Types Of Aspergillosis Research Articles

A Brief Review on Invasive Aspergillosis and the Host Immune Response and the Target Drugs

Background: Aspergillus spp. is ubiquitous, opportunistic fungi that invade and cause serious complication in man. Different species of Aspergillus causes various types of aspergillosis in man. Many predisposing factors have been attributed to the cause of the disease. Due to the nature of the disease, diagnosis is also difficult. Since this disease generally occurs in people who are immunocompromised, there is no effective immune response against this disease; therefore drugs are the only way to treat it. Depending on the state of the immune system, clinical symptoms can range from an excessive immune response to the formation of an aspergilloma in the immune-competent patients. Recognition and removal of the fungus by phagocytosis, production of antimicrobial peptides and recognition by pattern recognition receptors are the major components of the innate immune system involved in fighting the disease. Various classes of antifungal drugs are used to treat the disease but the fungus has its own machinery to overcome the effect and become resistant to the drugs. Conclusion: This review mainly focuses on the types of invasive aspergillosis and the immune response against the fungus by the host when it invades the host and the various classes of drugs that are employed to evade the infection. Keywords: Aspergillosis, immune response, Aspergillus spp., antifungal drugs, immunocompromised, phagocytosis.

Spectrum of aspergillosis: Pathogenesis, risk factors and management

This article reviews comprehensively the spectrum of diseases (aspergillosis) caused by Aspergillus spp, the commonest pathogenic form being the A.fumigatus. Aspergilus spp are ubiguitous in the environment and the respiratory tract is the portal of entry in most cases. Aspergillosis is associated with significant mortality and morbidity, the prevalence appears to be on the increase. About 10million people are at risk of aspergillosis, and 50% would die even with treatment. Immunodeficiency, especially neutropenia is central to the pathogenesis of aspergillosis. Diseases caused by A. fumigatus include;1) Invasive aspergillosis seen mostly in stem cell and organ transplant recipients, patients with haematological malignancies, cancer patients on chemotherapy and patients with AIDS. Invasive aspergillosis is life threatening, it affects the lungs and sinuses but could disseminate to affect the CNS, eye, skin and kidney. 2) Chronic pulmonary Aspergillosis occurs in the setting of previous cavitatry lung disease, most commonly tuberculous infections. 3) Allergic bronchopulmonary aspergillosis (ABPA) affects people with asthma and cystic fibrosis. A. fumigatus is also implicated in the exacerbation of asthma. The clinical symptoms of aspergillosis depend on the type and the systems affected; respiratory symptoms are more common as the respiratory tract is disproportionately affected in aspergillosis. Diagnostic features and treatment also depends on the type of aspergillosis. Diagnostic testing for aspergillosis includes radiologic tests, culture tests, galactomannan testing in body fluids, immunologic tests to detectAspergilus -specific immunoglobulins. Treatment modalities include surgery, use of antifungals and immunomodulatory therapy with cytokines.

Chronic bronchopulmonary aspergillosis in a horse with Cushing's syndrome

An atypical case of chronic equine bronchopulmonary aspergillosis with an unusual hyphal morphology was diagnosed in a horse with Cushing's syndrome. Because of the hyphal localization in chronic ectatic bronchi and bronchioles, and juxtabronchiolar processes, the observed type of aspergillosis is similar to 'saprophytic bronchopulmonary aspergillosis' or 'semi-invasive pulmonary aspergillosis' in humans. The aetiological diagnosis of aspergillosis was accomplished by the application of a panel of monospecific polyclonal and monoclonal antibodies in immunohistochemical techniques.

Aspergillosis: A disease with many faces

Aspergillus causes a variety of pulmonary diseases. For the most part, they can be divided into three groups: mycetoma, invasive aspergillosis, and allergic forms of aspergillosis. The mycetoma form of aspergillosis has no effective treatment other than surgery, which is reserved for the severely symptomatic patient, usually with massive hemoptysis. Invasive aspergillosis is a dangerous pulmonary infection seen in patients who are generally severely immunocompromised. It is treated with amphotericin B and success in treatment of this form of aspergillosis is limited. Two of the allergic forms of Aspergillus infection, allergic bronchopulmonary aspergillosis and bronchocentric granulomatosis, are treated with steroids. The third allergic type of reaction, hypersensitivity lung, is best treated by removal of the patient from exposure to the antigen. Although these are the characteristic forms of aspergillosis, there is occasional overlap of the different types of aspergillosis.

