Predictors of Pneumocystis carinii pneumonia in HIV-infected persons. Pulmonary Complications of HIV Infection Study Group

ICU-acquired infections in immunocompromised patients

Immunocompromised patients account for an increasing proportion of the typical intensive care unit (ICU) case-mix. Because of the increased availability of new drugs for cancer and auto-immune diseases, and improvement in the care of the most severely immunocompromised ICU patients (including those with hematologic malignancies), critically ill immunocompromised patients form a highly heterogeneous patient population. Furthermore, a large number of ICU patients with no apparent immunosuppression also harbor underlying conditions altering their immune response, or develop ICU-acquired immune deficiencies as a result of sepsis, trauma or major surgery. While infections are associated with significant morbidity and mortality in immunocompromised critically ill patients, little specific data are available on the incidence, microbiology, management and outcomes of ICU-acquired infections in this population. As a result, immunocompromised patients are usually excluded from trials and guidelines on the management of ICU-acquired infections. The most common ICU-acquired infections in immunocompromised patients are ventilator-associated lower respiratory tract infections (which include ventilator-associated pneumonia and tracheobronchitis) and bloodstream infections. Recently, several large observational studies have shed light on some of the epidemiological specificities of these infections-as well as on the dynamics of colonization and infection with multidrug-resistant bacteria-in these patients, and these will be discussed in this review. Immunocompromised patients are also at higher risk than non-immunocompromised hosts of fungal and viral infections, and the diagnostic and therapeutic management of these infections will be covered. Finally, we will suggest some important areas of future investigation.

Pulmonary tuberculosis complicated by pneumothorax, and acute respiratory distress syndrome (ARDS) in the settings of advanced HIV disease: A case report

Introduction

A large proportion of the global burden of HIV-associated TB occurs in sub-Saharan Africa; including 74% of new cases of TB and 79% of deaths occurs in this area. Spontaneous pneumothorax occurs more frequently in patients with AIDS than the general population with the estimated incidence to be about 2-5% of overall total cases. Tuberculosis ARDS and septic shock are rare but carries extremely poor prognosis.

Case summary

A 27 year old male with advanced HIV disease with very low CD4 count presented to Wolaita Sodo University comprehensive specialized hospital, Ethiopia on July 6, 2023. The patient diagnosed with spontaneous pneumothorax secondary to drug susceptible tuberculosis after positive urine LF-LAM and sputum gene expert. He was intubated after emergency tube thoracostomy, and subsequently treated with anti-TB, corticosteroid, broad-spectrum IV antibiotics and high dose cotrimoxazole. The patient developed ARDS due to possible tuberculosis related septic shock and died of multi-organ failure.

Discussion

Spontaneous pneumothorax in the setting of HIV raises concern for PCP, though in this case it could be secondary to TB. Tuberculosis related ARDS and septic shock are rare complication but carries poor prognosis especially in setting of AHD. We had limited experience and difficulties in the management of patient with persistent pneumothorax with the concomitant ARDS requiring lung protective management, and this part remain the future area of scientific research.

Conclusion

In patients with advanced HIV disease, who present with signs of respiratory failure, the likelihood of spontaneous pneumothorax, TB-ARDS and septic shock should be anticipated in the differential diagnosis and optimal management plan should be designed.

HIV-associated lung disease

Lung disease encompasses acute, infectious processes and chronic, non-infectious processes such as chronic obstructive pulmonary disease, asthma and lung cancer. People living with HIV are at increased risk of both acute and chronic lung diseases. Although the use of effective antiretroviral therapy has diminished the burden of infectious lung disease, people living with HIV experience growing morbidity and mortality from chronic lung diseases. A key risk factor for HIV-associated lung disease is cigarette smoking, which is more prevalent in people living with HIV than in uninfected people. Other risk factors include older age, history of bacterial pneumonia, Pneumocystis pneumonia, pulmonary tuberculosis and immunosuppression. Mechanistic investigations support roles for aberrant innate and adaptive immunity, local and systemic inflammation, oxidative stress, altered lung and gut microbiota, and environmental exposures such as biomass fuel burning in the development of HIV-associated lung disease. Assessment, prevention and treatment strategies are largely extrapolated from data from HIV-uninfected people. Smoking cessation is essential. Data on the long-term consequences of HIV-associated lung disease are limited. Efforts to continue quantifying the effects of HIV infection on the lung, especially in low-income and middle-income countries, are essential to advance our knowledge and optimize respiratory care in people living with HIV.

Immune Response in Pneumocystis Infections According to the Host Immune System Status

The host immune response is critical in Pneumocystis pneumonia (PCP). Immunocompetent hosts can eliminate the fungus without symptoms, while immunodeficient hosts develop PCP with an unsuitable excessive inflammatory response leading to lung damage. From studies based on rodent models or clinical studies, this review aimed to better understand the pathophysiology of Pneumocystis infection by analysing the role of immune cells, mostly lymphocytes, according to the immune status of the infected host. Hence, this review first describes the immune physiological response in infected immunocompetent hosts that are able to eliminate the fungus. The objective of the second part is to identify the immune elements required for the control of the fungus, focusing on specific immune deficiencies. Finally, the third part concentrates on the effect of the different immune elements in immunocompromised subjects during PCP, to better understand which cells are detrimental, and which, on the contrary, are beneficial once the disease has started. This work highlights that the immune response associated with a favourable outcome of the infection may differ according to the immune status of the host. In the case of immunocompetency, a close communication between B cells and TCD4 within tertiary lymphocyte structures appears critical to activate M2 macrophages without much inflammation. Conversely, in the case of immunodeficiency, a pro-inflammatory response including Th1 CD4, cytotoxic CD8, NK cells, and IFNγ release seems beneficial for M1 macrophage activation, despite the impact of inflammation on lung tissue.

Diagnostic Challenges of Pneumocystis Pneumonia during the COVID-19 Pandemic: A Case of a Young Patient with Ground Glass Opacities and Pulmonary Embolism on Chest CT

The coronavirus disease 2019 (COVID-19) pandemic is wreaking havoc across the globe. This pandemic has given rise to a mindset where physicians tend to neglect other causes of pneumonia, especially if the patient presents with signs and symptoms commonly associated with COVID-19. Herein, we report a case of a young man presenting to the emergency department with common clinical, radiological, and laboratory features of COVID-19 pneumonia such as shortness of breath, hypoxia, pulmonary embolism, elevated D-dimer, and bilateral ground glass opacities on computed tomography of the chest but was later diagnosed with Pneumocystis pneumonia that was treated with appropriate antibiotics and corticosteroids. This case highlights the importance of performing a thorough clinical history and differentiating the clinical and radiological features of COVID-19 pneumonia from pneumonia of other etiologies.

Narrative review of the relationship between COVID-19 and PJP: does it represent coinfection or colonization?

