Pulmonary manifestations of HIV infection in the era of highly active antiretroviral therapy

Coexistence of Competing Opportunistic Pathogens in Critically ill Patients with Advanced AIDS: A Case Report and Literature Review

Introduction:

Opportunistic infections (OIs) are the leading causes of morbidity and mortality among HIV-infected individuals. The incidence of OIs is greater in antiretroviral treatment (ART) naive patients. As of 30 June 2021, 28.2 (73%) people with HIV/AIDS (PLWHA) were accessing antiretroviral therapy (ART) globally, leaving the remaining 27% PLWHA without ART at risk for OIs. Multiple opportunistic infections are caused due to the coexistence of competing opportunistic pathogens that confound clinical manifestations, investigative procedures, and management protocols.

Case Presentation:

In this report, we describe the case of a critically ill HIV female patient admitted to the ICU. The patient was diagnosed with multiple opportunistic infections and subsequently died after her illness progressed. Due to the paucity of information on the subject, we conducted a retrospective study of 1440 case records of HIV/AIDS critically ill patients to determine the incidence and spectrum of multiple opportunistic infections. We performed a review of the available medical literature relevant to the subject.

Conclusion:

Knowledge of such events would guide and enhance the physician's diagnostic and management strategies, especially in resource limited regions.

Recent epidemiology of Pneumocystis pneumonia in Japan

OBJECTIVES

The objective of this study was to describe the recent epidemiology of Pneumocystis pneumonia (PCP) in Japan using a nationwide database.

METHODS

We extracted data of inpatients with PCP from the Diagnostic Procedure Combination database, a national inpatient database in Japan, from January 2010 to December 2016.

RESULTS

During the study period, 4293 PCP patients were identified, including 4073 adults and 220 children. In adults, the most common comorbidity was hematologic malignancy (31%), followed by diabetes mellitus (30%), rheumatic/collagen diseases (26%), and solid organ tumors (18%). In children, there were few patients with rheumatic diseases (5%) or diabetes mellitus (2%), but immunodeficiency (without human immunodeficiency virus) was more common (28%). Few biological products were used for adult and pediatric patients; CD20 inhibitors, TNF-α inhibitors, interleukin receptor inhibitors, and CTLA-4 inhibitor were used for 8.6% and 2.4%, 1.3% and 0%, 1.2% and 4.7%, and 0.2% and 0% of adult and pediatric patients, respectively. Based on data stratified by bed count, the annual numbers of PCP patients in Japan were estimated as 2221 adults and 123 pediatric patients. The mortality was higher in adults (27%) than in pediatric patients (21%) (P = 0.041).

CONCLUSIONS

The underlying disease and mortality were apparently different between adult and pediatric PCP patients.

A Rare Case of Multipathogenic Pneumonia in a Patient With Human Immunodeficiency Virus

The incidence of acquired immunodeficiency syndrome (AIDS)-related opportunistic infections has declined dramatically following the introduction of potent antiretroviral therapy (ART). However, pulmonary infections remain a significant cause of morbidity and mortality. The spectrum of pulmonary disease that can affect patients with human immunodeficiency virus (HIV) is wide and includes opportunistic infections with many bacterial, fungal, viral, and parasitic organisms. In this case, we present a 65-year-old woman with HIV, non-compliant with ART, who presented with subacute melena, fatigue, dyspnea, and hemoptysis. After extensive evaluation, she was found to have pneumonia caused by four different pathogens: Strongyloides stercoralis, Pneumocystis jirovecii, Cytomegalovirus (CMV), and Pseudomonas aeruginosa. She received trimethoprim-sulfamethoxazole, steroids, and ivermectin. However, her clinical condition did not improve and she passed away.

Pulmonary Toxoplasmosis Diagnosed on Transbronchial Lung Biopsy in a Mechanically Ventilated Patient

Toxoplasma gondii is a protozoan parasite that infects up to a third of the world's population. Infection is mainly acquired by ingestion of food or water that is contaminated with oocysts shed by cats or consuming undercooked meat containing tissue cysts. Primary infection is subclinical in immunocompetent hosts. Invasive toxoplasmosis often manifests as cerebral toxoplasmosis in immunosuppressed patients. In persons living with human immunodeficiency virus (HIV), toxoplasmosis occurs when CD4 counts are very low and is considered an acquired immunodeficiency syndrome (AIDS) defining illness. Pulmonary toxoplasmosis is rarely seen in the highly active antiretroviral therapy era. The diagnosis can be challenging due to the nonspecific nature of clinical and radiographic findings. In this report, we present a case of pulmonary toxoplasmosis in a new onset AIDS patient, which was initially clinically misdiagnosed as Pneumocystis jiroveci pneumonia (PJP). Due to a poor response to treatment for PJP, the patient underwent a transbronchial lung biopsy, which led to the diagnosis of pulmonary toxoplasmosis.

A Molecular Window into the Biology and Epidemiology of Pneumocystis spp

Pneumocystis, a unique atypical fungus with an elusive lifestyle, has had an important medical history. It came to prominence as an opportunistic pathogen that not only can cause life-threatening pneumonia in patients with HIV infection and other immunodeficiencies but also can colonize the lungs of healthy individuals from a very early age. The genus Pneumocystis includes a group of closely related but heterogeneous organisms that have a worldwide distribution, have been detected in multiple mammalian species, are highly host species specific, inhabit the lungs almost exclusively, and have never convincingly been cultured in vitro, making Pneumocystis a fascinating but difficult-to-study organism. Improved molecular biologic methodologies have opened a new window into the biology and epidemiology of Pneumocystis. Advances include an improved taxonomic classification, identification of an extremely reduced genome and concomitant inability to metabolize and grow independent of the host lungs, insights into its transmission mode, recognition of its widespread colonization in both immunocompetent and immunodeficient hosts, and utilization of strain variation to study drug resistance, epidemiology, and outbreaks of infection among transplant patients. This review summarizes these advances and also identifies some major questions and challenges that need to be addressed to better understand Pneumocystis biology and its relevance to clinical care.

