AIDS-related Pneumocystis carinii pneumonia in the era of adjunctive steroids: implication of BAL neutrophilia

Development of a clinical risk score for the prediction of Pneumocystis jirovecii pneumonia in hospitalised patients

BACKGROUND

The performance and availability of invasive and non-invasive investigations for the diagnosis of Pneumocystis jirovecii pneumonia (PCP) vary across clinical settings. Estimating the pre-test probability of PCP is essential to the optimal selection and interpretation of diagnostic tests, such as the 1,3-β-D-glucan assay (BDG), for the prioritization of bronchoscopy, and to guide empiric treatment decisions. We aimed to develop a multivariable risk score to estimate the pre-test probability of PCP.

METHODS

The score was developed from a cohort of 626 individuals who underwent bronchoscopy for the purposes of identifying PCP in a Canadian tertiary-care centre, between 2015 and 2018. We conducted a nested case-control study of 57 cases and 228 unmatched controls. Demographic, clinical, laboratory, and radiological data were included in a multivariable logistic regression model to estimate adjusted odds ratios for PCP diagnosis. A clinical risk score was derived from the multivariable model and discrimination was assessed by estimating the score's receiver operating characteristic curve.

RESULTS

Participants had a median age of 60 years (interquartile range [IQR] 49-68) and 115 (40%) were female; 40 (14%) had HIV and 49 (17%) had a solid organ transplant (SOT). The risk score included prior SOT or HIV with CD4 ≤ 200/µL (+ 2), serum lactate dehydrogenase ≥ 265.5 IU/mL (+ 2), radiological pattern typical of PCP on chest x-ray (+ 2) or CT scan (+ 2.5), and PCP prophylaxis with trimethoprim-sulfamethoxazole (-3) or other antimicrobials (-2). The median score was 4 points (IQR, 2-4.5) corresponding to a 28% probability of PCP. The risk prediction model had good discrimination with a c-statistic of 0.79 (0.71-0.84). Given the operating characteristics of the BDG assay, scores ≤ 3 in patients without HIV, and ≤ 5.5 in those with HIV, paired with a negative BDG, would be expected to rule out PCP with 95% certainty.

CONCLUSION

We propose the PCP Score to estimate pre-test probability of PCP. Once validated, it should help clinicians determine which patients to refer for invasive investigations, when to rely on serological testing, and in whom to consider pre-emptive treatment.

Pneumocystis murina promotes inflammasome formation and NETosis during Pneumocystis pneumonia

Pneumocystis jirovecii pneumonia (PjP) poses a serious risk to individuals with compromised immune systems, such as individuals with HIV/AIDS or undergoing immunosuppressive therapies for cancer or solid organ transplants. Severe PjP triggers excessive lung inflammation, resulting in lung function decline and consequential alveolar damage, potentially culminating in acute respiratory distress syndrome. Non-HIV patients face a 30%-60% mortality rate, emphasizing the need for a deeper understanding of inflammatory responses in PjP. Prior research emphasized macrophages in Pneumocystis infections, neglecting neutrophils' role in tissue damage. Consequently, the overemphasis on macrophages led to an incomplete understanding of the role of neutrophils and inflammatory responses. In the current investigation, our RNAseq studies on a murine surrogate model of PjP revealed heightened activation of the NLRP3 inflammasome and NETosis cell death pathways in their lungs. Immunofluorescence staining confirmed neutrophil extracellular trap (NET) presence in the lungs of the P. murina-infected mice, validating our findings. Moreover, isolated neutrophils exhibited NETosis when directly stimulated with P. murina. Isolated NETs compromised P. murina viability in vitro, highlighting the potential role of neutrophils in controlling fungal growth and promoting inflammation during P. murina pneumonia through NLRP3 inflammasome assembly and NETosis. These pathways, essential for inflammation and pathogen elimination, bear the risk of uncontrolled activation leading to excessive tissue damage and persistent inflammation. This pioneering study is the first to identify the formation of NETs and inflammasomes during Pneumocystis infection, paving the way for comprehensive investigations into treatments aimed at mitigating lung damage and augmenting survival rates for individuals with PjP.IMPORTANCEPneumocystis jirovecii pneumonia (PjP) affects individuals with weakened immunity, such as HIV/AIDS, cancer, and organ transplant patients. Severe PjP triggers lung inflammation, impairing function and potentially causing acute respiratory distress syndrome. Non-HIV individuals face a 30%-60% mortality rate, underscoring the need for deeper insight into PjP's inflammatory responses. Past research focused on macrophages in managing Pneumocystis infection and its inflammation, while the role of neutrophils was generally overlooked. In contrast, our findings in P. murina-infected mouse lungs showed neutrophil involvement during inflammation and increased expression of NLRP3 inflammasome and NETosis pathways. Detection of neutrophil extracellular traps further indicated their involvement in the inflammatory process. Although beneficial in combating infection, unregulated neutrophil activation poses a potential threat to lung tissues. Understanding the behavior of neutrophils in Pneumocystis infections is crucial for controlling detrimental reactions and formulating treatments to reduce lung damage, ultimately improving the survival rates of individuals with PjP.

Leukotriene B4-induced neutrophil extracellular traps impede the clearance of Pneumocystis

Pneumocystis pneumonia (PCP) is a fungal pulmonary disease with high mortality in immunocompromised patients. Neutrophils are essential in defending against fungal infections; however, their role in PCP is controversial. Here we aim to investigate the effects of neutrophil extracellular traps (NETs) on Pneumocystis clearance and lung injury using a mouse model of PCP. Intriguingly, although neutrophils play a fundamental role in defending against fungal infections, NETs failed to eliminate Pneumocystis, but instead impaired the killing of Pneumocystis. Mechanically, Pneumocystis triggered Leukotriene B4 (LTB4)-dependent neutrophil swarming, leading to agglutinative NET formation. Blocking Leukotriene B4 with its receptor antagonist Etalocib significantly reduced the accumulation and NET release of neutrophils in vitro and in vivo, enhanced the killing ability of neutrophils against Pneumocystis, and alleviated lung injury in PCP mice. This study identifies the deleterious role of agglutinative NETs in Pneumocystis infection and reveals a new way to prevent NET formation, which provides new insights into the pathogenesis of PCP.

Nomograms for Death from Pneumocystis jirovecii Pneumonia in HIV-Uninfected and HIV-Infected Patients

Purpose

Pneumocystis jirovecii pneumonia (PCP) is a major cause of death in immunocompromised patients. Many risk factors for poor prognosis have been reported, but few studies have created predictive models with these variables to calculate the death rate accurately. This study created nomogram models for the precise prediction of mortality risk in human immunodeficiency virus (HIV) uninfected and HIV-infected patients with PCP.

Patients and Methods

A retrospective study was performed over a 10-year period to evaluate the clinical characteristics and outcomes of PCP in HIV-uninfected and HIV-infected adults treated in Beijing, China from 2010 to 2019. Univariate and multivariate logistic regression analyses were used to identify mortality risk factors to create the nomograms. Nomogram models were evaluated by using a bootstrapped concordance index, calibration plots and receiver operating characteristic (ROC) curves.