Background

Pneumocystis jirovecii (P. jirovecii) is increasingly identified on lower respiratory tract specimens of COVID-19 patients. Our narrative review aims to determine whether the diagnosis of pneumocystis jirovecii pneumonia (PJP) in COVID-19 patients represents coinfection or colonization based on the evidence available in the literature. We also discuss the decision to treat COVID-19 patients with coinfection by PJP.

Methods

A literature search was performed through the Pubmed and Web of Science databases from inception to March 10, 2021.

Results

We identified 12 COVID-19 patients suspected to have PJP coinfection. All patients were critically ill and required mechanical ventilation. Many were immunosuppressed from HIV or long-term corticosteroids and other immunosuppressive agents. In both the HIV and non-HIV groups, severe lymphocytopenia was encountered with absolute lymphocyte and CD4+T cell count less than 900 and 200 cells/mm, respectively. The time to PJP diagnosis from the initial presentation was 7.8 (range 2–21) days. Serum lactate dehydrogenase and beta-D-glucan were elevated in those coinfected with PJP. All patients were treated with anti-PJP therapy, predominantly sulfamethoxazole-trimethoprim with corticosteroids. The overall mortality rate was 41.6%, and comparable for both HIV and non-HIV groups.

Conclusion

As the current evidence is restricted to case reports, the true incidence, risk factors, and prognosis of COVID-19 patients with PJP coinfections cannot be accurately determined. Comorbidities of poorly controlled HIV with lymphocytopenia and multiple immunosuppressive therapies are likely predisposing factors for PJP coinfection.

Pneumocystis jirovecii: a review with a focus on prevention and treatment

Introduction: Pneumocystis jirovecii (PJ) is an opportunistic fungal pathogen that can cause severe pneumonia in immunocompromised hosts. Risk factors for Pneumocystis jirovecii pneumonia (PJP) include HIV, organ transplant, malignancy, certain inflammatory or rheumatologic conditions, and associated therapies and conditions that result in cell-mediated immune deficiency. Clinical signs of PJP are nonspecific and definitive diagnosis requires direct detection of the organism in lower respiratory secretions or tissue. First-line therapy for prophylaxis and treatment remains trimethoprim-sulfamethoxazole (TMP-SMX), though intolerance or allergy, and rarely treatment failure, may necessitate alternate therapeutics, such as dapsone, pentamidine, atovaquone, clindamycin, primaquine and most recently, echinocandins as adjunctive therapy. In people living with HIV (PLWH), adjunctive corticosteroid use in treatment has shown a mortality benefit.Areas covered: This review article covers the epidemiology, pathophysiology, diagnosis, microbiology, prophylaxis indications, prophylactic therapies, and treatments.Expert opinion: TMP-SMX has been first-line therapy for treating and preventing pneumocystis for decades. However, its adverse effects are not uncommon, particularly during treatment. Second-line therapies may be better tolerated, but often sacrifice efficacy. Echinocandins show some promise for new combination therapies; however, further studies are needed to define optimal antimicrobial therapy for PJP as well as the role of corticosteroids in those without HIV.

Increased mRNA expression of key cytokines among suspected cases of Pneumocystis jirovecii infection

Background

Pneumocystis pneumonia (PCP) is a fatal infectious disease caused by Pneumocystis jirovecii (PJP). The major factor relevant to morbidity and mortality seems to be the host inflammatory reaction. The objective of this study was to evaluate the role of IL-2, IL-4, IL-10, and IL-13 cytokine mRNA expression among suspected P. jirovecii infection.

Methods

This was a cross-sectional analytical study undertaken in Aseer region, Saudi Arabia. One hundred suspected PCP cases and 100 healthy controls were included in the study. Basic clinical manifestations, radiological findings, microbiological and immunological findings were extracted from the hospital records from January 2019 to August 2019, Pneumocystis detection was done by immune-fluorescent staining (IFAT, Gomorimethanamine silver staining (GMSS), Giemsa staining, Toluidine blue O (TBO), and Pneumocystis RT-PCR.

Results

Increased more than 5 fold, 3 fold, 4 fold, and 7 fold of IL-2, IL-4, IL-10, and IL-13 mRNA expression were observed in PCP cases compared to controls. Higher expression of IL-2 mRNA was connected with crept, wheezing and chest X-ray findings like central perihilar infiltrate, patchy infiltrate, consolidation, hilar lymphadenopathy, pneumothorax, pleural effusion which showed higher expression compared to counterpart (p< 0.0001). Higher expression of IL-4 mRNA was found to be significantly associated with weight loss (p=0.002), dyspnea (p=0.003), crept (p=0.01), and chest X-ray findings (p< 0.0001). Significantly increased expression of IL-10 mRNA was observed to be associated with weight loss, dyspnea, night sweats, wheezing, and different findings of chest X-ray compared to their counterparts, whereas, IL-13 mRNA was observed in cases with fever. Suspected cases of PCP confirmed positive by IFTA with higher IL-2, IL-4, and IL-10 mRNA expression compared to negative cases. RT-PCR confirmed PCP cases had significantly higher expression of IL-2, IL-4, and IL-10 as well as IL-13 mRNA compared to negative cases. Positive detected cases by GMSS showed higher IL-2, IL-10 mRNA expression, while Giemsa showed only higher IL-4 mRNA expression compared to negative cases.

Conclusion

Confirmed cases of P. jirovecii showed higher IL-2, IL-4, IL-10, and IL-13 mRNA expression comparatively to negative cases. Increased expression of cytokines may be indicative of infection severity and could help in patients’ management.

Dyspnea in homosexual male patients: throwback to an occasionally forgotten but severe clinical presentation of HIV/AIDS

Pneumocystis jirovecii pneumonia (PJP) can be a severe indicator disease of acquired immunodeficiency syndrome (AIDS). We present two cases of homosexual male patients who came to the emergency unit of a Belgian hospital because of shortness of breath. Both men had been sent back home, initially diagnosed with a benign viral infection. Because of worsening symptoms and gradually evolving hypoxemia, both patients came back and were admitted to the hospital with a diagnosis of (microbiology proven) Pneumocystis jirovecii pneumonia. HIV serology in both men was tested and was clearly positive, indicating a new diagnosis of HIV infection. In this article, we provide an overview of this possibly severe AIDS defining condition. First, we give an introduction of the history of HIV/AIDS and its occurrence in homosexual males in Europe. Secondly, we provide an overview of the diagnosis and treatment of Pneumocystis jirovecii pneumonia. Finally, since the first case reports of Pneumocystis jirovecii pneumonia at the beginning of the AIDS epidemic also included homosexual men, we emphasize the potential importance of a sexual anamnesis in young male patients with an initial complaint of dyspnea.