Human immunodeficiency virus associated pulmonary conditions leading to hospital admission and the pulmonary rehabilitation services received by patients at two central hospitals in Harare

Objective

Use of highly active antiretroviral therapy has led to marked reductions in the incidence of HIV-associated opportunistic infections but has had comparatively less impact on the incidence of some pulmonary diseases. This study was done to determine the pulmonary conditions leading to hospital admissions in people living with HIV/AIDS at two central hospitals in Zimbabwe and the pulmonary rehabilitation intervention received.

Results

A total of 92 participants were recruited of which 60 (65.2%) were females. The mean age of the participants was 41.3 years (SD = 9.1). The most common pulmonary condition leading to hospital admission was tuberculosis in 53 (57.6%). About 52 (56.6%) of the participants suffered from pulmonary complications in the last 6 months, 48 (92.3%) were admitted and 26 (50.0%) of the participants received physiotherapy treatment during their admission. None of the participants indicated that they once attended an outpatient pulmonary rehabilitation clinic. Respiratory complication is one of the leading causes of morbidity associated with HIV but no pulmonary rehabilitation services are being offered to these patients. There is need for introduction of pulmonary rehabilitation programs for people living with HIV/AIDS in the current setting.

Refractory acute respiratory failure due to Pneumocystis jiroveci (PCP) and Cytomegalovirus (CMV) pneumonitis: A case report and review of literature

BACKGROUND

Opportunistic infections with Pneumocystis jiroveci pneumonia (PCP) are common in patients with HIV (human immunodeficiency virus) and are encountered once the CD4 count decreases below 200 cells/mm3. Cytomegalovirus (CMV) tends to cause disease once the CD4 count drops below 50 cells/mm3. CMV pneumonitis is not common in this population. However, detecting its presence in broncho-alveolar lavage (BAL) fluid has been associated with increased morbidity and mortality. The role of antiviral therapy against CMV remains unclear.

CASE PRESENTATION

We report a newly diagnosed HIV patient with a CD4 count of 44 cells/mm3 presenting with acute respiratory failure secondary to PCP that failed to respond to 3 weeks of standard therapy with trimethoprim-sulfamethoxazole and corticosteroids. He was later diagnosed to have a CMV co-infection causing pneumonitis with BAL cytology findings showing CMV cytopathic effects and PCP. Plasma CMV DNA PCR was 17,424 copies/mL. He responded well after introduction of intravenous ganciclovir.

CONCLUSION

The presence of histopathologic changes demonstrating viral cytopathic effects on BAL cytology along with a high plasma CMV DNA PCR should raise the specificity for diagnosing CMV pneumonitis. True PCP and CMV pneumonitis can occur, and the addition of antiviral therapy with ganciclovir may benefit such patients in the right clinical scenario.

HIV-related pneumococcal disease prevention in adults

INTRODUCTION

HIV-infected persons are particularly susceptible to the development of severe pneumococcal disease, even in the setting of combination antiretroviral therapy (cART), due to slow, incomplete recovery of anti-pneumococcal host defenses. This risk is increased by avoidable aspects of lifestyle, particularly smoking, which intensify immunosuppression. Clearly, more effective preventive measures are needed to counter this threat. Areas covered: This is a detailed review of the published literature focusing on currently available strategies for prevention of pneumococcal infection in HIV-infected patients, including cotrimoxazole prophylaxis, cART, pneumococcal vaccination, and smoking cessation strategies. This is preceded by a consideration of the epidemiology, clinical presentation, risk factors, and outcome of pneumococcal disease. Expert commentary: Cotrimoxazole prophylaxis has been shown to reduce morbidity and mortality in HIV-infected patients, although there is inconsistent data on the preventive efficacy against pneumococcal infections. Some recent studies have documented unchanged incidences of IPD in adult patients in the cART era. With regard to pneumococcal vaccination, routine acceptance of the efficacy of the PCV13/PPV23 sequential administration prime-boost strategy awaits the outcome of clinical trials in those with HIV infection. Smoking cessation, and discontinuation of excessive alcohol consumption and intravenous drug abuse, are priority strategies to prevent severe pneumococcal infection.

Lower Respiratory Tract Infections

This review will focus on the infectious etiologies and more common noninfectious causes of lower respiratory tract syndromes among major immunosuppressed populations. The changing epidemiology of infections in the era of highly active antiretroviral therapy (HAART) in the case of HIV-positive patients and the impacts of both newer immune-suppressant therapies and anti-infective prophylaxis for other immunocompromised hosts will be discussed, with emphasis on diagnostic approaches and practice algorithms.

Prescription of Pneumocystis Jiroveci Pneumonia Prophylaxis in HIV-Infected Patients

The US treatment guidelines recommend Pneumocystis jiroveci pneumonia (PCP) prophylaxis for all HIV-infected persons with a CD4 count <200 cells/mm³ (ie, eligible for PCP prophylaxis). However, some studies suggest PCP prophylaxis may be unnecessary in virally suppressed patients. Using national data of HIV-infected adults receiving medical care in the United States during 2009 to 2012, the authors assessed the weighted percentage of eligible patients who were prescribed PCP prophylaxis and the independent association between PCP prophylaxis prescription and viral suppression. Overall, 81% of eligible patients were prescribed PCP prophylaxis. Virally suppressed eligible patients were less likely to be prescribed PCP prophylaxis (prevalence ratio: 0.84; 95% confidence interval: 0.80-0.89). Although guidelines recommend PCP prophylaxis for all eligible patients, some HIV care providers might not prescribe PCP prophylaxis to virally suppressed patients. Additional data on the risk for PCP among virally suppressed patients are needed to clarify this controversy.