Results

A total of 167 HIV-uninfected and 193 HIV-infected PCP patients were included in the study. Pneumothorax, duration of fever after admission, CD4+ T cells ≤100/µL and trimethoprim-sulfamethoxazole (TMP-SMX) combined with caspofungin (CAS) treatment were independent risk factors for death in HIV-uninfected PCP patients. We derived a well calibrated nomogram for mortality by using these variables. The area under the curve was 0.865 (95% confidence interval 0.799–0.931). Independent risk factors for death in HIV-infected PCP patients were pneumothorax, platelet (PLT) ≤80×10⁹/L, haemoglobin (HGB) ≤90 g/L, albumin (ALB), cytomegalovirus (CMV) coinfection and TMP-SMX combined with CAS treatment. The nomogram showed good discrimination, with a C-index of 0.904 and excellent calibration.

Conclusion

The nomograms which were derived may be useful tools for the precise prediction of mortality in HIV-uninfected and HIV-infected patients, but require validation in clinical practice.

Outcome and prognostic factors of Pneumocystis jirovecii pneumonia in immunocompromised adults: a prospective observational study

Background

Pneumocystis jirovecii pneumonia (PJP) remains a severe disease associated with high rates of invasive mechanical ventilation (MV) and mortality. The objectives of this study were to assess early risk factors for severe PJP and 90-day mortality, including the broncho-alveolar lavage fluid cytology profiles at diagnosis.

Methods

We prospectively enrolled all patients meeting pre-defined diagnostic criteria for PJP admitted at Nantes university hospital, France, from January 2012 to January 2017. Diagnostic criteria for PJP were typical clinical features with microbiological confirmation of P. jirovecii cysts by direct examination or a positive specific quantitative real-time polymerase chain reaction (PCR) assay. Severe PJP was defined as hypoxemic acute respiratory failure requiring high-flow nasal oxygen with at least 50% FiO₂, non-invasive ventilation, or MV.

Results

Of 2446 respiratory samples investigated during the study period, 514 from 430 patients were positive for P. jirovecii. Of these 430 patients, 107 met criteria for PJP and were included in the study, 53 (49.5%) patients had severe PJP, including 30 who required MV. All patients were immunocompromised with haematological malignancy ranking first (n = 37, 35%), followed by solid organ transplantation (n = 27, 25%), HIV-infection (n = 21, 20%), systemic diseases (n = 13, 12%), solid tumors (n = 12, 11%) and primary immunodeficiency (n = 6, 8%). By multivariate analysis, factors independently associated with severity were older age (OR, 3.36; 95% CI 1.4–8.5; p < 0.05), a P. jirovecii microscopy-positive result from bronchoalveolar lavage (BAL) (OR, 1.3; 95% CI 1.54–9.3; p < 0.05); and absence of a BAL fluid alveolitis profile (OR, 3.2; 95% CI 1.27–8.8; p < 0.04). The 90-day mortality rate was 27%, increasing to 50% in the severe PJP group. Factors independently associated with 90-day mortality were worse SOFA score on day 1 (OR, 1.05; 95% CI 1.02–1.09; p < 0.001) whereas alveolitis at BAL was protective (OR, 0.79; 95% CI 0.65–0.96; p < 0.05). In the subgroup of HIV-negative patients, similar findings were obtained, then viral co-infection were independently associated with higher 90-day mortality (OR, 1.25; 95% CI 1.02–1.55; p < 0.05).

Conclusions

Older age and P. jirovecii oocysts at microscopic examination of BAL were independently associated with severe PJP. Both initial PJP severity as evaluated by the SOFA score and viral co-infection predicted 90-day mortality. Alveolitis at BAL examination was associated with less severe PJP. The pathophysiological mechanism underlying this observation deserves further investigation.

A Multivariable Prediction Model for Pneumocystis jirovecii Pneumonia in Hematology Patients with Acute Respiratory Failure

RATIONALE

The incidence of Pneumocystis jirovecii pneumonia (PjP) is rising. Longer time to treatment is associated with higher mortality.

OBJECTIVES

To develop a multivariable risk prediction model for PjP diagnosis.

METHODS

In a prospective multicenter cohort of ICU patients with hematological malignancies and acute respiratory failure, factors associated with documented PjP were identified. The risk prediction model was tested in an independent prospective multicenter cohort. We assessed discrimination (by areas under the receiver operating characteristic curves [AUCs]) and goodness of fit (by Hosmer-Lemeshow statistics). Model performance was assessed using 30 sets of imputed data sets.

MEASUREMENTS AND MAIN RESULTS

Among the 1,330 patients, 134 of 1,092 (12.3%; 95% confidence interval [CI], 10.4-14.4%) had proven PjP in the derivation cohort, as did 15 of 238 (6.3%, 95% CI, 3.6-10.2%) in the validation cohort. The model included age, lymphoproliferative disease, anti-Pneumocystis prophylaxis, the number of days between respiratory symptom onset and ICU admission, shock, chest radiograph pattern, and pleural effusion. The median (interquartile range) score was 3.5 (1.5-5.0) (range, -3.5 to 8.5) in the derivation cohort and 1.0 (0-2.0) (range, -3.5 to 6.0) in the validation cohort. The best threshold was defined on the validation sample as 3, allowing us to reach 86.7% sensitivity and 67.7% specificity for PjP, with a negative predictive value of 97.9% in the case of 10% prevalence. The score had good calibration (goodness of fit, -0.75) and discrimination in the derivation cohort (mean AUC, 0.80; 95% CI, 0.76-0.84) and validation cohort (mean AUC, 0.83; 95% CI, 0.72-0.93).

CONCLUSIONS

The PjP score for hematology patients with acute respiratory failure can be computed at admission, based on readily available variables. Potential clinical benefits of using this score deserve assessment.

Risk factors for mortality from pneumocystis carinii pneumonia (PCP) in non-HIV patients: a meta-analysis

The number of patients with non-human immunodeficiency virus (HIV) related pneumocystis carinii pneumonia (PCP) is increasing with widespread immunosuppressive treatment. We performed a meta-analysis to describe the clinical characteristics and factors associated with outcomes of PCP in HIV-negative patients. A total of 13 studies including 867 patients with non-HIV related PCP was included. The overall mortality for non-HIV patients with PCP was 30.6%. The most common underlying disorder for the development of PCP is hematological malignancies (29.1%), followed by autoimmune disease (20.1%), organ or bone marrow transplantation (14.0%), and solid tumors (6.0%). Risk factors associated with increased mortality rate including old age, female sex, longer time from onset of symptoms to diagnosis, respiratory failure, solid tumors, high lactate dehydrogenase, low serum albumin, bacterial, and aspergillus co-infection, etc (P < 0.05). Adjunctive corticosteroid and PCP prophylaxis was not shown to improve the outcome of PCP in non-HIV patients (P > 0.05). Our findings indicate that mortality in non-HIV patients with PCP is high. Improved knowledge about the prognostic factors may guide the early treatment.

Survival after Pneumocystis jirovecii pneumonia requiring ventilation: A case report

Pneumocystis pneumonia (PCP) in patients with the human immunodeficiency virus (HIV) is associated with a high mortality rate, which increases substantially with the need for mechanical ventilation. Local experience of patients with PCP admitted to the intensive care unit has revealed mortality rates close to 100%. We present a case of a 39-year-old HIV-infected man diagnosed with PCP who was successfully weaned from mechanical ventilation after presenting with respiratory distress and severe hypoxaemia. A short review of the literature will also be presented.