Pneumocystis Jirovecii detection and comparison of multiple diagnostic methods with quantitative real-time PCR in patients with respiratory symptoms

Pneumocystis jirovecii (PCP) remains a significant cause of mortality and morbidity in patients with respiratory infections. Accurate diagnosis of PCP is still a diagnostic challenge. Hence, the main objectives were to study the incidence of Pneumocystis Jirovecii pneumonia infection among respiratory problems patients and to compare the real-time quantitative PCR technique with various diagnostic methodologies. Patients who have respiratory symptoms of PCP like breathlessness, cough, and fever were enrolled. Bronchoalveolar lavage (BAL) samples were collected and homogenized, and then smears were prepared for examination by Gomorimethanamine silver staining (GMSS), Immunofluorescent staining (IFAT), Toludine blue O (TBO), and Giemsa staining. Further, RT-PCR was also performed for the detection of PCP. The mean patients’ age was 52 (SD ± 16) years. 41% were female, and 59% of the patients were male. Weight loss (80%), fever (92%), cough (100%), and dyspnea (76%) were the most common complaints. Twenty-eight patients have been diagnosed with pulmonary infiltrates using chest X-ray. Out of 100 patients, 35% were positive for PCP. The organism was detected using IFAT in all the 35 specimens, 15 of 35 (42.86%) by GMSS, 8 of 35 (17.6%) by Giemsa stain, and 1 of 35 (2.8%) was detected by TBO stains. RT-PCR showed that 39 patients was found to be positive for PCP. Thirty-five of these 39 patients had a positive IFAT (89.74%); the IFAT was negative or undefined in 4 samples. All 39 patients (100%) had signs and symptoms for PCP. Our results suggest that RT-PCR is still the most highly sensitive method for Pneumocystis Jirovecii detection. In poor resource settings where RT-PCR and IFAT is not available, diagnosis of Pneumocystis jirovecii pneumonia remains a complicated issue. In settings where RT-PCR & IFAT are not available, GMSS staining may be the next best choice to detect PCP.

The association between lymphopenia and serious infection risk in rheumatoid arthritis

OBJECTIVES

To investigate the relationship between occurrence of serious infection (SI) and lymphocyte counts in patients with RA using data from a single centre.

METHODS

We used routinely captured data from a single tertiary rheumatology centre to explore the relationship between lymphopenia and SI risk. Adult RA patients were included over a 5-year follow-up period. Admissions due to confirmed SI were considered. SI rate with 95% confidence intervals was calculated. The association between SI with baseline lymphocyte counts, time-averaged lymphocyte counts throughout all follow-up, and a nadir lymphocyte count was assessed using Cox proportional hazards regression. The relationship between lymphopenia over time and SI was analysed using a mixed-effect model of lymphocyte counts prior to SI.

RESULTS

This analysis included 1095 patients with 205 SIs during 2016 person-years of follow-up. The SI rate was 4.61/100 patient-years (95% CI: 3.76, 5.65). Compared with patients with nadir lymphocyte counts >1.5 × 109 cells/l, nadir lymphopenia <1 × 109 cells/l was significantly associated with higher SI risk (HR 3.28; 95% CI: 1.59, 6.76), increasing to HR 8.08 (95% CI: 3.74, 17.44) in patients with lymphopenia <0.5 × 109 cells/l. Lymphocyte counts were observed to be reduced in the 30-day period prior to SI.

CONCLUSION

Lymphocyte counts below <1.0 × 109 cells/l were associated with higher SI risk in RA patients; the strongest association between lymphopenia and SI was observed when lymphocyte counts were below <0.5 × 109 cells/l. Lymphopenia may be used as a measure to stratify patients at risk of SI.

IL-4 polymorphism influences susceptibility to Pneumocystis jirovecii pneumonia in HIV-positive patients

OBJECTIVES

Pneumocystis jirovecii pneumonia (PJP) is an important cause of morbidity and mortality in HIV-positive patients. Polymorphisms in immune genes are increasingly reported to influence susceptibility to fungal infections. We analysed the role of 21 single nucleotide polymorphisms from 19 candidate genes on PJP development in patients from the Swiss HIV Cohort Study.

DESIGN AND METHODS

The analysis included patients with a nadir CD4 T-cell count less than 200 cells/μl, divided into a discovery (N = 1645) and a replication (N = 1861) cohort. The associations were analysed by using cumulative incidence curves as well as competing risk regression over 18 years, starting from the estimated date of HIV infection, considering death a competing risk, with censoring at lost follow-up, and assuming the dominant mode of inheritance.

RESULTS

The minor allele of rs2243250 in IL-4 was associated with the risk of PJP in the discovery cohort (cumulative incidence 0.18 versus 0.12, P = 0.002). This association was replicated in the validation cohort (0.16 versus 0.12, P = 0.02). It was still significant in multivariate models, adjusted for HIV transmission mode, viral load, CD4 T cells slope, age, antiretroviral therapy, tobacco smoking, hepatitis C virus coinfection, year of cohort entry and PJP prophylaxis (global subhazard ratio 1.42, 95% confidence interval 1.17-1.73, P = 0.0004).

CONCLUSION

Our data suggest rs2243250, a single nucleotide polymorphism known to influence IL-4 production, is associated with susceptibility to PJP in HIV-positive patients.

Pneumocystis Infection in Children: National Trends and Characteristics in the United States, 1997-2012

BACKGROUND

Although the epidemiology of immunocompromising condition in children has evolved over time, updated epidemiology of pediatric pneumocystis infection in the United States is not available.

METHODS

We performed a retrospective analysis using the Kids' Inpatient Database, a nationally representative sample of US pediatric hospital discharges collected in 1997, 2000, 2003, 2006, 2009 and 2012. Pneumocystis cases were identified using International Classification of Diseases, Ninth Revision, Clinical Modification, code 136.3 among children 0-18 years of age. Demographic data of cases with and without mortality were compared.

RESULTS

We identified 1902 [standard error (SE): 95] pneumocystis cases during the study period. The pneumocystis hospitalization rate decreased from 7.5 (SE: 0.91) to 2.7 (SE: 0.31) per a million US children from 1997 to 2012 (63.2% decrease). Cases with HIV infection decreased from 285 (SE: 56) cases in 1997 to 29 (SE: 7) cases in 2012, whereas hematologic malignancy and primary immunodeficiency became more prominent. Infants were the most commonly affected [510 cases (SE: 40)]. All-cause in-hospital mortality was 11.7% (SE: 1.3%) and was particularly high among cases with hematopoietic stem cell transplant [32.4%(SE: 7.1%); P < 0.001].

CONCLUSIONS

Pneumocystis infection in children showed a marked decrease from 1997 to 2012 in the United States, largely driven by the reduction in HIV-associated cases, and cases with non-HIV illnesses became more prominent. Hematopoietic stem cell transplant-associated cases had particularly high mortality. Clinicians should be aware of high-risk groups that may benefit from chemoprophylaxis, particularly in infancy.