Life-Threatening Complications of HIV Infection

Few modern diseases have experienced as rapid and dramatic change in prognosis and treatment as HIV infection. The introduction of active antiretroviral therapy (ART) and effective prophylaxis of opportunistic infections ushered in a new era in the treatment of HIV infection and changed dramatically the natural history of this disease. The rates of admission to the intensive care unit (ICU) and intensive care mortality in patients with HIV infection have shifted repeatedly during the AIDS epidemic, influenced by attitudes of patients and providers toward utility of care. In the ART era, patients with HIV infection admitted to the ICU fall into 3 general categories: those with AIDS-related opportunistic infections, those who are experiencing complications related to ART, and those with medical problems unrelated to HIV infection. In this article, the authors provide a review of the most common life-threatening complications in patients with HIV infection.

Pulmonary toxoplasmosis in human immunodeficiency virus-infected patients in the era of antiretroviral therapy

Toxoplasmosis is a severe opportunistic infection in patients infected with the human immunodeficiency virus (HIV). The lung is a major site of infection after the central nervous system. In this report we described two cases of pneumonia due to Toxoplasma gondii infection in HIV patients with antiretroviral therapy. Clinical and radiological abnormalities are not specific. Pulmonary toxoplasmosis should be considered in HIV-infected patients with late stage of HIV, CD4 count less than 100 cells/µl and a poor adherence to HAART.

Use of Oropharyngeal Washes to Diagnose and Genotype Pneumocystis jirovecii

Pneumocystis jirovecii is a symbiotic respiratory fungus that presents in 2 clinical forms: pneumonia in immunocompromised patients or colonization, defined by the presence of the organism without associated clinical symptoms. Currently, diagnosis requires invasive bronchoscopy, which may not be available in some settings and is inappropriate for detecting colonization in healthy individuals. Noninvasive diagnostic techniques and molecular strain typing tools that can be used on these samples are critical for conducting studies to better understand transmission. We evaluated 2 real-time polymerase chain reaction (PCR) assays targeting dihydropteroate synthase and the major surface glycoprotein for detection in 77 oropharyngeal washes (OPWs) from 43 symptomatic human immunodeficiency virus-infected patients who underwent bronchoscopy. We also evaluated the ability of a new microsatellite (MS) genotyping panel to strain type infections from these samples. Each PCR used individually provided a high sensitivity (>80%) for detection of pneumonia but a modest specificity (<70%). When used in combination, specificity was increased to 100% with a drop in sensitivity (74%). Concentration of organisms by PCR in the OPW tended to be lower in colonized individuals compared with those with pneumonia, but differences in concentration could not clearly define colonization in symptomatic individuals. Oropharyngeal wash samples were genotyped using 6 MSs with ≥4 alleles successfully genotyped in the majority of colonized patients and ≥5 alleles in patients with pneumonia. The MS profile was consistent over time within patients with serial OPWs analyzed. Microsatellite genotyping on noninvasive samples may aid in studying the molecular epidemiology of this pathogen without requiring invasive diagnostic techniques.

Comparing clinical outcomes in HIV-infected and uninfected older men hospitalized with community-acquired pneumonia

OBJECTIVES

Outcomes of community-acquired pneumonia (CAP) among HIV-infected older adults are unclear.

METHODS

Associations between HIV infection and three CAP outcomes (30-day mortality, readmission within 30 days post-discharge, and hospital length of stay [LOS]) were examined in the Veterans Aging Cohort Study (VACS) of male Veterans, age ≥ 50 years, hospitalized for CAP from 10/1/2002 through 08/31/2010. Associations between the VACS Index and CAP outcomes were assessed in multivariable models.

RESULTS

Among 117 557 Veterans (36 922 HIV-infected and 80 635 uninfected), 1203 met our eligibility criteria. The 30-day mortality rate was 5.3%, the mean LOS was 7.3 days, and 13.2% were readmitted within 30 days of discharge. In unadjusted analyses, there were no significant differences between HIV-infected and uninfected participants regarding the three CAP outcomes (P > 0.2). A higher VACS Index was associated with increased 30-day mortality, readmission, and LOS in both HIV-infected and uninfected groups. Generic organ system components of the VACS Index were associated with adverse CAP outcomes; HIV-specific components were not. Among HIV-infected participants, those not on antiretroviral therapy (ART) had a higher 30-day mortality (HR 2.94 [95% CI 1.51, 5.72]; P = 0.002) and a longer LOS (slope 2.69 days [95% CI 0.65, 4.73]; P = 0.008), after accounting for VACS Index. Readmission was not associated with ART use (OR 1.12 [95% CI 0.62, 2.00] P = 0.714).

CONCLUSION

Among HIV-infected and uninfected older adults hospitalized for CAP, organ system components of the VACS Index were associated with adverse CAP outcomes. Among HIV-infected individuals, ART was associated with decreased 30-day mortality and LOS.

Update on opportunistic infections in the era of effective antiretroviral therapy

Despite enormous improvements in effectiveness of treatment for HIV infection, opportunistic infections continue to occur in those who have not yet been diagnosed with HIV and in those who are not receiving antiretroviral therapy. This review focuses on tuberculosis and cryptococcal infections, the most common opportunistic infections (OIs) in patients living with human immunodeficiency virus infection around the world, as well as on new developments in progressive multifocal leukoencephalopathy and pneumocystis pneumonia. In the sections on these conditions, updates on diagnosis, treatment, and complications, as well as information on when to start antiretroviral therapy is provided. The article concludes with a discussion of new data on 2 vaccine-preventable OIs, human papillomavirus and varicella-zoster virus.