The life cycle stages of Pneumocystis murina have opposing effects on the immune response to this opportunistic, fungal pathogen

The cyst cell wall β-glucans of Pneumocystis have been shown to stimulate immune responses in lung epithelial cells, dendritic cells, and alveolar macrophages. Little is known about how the trophic life forms, which do not have a fungal cell wall, interact with these innate immune cells. Here, we report differences in the responses of both neonatal and adult mice to the trophic and cystic life cycle stages of Pneumocystis murina The adult and neonatal immune responses to infection with Pneumocystis murina trophic forms were less robust than the response to infection with a physiologically normal mixture of cysts and trophic forms. Cysts promoted the recruitment of nonresident innate immune cells and T and B cells into the lungs. Cysts, but not trophic forms, stimulated increased IFN-γ cytokine concentrations in the alveolar spaces, and an increase in IFN-γ-producing CD4⁺ T cells. In vitro, bone marrow-derived dendritic cells (BMDCs) stimulated with cysts produced the proinflammatory cytokines IL-1β and IL-6. In contrast, trophic forms suppressed β-glucan-, LTA-, and LPS-induced IL-1β, IL-6, and TNFα production by BMDCs and antigen presentation to CD4⁺ T cells. The negative effects of trophic forms were not due to ligation of mannose receptor. Our results indicate that optimal innate and adaptive immune responses to Pneumocystis species are dependent on stimulation with the cyst life cycle stage. Conversely, trophic forms suppress β-glucan-induced proinflammatory responses in vitro, suggesting that the trophic forms dampen cyst-induced inflammation in vivo.

Pneumocystis Pneumonia in Human Immunodeficiency Virus-infected Adults and Adolescents: Current Concepts and Future Directions

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in human immunodeficiency virus–infected adults. Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, polymerase chain reaction has been shown to have a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for the evaluation of immunocompromised patients with suspected PCP and normal chest radiography. Trimethoprim–sulfamethoxazole (TMP-SMX) is the first-line agent for the treatment of mild to severe PCP, although it is often complicated with various side effects. Since TMP-SMX is widely used for the prophylaxis, the putative drug resistance is an emerging concern.

Cellular profiles of bronchoalveolar lavage fluid and their prognostic significance for non-HIV-infected patients with Pneumocystis jirovecii pneumonia

The usefulness of bronchoalveolar lavage (BAL) fluid cellular analysis in non-human immunodeficiency virus (HIV)-infected patients with Pneumocystis jirovecii pneumonia (PCP) has not been adequately evaluated. The objective of this study was to analyze the cellular profiles of BAL fluid and to evaluate their prognostic significance in non-HIV-infected patients with PCP. A 7-year retrospective cohort study of 166 non-HIV-infected adult patients with PCP who underwent BAL was performed in a tertiary care hospital. The median total BAL fluid white blood cell count was 180/μl (interquartile range, 80 to 330) and was unaffected by the severity of PCP. The median percentages of BAL fluid neutrophils, lymphocytes, and alveolar macrophages were 13.1%, 31.7%, and 30.2%, respectively. The median percentage of BAL fluid neutrophils was significantly higher in severe than in mild-to-moderate PCP (20.4% versus 6.0%, P<0.001), as was the absolute neutrophil count (24/μl versus 13/μl, P=0.001). The percentage of BAL fluid neutrophils was an independent predictor of 30-day (adjusted odds ratio [aOR], 1.02; 95% confidence interval [CI], 1.01 to 1.03) and 60-day (aOR, 1.02; 95% CI, 1.01 to 1.04) mortalities. The 30-day and 60-day mortalities increased at rates of 15% (P=0.006) and 21% (P<0.001) per 10% increment of BAL fluid neutrophil levels, respectively. The degree of BAL fluid pleocytosis was relatively low without regard to the severity of PCP. The percentage of BAL fluid neutrophils can be used as a prognostic marker in non-HIV-infected patients with PCP.

Adjunctive steroid in HIV-negative patients with severe Pneumocystis pneumonia

Background

High-dose steroid therapy has been proven effective in AIDS-related Pneumocystis pneumonia (PCP) but not in non-AIDS-related cases. We evaluated the effects on survival of steroids in HIV-negative patients with PCP.

Methods

Retrospective study patients admitted to the ICU with hypoxemic PCP. We compared patients receiving HDS (≥1 mg/Kg/day prednisone equivalent), low-dose steroids (LDS group, <1 mg/Kg/day prednisone equivalent), and no steroids (NS group). Variables independently associated with ICU mortality were identified.

Results

139 HIV-negative patients with PCP were included. Median age was 48 [40–60] years. The main underlying conditions were hematological malignancies (n=55, 39.6%), cancer (n=11, 7.9%), and solid organ transplantation (n=73, 52.2%). ICU mortality was 26% (36 deaths). The HDS group had 72 (51.8%) patients, the LDS group 35 (25%) patients, and the NS group 32 (23%) patients. Independent predictors of ICU mortality were SAPS II at ICU admission (odds ratio [OR], 1.04/point; [95%CI], 1.01-1.08, P=0.01), non-hematological disease (OR, 4.06; [95%CI], 1.19-13.09, P=0.03), vasopressor use (OR, 20.31; 95%CI, 6.45-63.9, P<0.001), and HDS (OR, 9.33; 95%CI, 1.97-44.3, P=0.02). HDS was not associated with the rate of ICU-acquired infections.

Conclusions

HDS were associated with increased mortality in HIV-negative patients with PCP via a mechanism independent from an increased risk of infection.

Abnormalities in host defense associated with HIV infection

The broad variety of pulmonary infections encountered in human immunodeficiency virus (HIV)-infected individuals demonstrates that the host defense network is impaired. An improved understanding of these events in the lung can lead to specific interventions aimed at restoration of deficient function. This review summarizes the pulmonary host defense deficits in HIV-infected individuals, focusing on lymphocytes, alveolar macrophages, and neutrophils.

Accumulation of myeloid-derived suppressor cells in the lungs during Pneumocystis pneumonia

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of hematopoietic precursors with the ability to adversely affect host immunity. They have been shown to accumulate in pathological conditions, such as cancer and some microbial diseases. In the mouse and rat models of Pneumocystis pneumonia (PcP), we found a distinct population of cells with MDSC-like morphology in the bronchoalveolar lavage (BAL) fluid, constituting up to 50% of the total cells in BAL fluid. These cells were not seen in the BAL fluid from normal animals or from Pneumocystis-infected animals that had been successfully treated for PcP with a combination of trimethoprim and sulfamethoxazole. With flow cytometry, these cells were found to express the characteristic MDSC surface markers Gr-1 and CD11b in mice or CD11bc and His48 in rats. Using reverse transcription-PCR, we demonstrated that these cells produced high levels of arginase-1 and inducible nitric oxide synthase (iNOS) mRNA. These cells were shown to suppress CD4(+) T-cell proliferation in response to stimulation by anti-CD3 and anti-CD28 antibodies. Adoptive transfer of these cells to normal mice caused lung damage, as indicated by elevated levels of albumin and lactate dehydrogenase in the BAL fluid. These experiments provide evidence of the presence of MDSCs in the lungs during PcP. Further studies on the roles of MDSCs in PcP are warranted in order to develop treatment strategies which can reduce the number of MDSCs and the damage caused by these cells.