Lessons learned from a pneumocystis pneumonia outbreak at a Scottish renal transplant centre

BACKGROUND

Pneumocystis pneumonia (PCP) is an opportunistic infection occurring in renal transplant patients. Over a 14-month period an increase in PCP cases was identified among our renal transplant cohort.

AIM

The outbreak population was studied to identify potential risk factors for the development of PCP.

METHODS

A retrospective analysis of hospital records was carried out, with each case being matched with two case-linked controls. Information was collected on patient demographics, laboratory tests, and hospital visits pre and post development of infection.

FINDINGS

No patients were receiving PCP prophylaxis at the time of infection and mean time from transplantation to developing PCP was 4.7 years (range: 0.51-14.5). The PCP group had a significantly lower mean estimated glomerular filtration rate than the control group (29.3 mL/min/1.73 m² vs 70 mL/min^-1 (P = 0.0007)). Three patients were treated for active cytomegalovirus (CMV) infection prior to PCP diagnosis and two had active CMV at the time of diagnosis compared to none in the control group (P = 0.001). Those who developed PCP were more likely to have shared a hospital visit with another patient who went on to develop PCP; 37% of clinic visits vs 19% (P = 0.014).

CONCLUSION

This study highlights the ongoing risk of opportunistic infection several years after transplantation and adds weight to potential person-to-person Pneumocystis jirovecii transmission. Risk factors have been identified which may highlight those most at risk, enabling targeted rather than blanket long-term PCP prophylaxis.

Clinical, Diagnostic, and Treatment Disparities between HIV-Infected and Non-HIV-Infected Immunocompromised Patients with Pneumocystis jirovecii Pneumonia

The substantial decline in the Pneumocystis jirovecii pneumonia (PCP) incidence in HIV-infected patients after the introduction of antiretroviral therapy (ART) in resource-rich settings and the growing number of non-HIV-infected immunocompromised patients at risk leads to considerable epidemiologic changes with clinical, diagnostic, and treatment consequences for physicians. HIV-infected patients usually develop a subacute course of disease, while non-HIV-infected immunocompromised patients are characterized by a rapid disease progression with higher risk of respiratory failure and higher mortality. The main symptoms usually include exertional dyspnea, dry cough, and subfebrile temperature or fever. Lactate dehydrogenase may be elevated. Typical findings on computed tomography scans of the chest are bilateral ground-glass opacities with or without cystic lesions, which are usually associated with the presence of AIDS. Empiric treatment should be initiated as soon as PCP is suspected. Bronchoalveolar lavage has a higher diagnostic yield compared to induced sputum. Immunofluorescence is superior to conventional staining. A combination of different diagnostic tests such as microscopy, polymerase chain reaction, and (1,3)-β-D-glucan is recommended. Trimeth-oprim/sulfamethoxazole for 21 days is the treatment of choice in adults and children. Alternative treatment regimens include dapsone with trimethoprim, clindamycin with primaquine, atovaquone, or pentamidine. Patients with moderate to severe disease should receive adjunctive corticosteroids. In newly diagnosed HIV-infected patients with PCP, ART should be initiated as soon as possible. In non-HIV-infected immunocompromised patients, improvement of the immune status should be discussed (e.g., temporary reduction of immunosuppressive agents). PCP prophylaxis is effective and depends on the immune status of the patient and the underlying immunocompromising disease.

Lymphopenia is associated with late onset Pneumocystis jirovecii pneumonia in solid organ transplantation

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) affected 5%-15% of solid organ transplant (SOT) recipients prior to universal prophylaxis, classically with trimethoprim-sulfamethoxazole (TMP-SMX). Guidelines generally recommend 6-12 months of prophylaxis post-SOT, yet optimal duration and robust PJP risk stratification have not been established.

METHODS

A retrospective, single-center, case-control study of PJP among SOT recipients from January 1998 to December 2013 was conducted. Cases had positive PJ direct fluorescent antibody assay of respiratory specimens. Controls were matched 4:1 by nearest date of SOT. Univariate testing and multivariate logistic regressions were performed.

RESULTS

Fifteen cases were identified among 5505 SOT recipients (0.27% rate) and analyzed vs 60 controls. PJP occurred on average 6.1 years (range 0.9-13.8) post-SOT; no case was receiving PJP prophylaxis at diagnosis. Most were treated with reduced immunosuppression and TMP-SMX plus steroids (80%). Six patients (40%) required critical care; 3 (20%) died. There were no significant demographic differences, though cases tended to be older at SOT (54 vs 48 years, P = .1). In univariate analysis, prior viral infection was more common among cases (67% vs 37%, P = .08). Lower absolute lymphocyte count (ALC) at diagnosis date was strongly associated with PJP (400 vs 1230 × 10⁶  cells/μL, P < .001); odds of infection were high with ALC ≤ 500 × 10⁶ cells (OR 18.7, P < .01).

CONCLUSION

Pneumocystis jirovecii pneumonia is a rare, late complication of SOT with significant morbidity and mortality. Severe lymphopenia may be useful in identifying SOT recipients who warrant continued or reinstated PJP prophylaxis.

Pneumocystis Pneumonia Secondary to Idiopathic CD4+ T-lymphocytopenia: A Comparison of AIDS and Non-AIDS Patients

A 67-year-old man was admitted to our hospital complaining of dry cough. Chest computed tomography showed diffuse infiltrates and ground-glass opacities in the bilateral lung fields. Transbronchial lung biopsy specimens showed alveoli filled with yeast-like fungi. With a diagnosis of pneumocystis pneumonia (PCP), he was given oral sulfamethoxazole/trimethoprim, to which he responded well. However, seven months later, PCP relapsed. Analyses revealed a low bronchoalveolar lavage fluid CD4/CD8 ratio of 0.04 and CD4+ lymphocytopenia (250/μL). Despite intensive work-up, we were unable to detect the underlying cause of CD4+ lymphocytopenia; therefore, a final diagnosis of idiopathic CD4+ T-lymphocytopenia was made.