Bacterial Infections in Adult HIV-Infected Patients

PURPOSE

The purpose of this article is to critically review articles published from the pre-HAART era to the present on bacterial infections in adult HIV-infected patients.

METHOD

Literature search on bacterial infections in HIV-infected patients yields predominantly small case series from single centers, many of which are retrospectively collected.

RESULTS

Variations in case selection limit the utility of these articles for assessing the epidemiology and clinical features of a particular infection. Nonetheless, numerous articles indicate that certain bacterial infections occur most often when CD4 cell counts are < 200/mm3. In the pre-HAART era, others suggest that PcP prophylaxis with TMP/SMX and MAC prophylaxis with macrolides reduced rates of several bacterial infections. Since the advent of HAART, however, some articles suggest that the incidence of various infections has declined and that withdrawal of OI prophylaxis in patients who have had HAART restoration of CD4 cell counts has not led to an increase in certain bacterial infections.

CONCLUSION

This review suggests that bacterial infections may have declined in the HAART era, as multicenter cohort studies have shown to be the case with AIDS-associated OIs. Nonetheless, preventive measures such as pneumococcal vaccination and smoking cessation remain effective strategies.

[Diagnosis delay of pleural and pulmonary tuberculosis]

Tuberculosis (TB) is still being endemic in our country. Time until management determines both evolution and prognosis of this condition. The aim of this work is to evaluate the delay in diagnosis of TB in a respiratory unit from a university hospital series. The authors conducted a cross-sectional study including patients with pulmonary TBC and/or pleural. An evaluation of time management was conducted from the beginning of symptoms and various consultations with reference to the date of hospitalization and treatment set up. One hundred patients were included (pulmonary TB: 68 cases, pleural TB 23 cases, miliary pulmonary TB: 4 cases, pulmonary TB associated with other extrathoracic locations: 5 cases). The mean time of patient delay and total delay institution were respectively 43.6, 25.7 and 69.3 days. Variables responsible for long delays were: number of consultations more than 3 before hospitalization, empirical antibiotic therapy, of a regional hospital first consultation and the presence of extra-respiratory impairment. The patient delay was considered long. A reorganization of the TB control program, in particular by partial decentralization of care and health education is imperative in order to improve the quality of tuberculosis management in our country.

Multilocus microsatellite genotyping array for investigation of genetic epidemiology of Pneumocystis jirovecii

Pneumocystis jirovecii is a symbiotic respiratory fungus that causes pneumonia (PcP) in immunosuppressed patients. Because P. jirovecii cannot be reliably cultured in vitro, it has proven difficult to study and gaps in our understanding of the organism persist. The release of a draft genome for the organism opens the door for the development of new genotyping approaches for studying its molecular epidemiology and global population structure. We identified and validated 8 putatively neutral microsatellite markers and 1 microsatellite marker linked to the dihydropteroate synthase gene (dhps), the enzymatic target of sulfa drugs used for PcP prevention and treatment. Using these tools, we analyzed P. jirovecii isolates from HIV-infected patients from three geographically distant populations: Uganda, the United States, and Spain. Among the 8 neutral markers, we observed high levels of allelic heterozygosity (average He, 0.586 to 0.842). Consistent with past reports, we observed limited global population structuring, with only the Ugandan isolates showing minor differentiation from the other two populations. In Ugandan isolates that harbored mutations in dhps, the microsatellite locus linked to dhps demonstrated a depressed He, consistent with positive directional selection for sulfa resistance mutations. Using a subset of these microsatellites, analyses of individual and paired samples from infections in San Francisco, CA, showed reliable typeability within a single infection and high discriminatory power between infections. These features suggest that this novel microsatellite typing approach will be an effective tool for molecular-epidemiological investigations into P. jirovecii population structure, transmission, and drug resistance.

Association of bronchoalveolar lavage yield with chest computed tomography findings and symptoms in immunocompromised patients

INTRODUCTION:

Fiber-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) is a common procedure performed in immunocompromised patients with undiagnosed pulmonary pathology. Identifying patients with the highest potential diagnostic yield may help to avoid morbidity in patients unlikely to benefit from the procedure. We sought to determine which patient factors, specifically chest computed tomography (CT) findings, affected diagnostic yield of BAL.

METHODS:

Retrospective chart review of immunocompromised patients who underwent FOB with BAL from 01/01/2010 to 12/31/2011 at an academic medical center was performed. The lung lobe lavaged, characteristics of pulmonary infiltrate on radiograph, patient symptoms, and diagnostic yield were collected. A positive diagnostic yield was defined as a positive microbiological culture, finding on cytopathologic staining, diffuse alveolar hemorrhage, alveolar eosinophilia or a positive immunologic or nucleic acid assay.

RESULTS:

The overall diagnostic yield was 52.6%. Infiltrates that were predominantly reticular or nodular by CT had a lower diagnostic yield than predominantly consolidated, ground-glass, or tree-in-bud infiltrates (36.5% vs. 61.2%, P = 0.0058). The diagnostic yield was significantly improved in patients with both fever and chest symptoms compared to patients without symptoms (61.3% vs. 29.6%, P = 0.0066).

CONCLUSION:

CT findings of reticular and nodular infiltrates portend a worse diagnostic yield from BAL than those that are alveolar in nature. Symptomatic patients are more likely to have diagnostic FOB with BAL than asymptomatic patients.