Early diagnosis and treatment are crucial for the survival of Pneumocystis pneumonia patients without human immunodeficiency virus infection

The mortality of Pneumocystis pneumonia (PCP) patients without human immunodeficiency virus (HIV) infection ranges from 0 to 70 %, whereas that of HIV-infected PCP patients ranges from 10 to 20 %. The reasons for these differences are not known. We retrospectively analyzed factors contributing to the survival of 23 patients with PCP and without HIV infection, in whom PCP developed as community-acquired pneumonia (CAP). The interval from admission to the start of PCP-specific treatment was significantly shorter for survivors (2.71 ± 3.64 days; n = 14) than for non-survivors (8.67 ± 5.5 days; n = 9; p = 0.003). Moreover, although the severity scores/classes assessed by A-DROP, CURB-65, and PSI were no different on admission, scores/classes at the start of PCP-specific treatment were significantly higher for non-survivors. Overall mortality was 39 %, but mortality was approximately 70-100 % for patients classified as severe grade by A-DROP, CURB-65, or PSI scores/classes at the time when PCP-specific treatment was started, which was far higher than expected for these guidelines. In conclusion, early diagnosis and treatment within 3 days are crucial for the survival of PCP patients without HIV infection. We emphasize the limitations of application of guidelines for CAP to patients with PCP.

Acute respiratory failure in kidney transplant recipients: a multicenter study

INTRODUCTION

Data on pulmonary complications in renal transplant recipients are scarce. The aim of this study was to evaluate acute respiratory failure (ARF) in renal transplant recipients.

METHODS

We conducted a retrospective observational study in nine transplant centers of consecutive kidney transplant recipients admitted to the intensive care unit (ICU) for ARF from 2000 to 2008.

RESULTS

Of 6,819 kidney transplant recipients, 452 (6.6%) required ICU admission, including 200 admitted for ARF. Fifteen (7.5%) of these patients had combined kidney-pancreas transplantations. The most common causes of ARF were bacterial pneumonia (35.5%), cardiogenic pulmonary edema (24.5%) and extrapulmonary acute respiratory distress syndrome (ARDS) (15.5%). Pneumocystis pneumonia occurred in 11.5% of patients. Mechanical ventilation was used in 93 patients (46.5%), vasopressors were used in 82 patients (41%) and dialysis was administered in 104 patients (52%). Both the in-hospital and 90-day mortality rates were 22.5%. Among the 155 day 90 survivors, 115 patients (74.2%) were dialysis-free, including 75 patients (65.2%) who recovered prior renal function. Factors independently associated with in-hospital mortality were shock at admission (odds ratio (OR) 8.70, 95% confidence interval (95% CI) 3.25 to 23.29), opportunistic fungal infection (OR 7.08, 95% CI 2.32 to 21.60) and bacterial infection (OR 2.53, 95% CI 1.07 to 5.96). Five factors were independently associated with day 90 dialysis-free survival: renal Sequential Organ Failure Assessment (SOFA) score on day 1 (OR 0.68/SOFA point, 95% CI 0.52 to 0.88), bacterial infection (OR 0.43, 95% CI 0.21 to 0.90), three or four quadrants involved on chest X-ray (OR 0.44, 95% CI 0.21 to 0.91), time from hospital to ICU admission (OR 0.98/day, 95% CI 0.95 to 0.99) and oxygen flow at admission (OR 0.93/liter, 95% CI 0.86 to 0.99).

CONCLUSIONS

In kidney transplant recipients, ARF is associated with high mortality and graft loss rates. Increased Pneumocystis and bacterial prophylaxis might improve these outcomes. Early ICU admission might prevent graft loss.

Investigation of the significance of Oil Red O-positive macrophage excess in bronchoalveolar lavage fluid during HIV infection

OBJECTIVE

To assess the significance of increased levels of Oil Red O-positive macrophages (ORO-PM) in bronchoalveolar lavage fluids (BALFs) from HIV-positive patients.

METHODS

Cytological data for seventy BALF samples from 66 consecutive HIV-infected patients were analysed according to antiretroviral therapy regimen, presence of Pneumocystis jiroveci infection, blood CD4(+) T cell count, HIV-1 viral load and plasma lipid levels. Non-parametric tests were used to compare the values between groups.

RESULTS

The percentages of ORO-PM were high in this group: 40% [6-80] (median [interquartile range]). They were positively correlated with the BALF total cell count, 21% [5-48.5] for <300 cells/mm(3) and 60% [26.5-80] for >300 cells/mm(3) (P<0.01) but inversely correlated with the percentage of BALF lymphocytes, 50% [20-80] for <15% lymphocytes and 11.5% [2-47] for ≥15% lymphocytes (P<0.01). Antiretroviral therapy with or without protease inhibitors, plasma lipid levels, HIV-1 viral load, blood CD4(+) T cell count or presence of a Pneumocystis jiroveci infection were not correlated with the ORO-PM status.

CONCLUSION

Significantly increased numbers of ORO-PM were correlated with high total cell counts and low lymphocyte counts in BALF, irrespective of disease activity or treatment. Extended work on a larger series of patients needs to be conducted.

Minimally Invasive Diagnostic Strategy in Immunocompromised Patients with Pulmonary Infiltrates

Acute respiratory failure (ARF) is the main reason for ICU admission in patients with haematological malignancies. High mortality rates of up to 50% are reported in this situation, and mortality is highest when mechanical ventilation is needed. Rapid and accurate diagnostic methods are needed in these vulnerable patients to ensure the prompt initiation of effective treatment. However, the broad array of possible cause of ARF raises diagnostic challenges. In this review, we discuss the DIRECT strategy, which identifies the most plausible diagnosis in each patient based on the type of immune deficiency and clinical presentation. We will focus on non-invasive laboratory tests developed in recent years, discussing their sensitivity and specificity. We also discuss the usefulness in cancer patients with specific organ dysfunctions of biomarkers introduced over the past few years.

Diagnostic strategy for hematology and oncology patients with acute respiratory failure: randomized controlled trial

RATIONALE

Respiratory events are common in hematology and oncology patients and manifest as hypoxemic acute respiratory failure (ARF) in up to half the cases. Identifying the cause of ARF is crucial. Fiberoptic bronchoscopy with bronchoalveolar lavage (FO-BAL) is an invasive test that may cause respiratory deterioration. Recent noninvasive diagnostic tests may have modified the risk/benefit ratio of FO-BAL.

OBJECTIVES

To determine whether FO-BAL in cancer patients with ARF increased the need for intubation and whether noninvasive testing alone was not inferior to noninvasive testing plus FO-BAL.

METHODS

We performed a multicenter randomized controlled trial with sample size calculations for both end points. Patients with cancer and ARF of unknown cause who were not receiving ventilatory support at intensive care unit admission were randomized to early FO-BAL plus noninvasive tests (n = 113) or noninvasive tests only (n = 106). The primary end point was the number of patients needing intubation and mechanical ventilation. The major secondary end point was the number of patients with no identified cause of ARF.

MEASUREMENTS AND MAIN RESULTS

The need for mechanical ventilation was not significantly greater in the FO-BAL group than in the noninvasive group (35.4 vs. 38.7%; P = 0.62). The proportion of patients with no diagnosis was not smaller in the noninvasive group (21.7 vs. 20.4%; difference, -1.3% [-10.4 to 7.7]).

CONCLUSIONS

FO-BAL performed in the intensive care unit did not significantly increase intubation requirements in critically ill cancer patients with ARF. Noninvasive testing alone was not inferior to noninvasive testing plus FO-BAL for identifying the cause of ARF. Clinical trial registered with www.clinicaltrials.gov (NCT00248443).

Survival trends in critically ill HIV-infected patients in the highly active antiretroviral therapy era

Introduction

The widespread use of highly active antiretroviral therapy (ART) has reduced HIV-related life-threatening infectious complications. Our objective was to assess whether highly active ART was associated with improved survival in critically ill HIV-infected patients.

