

The case presented is the first patient with concurrent acute interstitial pneumonia and pulmonary embolism associated with combined treatment of peginterferon and ribavirin for hepatitis C.

Pulmonary arterial hypertension in patients treated with interferon

Isolated cases of pulmonary arterial hypertension (PAH) in patients treated with interferon (IFN) α or β have been reported in the literature. The aim of this study was to describe all consecutive cases of PAH patients with a history of IFN exposure identified in the French reference centre for severe pulmonary hypertension between 1998 and 2012. A total of 53 patients with PAH and a history of IFN therapy were identified. 48 patients had been treated with IFNα for chronic hepatitis C. Most of them had portal hypertension (85%) and 56% had HIV co-infection. Five additional patients had been treated with IFNβ for multiple sclerosis. The diagnosis of PAH was made within 3 years after IFN therapy in 66% of patients. Repeated haemodynamic assessment was available in 13 out of 16 patients exposed to IFN after the diagnosis of PAH. Increased pulmonary vascular resistance >20% was observed in 11 out of 13 cases (median 43% increase; IQR 32-67%). In five of these patients, IFN withdrawal resulted in spontaneous haemodynamic improvement. This retrospective analysis suggests that IFN therapy may trigger PAH. However, most of these patients had other risk factors for PAH. A prospective case-control study is necessary to definitively establish a link between IFN exposure and PAH.

Endothelin-1 as a mediator and potential biomarker for interferon induced pulmonary toxicity

Endothelin-1 is a potent vasoconstrictor and a therapeutic target in pulmonary arterial hypertension. Endothelial cells are the physiological source of endothelin-1 but in vitro data from our group shows that interferons (IFNα, IFNβ or IFNγ) induce endothelin-1 in pulmonary vascular smooth muscle cells. IFNs are integral to innate immunity and their antiviral and immunomodulatory capability has been harnessed therapeutically; for example, IFNα plays a critical role in the treatment of chronic hepatitis C infection. However, in some patients, IFN causes pneumonitis and possibly irreversible pulmonary arterial hypertension. In this study, we found that of 16 patients undergoing a six-month course of IFNα therapy, two demonstrated considerably increased serum levels of endothelin-1. We propose that IFN therapy results in elevated levels of endothelin-1 in some patients and when clinically significant levels are reached, pulmonary side effects could ensue. This hypothesis can be easily tested in IFN-treated patients by measuring serum endothelin-1 levels and cardiopulmonary physiological parameters.

Pharmacology and therapeutic potential of interferons

Interferon (IFN) is widely recognised to be an integral part of the innate immune response to viral infection. Since its initial discovery in 1957 by Isaacs and Lindenmann, various IFN sub-types have been identified and there are now three distinct classes recognised-Type I (IFN-α and IFN-β), Type II (IFN-γ) and Type III (IFN-λ), distinguished by their differing receptors. As well as displaying profound antiviral activity in vivo, IFN has anti-proliferative, cytotoxic and anti-tumoural roles. In an attempt to harness their immunomodulatory potential, investigators and clinicians have investigated the use of IFNs for the treatment of human diseases with considerable success. For example, IFN-α preparations are now a critical component in the treatment of chronic Hepatitis C infection and IFN-β therapy is now the first line treatment for relapsing remitting multiple sclerosis. However, IFN therapy is also associated with significant morbidity and in some patients is poorly tolerated. In this review, we explore the scientific basis for IFN therapy and outline its therapeutic scope. We describe the commonly encountered side effects and attempt to explain the less well recognised pulmonary complications including emerging evidence of life threatening and irreversible pulmonary vascular pathology. Finally, we look to the future of interferon drug treatment, examining the potential for emerging therapies.

Therapeutic effects of the oriental herbal medicine Sho-saiko-to on liver cirrhosis and carcinoma

The traditional Chinese herbal medicine Sho-saiko-to is a mixture of seven herbal preparations that has long been used in the treatment of chronic liver disease. Various clinical trials have shown that Sho-saiko-to protects against the development of hepatocellular carcinoma in cirrhotic patients. However, the mechanism by which Sho-saiko-to protects hepatocytes against hepatic fibrosis and carcinoma is not yet known. Basic science studies have demonstrated that Sho-saiko-to reduces hepatocyte necrosis and enhances liver function. Sho-saiko-to significantly inhibits hepatic fibrosis by inhibiting the activation of stellate cells, the major producers of collagen in the liver, as well as by inhibiting hepatic lipid peroxidation, promoting matrix degradation, and suppressing extracellular matrix (ECM) accumulation. Furthermore, clinical trials have shown that Sho-saiko-to lowers the rate of hepatocellular carcinoma (HCC) development in patients with cirrhosis and increases the survival of patients with HCC. Unfortunately, some case reports have shown the side effects of Sho-saiko-to. Most of the side effects were interstitial pneumonia and acute respiratory failure induced by Sho-saiko-to in Japan. As a result of analyzing these case reports, the incidence and risk are increased by co-administration of interferon, duration of medication, and, high in an elderly population. This review discusses the properties of Sho-saiko-to with regards to the treatment of chronic liver diseases and suggests the side effects of Sho-saiko-to.