Treatment of Pneumocystis jirovecii pneumonia in HIV-infected patients: a review

INTRODUCTION

Pneumocystis pneumonia is a potentially life-threatening pulmonary infection that occurs in immunocompromised individuals and HIV-infected patients with a low CD4 cell count. Trimethoprim-sulfamethoxazole has been used as the first-line agent for treatment, but mutations within dihydropteroate synthase gene render potential resistance to sulfamide. Despite advances of combination antiretroviral therapy (cART), Pneumocystis pneumonia continues to occur in HIV-infected patients with late presentation for cART or virological and immunological failure after receiving cART. Areas covered: This review summarizes the diagnosis and first-line and alternative treatment and prophylaxis for Pneumocystis pneumonia in HIV-infected patients. Articles for this review were identified through searching PubMed. Search terms included: 'Pneumocystis pneumonia', 'Pneumocystis jirovecii pneumonia', 'Pneumocystis carinii pneumonia', 'trimethoprim-sulfamethoxazole', 'primaquine', 'trimetrexate', 'dapsone', 'pentamidine', 'atovaquone', 'echinocandins', 'human immunodeficiency virus infection', 'acquired immunodeficiency syndrome', 'resistance to sulfamide' and combinations of these terms. We limited the search to English language papers that were published between 1981 and March 2017. We screened all identified articles and cross-referenced studies from retrieved articles. Expert commentary: Trimethoprim-sulfamethoxazole will continue to be the first-line agent for Pneumocystis pneumonia given its cost, availability of both oral and parenteral formulations, and effectiveness or efficacy in both treatment and prophylaxis. Whether resistance due to mutations within dihydropteroate synthase gene compromises treatment effectiveness remains controversial. Continued search for effective alternatives with better safety profiles for Pneumocystis pneumonia is warranted.

Approach to Fungal Infections in Human Immunodeficiency Virus-Infected Individuals: Pneumocystis and Beyond

Many fungi cause pulmonary disease in patients with human immunodeficiency virus (HIV) infection. Pathogens include Pneumocystis jirovecii, Cryptococcus neoformans, Aspergillus spp, Histoplasma capsulatum, Coccidioides spp, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Talaromyces marneffei, and Emmonsia spp. Because symptoms are frequently nonspecific, a high index of suspicion for fungal infection is required for diagnosis. Clinical manifestations of fungal infection in HIV-infected patients frequently depend on the degree of immunosuppression and the CD4⁺ helper T cell count. Establishing definitive diagnosis is important because treatments differ. Primary and secondary prophylaxes depend on CD4⁺ helper T cell counts, geographic location, and local prevalence of disease.

Acute hemolysis in a patient with a newly diagnosed glioblastoma

We describe a 62-year-old of Egyptian origin who presented with sudden, severe and symptomatic anemia requiring hospitalization shortly after beginning concurrent radiation and temozolomide for his newly diagnosed glioblastoma. He had also recently been started on steroids, anticonvulsants and Pneumocystis jirovecii prophylaxis. He was ultimately diagnosed with G6PD deficiency with an acute hemolytic anemia precipitated by dapsone. Screening for G6PD deficiency should be considered in high-risk patient populations where P. jirovecii prophylaxis is planned.

Pneumocystis pneumonia in HIV patients: a diagnostic challenge till date

HIV has become a major health problem in India, patients commonly succumb to opportunistic infections (OIs), respiratory infections being an important cause of morbidity and their accurate diagnosis is still a challenge. Our aim was to study the occurrence of Pneumocystis pneumonia (PCP) in HIV/AIDS patients with respiratory complaints attending ART clinic and to compare various diagnostic methodologies. One hundred and twenty five HIV/AIDS patients presenting with respiratory symptoms like cough, fever, breathlessness etc, were enrolled, and induced sputum samples were collected. Samples were homogenized using glass beads and Dithiothretol. Smears were prepared and examined by Immunoflourescent staining (IFAT), Gomori methanamine silver staining (GMSS), Toludine blue O staining (TBO) and Giemsa staining for Pneumocystis jiroveci. Among the 125 patients who presented with respiratory complaints, 34 cases (27.2%) were diagnosed as having PCP. All 34 cases were detected by IFAT followed by GMSS, Giemsa and Toludine blue O staining in decreasing order. The mean CD4 count was 67.27cells/μl. PCP has become an important health problem in HIV/AIDS patients with low CD4 counts in India. IFAT remains the most sensitive method for the detection of this uncultivable organism. In resource poor settings where an immunoflourecent microscope is not available, diagnosis of PCP still remains problematic.

Infections in the immunosuppressed host

The interaction between host immunity and infections in the context of a suppressed immune system presents an opportunity to study the interaction of colonization and infection with the development of acute and chronic pulmonary morbidity and mortality. This article summarizes presentations at the Pittsburgh International Lung Conference about comorbid consequences in two categories of immunosuppressed hosts: HIV-infected individuals and lung transplant recipients. Specifically, chronic obstructive pulmonary disease, pulmonary hypertension, and chronic lung rejection after transplant are three diseases that may be consequences of colonization or infection by viruses or fungi, whether HIV itself or the opportunistic infections Pneumocystis and cytomegalovirus. In the fourth section, we discuss unique aspects of infections after lung transplant as well as the battle against multidrug-resistant organisms in this population and theorize that the immunosuppressed population may provide a unique group of patients in which to study ways to overcome nosocomial pathogenic challenges. These host-pathogen interactions serve as models for developing new strategies to reduce acute and chronic morbidity due to colonization and subclinical infection, and potential therapeutic avenues, which are often overlooked in the clinical arena.

Anti-CD20 antibody therapy and susceptibility to Pneumocystis pneumonia

Anti-CD20 antibody therapy has been a useful medication for managing non-Hodgkin's lymphoma as well as autoimmune diseases characterized by autoantibody generation. CD20 is expressed during most developmental stages of B lymphocytes; thus, CD20 depletion leads to B-lymphocyte deficiency. As the drug has become more widely used, there has been an increase in the number of case reports of patients developing Pneumocystis pneumonia. The role of anti-CD20 in Pneumocystis jirovecii infection is under debate due to the fact that most patients receiving it are on a regimen of multiple immunosuppressive medications. To address the specific role of CD20 depletion in host immunity against Pneumocystis, we examined a murine anti-CD20 depleting antibody. We demonstrated that anti-CD20 alone is permissive for Pneumocystis infection and that anti-CD20 impairs components of type II immunity, such as production of interleukin-4 (IL-4), IL-5, and IL-13 by whole-lung cells, in response to Pneumocystis murina. We also demonstrated that CD4(+) T cells from mice treated with anti-CD20 during Pneumocystis infection are incapable of mounting a protective immune response when transferred into Rag1(-/-) mice. Thus, CD20(+) cells are critical for generating protective CD4(+) T-cell immune responses against this organism.

The expanding role of co-trimoxazole in developing countries

Co-trimoxazole is an inexpensive, broad-spectrum antimicrobial drug that is widely used in developing countries. Before antiretroviral therapy (ART) scale-up, co-trimoxazole prophylaxis reduced morbidity and mortality in adults and children with HIV by preventing bacterial infections, diarrhoea, malaria, and Pneumocystis jirovecii pneumonia, despite high levels of microbial resistance. Co-trimoxazole prophylaxis reduces early mortality by 58% (95% CI 39-71) in adults starting ART. Co-trimoxazole provides ongoing protection against malaria and non-malaria infections after immune reconstitution in ART-treated individuals in sub-Saharan Africa, leading to a change in WHO guidelines, which now recommend long-term co-trimoxazole prophylaxis for adults and children in settings with a high prevalence of malaria or severe bacterial infections. Co-trimoxazole prophylaxis is recommended for HIV-exposed infants from age 4-6 weeks; however, the risks and benefits of co-trimoxazole during infancy are unclear. Co-trimoxazole prophylaxis reduces anaemia and improves growth in children with HIV, possibly by reducing inflammation, either through direct immunomodulatory activity or through effects on the intestinal microbiota leading to reduced microbial translocation. Ongoing trials are now assessing the ability of adjunctive co-trimoxazole to reduce mortality in children after severe anaemia or severe acute malnutrition. In this Review, we discuss the mechanisms of action, benefits and risks, and clinical trials of co-trimoxazole in developing countries.