Evaluation of the diagnostic value of the measurement of (1-->3)-beta-D-glucan in patients with pulmonary aspergillosis.

The value of the measurement of (1-->3)-beta-D-glucan, a major and common cell wall constituent of fungi, for diagnosing pulmonary aspergillosis was assessed in comparison with that of conventional examinations. The concentrations of (1-->3)-beta-D-glucan in sera was elevated in 7 out of 8 patients with active aspergillosis, but not in cases without active diseases, except for one sample. Further, the concentrations well reflected the activity of the aspergillosis in each case. Regarding conventional examinations, with the immunodiffusion test it was difficult to detect the present activity of the disease. The radioallergosorbent test was useful for diagnosing bronchopulmonary aspergillosis, but not for other types of aspergillosis. The Aspergillus-specific component, galactomannan, was insensitive and the enzyme-linked immunosorbent assay gave highly variable results. Thus, although the assessment of the specificity of the assay is still necessary, compared with other tests, the assay of (1-->3)-beta-D-glucan has the advantage of diagnosing pulmonary aspergillosis and also of assessing the disease activity.

Serolodiagnosis of Some Types of Aspergillosis using Culture Filtrate Antigensfrom Aspergillus fumigatus.

Culture filtrate antigens derived from a strain of Aspergillus fumigatus were used in diagnosing aspergillosis, such as aspergilloma, allergic bronchopulmonary aspergillosis and tissue invasive aspergillosis, by the Western immunoblot method detecting the serum specific antibodies, immunoglobulin M (IgM) and immunoglobulin G (IgG). These antibodies in the sera from all patients with those types of aspergillosis were thus detected significantly more clearly than in the healthy, normal controls.Double diffusion tests using the same antigens were also performed to compare the efficacy of these two methods. In several cases showing negative in the double diffusion test, these antibodies were found to react with proteins possessing the molecular weight of 20, 35, 50, 65 and 73kDa, while in other cases showing positive in the double diffusion test, the antibodies could not be distinguished from each other. We therefore used the Western blotting method to distinguish them.From the data obtained it was concluded that serologic diagnosis by the detection of IgM and IgG using the immunoblot method plays an important role in strengthening the clinical diagnosis.

The spectrum of pulmonary aspergillosis.

Aspergillus species can produce a wide range of pulmonary disorders. Classically, pulmonary aspergillosis has been categorized into invasive, saprophytic, and allergic forms, all of which differ in their manifestations and therapy. More recently, however, other types of infection by this fungus have been recognized that do not fit into these traditional categories; an example is semi-invasive (chronic necrotizing) aspergillosis. In fact, these forms have features that are intermediate between those of the invasive and saprophytic types. The various types of aspergillosis can be regarded as constituting a continuous spectrum, ranging from invasive disease in the severely immunosuppressed patient to hypersensitivity reactions such as allergic bronchopulmonary aspergillosis (and bronchocentric granulomatosis) in the hyperreactive patient. Between these extremes are chronic necrotizing disease seen in midly immunocompromised hosts, and the noninvasive aspergilloma, which is due to saprophytic growth within a previously diseased area of lung in an otherwise normal host. Other intermediate forms may be encountered, their behavior being determined by the host immune status in combination with the underlying lung morphology. The radiographic and clinical features of these various forms of pulmonary aspergillosis are reviewed, including the more recently reported forms of infection such as Aspergillus tracheobronchitis and aspergillosis associated with acquired immunodeficiency syndrome and cystic fibrosis. The proposed concept of a disease spectrum is emphasized.

Itraconazole therapy in aspergillosis: Study in 49 patients

Itraconazole, 200 to 400 mg once daily, was administered to 49 patients with different types of aspergillosis: pulmonary aspergilloma (14 patients), chronic necrotizing pulmonary aspergillosis (14), and invasive aspergillosis (21). Itraconazole was prescribed alone or in combination or after treatment with amphotericin B and flucytosine. Of 14 aspergilloma patients, 2 were cured and 8 had symptomatic improvement. In chronic necrotizing pulmonary aspergillosis, 7 of 14 patients were cured and 6 improved significantly. In invasive aspergillosis treatment failed in 6 patients and 15 were cured. Itraconazole can be an alternative to amphotericin B in the treatment of invasive aspergillosis and chronic necrotizing pulmonary aspergillosis. In aspergilloma itraconazole may be useful in inoperable cases.