Clinical review: Respiratory failure in HIV-infected patients--a changing picture

Respiratory failure in HIV-infected patients is a relatively common presentation to ICU. The debate on ICU treatment of HIV-infected patients goes on despite an overall decline in mortality amongst these patients since the AIDS epidemic. Many intensive care physicians feel that ICU treatment of critically ill HIV patients is likely to be futile. This is mainly due to the unfavourable outcome of HIV patients with Pneumocystis jirovecii pneumonia who need mechanical ventilation. However, the changing spectrum of respiratory illness in HIV-infected patients and improved outcome from critical illness remain under-recognised. Also, the awareness of certain factors that can affect their outcome remains low. As there are important ethical and practical implications for intensive care clinicians while making decisions to provide ICU support to HIV-infected patients, a review of literature was undertaken. It is notable that the respiratory illnesses that are not directly related to underlying HIV disease are now commonly encountered in the highly active antiretroviral therapy (HAART) era. The overall incidence of P. jirovecii as a cause of respiratory failure has declined since the AIDS epidemic and sepsis including bacterial pneumonia has emerged as a frequent cause of hospital and ICU admission amongst HIV patients. The improved overall outcome of HIV patients needing ICU admission is related to advancement in general ICU care, including adoption of improved ventilation strategies. An awareness of respiratory illnesses in HIV-infected patients along with an appropriate diagnostic and treatment strategy may obviate the need for invasive ventilation and improve outcome further. HIV-infected patients presenting with respiratory failure will benefit from early admission to critical care for treatment and support. There is evidence to suggest that continuing or starting HAART in critically ill HIV patients is beneficial and hence should be considered after multidisciplinary discussion. As a very high percentage (up to 40%) of HIV patients are not known to be HIV infected at the time of ICU admission, the clinicians should keep a low threshold for requesting HIV testing for patients with recurrent pneumonia.

HIV-associated bacterial pneumonia

Community-acquired bacterial pneumonia (CAP) remains one of the most common opportunistic infections in patients who are infected with the human immunodeficiency virus (HIV). The risk of CAP increases as the CD4 cell count decreases. The common bacterial pathogens that cause CAP in HIV-infected persons are similar to those in HIV-uninfected individuals, with the pneumococcus being the most common pathogen. Prevention of CAP remains critical and necessitates a comprehensive approach addressing, among many other factors, cigarette smoking cessation strategies, antiretroviral therapy adherence, and immunization against those infections for which effective vaccinations are available.

Trends of mortality and cause of death among HIV-infected patients in Korea, 1990-2011

Although a decrease in acquired immunodeficiency syndrome (AIDS)-related mortality has been documented in highly active antiretroviral therapy (HAART) era, there are no published data comparing specific causes of death between pre-HAART and HAART era in Korea. Mortality and cause of death were analyzed in three treatment periods; pre-HAART (1990-1997), early-HAART (1998-2001), and late-HAART period (2002-2011). The patients were retrospectively classified according to the treatment period in which they were recruited. Although mortality rate per 100 person-year declined from 8.7 in pre-HAART to 4.9 in late-HAART period, the proportion of deaths within 3 months of initial visit to study hospital significantly increased from 15.9% in pre-HAART to 55.1% in late-HAART period (P < 0.001). Overall, 59% of deaths were attributable to AIDS-related conditions, and Pneumocystis pneumonia (PCP) was the most common cause of death (20.3%). The proportion of PCP as cause of death significantly increased from 8.7% in pre-HAART to 31.8% in late-HAART period (P < 0.001). Despite of significant improvement of survival, there was still a high risk of early death in patients presenting in HAART era, mainly due to late human immunodeficiency virus (HIV) diagnosis and late presentation to care.

HIV-associated lung infections and complications in the era of combination antiretroviral therapy

The spectrum of lung diseases associated with HIV is broad, and many infectious and noninfectious complications of HIV infection have been recognized. The nature and prevalence of lung complications have not been fully characterized since the Pulmonary Complications of HIV Infection Study more than 15 years ago, before antiretroviral therapy (ART) increased life expectancy. Our understanding of the global epidemiology of these diseases in the current ART era is limited, and the mechanisms for the increases in the noninfectious conditions, in particular, are not well understood. The Longitudinal Studies of HIV-Associated Lung Infections and Complications (Lung HIV) Study (ClinicalTrials.gov number NCT00933595) is a collaborative multi-R01 consortium of research projects established by the National Heart, Lung, and Blood Institute to examine a diverse range of infectious and noninfectious pulmonary diseases in HIV-infected persons. This article reviews our current state of knowledge of the impact of HIV on lung health and the development of pulmonary diseases, and highlights ongoing research within the Lung HIV Study.

Imaging lung manifestations of HIV/AIDS

Advances in our understanding of human immunodeficiency virus (HIV) infection have led to improved care and incremental increases in survival. However, the pulmonary manifestations of HIV/acquired immunodeficiency syndrome (AIDS) remain a major cause of morbidity and mortality. Respiratory complaints are not infrequent in patients who are HIV positive. The great majority of lung complications of HIV/AIDS are of infectious etiology but neoplasm, interstitial pneumonias, Kaposi sarcoma and lymphomas add significantly to patient morbidity and mortality. Imaging plays a vital role in the diagnosis and management of lung of complications associated with HIV. Accurate diagnosis is based on an understanding of the pathogenesis of the processes involved and their imaging findings. Imaging also plays an important role in selection of the most appropriate site for tissue sampling, staging of disease and follow-ups. We present images of lung manifestations of HIV/AIDS, describing the salient features and the differential diagnosis.