Level of understanding of co-trimoxazole use among HIV infected, recurrent pulmonary tuberculosis suspects at a national referral tuberculosis clinic in Kampala, Uganda: a qualitative analysis

BACKGROUND

Co-trimoxazole use is the standard of care for preventing Pneumocystis jirovecii pneumonia in sub-Saharan Africa but implementation remains slow. Co-trimoxazole is self- administered with uncertain adherence. Knowledge of co-trimoxazole use among HIV infected persons is unknown.

OBJECTIVES

To assess knowledge, attitudes and practices of co-trimoxazole use among HIV infected adults evaluated for recurrent PTB in Kampala, Uganda.

METHODS

A qualitative study utilizing 5 focus group discussions among 30 HIV infected PTB suspects at the national referral tuberculosis treatment centre in Kampala.

RESULTS

Males and females had similar median ages. 80% were currently on co-trimoxazole and 50% of participants were on HAART. Majority of participants defined co-trimoxazole as an analgesic. Few noted co-trimoxazole was a drug to treat cough and chest pain. However, few responses revealed that co-trimoxazole prevents opportunistic diseases among PLHIV. Most of participants believed HAART and anti-TB drugs work as co-trimoxazole thus it should not be taken together with them. This belief may lead to increased risk of opportunistic infections, morbidity and mortality.

CONCLUSIONS

We revealed gaps in understanding of co-trimoxazole use among study participants. We therefore recommend that more facts about co-trimoxazle as prophylaxis against P. jirovecii, bacterial and diarrheal pathogens should be incorporated in VCT fact sheets.

Invasive diagnostic strategies in immunosuppressed patients with acute respiratory distress syndrome

Immunosuppression predisposes the host to development of pulmonary infections, which can lead to respiratory failure and the development of acute respiratory distress syndrome (ARDS). There are multiple mechanisms by which a host can be immunosuppressed and each is associated with specific infectious pathogens. Early invasive diagnostic modalities such as fiber-optic bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and open lung biopsy are complementary to serologic and noninvasive studies and assist in rapidly establishing an accurate diagnosis, which allows initiation of appropriate therapy and may improve outcomes with relative safety.

[Pulmonary manifestations in HIV-infected patients: a diagnostic approach]

The spectrum of pulmonary diseases that can affect human immunodeficiency virus (HIV)-infected patients is wide and includes both HIV and non-HIV-related conditions. Opportunistic infections and neoplasms remain a major concern even in the current era of combination antiretroviral therapy. Although these diseases have characteristic clinical and radiological features, there can be considerable variation in these depending on the patient's CD4 lymphocyte count. The patient's history, physical examination, CD4 count and chest radiograph features must be considered in establishing an appropriate diagnostic algorithm. In this article, we propose different diagnostic approaches HIV infected to patients with respiratory symptoms depending on their clinico-radiological pattern.

HIV infection is associated with reduced pulmonary diffusing capacity

INTRODUCTION

Prior studies comparing abnormalities in pulmonary function between HIV-infected and HIV-uninfected persons in the current era are limited.

OBJECTIVES

To determine the pattern and severity of impairment in pulmonary function in HIV-infected compared with HIV-uninfected individuals.

METHODS

Cross-sectional analysis of 300 HIV-infected men and 289 HIV-uninfected men enrolled from 2009 to 2011 in 2 clinical centers of the Lung HIV Study. Participants completed pre- and postbronchodilator spirometry, diffusing capacity of the lung for carbon monoxide (DLCO) measurement, and standardized questionnaires.

RESULTS

Most participants had normal airflow; 18% of HIV-infected and 16% of HIV-uninfected men had airflow obstruction. The mean percent predicted DLCO was 69% in HIV-infected vs. 76% in HIV-uninfected men (P < 0.001). A moderately to severely reduced DLCO of ≤60% was observed in 30% of HIV-infected compared with 18% of HIV-uninfected men (P < 0.001), despite the fact that 89% of those with HIV were on antiretroviral therapy. A reduced DLCO was significantly associated with HIV and CD4 cell count in linear regression adjusting for smoking and other confounders. The DLCO was lowest in HIV-infected men with CD4 cell counts <200 cells per microliter compared with those with CD4 cell counts ≥200 cells per microliter and to HIV-uninfected men. Respiratory symptoms of cough, phlegm and dyspnea were more prevalent in HIV-infected patients particularly those with abnormal pulmonary function compared with HIV-uninfected patients.

CONCLUSIONS

HIV infection is an independent risk factor for reduced DLCO, particularly in individuals with a CD4 cell count below 200 cells per microliter. Abnormalities in pulmonary function among HIV-infected patients manifest clinically with increased respiratory symptoms. Mechanisms accounting for the reduced DLCO require further evaluation.

An evaluation of the association of leukopenia and severe infection in patients with systemic lupus erythematosus

BACKGROUND

Leukopenia is a common finding in systemic lupus erythematosus (SLE) and may contribute to severe infections.

OBJECTIVES

The objectives of this study were to determine the prevalence of leukopenia in SLE patients and examine the association between these conditions and severe infections noting the risk factor of severe infections.

METHODS

This study was a prospective inception lupus cohort of newly diagnosed SLE patients seen between May 2007 and June 2011. Only cases that had been observed for a minimum of 1 year or died during the study were included.

RESULTS

There were 89 SLE patients (92% females), with their mean (SD) age and disease duration at the study entry of 31.7 (12.2) years and 2.4 (2.9) months. Leukopenia was found at the diagnosis in 51.6% of the cases. The cumulative prevalence of leukopenia, lymphopenia, and neutropenia was observed in 57.3%, 96.6%, and 60.7%, respectively. Persistent lymphopenia, noted continuously for more than or equal to 75% of the observation period, was found in 41.6%, but there was no persistent neutropenia. The incidence rate of severe infection was 12.4 per 100 patient-years. There was no difference of severe infection-free survival rate between patients who ever and never had leukopenia. In the multivariate analysis, using cyclophosphamide was the independent predictor for severe infection in SLE (hazard ratio, 2.73; 95% confidence interval, 1.10-6.77).