Methods

A retrospective study from 1996 to 2005 was performed in a medical intensive care unit (ICU) in a university hospital specialized in the management of immunocompromised patients. A total of 284 critically ill HIV-infected patients were included. Differences were sought across four time periods. Risk factors for death were identified by multivariable logistic regression.

Results

Among the 233 (82%) patients with known HIV infection before ICU admission, 64% were on highly active ART. Annual admissions increased over time, with no differences in reasons for admission: proportions of patients with newly diagnosed HIV, previous opportunistic infection, CD4 counts, viral load, or acute disease severity. ICU and 90-day mortality rates decreased steadily: 25% and 37.5% in 1996 to 1997, 17.1% and 17.1% in 1998 to 2000, 13.2% and 13.2% in 2001 to 2003, and 8.6% in 2004 to 2005. Five factors were independently associated with increased ICU mortality: delayed ICU admission (odds ratio (OR), 3.04; 95% confidence interval (CI), 1.29 to 7.17), acute renal failure (OR, 4.21; 95% CI, 1.63 to 10.92), hepatic cirrhosis (OR, 3.78; 95% CI, 1.21 to 11.84), ICU admission for coma (OR, 2.73; 95% CI, 1.16 to 6.46), and severe sepsis (OR, 3.67; 95% CI, 1.53 to 8.80). Admission to the ICU in the most recent period was independently associated with increased survival: admission from 2001 to 2003 (OR, 0.28; 95% CI, 0.08 to 0.99), and between 2004 and 2005 (OR, 0.13; 95% CI, 0.03 to 0.53).

Conclusions

ICU survival increased significantly in the highly active ART era, although disease severity remained unchanged. Co-morbidities and organ dysfunctions, but not HIV-related variables, were associated with death. Earlier ICU admission from the hospital ward might improve survival.

Severity and outcomes of Pneumocystis pneumonia in patients newly diagnosed with HIV infection: an observational cohort study

It is unclear whether patients who are unaware of their HIV infection have different severity or outcomes of Pneumocystis pneumonia (PCP) compared to patients who have been previously diagnosed with HIV. In this retrospective observational cohort study of consecutive HIV-infected patients with microscopically diagnosed PCP at San Francisco General Hospital between 1997 and 2006, 121 of 522 patients (23%) were unaware of their HIV infection prior to their diagnosis of PCP. The proportion of patients with concurrently diagnosed HIV and PCP each year remained unchanged during the study period. Patients with newly diagnosed HIV had a significantly higher alveolar-arterial oxygen gradient at presentation (median 51 vs 45 mm Hg, p =0.03), but there were no differences in mortality, frequency of mechanical ventilation, or admission to intensive care compared to patients with previously diagnosed HIV infection. In multivariate analysis, patients who reported a sexual risk factor for HIV infection were more likely to be newly diagnosed with HIV than patients who reported injection drug use as their only HIV risk factor (odds ratio = 3.14, 95% CI 1.59-6.18, p=0.001). This study demonstrates a continued need for HIV education and earlier HIV testing, particularly in patients with high-risk sexual behavior.

Pneumocystis jirovecii Pneumonia

Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.

Predicting mortality from HIV-associated Pneumocystis pneumonia at illness presentation: an observational cohort study

BACKGROUND

Although the use of antiretroviral therapy has led to dramatic declines in AIDS-associated mortality, Pneumocystis pneumonia (PCP) remains a leading cause of death in HIV-infected patients.

OBJECTIVES

To measure mortality, identify predictors of mortality at time of illness presentation and derive a PCP mortality prediction rule that stratifies patients by risk for mortality.

METHODS

An observational cohort study with case note review of all HIV-infected persons with a laboratory diagnosis of PCP at San Francisco General Hospital from 1997 to 2006.

RESULTS

451 patients were diagnosed with PCP on 524 occasions. In-hospital mortality was 10.3%. Multivariate analysis identified five significant predictors of mortality: age (adjusted odds ratio (AOR) per 10-year increase, 1.69; 95% CI 1.08 to 2.65; p = 0.02); recent injection drug use (AOR 2.86; 95% CI 1.28 to 6.42; p = 0.01); total bilirubin >0.6 mg/dl (AOR 2.59; 95% CI 1.19 to 5.62; p = 0.02); serum albumin <3 g/dl (AOR 3.63; 95% CI 1.72-7.66; p = 0.001); and alveolar-arterial oxygen gradient >or=50 mm Hg (AOR 3.02; 95% CI 1.41 to 6.47; p = 0.004). Using these five predictors, a six-point PCP mortality prediction rule was derived that stratifies patients according to increasing risk of mortality: score 0-1, 4%; score 2-3, 12%; score 4-5, 48%.

CONCLUSIONS

The PCP mortality prediction rule stratifies patients by mortality risk at the time of illness presentation and should be validated as a clinical tool.

Plagues in the ICU: a brief history of community-acquired epidemic and endemic transmissible infections leading to intensive care admission

The ability to diagnose and treat infectious diseases and handle infectious disease outbreaks continues to improve. For the most part, the major plagues of antiquity remain historical footnotes, yet, despite many advances, there is clear evidence that major pandemic illness is always just one outbreak away. In addition to the HIV pandemic, the smaller epidemic outbreaks of Legionnaire's disease, hantavirus pulmonary syndrome, and severe acute respiratory syndrome, among many others, points out the potential risk associated with a lack of preplanning and preparedness. Although pandemic influenza is at the top of the list when discussing possible future major infectious disease outbreaks, the truth is that the identity of the next major pandemic pathogen cannot be predicted with any accuracy. We can only hope that general preparedness and the lessons learned from previous outbreaks suffice.

Etiologies and outcome of acute respiratory failure in HIV-infected patients

Objective

To assess the etiologies and outcome of acute respiratory failure (ARF) in HIV-infected patients over the first decade of combination antiretroviral therapy (ART) use.

Methods

Retrospective study of all HIV-infected patients (n = 147) admitted to a single intensive care unit (ICU) for ARF between 1996 and 2006.

Results

ARF revealed the diagnosis of HIV infection in 43 (29.2%) patients. Causes of ARF were bacterial pneumonia (n = 74), Pneumocystis jirovecii pneumonia (PCP, n = 52), other opportunistic infections (n = 19), and noninfectious pulmonary disease (n = 33); the distribution of causes did not change over the 10-year study period. Two or more causes were identified in 33 patients. The 43 patients on ART more frequently had bacterial pneumonia and less frequently had opportunistic infections (P = 0.02). Noninvasive ventilation was needed in 49 patients and endotracheal intubation in 42. Hospital mortality was 19.7%. Factors independently associated with mortality were mechanical ventilation [odds ratio (OR) = 8.48, P < 0.0001], vasopressor use (OR, 4.48; P = 0.03), time from hospital admission to ICU admission (OR, 1.05 per day; P = 0.01), and number of causes (OR, 3.19; P = 0.02). HIV-related variables (CD4 count, viral load, and ART) were not associated with mortality.

Conclusion

Bacterial pneumonia and PCP remain the leading causes of ARF in HIV-infected patients in the ART era. Hospital survival has improved, and depends on the extent of organ dysfunction rather than on HIV-related characteristics.

Clinical utility of serum beta-D-glucan and KL-6 levels in Pneumocystis jirovecii pneumonia

OBJECTIVE

New serum markers (1-->3) beta-D-glucan (beta-D-glucan) and KL-6 are reported to be useful for the clinical diagnosis of Pneumocystis jirovecii pneumonia (PCP). However, the utility of these markers in PCP with HIV infection (HIV PCP) and without HIV (non-HIV PCP) is unknown. This study was aimed to evaluate the utility of beta-D-glucan and KL-6 for the diagnosis of PCP in patients with HIV infection (HIV PCP) and non-HIV PCP.