Evaluation of the current management protocols for prophylaxis against Pneumocystis jiroveci pneumonia and other opportunistic infections in patients living with HIV/AIDS

Opportunistic infections (OIs) are a leading cause of mortality and morbidity in patients living with HIV/AIDS. Data on the proper administration of prophylactic regimes for the prevention of OIs in such patients are scarce. A total of 205 confirmed HIV-infected patients were enrolled in the study from the inpatient wards and outpatient services. The treatment given to them for the prevention of Pneumocystis carinii (jiroveci) pneumonia was compared with the established guidelines and the proportions of those receiving proper treatment were calculated. Primary prophylaxis was seen to be satisfactory in the case of P. carinii (jiroveci) pneumonia. The prophylaxis was not given properly for tuberculosis and other common OIs. Secondary prophylaxis was up to the mark. Prophylaxis in AIDS patients seems to be a major problem area and a lot of efforts need to be directed toward it since patients suffering from AIDS are bound to have a downhill course despite provision of all available treatment options.

AIDS Patients in the ICU

At the beginning of the AIDS epidemic, there were higher mortality rates in patients requiring admission to an intensive care unit (ICU) most likely due to acute respiratory failure. Whereas the use of prophylaxis and corticosteroids for Pneumocystisjiroveci pneumonia and highly active antiretroviral therapy has changed this outcome and has improved survival rate. However, respiratory failure has remained the most common indication for an ICU admission. When HIV-infected patients are admitted to the ICU, intensivists need to be knowledgeable about the manifestations of common diseases and the new manifestations related to antiretroviral therapy. Much HIV mortality has been linked directly to late diagnosis and late initiation of appropriate antiviral therapy. This l, the most important cause of ICU admission for AIDS patients. We analyzed the characteristics of P.jiroveci pneumonia, bacterial pneumonia, cytomegalovirus pneumonia, mycobacterial infections, pulmonary invasive fungal infections, Kaposi’s sarcoma, and the immune reconstitution inflammatory syndrome.

Pneumonia and influenza hospitalization in HIV-positive seniors

HIV-positive persons and the elderly have increased risk for influenza-related complications, including pneumonia. Using claims data for pneumonia and influenza (P&I) hospitalization in the USA, we described the temporo-demographic trends and in-patient case-fatality in persons aged ≥ 65 years by HIV status. Our results showed a near doubling in the fraction of P&I admissions representing HIV-positive persons between 1991 and 2004 [relative risk (RR) 1·95, 95% confidence interval (CI) 1·80-2·13]. HIV-positive adults were younger (70·3 vs. 79·9 years, P<0·001), and had higher case-fatality (18·0% vs. 12·6%, P<0·001). Adjusting for other variables, case-fatality decreased by 5·8% in HIV-positive persons with the availability of highly active antiretroviral therapy (P=0·032). However, HIV-positive seniors were still 51% more likely to die during hospitalization than HIV-negative persons in 2004 (OR 1·51, 95% CI 1·23-1·85). HIV-infected persons represent a growing fraction of the elderly population hospitalized with P&I. Additional measures are needed to reduce case-fatality associated with P&I in this population.

Risk of pneumocystosis after early discontinuation of prophylaxis among HIV-infected patients receiving highly active antiretroviral therapy

BACKGROUND

Risk of pneumocystosis after discontinuation of primary or secondary prophylaxis among HIV-infected patients before CD4 counts increase to >==200 cells/microL (early discontinuation) after receiving highly active antiretroviral therapy (HAART) is rarely investigated.

METHODS

Medical records of 660 HIV-infected patients with baseline CD4 counts <200 cells/microL who sought HIV care and received HAART at a university hospital in Taiwan between 1 April, 1997 and 30 September, 2007 were reviewed to assess the incidence rate of pneumocystosis after discontinuation of prophylaxis for pneumocystosis.

RESULTS

The incidence rate of pneumocystosis after HAART was 2.81 per 100 person-years among 521 patients who did not initiate prophylaxis or had early discontinuation of prophylaxis, which was significantly higher than the incidence rate of 0.45 per 100 person-years among 139 patients who continued prophylaxis until CD4 counts increased to >==200 cells/microL (adjusted risk ratio, 5.32; 95% confidence interval, 1.18, 23.94). Among the 215 patients who had early discontinuation of prophylaxis after achievement of undetectable plasma HIV RNA load, the incidence rate of pneumocystosis was reduced to 0.31 per 100 person-years, which was similar to that of the patients who continued prophylaxis until CD4 counts increased to >==200 cells/microL (adjusted risk ratio, 0.63; 95% confidence interval, 0.03, 14.89).

CONCLUSIONS

Compared with the risk of pneumocystosis among patients who continued prophylaxis until CD4 counts increased to >==200 cells/microL after HAART, the risk was significantly higher among patients who discontinued prophylaxis when CD4 counts remained <200 cells/microL, while the risk could be reduced among patients who achieved undetectable plasma HIV RNA load after HAART.

Pulmonary infections in the HIV-infected patient in the era of highly active antiretroviral therapy: an update

The highly active antiretroviral therapy (HAART) era began in 1996 when the combination of multiple antiretroviral agents was found to improve outcomes in HIV-infected patients. HAART has made a tremendous impact on the progression of HIV and on the morbidity and mortality associated with its opportunistic infections. HIV-positive patients who respond to HAART have a decreased incidence of opportunistic infections. Studies have documented close to a 50% decline in the incidence of pneumocystis pneumonia and bacterial pneumonia with the use of antiretroviral therapy. Primary and secondary prophylaxis for pneumocystis pneumonia can be discontinued in patients who show a sustained response to antiretroviral therapy. Unique to the HAART era, immune reconstitution syndrome is characterized by a paradoxical deterioration of a preexisting infection that is temporally related to the recovery of the immune system. Recently, more and more patients are being admitted for non-AIDS related illnesses in the HAART era.

