Pulmonary disease in the immunocompromised host. 1

Gut microbiota dysbiosis-related susceptibility to nontuberculous mycobacterial lung disease

The role of gut microbiota in host defense against nontuberculous mycobacterial lung disease (NTM-LD) was poorly understood. Here, we showed significant gut microbiota dysbiosis in patients with NTM-LD. Reduced abundance of Prevotella copri was significantly associated with NTM-LD and its disease severity. Compromised TLR2 activation activity in feces and plasma in the NTM-LD patients was highlighted. In the antibiotics-treated mice as a study model, gut microbiota dysbiosis with reduction of TLR2 activation activity in feces, sera, and lung tissue occurred. Transcriptomic analysis demonstrated immunocompromised in lung which were closely associated with increased NTM-LD susceptibility. Oral administration of P. copri or its capsular polysaccharides enhanced TLR2 signaling, restored immune response, and ameliorated NTM-LD susceptibility. Our data highlighted the association of gut microbiota dysbiosis, systematically compromised immunity and NTM-LD development. TLR2 activation by P. copri or its capsular polysaccharides might help prevent NTM-LD.

Anatomic Approach to Common and Uncommon Manifestations of Thoracic Leukemias with Radiologic-Pathologic Correlation

Leukemias are hematopoietic malignancies characterized by the production of abnormal leukocytes in the bone marrow. Clinical manifestations arise from either bone marrow suppression or leukemic organ infiltration. Lymphadenopathy is the most common direct manifestation of intrathoracic leukemia. However, leukemic cells may also infiltrate the lungs, pleura, heart, bones, and soft tissues. Pulmonary complications in patients with leukemia typically include pneumonia, hemorrhage, pulmonary edema, and sequelae of leukemia treatment. However, pulmonary abnormalities can also be related directly to leukemia, including leukemic pulmonary infiltration. The direct, non-treatment-related effects of leukemia on intrathoracic structures will be the focus of this imaging essay. Given the typical anatomic approach for image interpretation, an organ-based depiction of common and less common intrathoracic findings directly caused by leukemic involvement is presented, emphasizing imaging findings with pathologic correlations. Keywords: Leukemia, Pulmonary, Thorax, Soft Tissues/Skin, Hematologic, Bone Marrow © RSNA, 2023.

Breathless Revelation: Unmasking Acute Myeloid Leukemia Through Acute Respiratory Failure

Establishing a diagnosis of acute myeloid leukemia (AML) in a patient presenting with acute respiratory failure is rare. Here, we present a case of AML initially appearing as hypoxemic respiratory failure linked to presumed community-acquired pneumonia. This case report unravels the intricate diagnostic odyssey of an atypical AML presentation masquerading as an acute respiratory failure, accentuating the multifaceted challenges clinicians encounter in discerning the actual underlying pathology amidst the haze of mimicry. Upon meticulous diagnostic expedition, infection was ruled out as a cause of respiratory failure, and the patient underwent a malignancy workup, ultimately culminating in the diagnosis. This case underscores the importance of broader diagnostic vigilance. Comprehensive assessments, combined with interdisciplinary collaboration, emerged as crucial for accurate diagnosis, emphasizing the need to consider hematologic pathologies despite seemingly unrelated clinical presentations.

Percutaneous transthoracic needle biopsies in immunocompromised hosts with suspicious pulmonary infection: diagnostic yields and complications

BACKGROUND

Pulmonary infection is a major cause of morbidity and mortality in immunocompromised patients, in whom diagnostic yields of cone-beam computed tomography (CBCT)-guided percutaneous transthoracic needle biopsies (PTNBs) have not been evaluated so far.

PURPOSE

To evaluate diagnostic yields and complications of CBCT-guided PTNBs in immunocompromised patients.

MATERIAL AND METHODS

From January 2015 to January 2018, 43 patients (25 men, 18 women; mean age 54.1 ± 16.4 years) who were suspected of having pulmonary infections were included in this retrospective study. Electronic medical records and radiologic studies were reviewed, including the underlying medical status, information on target lesions, PTNB procedural factors, and pathologic results. Logistic regression was performed to explore factors related with post-PTNB complications.