METHODS

Retrospective study.

PATIENTS

We reviewed the medical records of consecutive 35 patients. The serum levels of beta-D-glucan and KL-6 in HIV PCP and non-HIV PCP were comparatively evaluated. We evaluated these markers in survivors and non survivors.

RESULTS

The detection rates of serum beta-D-glucan and KL-6 levels in non-HIV PCP were lower than those in HIV PCP (88% vs. 100%, 66% vs. 88%, respectively). The false positive rates of these markers in both groups were similar (12%, 37%, respectively). Oxygenation index, serum albumin, and mechanical ventilation were the variables which were significantly associated with poor outcome in the univariate analysis.

CONCLUSION

In conclusion, beta-D-glucan was a reliable diagnostic marker for PCP. However, the detection rate of beta-D-glucan and KL-6 in non-HIV PCP was lower than in HIV PCP. Neither beta-D-glucan nor KL-6 was associated with the outcome of PCP.

Diagnostic bronchoscopy in hematology and oncology patients with acute respiratory failure: prospective multicenter data

OBJECTIVE

To describe the diagnostic yields of test strategies with and without fiberoptic bronchoscopy and bronchoalveolar lavage (FO-BAL), as well as outcomes, in cancer patients with acute respiratory failure (ARF).

DESIGN

Prospective observational study.

SETTING

Fifteen intensive care units in France.

PATIENTS

In all, 148 cancer patients, including 45 bone marrow transplant recipients (27 allogeneic, 18 autologous) with hypoxemic ARF.

INTERVENTION

None.

RESULTS

Overall, 146 causes of ARF were identified in 128 patients (97 [66.4%] pulmonary infections). The cause of ARF was identified in 50.5% of the 101 patients who underwent FO-BAL and in 66.7% of the other patients. FO-BAL was the only conclusive test in 34 (33.7%) of the 101 investigated patients. Respiratory status deterioration after FO-BAL occurred in 22 of 45 (48.9%) nonintubated patients, including 16 (35.5%) patients who required ventilatory support. Hospital mortality was 55.4% (82 deaths) overall and was not significantly different in the groups with and without FO-BAL. By multivariate analysis, mortality was affected by characteristics of the malignancy (remission, allogeneic bone marrow transplantation), cause of ARF (ARF during neutropenia recovery, cause not identified), and need for life-sustaining treatments (mechanical ventilation and vasopressors).

CONCLUSION

In critically ill cancer patients with ARF, a diagnostic strategy that does not include FO-BAL may be as effective as FO-BAL without exposing the patients to respiratory status deterioration.

Role of CD8 lymphocytes and neutrophilic alveolitis in Pneumocystis jiroveci pneumonia

We described the characteristics of bronchoalveolar inflammatory cells and their correlation with lung injury in patients with Pneumocystis jiroveci pneumonia. We reviewed all cases of patients with Pneumocystis jiroveci pneumonia in newly diagnosed HIV infected patients admitted to a large metropolitan referral hospital during June 2003 to December 2004. Nine patients (5M, 4F) with Pneumocystis jiroveci pneumonia diagnosed with bronchoscopy and cytological examination of bronchoalveolar lavage (BAL) were identified. There was a positive correlation between peripheral CD8 count and BAL neutrophilia and negative correlation with hypoxemia. Although the number patients in this case series is small, our findings suggest that CD8 cells and alveolar neutrophilic inflammation have a role in lung injury in Pneumocystis jiroveci pneumonia. These findings are consistent with data from animal studies.

[Infectious pulmonary complications in HIV-infected patients in the high by active antiretroviral therapy era in Spain]

Pulmonary complications in HIV-infected patients are at present a first-rate problem. They are the main cause of hospital admission of these patients in our country. Most HIV-patients have a pulmonary complication during the evolution of the infection. The main etiologic diagnosis is bacterial pneumonia, especially pneumococcal pneumonia; the second most frequent cause is Pneumocystis jiroveci (previously named P. carinii) pneumonia and the third cause is mycobacteriosis, particularly Mycobacterium tuberculosis. From early studies, important changes in the epidemiology of HIV-related pulmonary complications have occurred. General prescription of P. jiroveci primary prophylaxis is probably one of the main causes, and, more recently, the use of highly active antiretroviral therapy may also be an underlying explanation. In this review, epidemiology, diagnosis and outcome of HIV-related pulmonary complications in our country are update.

The prognosis of acute respiratory failure in critically ill cancer patients

Acute respiratory failure (ARF) in patients with cancer is frequently a fatal event. To identify factors associated with survival of cancer patients admitted to an intensive care unit (ICU) for ARF, we conducted a prospective 5-year observational study in a medical ICU in a teaching hospital in Paris, France. The patients were 203 cancer patients with ARF mainly due to infectious pneumonia (58%), but also noninfectious pneumonia (9%), congestive heart failure (12%), and no identifiable cause (21%). We measured clinical characteristics and ICU and hospital mortality rates.ICU mortality was 44.8% and hospital mortality was 47.8%. Noninvasive mechanical ventilation was used in 79 (39%) patients and conventional mechanical ventilation in 114 (56%), the mortality rates being 48.1% and 75.4%, respectively. Among the 14 patients with late noninvasive mechanical ventilation failure (>48 hours), only 1 survived. The mortality rate was 100% in the 19 noncardiac patients in whom conventional mechanical ventilation was started after 72 hours. By multivariable analysis, factors associated with increased mortality were documented invasive aspergillosis (odds ratio [OR], 2.13; 95% confidence intervals [CI], 1.05-14.74), no definite diagnosis (OR, 3.85; 95% CI, 1.26-11.70), vasopressors (OR, 3.19; 95% CI, 1.28-7.95), first-line conventional mechanical ventilation (OR, 8.75; 95% CI, 2.35-35.24), conventional mechanical ventilation after noninvasive mechanical ventilation failure (OR, 17.46; 95% CI, 5.04-60.52), and late noninvasive mechanical ventilation failure (OR, 10.64; 95% CI, 1.05-107.83). Hospital mortality was lower in patients with cardiac pulmonary edema (OR, 0.16; 95% CI, 0.03-0.72). Survival gains achieved in critically ill cancer patients in recent years extend to patients requiring ventilatory assistance. The impact of conventional mechanical ventilation on survival depends on the time from ICU admission to conventional mechanical ventilation and on the patient's response to noninvasive mechanical ventilation.

Neither neutrophils nor reactive oxygen species contribute to tissue damage during Pneumocystis pneumonia in mice

Neutrophils are implicated in the damage of lung tissue in many disease states, including infectious diseases and environmental insults. These effects may be due to oxidative or nonoxidative functions of the neutrophil or both. We examined the role of neutrophils in pulmonary damage during infection with the opportunistic fungal pathogen Pneumocystis sp. in four mouse models of neutrophil dysfunction. These were (i) a knockout of the gp91(phox) component of NADPH oxidase, in which reactive oxygen species (ROS) production is greatly reduced; (ii) a double knockout of gp91(phox) and inducible nitric oxide synthase, in which ROS and nitric oxide production is greatly decreased; (iii) a knockout of the chemokine receptor CXCR2, in which accumulation of intra-alveolar neutrophils is severely diminished; and (iv) antibody depletion of circulating neutrophils in wild-type mice with the monoclonal antibody RB6. Surprisingly, in each case, indicators of pulmonary damage (respiratory rates, arterial oxygen partial pressures, and intra-alveolar albumin concentrations) were the same in knockout mice and comparable wild-type mice. Therefore, whereas neutrophils are a valid correlative marker of lung damage during Pneumocystis infection, neither neutrophils nor ROS appear to be the causative agent of tissue damage. We also show that there is no difference in Pneumocystis burdens between wild-type and knockout mice, which supports the idea that neutrophils do not have a major role in the clearance of this organism.