CONCLUSIONS

Leukopenia was common in SLE but usually not persistent. In this study, the presence of leukopenia at any time was not the risk factor for severe infection in SLE. Cyclophosphamide was the important predictor for severe infection in SLE.

Dectin immunoadhesins and pneumocystis pneumonia

The opportunistic pathogen Pneumocystis jirovecii is a significant cause of disease in HIV-infected patients and others with immunosuppressive conditions. Pneumocystis can also cause complications in treatment following antiretroviral therapy or reversal of immunosuppressive therapy, as the newly reconstituted immune system can develop a pathological inflammatory response to remaining antigens or a previously undetected infection. To target β-(1,3)-glucan, a structural component of the Pneumocystis cell wall with immune-stimulating properties, we have developed immunoadhesins consisting of the carbohydrate binding domain of Dectin-1 fused to the Fc regions of the 4 subtypes of murine IgG (mIgG). These immunoadhesins bind β-glucan with high affinity, and precoating the surface of zymosan with Dectin-1:Fc can reduce cytokine production by macrophages in an in vitro stimulation assay. All Dectin-1:Fc variants showed specificity of binding to the asci of Pneumocystis murina, but effector activity of the fusion molecules varied depending on Fc subtype. Dectin-1:mIgG2a Fc was able to reduce the viability of P. murina in culture through a complement-dependent mechanism, whereas previous studies have shown the mIgG1 Fc fusion to increase macrophage-dependent killing. In an in vivo challenge model, systemic expression of Dectin-1:mIgG1 Fc significantly reduced ascus burden in the lung. When administered postinfection in a model of immune reconstitution inflammatory syndrome (IRIS), both Dectin-1:mIgG1 and Dectin-1:mIgG2a Fc reduced hypoxemia despite minimal effects on fungal burden in the lung. Taken together, these data indicate that molecules targeting β-glucan may provide a mechanism for treatment of fungal infection and for modulation of the inflammatory response to Pneumocystis and other pathogens.

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.

Lower incidence of Pneumocystis jirovecii pneumonia among Africans in the Netherlands host or environmental factors?

BACKGROUND AND OBJECTIVE

HIV-associated Pneumocystis jirovecii pneumonia (PJP) remains one of the commonest opportunistic infections in Western countries. Although it has been suggested that racial differences in PJP incidence exist, early studies report conflicting results. This study aimed to investigate differences in PJP incidence in a developed country among patients originating from sub-Saharan Africa compared with other regions of origin.

DESIGN AND METHODS

A retrospective observational cohort study was performed among 13,844 HIV-infected patients from the Dutch ATHENA cohort. The main outcome measure was occurrence of PJP.

RESULTS

A total number of 1055 PJP infections were diagnosed. Patients originating from sub-Saharan Africa had a significantly lower risk of having PJP at the time of HIV diagnosis after adjustment of confounders compared with patients from Western origin [Western Europe, Australia and New Zealand; adjusted odds ratio (aOR) 0.21 (95% confidence interval (CI) 0.15-0.29)]. Other factors associated with higher PJP risk were increasing age [aOR 1.01 per year (95% CI 1.00-1.02)], a low CD4 count at HIV diagnosis [CD4 <50 versus >350 cells/μl aOR 123.3 (95% CI 77.8-195.5)] and a high plasma HIV-RNA (>100,000 copies/ml) at HIV diagnosis [aOR 1.41 (95% CI 1.19-1.66)]. Moreover, a clearly lower risk for PJP acquisition later during follow-up was observed among sub-Saharan Africans versus Western patients [adjusted hazard ratio 0.60 (95% CI 0.39-0.90)].

CONCLUSION

Among HIV-infected patients living in the Netherlands, PJP occurrence is substantially lower in patients originating from sub-Saharan Africa, as compared to Western patients. Differences in genetic susceptibility may partially explain the lower PJP incidence in these patients.

Evaluation of respiratory disease

The spectrum of HIV-associated pulmonary diseases is broad. Opportunistic infections, neoplasms, and noninfectious complications are all major considerations. Clinicians caring for persons infected with HIV must have a systematic approach. The approach begins with a thorough history and physical examination and often involves selected laboratory tests and a chest radiograph. Frequently, the clinical, laboratory, and chest radiographic presentation suggests a specific diagnosis or a few diagnoses, which then prompts specific diagnostic testing and treatment. This article presents an overview of the evaluation of respiratory disease in persons with HIV/AIDS.

Pneumocystis pneumonia associated with human immunodeficiency virus

Pneumocystis pneumonia (PCP) is caused by the yeastlike fungus Pneumocystis. Despite the widespread availability of specific anti-Pneumocystis prophylaxis and of combination antiretroviral therapy (ART), PCP remains a common AIDS-defining presentation. PCP is increasingly recognized among persons living in Africa. Pneumocystis cannot be cultured and bronchoalveolar lavage is the gold standard diagnostic test to diagnose PCP. Use of adjunctive biomarkers for diagnosis requires further evaluation. Trimethoprim-sulfamethoxazole remains the preferred first-line treatment regimen. In the era of ART, mortality from PCP is approximately 10% to 12%. The optimal time to start ART in a patient with PCP remains uncertain.

Colonization by Pneumocystis jirovecii and its role in disease

Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.

Lung Disease in Older Patients with HIV

Successful treatment of HIV with combination antiretroviral therapy (ART) has resulted in an aging HIV-infected population. As HIV-infected patients are living longer, noninfectious pulmonary diseases are becoming increasingly prevalent with a proportional decline in the incidence of opportunistic infections (OIs). Pulmonary OIs such as Pneumocystis jirovecii pneumonia (PCP) and tuberculosis are still responsible for a significant proportion of pulmonary diseases in HIV-infected patients. However, bacterial pneumonia (BP) and noninfectious pulmonary diseases such as chronic obstructive pulmonary disease (COPD), lung cancer, pulmonary arterial hypertension (PAH), and interstitial lung disease (ILD) account for a growing number of pulmonary diseases in aging HIV-infected patients. The purpose of this chapter is to discuss the spectrum and management of pulmonary diseases in aging HIV-infected patients, although limited data exists to guide management of many noninfectious pulmonary diseases in HIV-infected patients. In the absence of such data, treatment of lung diseases in HIV-infected patients should generally follow guidelines for management established in HIV-uninfected patients.