RESULTS

Among 43 patients, specific causative organisms or family of organisms were identified by PTNBs in 16 patients (37.2%). The most common causative organism was fungus (10/16, 62.5%), while bacterial infection was pathologically proven only in one patient (6.3%). Clinically significant change in management occurred in 12 of 43 patients (27.9%). Post-PTNB complications developed in 12 patients (27.9%; pneumothorax [n = 6] and hemoptysis [n = 6]) without PTNB-related mortality. Lower lobar location (odds ratio [OR] = 0.07, P = 0.006) was related with post-PTNB pneumothorax, while lower platelet counts (≤127 × 10³/µL) were associated with post-PTNB hemoptysis (OR = 9.82, P = 0.025).

CONCLUSION

CBCT-guided PTNBs revealed microbiological pathogens in 37.2% of immunocompromised patients and led to subsequent clinical actions in 27.9% of patients. Post-PTNB complications occurred in 27.9% of patients, and it might be necessary to perform PTNBs more carefully in immunocompromised patients with lower platelet counts.

A Nomogram Based on Comorbidities and Infection Location to Predict 30 Days Mortality of Immunocompromised Patients in ICU: A Retrospective Cohort Study

Background

The existing comorbidity indexes, like Charlson Comorbidity Index (CCI) and the Elixhauser Comorbidity Index (ECI), do not take infection factors into account for critically ill patients with immunocompromise, bringing about a decrease of prediction accuracy. Therefore, we attempted to incorporate infection location into the analysis to construct a rapid comorbidity scoring system independent of laboratory tests.

Methods

Data were extracted from the Multiparameter Intelligent Monitoring in Intensive Care III database. A total of 3904 critically ill patients with immunocompromise admitted to ICU were enrolled and assigned into training or validation sets according to the date of ICU admission. The predictive nomogram was constructed in the training set based on logistic regression analysis and then undergone validation in the validation set in comparison with SOFA, CCI and ECI.

Results

Factors eligible for the nomogram included patient’s age, gender, ethnicity, underlying disease of immunocompromise like metastatic cancer and leukemia, possible infection on admission including pulmonary infection, urinary tract infection and blood infection, and one comorbidity, coagulopathy. The nomogram we developed exhibited better discrimination than SOFA, CCI and ECI with an area under the receiver operating characteristic curve (AUC) of 0.739 (95% CI 0.707–0.771) and 0.746 (95% CI 0.713–0.779) in the training and validation sets, respectively. Combining the nomogram and SOFA could bring a new prediction model with a superior predictive effect in both sets (training set AUC = 0.803 95% CI 0.777–0.828, validation set AUC = 0.818 95% CI 0.783–0.854). The calibration curve exhibited coherence between the nomogram and ideal observation for two cohorts (p>0.05). Decision curve analysis revealed the clinical usefulness of the nomogram in both sets.

Conclusion

We established a nomogram that could provide an accurate assessment of 30 days ICU mortality in critically ill patients with immunocompromise, which can be employed to evaluate the short-term prognosis of those patients and bring more clinical benefits without dependence on laboratory tests.

Clinical Utility of Surgical Lung Biopsy for Patients with Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

Surgical lung biopsy (SLB) is performed in patients with acute respiratory distress syndrome (ARDS); however, its clinical utility remains unclear.

OBJECTIVES

We categorized the pathological diagnoses and investigated the predictive value for short-term mortality.

METHOD

Three electronic databases (MEDLINE, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov) were searched for the included studies. The QUADAS-2 was used to evaluate the risk of bias and its applicability. The types and populations of pathological diagnoses were investigated. The pooled sensitivity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR) were estimated at a fixed specificity. Hierarchical summary receiver operating characteristic curves were drawn.

RESULTS

A total of 16 studies that enrolled 758 patients were included. The pathological diagnoses were as follows: diffuse alveolar damage (DAD) 29.9%; infection 24.7%; interstitial lung disease 17.2%; malignancy 3.6%; cardiovascular disease 3.6%; drug toxicity 2.3%; connective tissue disease 2.2%; allergic disease 1.1%; and nonspecific diagnosis 15.4%. To predict short-term mortality, 13 studies that enrolled 613 patients used DAD as an index test and recorded a mortality rate of 56.9% (349 of 613 patients). A total of 3 studies that used index tests other than DAD were excluded. The pooled sensitivity, fixed specificity, LR+, LR-, and DOR were 0.46 (95% confidence interval [CI]: 0.29-0.56), 0.69, 1.48 (95% CI: 0.92-1.81), 0.78 (95% CI: 0.63-1.03), and 1.90 (95% CI: 0.89-2.86), respectively.