Pneumocystis carinii pneumonia in critically ill patients with malignancy: a descriptive study

There are few data on Pneumocystis carinii pneumonia (PCP) in critically ill human immunodeficiency virus (HIV)-negative patients. Improved knowledge of the presenting symptoms of and prognostic factors for PCP may help to reduce the high mortality rate associated with PCP in such patients. We retrospectively studied 39 consecutive patients with acute PCP-related respiratory failure and malignancy who were treated at 2 intensive care units (ICUs) during a 10-year period. Univariate logistic regression identified the following 8 predictors of mortality at 30 days after patient admission to the ICU (30-day mortality rate, 33%): complete remission of the malignancy (odds ratio [OR], 0.18), receipt of >1 course of antimalignancy chemotherapy (OR, 17.2), involvement of 4 lobes noted on a chest radiograph (OR, 5), >15% neutrophils in bronchoalveolar lavage [BAL] fluid specimens (OR, 6), Organ System Failure score (OR, 7.33), Simplified Acute Physiology Score II (OR, 1.12), and the need for either mechanical ventilation (OR, 63) or vasopressors (OR, 25.9). Studies are needed to determine whether aggressive monitoring and treatment of patients with >15% neutrophils in BAL fluid specimens can improve the outcome of critically ill patients with malignancy and PCP.

Electrocardiogram in Pneumocystis carinii pneumonia: can it be used as a prognostic variable?

OBJECTIVE

Many prognostic variables have been studied in patients with Pneumocystis carinii pneumonia and acquired immunodeficiency syndrome (AIDS). The role of the electrocardiogram in this setting has not been previously evaluated. We analyzed the admission electrocardiogram in patients with Pneumocystis carinii pneumonia and AIDS in an attempt to identify electrocardiogram findings that could be associated with adverse clinical outcomes and worse prognostic variables.

DESIGN

A retrospective medical chart review.

SETTING

All confirmed cases of Pneumocystis carinii pneumonia in patients positive for human immunodeficiency virus admitted to Albert Einstein Medical Center from 1994 to 2000.

METHODS

Patients were assigned increasing severity ranks based on the findings on the admission electrocardiogram (normal sinus rhythm, sinus tachycardia, and right ventricular strain pattern). Data were extracted regarding study outcomes (admission to intensive care unit, mechanical ventilation, and hospital mortality) and prognostic variables.

MAIN RESULTS

Of the 40 study patients, 14 (35%) had normal sinus rhythm, 15 (37.5%) had sinus tachycardia, and 11 (27.5%) presented with signs of right ventricular strain. The number of admissions to the intensive care unit, use of mechanical ventilation, and hospital mortality rate all increased with the severity of the electrocardiogram findings (p < or =.03). The serum lactate dehydrogenase concentrations and the alveolar-arterial oxygen gradient both increased with the severity of the electrocardiogram findings (p < or =.02).

CONCLUSION

Electrocardiogram findings of sinus tachycardia and right heart strain are common in Pneumocystis carinii pneumonia. These findings are associated with adverse clinical outcomes as well as worsening of prognostic variables. The electrocardiogram may be useful in predicting outcome in patients with Pneumocystis carinii pneumonia.

Independent risk of mechanical ventilation for AIDS-related Pneumocystis carinii pneumonia associated with bronchoalveolar lavage neutrophilia

The use of mechanical ventilation (MV) for AIDS-related Pneumocystis carinii pneumonia (PCP) has varied over time. The introduction of adjunctive corticosteroid therapy has changed the pathophysiology of PCP. In the present study, we attempted to identify factors predictive of severe respiratory failure requiring MV amongst patients with PCP treated in the era of adjunctive corticosteroid therapy. Furthermore, we studied factors associated with survival in relation to MV. Of 170 consecutive patients with AIDS-related PCP, 18 (11%) required MV. Thirteen of 18 ventilated patients died (72%). In a logistic regression analysis, higher age, increased bronchoalveolar lavage (BAL) neutrophilia and a positive BAL cytomegalovirus CMV culture were associated with the need of MV. In multivariate analyses, only BAL neutrophilia remained independently predictive of mechanical ventilation. In conclusion, short-term mortality remained high after the introduction of adjunctive corticosteroid therapy. BAL neutrophilia may be a useful prognostic marker to identify patients at high risk of requiring mechanical ventilation.

Pleural effusions and pneumothoraces in AIDS

Pneumothorax occurs in 1 to 2% of hospitalized patients with HIV and is associated with 34% mortality. Pneumocystis carinii pneumonia and chest radiographic evidence of cysts, pneumatoceles, or bullae are risk factors for spontaneous pneumothorax. Tube thoracostomy, pleurodesis, and surgical treatment are usually needed to manage spontaneous pneumothorax in AIDS. Pleural effusion is seen in 7 to 27% of hospitalized patients with HIV infection. Its three leading causes are parapneumonic effusions, tuberculosis, and Kaposi sarcoma. Pleural effusions occur in 15 to 89% of cases of pulmonary Kaposi sarcoma and in 68% of cases of thoracic non-Hodgkin lymphoma in patients with AIDS. Primary effusion lymphoma accounts for 1 to 2% of non-Hodgkin lymphomas. Kaposi sarcoma and primary effusion lymphoma are associated with human herpesvirus 8. The prognosis of patients with pleural Kaposi sarcoma and non-Hodgkin lymphoma in AIDS is poor, and the major goal of treatment is palliation.

Pulmonary infiltrates in HIV-infected patients in the highly active antiretroviral therapy era in Spain

OBJECTIVE

To study the incidence, etiology, and outcome of pulmonary infiltrates (PIs) in HIV-infected patients and to evaluate the yield of diagnostic procedures.

DESIGN

Prospective observational study of consecutive hospital admissions.

SETTING

Tertiary hospital.

PATIENTS

HIV-infected patients with new-onset radiologic PIs from April 1998 to March 1999.

METHODS

The study protocol included chest radiography, blood and sputum cultures, serologic testing for "atypical" causes of pneumonia, testing for Legionella urinary antigen, testing for cytomegalovirus antigenemia, and bronchoscopy in case of diffuse or progressive PIs.

RESULTS

One hundred two episodes in 92 patients were recorded. The incidence of PIs was 18 episodes per 100 hospital admission-years (95% confidence interval [CI]: 15-21). An etiologic diagnosis was achieved in 62 cases (61%). Bacterial pneumonia (BP), Pneumocystis carinii pneumonia (PCP), and mycobacteriosis were the main diagnoses. The incidences of BP and mycobacteriosis were not statistically different in highly active antiretroviral therapy (HAART) versus non-HAART patients. The incidence of PCP was lower in those receiving HAART (p =.011), however. Nine patients died (10%). Independent factors associated with higher mortality were mechanical ventilation (odds ratio [OR] = 83; CI: 4.2-1,682), age >50 years (OR = 23; CI: 2-283), and not having an etiologic diagnosis (OR = 22; CI: 1.6-293).

