Infectious Lung Complications in Patients with HIV/AIDS
Purpose of Review: The aim of this article is to review recent observations in the area of infectious lung complications in individuals with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). Since the immunodeficiency was first characterized, it has been associated with enhanced susceptibility to opportunistic infection, and life-threatening infections of the lung in particular. In the past few years there have been a large number of reports documenting the changes to this disease profile in the age of highly active antiretroviral therapy (HAART). Furthermore, there have been considerable advances in our understanding of the immunology and vaccinology of many of the pathogens implicated in pulmonary infections in this context, including Mycobacterium tuberculosis , Streptococcus pneumoniae and Pneumocystis pneumonia.
Recent Findings: In considering the time-course and spectrum of HIV-associated respiratory infections, the field must now be divided into studies undertaken in parts of the world where HAART is accessible and those where it is not. Despite the enormous impact of HAART, it has brought with it a new set of concerns, including the effects of immune restoration disease (IRD), and the complex interplay between HAART and tuberculosis therapy.
Summary: The overriding conclusion from recent experience is that HAART, in those parts of the world where it is readily available, has changed the clinical picture of infections associated with HIV, and needs to be available to patients across the developing world as well. Furthermore there have been important developments in vaccination programs against pathogens involved in HIV-associated pneumonia.
Since acquired immune deficiency syndrome was first reported in the early 1980s, a hallmark of the syndrome has been the increased incidence of opportunistic infections and respiratory disease. Respiratory infection was then and still remains now a key cause of morbidity and mortality (Fig. 1). The pathogens include bacteria and mycobacteria such as Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas, Mycobacterium tuberculosis and Mycobacterium avium . HIV infection is an important risk factor for development of tuberculosis. Fungal infections commonly identified are Pneumocystis jirovecii, Cryptococcus and Aspergillus . Among the parasitic infections that may be implicated are Toxoplasma gondii and Cryptosporidium .
(Enlarge Image)
Infectious lung complications in patients with HIV/AIDS.When considering disease epidemiology, patterns of pathogenesis and therapeutic options, the tendency is to divide the analysis into findings from the pre-HAART and post-HAART eras of HIV therapeutics (in the developed world, roughly pre- and post- 1996), because of the enormous impact that these drugs have had on the disease profile. A further consequence of this split is that reports from the developing world, where HAART treatment has not been commonplace, may differ considerably from observations in the developed world, where HAART has had such a major impact.
With these points in mind, the following review aims to summarize some of the major developments in this field, attempting to draw together epidemiology, basic disease mechanisms and immunology, therapeutics and vaccinology. Recent developments in HIV research have focused particularly on HIV biology at mucosal sites and the impact there on local T cell responses. It seems likely that the extreme susceptibility of the lung to disease pathology during HIV infection relates to depletion of local T cell immunity at that site.
Purpose of Review: The aim of this article is to review recent observations in the area of infectious lung complications in individuals with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). Since the immunodeficiency was first characterized, it has been associated with enhanced susceptibility to opportunistic infection, and life-threatening infections of the lung in particular. In the past few years there have been a large number of reports documenting the changes to this disease profile in the age of highly active antiretroviral therapy (HAART). Furthermore, there have been considerable advances in our understanding of the immunology and vaccinology of many of the pathogens implicated in pulmonary infections in this context, including Mycobacterium tuberculosis , Streptococcus pneumoniae and Pneumocystis pneumonia.
Recent Findings: In considering the time-course and spectrum of HIV-associated respiratory infections, the field must now be divided into studies undertaken in parts of the world where HAART is accessible and those where it is not. Despite the enormous impact of HAART, it has brought with it a new set of concerns, including the effects of immune restoration disease (IRD), and the complex interplay between HAART and tuberculosis therapy.
Summary: The overriding conclusion from recent experience is that HAART, in those parts of the world where it is readily available, has changed the clinical picture of infections associated with HIV, and needs to be available to patients across the developing world as well. Furthermore there have been important developments in vaccination programs against pathogens involved in HIV-associated pneumonia.
Since acquired immune deficiency syndrome was first reported in the early 1980s, a hallmark of the syndrome has been the increased incidence of opportunistic infections and respiratory disease. Respiratory infection was then and still remains now a key cause of morbidity and mortality (Fig. 1). The pathogens include bacteria and mycobacteria such as Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas, Mycobacterium tuberculosis and Mycobacterium avium . HIV infection is an important risk factor for development of tuberculosis. Fungal infections commonly identified are Pneumocystis jirovecii, Cryptococcus and Aspergillus . Among the parasitic infections that may be implicated are Toxoplasma gondii and Cryptosporidium .
(Enlarge Image)
Infectious lung complications in patients with HIV/AIDS.When considering disease epidemiology, patterns of pathogenesis and therapeutic options, the tendency is to divide the analysis into findings from the pre-HAART and post-HAART eras of HIV therapeutics (in the developed world, roughly pre- and post- 1996), because of the enormous impact that these drugs have had on the disease profile. A further consequence of this split is that reports from the developing world, where HAART treatment has not been commonplace, may differ considerably from observations in the developed world, where HAART has had such a major impact.
With these points in mind, the following review aims to summarize some of the major developments in this field, attempting to draw together epidemiology, basic disease mechanisms and immunology, therapeutics and vaccinology. Recent developments in HIV research have focused particularly on HIV biology at mucosal sites and the impact there on local T cell responses. It seems likely that the extreme susceptibility of the lung to disease pathology during HIV infection relates to depletion of local T cell immunity at that site.
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