The changing epidemiology of HIV-infected patients in the intensive care unit

With the introduction of highly active antiretroviral therapy (HAART), HIV has become a chronic disease. As HIV-infected patients are aging, they are at increased risk for comorbid diseases. These non-AIDS related diseases account for a growing proportion of intensive care unit (ICU) admissions in HIV-infected patients in recent studies. HIV-infected patients still present to the ICU with HIV-related conditions such as Pneumocystis jirovecii pneumonia (PCP), but these conditions are becoming less common. Respiratory failure remains the most common indication for ICU admission. Immune reconstitution inflammatory response syndrome and toxicities related to HAART may also result in ICU admission. While ICU survival has improved since the earliest era of the HIV epidemic, hospital mortality for HIV-infected patients admitted to the ICU remains around 30%. Risk factors for ICU mortality include poor functional status, weight loss, more than one year between HIV diagnosis and ICU admission, lower serum albumin, higher severity of illness, need for mechanical ventilation, and respiratory failure-particularly if due to PCP and accompanied by pneumothorax. The impact of HAART on ICU outcomes is unclear. HAART administration in the ICU can be challenging due to limited delivery routes, concern for viral resistance and medication toxicities. There are no data to determine the safety or efficacy of HAART initiation in the ICU. Future studies are needed to address the role of age, associated comorbidities and impact of HAART on outcomes of HIV-infected patients admitted to the ICU.

Serum antibody levels to the Pneumocystis jirovecii major surface glycoprotein in the diagnosis of P. jirovecii pneumonia in HIV+ patients

Background

Pneumocystis jirovecii remains an important cause of fatal pneumonia (Pneumocystis pneumonia or PcP) in HIV+ patients and other immunocompromised hosts. Despite many previous attempts, a clinically useful serologic test for P. jirovecii infection has never been developed.

Methods/Principal Findings

We analyzed serum antibody responses to the P. jirovecii major surface glycoprotein recombinant fragment C1 (MsgC1) in 110 HIV+ patients with active PcP (cases) and 63 HIV+ patients with pneumonia due to other causes (controls) by an enzyme-linked immunosorbent assay (ELISA). The cases had significantly higher IgG and IgM antibody levels to MsgC1 than the controls at hospital admission (week 0) and intervals up to at least 1 month thereafter. The sensitivity, specificity and positive predictive value (PPV) of IgG antibody levels increased from 57.2%, 61.7% and 71.5% at week 0 to 63.4%, 100%, and 100%, respectively, at weeks 3–4. The sensitivity, specificity and PPV of IgM antibody levels rose from 59.7%, 61.3%, and 79.3% at week 0 to 74.6%, 73.7%, and 89.8%, respectively, at weeks 3–4. Multivariate analysis revealed that a diagnosis of PcP was the only independent predictor of high IgG and IgM antibody levels to MsgC1. A high LDH level, a nonspecific marker of lung damage, was an independent predictor of low IgG antibody levels to MsgC1.

Conclusions/Significance

The results suggest that the ELISA shows promise as an aid to the diagnosis of PCP in situations where diagnostic procedures cannot be performed. Further studies in other patient populations are needed to better define the usefulness of this serologic test.

Immune reconstitution during Pneumocystis lung infection: disruption of surfactant component expression and function by S-nitrosylation

Pneumocystis pneumonia (PCP), the most common opportunistic pulmonary infection associated with HIV infection, is marked by impaired gas exchange and significant hypoxemia. Immune reconstitution disease (IRD) represents a syndrome of paradoxical respiratory failure in patients with active or recently treated PCP subjected to immune reconstitution. To model IRD, C57BL/6 mice were selectively depleted of CD4(+) T cells using mAb GK1.5. Following inoculation with Pneumocystis murina cysts, infection was allowed to progress for 2 wk, GK1.5 was withdrawn, and mice were followed for another 2 or 4 wk. Flow cytometry of spleen cells demonstrated recovery of CD4(+) cells to >65% of nondepleted controls. Lung tissue and bronchoalveolar lavage fluid harvested from IRD mice were analyzed in tandem with samples from CD4-depleted mice that manifested progressive PCP for 6 wks. Despite significantly decreased pathogen burdens, IRD mice had persistent parenchymal lung inflammation, increased bronchoalveolar lavage fluid cellularity, markedly impaired surfactant biophysical function, and decreased amounts of surfactant phospholipid and surfactant protein (SP)-B. Paradoxically, IRD mice also had substantial increases in the lung collectin SP-D, including significant amounts of an S-nitrosylated form. By native PAGE, formation of S-nitrosylated SP-D in vivo resulted in disruption of SP-D multimers. Bronchoalveolar lavage fluid from IRD mice selectively enhanced macrophage chemotaxis in vitro, an effect that was blocked by ascorbate treatment. We conclude that while PCP impairs pulmonary function and produces abnormalities in surfactant components and biophysics, these responses are exacerbated by IRD. This worsening of pulmonary inflammation, in response to persistent Pneumocystis Ags, is mediated by recruitment of effector cells modulated by S-nitrosylated SP-D.

Post-translational tyrosine nitration of eosinophil granule toxins mediated by eosinophil peroxidase

Nitration of tyrosine residues has been observed during various acute and chronic inflammatory diseases. However, the mechanism of tyrosine nitration and the nature of the proteins that become tyrosine nitrated during inflammation remain unclear. Here we show that eosinophils but not other cell types including neutrophils contain nitrotyrosine-positive proteins in specific granules. Furthermore, we demonstrate that the human eosinophil toxins, eosinophil peroxidase (EPO), major basic protein, eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP), and the respective murine toxins, are post-translationally modified by nitration at tyrosine residues during cell maturation. High resolution affinity-mass spectrometry identified specific single nitration sites at Tyr349 in EPO and Tyr33 in both ECP and EDN. ECP and EDN crystal structures revealed and EPO structure modeling suggested that the nitrated tyrosine residues in the toxins are surface exposed. Studies in EPO(-/-), gp91phox(-/-), and NOS(-/-) mice revealed that tyrosine nitration of these toxins is mediated by EPO in the presence of hydrogen peroxide and minute amounts of NOx. Tyrosine nitration of eosinophil granule toxins occurs during maturation of eosinophils, independent of inflammation. These results provide evidence that post-translational tyrosine nitration is unique to eosinophils.

[Pneumocystis jiroveci pneumonia during prolonged corticosteroid therapy in an immunocompetent infant]

INTRODUCTION

Pneumocystis jiroveci (PJ) infection is rare in infants and is suggestive of primary or secondary immunodeficiency. We report on a case of severe PJ pneumonia in an immunocompetent infant after prolonged corticosteroid treatment.

CASE REPORT

A 5 1/2 month-old girl presented with hypoxemic respiratory distress. Her medical record was remarkable only for a bulky parotid haemangioma, which was treated with prolonged oral corticosteroid therapy. The chest X-ray showed a mixed alveolar-interstitial pattern, and bronchoalveolar lavage revealed the presence of PJ. A favourable outcome was obtained after three weeks of intravenous trimethoprim-sulfamethoxazole treatment.

CONCLUSION

PJ infection should be suspected in infants presenting with progressive respiratory distress associated with a mixed alveolar-interstitial pattern. Its potential seriousness justifies prophylactic therapy during prolonged immunosuppressive treatment (chemotherapy, corticosteroid treatment).