CONCLUSIONS

Pulmonary infiltrates are still a frequent cause of hospital admission in the HAART era, and BP is the main etiology. There was no difference in the rate of BP and mycobacteriosis in HAART and non-HAART patients. Not having an etiologic diagnosis is an independent factor associated with mortality.

Pulmonary infiltrates in HIV-infected patients in the highly active antiretroviral therapy era in Spain

OBJECTIVE

To study the incidence, etiology, and outcome of pulmonary infiltrates (PIs) in HIV-infected patients and to evaluate the yield of diagnostic procedures.

DESIGN

Prospective observational study of consecutive hospital admissions.

SETTING

Tertiary hospital.

PATIENTS

HIV-infected patients with new-onset radiologic PIs from April 1998 to March 1999.

METHODS

The study protocol included chest radiography, blood and sputum cultures, serologic testing for "atypical" causes of pneumonia, testing for Legionella urinary antigen, testing for cytomegalovirus antigenemia, and bronchoscopy in case of diffuse or progressive PIs.

RESULTS

One hundred two episodes in 92 patients were recorded. The incidence of PIs was 18 episodes per 100 hospital admission-years (95% confidence interval [CI]: 15-21). An etiologic diagnosis was achieved in 62 cases (61%). Bacterial pneumonia (BP), Pneumocystis carinii pneumonia (PCP), and mycobacteriosis were the main diagnoses. The incidences of BP and mycobacteriosis were not statistically different in highly active antiretroviral therapy (HAART) versus non-HAART patients. The incidence of PCP was lower in those receiving HAART (p =.011), however. Nine patients died (10%). Independent factors associated with higher mortality were mechanical ventilation (odds ratio [OR] = 83; CI: 4.2-1,682), age >50 years (OR = 23; CI: 2-283), and not having an etiologic diagnosis (OR = 22; CI: 1.6-293).

CONCLUSIONS

Pulmonary infiltrates are still a frequent cause of hospital admission in the HAART era, and BP is the main etiology. There was no difference in the rate of BP and mycobacteriosis in HAART and non-HAART patients. Not having an etiologic diagnosis is an independent factor associated with mortality.

Prognostic markers of short-term mortality in AIDS-associated Pneumocystis carinii pneumonia

BACKGROUND

Since 1990, corticosteroids have been recommended as adjunctive therapy for patients with AIDS-associated Pneumocystis carinii pneumonia (PCP) and respiratory failure. We hypothesized that the natural course of AIDS-associated PCP has changed in the era of adjunctive corticosteroid therapy.

OBJECTIVE

To study variables obtained on hospital admission for possible prognostic value of short-term (3-month) outcome of PCP.

DESIGN AND PATIENTS

Prospective observational study of 176 consecutive HIV-1-infected individuals with PCP between 1990 and 1999.

METHOD

Cox proportional-hazards regression models.

RESULTS

Univariate analysis showed that age, one or more prior episodes of PCP, use of antimicrobial therapy other than trimethoprim-sulfamethoxazole (TMP-SMZ), use of PCP prophylaxis at diagnosis, and culture of cytomegalovirus (CMV) in BAL predicted progression to death within 3 months. After adjustment, age (relative risk [RR], 4.1; 95% confidence interval [CI], 1.8 to 9.3), initial antimicrobial therapy other than TMP-SMZ (RR, 3.1; 95% CI, 1.2 to 8.5), use of PCP prophylaxis (RR, 5.6; 95% CI, 2.2 to 14.4), and culture of CMV in BAL fluid (RR, 2.7; 95% CI, 1.3 to 5.6) remained independent predictors of a poor outcome. In contrast, neither PO(2) nor serum lactate dehydrogenase, which in earlier studies were identified as prognostic markers, were predictors of mortality.

CONCLUSION

Age, initial anti-PCP therapy, use of PCP prophylaxis, and BAL CMV status may be useful predictors of outcome of PCP in patients treated in the era of adjunctive corticosteroid therapy.

Correlation of leukocyte esterase detection by reagent strips and the presence of neutrophils: a study in BAL fluid

STUDY OBJECTIVE

In the present study, we evaluated the leukocyte esterase (LE) area of a reagent strip designed for urinalysis for the semiquantitative measurement of the percentage of polymorphonuclear neutrophils (PMNs) in BAL fluid.

DESIGN

Prospective. The relative PMN counts (obtained by conventional microscopy and expressed as a percentage of a 500 cell count) of consecutive BAL fluid samples were compared with the corresponding LE categories as read with a urine chemistry reader. LE categories were graded as follows: negative, trace, +, + +, and + + +.

RESULTS

A total of 153 BAL fluid samples were included. The mean PMN counts of the negative LE category (4.1 +/- 4.3%; n = 43) and the + + + category (81.8 +/- 16.3%; n = 37) differed significantly from each other and from the mean PMN counts of the other categories. Within the trace, +, and + + categories, a considerable overlap of PMN counts was noted. Assignment of a BAL fluid to the negative LE category consistently predicted a PMN count < 20%. At a threshold value of 50% PMNs, the + + + LE category predicted the BAL fluid samples to the correct group (PMNs > 50% vs < 50%) with a sensitivity of 70.8% and a specificity of 97.1%.

CONCLUSIONS

The reagent strips proved to be useful as a rapid test for semiquantitative measurement of the relative PMN counts in BAL fluid. However, the low predictive value for the exclusion of a high PMN count may limit their application.

S-adenosylmethionine and Pneumocystis carinii

We previously reported that S-adenosylmethionine (AdoMet), a key molecule in methylation reactions and polyamine biosynthesis, enhances axenic culture of the AIDS-associated opportunistic fungal pathogen Pneumocystis carinii. Here we report that AdoMet is absolutely required for continuous growth. Two transporters are present, one high affinity, K(m) = 4.5 microm, and one low affinity, K(m) = 333 microm. The physiologically relevant high affinity transporter has a pH optimum of 7.5 and no related natural compounds compete for uptake. Transport is 98% inhibited at 4 degrees C, 24% inhibited by 20 mm sodium azide, and 95% inhibited by the combination of 20 mm sodium azide and 1 mm salicylhydroxamic acid; thus transport is active and dependent on both a cytochrome chain and an alternative oxidase. In vitro, AdoMet is used at a rate of 1. 40 x 10(7) molecules cell(-1) min(-1). AdoMet synthetase activity was not detected by a sensitive radiolabel incorporation assay capable of detecting 0.1% of the activity in rat liver. In addition, the AdoMet plasma concentration of rats is inversely correlated with the number of P. carinii in the lungs. These findings demonstrate that P. carinii is an AdoMet auxotroph. The uptake and metabolism of this compound are rational chemotherapeutic targets.

Human immunodeficiency virus and respiratory infection

Pulmonary disease remains a major problem for the 33 million individuals who are thought to be infected with human immunodeficiency virus (HIV) worldwide. Respiratory infections are responsible for a large number of the 2 million deaths that occur each year in association with HIV disease. In countries where the majority of the population can access highly active antiretroviral therapy, morbidity and mortality rates have been cut by up to 80%. This has allowed the withdrawal of specific opportunistic infection prophylaxis when immune restoration is deemed to be adequate. Recommendations have been published concerning Pneumocystis carinii prophylaxis. This year has also seen further reports of drug-resistant isolates of Pneumocystis carinii. The clinical relevance of this is still debated. Tuberculosis remains a global problem. The complexity of the interactions between specific anti-HIV and anti-tuberculous treatment have been highlighted. In the developing world, the importance of immunization and prophylaxis (against bacteria and mycobacteria) have recently been further defined in a number of studies.