Measurement of antiretroviral drugs in the lungs of HIV-infected patients

AIMS: Prior studies have shown that HAART is associated with decreased HIV viral load in the lungs. The correlation between antiretroviral exposure in bronchoalveolar lavage (BAL) fluid and virologic response was evaluated in patients starting HAART and enrolled in The AIDS Clinical Trial Group Protocol 723. MATERIALS #ENTITYSTARTX00026; METHODS: A total of 24 subjects underwent blood and BAL sampling prior to starting HAART, and after 4 and 24 weeks of HAART. Drug concentrations and HIV RNA were measured in paired plasma and BAL samples. RESULTS: Antiretroviral drugs, including efavirenz, were detectable in BAL fluid of HIV-infected subjects beginning HAART. Efavirenz was also associated with a higher likelihood of clearing HIV RNA from the lungs. CONCLUSION: These results suggest the excellent pulmonary virologic response to antiretroviral therapy may, in part, be due to penetration of antiretroviral drugs into the alveolar compartment.

Approach to the immunocompromised host with infection in the intensive care unit

Despite significant advances in the prevention, diagnosis, and treatment of infection in the immunocompromised host, it remains a major cause of morbidity, increased length of stay, total costs, and of course mortality. Intensive care mortality rates are significantly higher among immunocompromised hosts in part due to the higher incidence of infection severity. The superimposition of the compromised host defenses and critical illness makes the detection and management of infections in such patients more difficult, but crucial toward salvaging patient outcome. Moreover, although there is a rapidly increasing evidence base in intensive care medicine, many interventional trials for the management of severe sepsis (activated protein C, adjunctive corticosteroids, goal-based resuscitation), acute lung injury (low stretch ventilation), and other organ failures have excluded immunocompromised hosts.

Linking Pneumocystis jiroveci sulfamethoxazole resistance to the alleles of the DHPS gene using functional complementation in Saccharomyces cerevisiae

Curative and prophylactic therapy for Pneumocystis jiroveci pneumonia relies mainly on cotrimoxazole, an association of trimethoprim and sulfamethoxazole (SMX). SMX inhibits the folic acid pathway through competition with para-aminobenzoic acid (pABA), one of the two substrates of the dihydropteroate synthase (DHPS), a key enzyme in de novo folic acid synthesis. The most frequent non-synonymous single nucleotide polymorphisms (SNPs) in P. jiroveci DHPS are seen at positions 165 and 171, the combination leading to four possible different genetic alleles. A number of reports correlate prophylaxis failure and mutation in the P. jiroveci DHPS but, because of the impossibility of reliably cultivating P. jiroveci, the link between DHPS mutation(s) and SMX susceptibility is not definitively proven. To circumvent this limitation, the yeast Saccharomyces cerevisiae was used as a model. The introduction of the P. jiroveci DHPS gene, with or without point mutations, directly amplified from a clinical specimen and cloned in a centromeric plasmid into a DHPS-deleted yeast strain, allowed a fully effective complementation. However, in the presence of SMX at concentrations >250 mg/L, yeasts complemented with the double mutated allele showed a lower susceptibility compared with strains complemented with either a single mutated allele or wild-type alleles. These results confirm the need for prospective study of pneumocystosis, including systematic determination of the DHPS genotype, to clarify further the impact of mutations on clinical outcome. Additionally, the S. cerevisiae model proves to be useful for the study of still uninvestigated biological properties of P. jiroveci.

CMV DNA levels and CMV gB subtypes in ART-naive HAART-treated patients: a 2-year follow-up study in The Netherlands

OBJECTIVE

In the pre-HAART period, HIV-1 patients were greatly at risk for cytomegalovirus (CMV) disease. In HAART-treated patients, the incidence of CMV disease has decreased dramatically and the timing and presentation of CMV infection may be different. Also the relevance of different CMV genotypes is part of debate.

DESIGN AND METHODS

A total of 132 antiretroviral naive patients starting HAART were selected for a 2-year follow-up study in the Netherlands.

RESULTS

In 105 (80%) patients, CMV DNA were less than 100 copies/ml in all plasma samples during follow-up. In 27 (20%) patients, a detectable CMV load was found during follow-up. In seven patients, the initial decrease in HIV-1 loads during HAART was accompanied by an increase in CMV loads. Of 1348 plasma samples, only 50 (3.7%) samples were positive with a CMV load more of than 100 copies/ml plasma. CMV loads more than 1000 copies/ml were found only in samples with CD4 levels less than 250 x 10 cells/l and with detectable HIV-1 loads. CMV glycoprotein B (gB) typing was possible in 19 patients. Among these patients, including four patients with triple CMV infection and seven patients with double infection, the most prevalent genotype was gB3 (16x) followed by gB2 (9x), gB1 (5x) and gB4 (4x).

CONCLUSION

CMV disease during HAART is very unlikely as soon as the HIV-1 viral load becomes undetectable (<50 copies/ml) and/or CD4 cell levels are restored to more than 250 x 10 cells/l. Within Dutch HAART treated patients, infection with CMV gB3 is most prevalent, but also double or triple infection with other CMV gB strains are common.

Trends in hospitalizations for AIDS-associated Pneumocystis jirovecii Pneumonia in the United States (1986 to 2005)

BACKGROUND

Although hospitalizations for AIDS-associated Pneumocystis jirovecii pneumonia (PCP) in the United States have decreased since the introduction of chemoprophylaxis and potent combination antiretroviral therapy (ART), PCP remains an important cause of illness and death among AIDS patients.

METHODS

We analyzed trends in AIDS-associated PCP hospital discharges using the National Hospital Discharge Surveys between 1986 and 2005.

RESULTS

An estimated 539 million patients were discharged from hospitals between 1986 and 2005, of whom an estimated 312,411 had AIDS-associated PCP. The proportion of patients discharged from the hospital with AIDS-associated PCP decreased from 31% before the introduction of chemoprophylaxis (1986 to 1989) to 17% with chemoprophylaxis (1990 to 1995) and subsequently to 9% after the introduction of ART in 1996 (p < 0.001). Mortality from AIDS-associated PCP decreased from 21 to 16% and subsequently to 7% between these three time periods (p < 0.001). Among those who received mechanical ventilation, mortality decreased from 79% in the prechemoprophylaxis era to 31% in the ART era (p < 0.001) alongside an increase (from 5 to 11%) in the use of mechanical ventilation. We also observed a shift in the population at-risk for PCP over time: a greater proportion of black people, women, and people from Southern states were affected (all p < 0.001).

CONCLUSIONS

While there have been significant reductions in hospitalizations and hospital mortality for AIDS-associated PCP over the last 20 years, these reductions have not been homogenous across demographic subpopulations and geographic regions and point to new at-risk populations. Furthermore, mortality in severe cases of PCP that require mechanical ventilation has improved substantially.

Th17 cytokines and mucosal immunity

The T-helper 17 (Th17) lineage is a recently described subset of memory T cells that is characterized by its CD4(+) status and its ability to make a constellation of cytokines including interleukin-17A (IL-17A), IL-17F, IL-22, and, in humans, IL-26. Although most extensively described in the autoimmunity literature, there is growing evidence that the Th17 lineage plays a significant role in mediating host mucosal immunity to a number of pulmonary pathogens. This review highlights our current understanding of the role of the Th17 lineage and Th17 cytokines in mediating mucosal immunity to both pulmonary and gastrointestinal pathogens. While we have the strongest evidence that the Th17 lineage is centrally involved in mediating the host response to Gram-negative extracellular pulmonary pathogens, this literature is rapidly evolving and demonstrates a central role for Th17 cytokines both in primary infection and in recall responses seen in vaccine studies. In this review, we summarize the current state of this literature and present possible applications of Th17-targeted immunotherapy in the treatment and prevention of infection.

Computed tomography for the diagnosis of infectious diseases of the chest

BACKGROUND

Pulmonary infection is a common reason for imaging of the lung in immunocompetent and immunosuppressed patients. Findings on chest radiography are nonspecific and encompass poor sensitivity. The role of computed tomography (CT) has been evolving in the diagnosis of lung infections.

OBJECTIVE

This paper reviews recent developments in the efficacy and utility of CT in the diagnosis of suspected pulmonary infections in a variety of patient populations.

METHODS

Recent published literature was reviewed to prepare this treatise on the role of CT.

CONCLUSION

Knowledge and skills at pattern recognition are crucial for the CT interpretation in lung infections. Computed tomography scan is increasingly used to increase the sensitivity of the radiologic diagnosis of thoracic infections. The greatest value of CT is when the radiograph is normal, findings are equivocal, and to differentiate infection from non-infectious disorders.

Interleukin-17 in pulmonary host defense

Interleukin (IL)-17A and IL-17F are produced by a novel class of effector alphabeta T cells called Th17 cells as well as gammadelta T cells. alphabeta IL-17-producing T cells are controlled by the transcription factor RORgammat and develop independent of GATA-3, T-bet, Stat 4, and Stat 6. Effector molecules produced by these cells include IL-17A, IL-17F, and IL-22. IL-17A and IL-17F bind to IL-17 receptor (IL-17R) and receptor signaling is critical for host defense against extracellular bacteria by regulating chemokine gradients for neutrophil emigration into infected tissue sites as well as via regulation of host granulopoiesis. Furthermore, it has recently been shown that IL-17 and IL-22 regulate the production of antimicrobial proteins in epithelium. Although Th17 cells are important in mucosal host defense, in the setting of retained antigenic stimulation, such as in the setting of asthma or chronic infection, such as in cystic fibrosis, or in the setting of autoimmunity, these cells can mediate immunopathology.

Behandlung von Patienten mit HIV-Infektion auf der Intensivstation

HIV-infizierte Patienten können aus einer Reihe von Indikationen heraus der Intensivbehandlung bedürfen (·Abb. 66.1; [7, 17, 19, 33, 41, 44, 51]). In 50–75% der Fälle stellt akutes respiratorisches Versagen die Indikation für die Behandlung HIV-Infizierter auf der Intensivstation dar [7, 17, 19, 33, 41, 44, 51]. Bei 55–90% dieser Patienten mit intensiv behandlungsbedürftigem respiratorischen Versagen stellt Pneumocystis carinii das für die Erkrankung verantwortliche Pathogen dar [7, 33, 44].

Th17 cells and mucosal host defense

Th17 cells are a new lineage of T-cells that are controlled by the transcription factor RORgammat and develop independent of GATA-3, T-bet, Stat 4 and Stat 6. Novel effector molecules produced by these cells include IL-17A, IL-17F, IL-22, and IL-26. IL-17RA binds IL-17A and IL-17F and is critical for host defense against extracellular planktonic bacteria by regulating chemokine gradients for neutrophil emigration into infected tissue sites as well as host granulopoiesis. Moreover, IL-17 and IL-22 regulate the production of antimicrobial proteins in mucosal epithelium. Although TGF-beta1 and IL-6 have been shown to be critical for development of Th17 cells from naive precursors, IL-23 is also important in regulating IL-17 release in mucosal tissues in response to infectious stimuli. Compared to Th1 cells, IL-23 and IL-17 show limited roles in controlling host defense against primary infections with intracellular bacteria such as Mycobacterium tuberculosis suggesting a predominate role of the Th17 lineage in host defense against extracellular pathogens. However, in the setting of chronic biofilm infections, as that occurs with cystic fibrosis or bronchiectasis, Th17 cells may be key contributors of tissue injury.