CONCLUSIONS

SLB is unlikely to provide a specific diagnosis and should not be recommended for confirming DAD or predicting ARDS prognosis.

Secondary Immunodeficiency in Hematological Malignancies: Focus on Multiple Myeloma and Chronic Lymphocytic Leukemia

Secondary immunodeficiency is reported in most patients with hematological malignancies such as chronic lymphocytic leukemia and multiple myeloma. The aim of our review was to evaluate the existing literature data on patients with hematological malignancies, with regard to the effect of immunodeficiency on the outcome, the clinical and therapeutic approach, and on the onset of noninfectious complications, including thrombosis, pleural effusion, and orofacial complications. Immunodeficiency in these patients has an intense impact on their risk of infection, in turn increasing morbidity and mortality even years after treatment completion. However, these patients with increased risk of severe infectious diseases could be treated with adequate vaccination coverage, but the vaccines' administration can be associated with a decreased immune response and an augmented risk of adverse reactions. Probably, immunogenicity of the inactivated is analogous to that of healthy subjects at the moment of vaccination, but it undertakes a gradual weakening over time. However, the dispensation of live attenuated viral vaccines is controversial because of the risk of the activation of vaccine viruses. A particular immunization schedule should be employed according to the clinical and immunological condition of each of these patients to guarantee a constant immune response without any risks to the patients' health.

Pneumonia Detection in Chest X-Ray Dose-Equivalent CT: Impact of Dose Reduction on Detectability by Artificial Intelligence

RATIONALE AND OBJECTIVES

There has been a significant increase of immunocompromised patients in recent years due to new treatment modalities for previously fatal diseases. This comes at the cost of an elevated risk for infectious diseases, most notably pathogens affecting the respiratory tract. Because early diagnosis and treatment of pneumonia can help reducing morbidity and mortality, we assessed the performance of a deep neural network in the detection of pulmonary infection in chest X-ray dose-equivalent computed tomography (CT).

MATERIALS AND METHODS

The 100 patients included in this retrospective study were referred to our department for suspicion of pulmonary infection and/or follow-up of known pulmonary nodules. Every patient was scanned with a standard dose (1.43 ± 0.54 mSv) and a 20 times dose-reduced (0.07 ± 0.03 mSv) CT protocol. We trained a deep neural network to perform binary classification (pulmonary consolidation present or not) and assessed diagnostic performance on both standard dose and reduced dose CT images.

RESULTS

The areas under the curve of the deep learning algorithm for the standard dose CT was 0.923 (confidence interval [CI] 95%: 0.905-0.941) and significantly higher than the areas under the curve (0.881, CI 95%: 0.859-0.903) of the reduced dose CT (p = 0.001). Sensitivity and specificity of the standard dose CT was 82.9% and 93.8%, and of the reduced dose CT 71.0% and 93.3%.

CONCLUSION

Pneumonia detection with X-ray dose-equivalent CT using artificial intelligence is feasible and may contribute to a more robust and reproducible diagnostic performance. Dose reduction lowered the performance of the deep neural network, which calls for optimization and adaption of CT protocols when using AI algorithms at reduced doses.

Percutaneous CT-guided lung biopsy for the diagnosis of persistent pulmonary consolidation

PURPOSE

The primary objective of this study was to determine the diagnostic accuracy of percutaneous computed tomography (CT)-guided biopsy of persistent pulmonary consolidations. The secondary objective was to determine the complication rate and identify factors affecting diagnostic yield.

MATERIALS AND METHODS

Two radiologists retrospectively reviewed 98 percutaneous CT-guided biopsies performed in 93 patients (60 men, 33 women; mean age, 62±14.0 (SD) years; range: 18-88 years) with persistent pulmonary consolidations. Final diagnoses were based on surgical outcomes or 12 months clinical follow-up findings. Biopsy results were compared to the final diagnosis to estimate diagnostic yield.

RESULTS

A final diagnosis was obtained for all patients: 51/93 (54.8%) had malignant lesions, 12/93 (12.9%) specific definite benign lesions (including 9 infections, two pneumoconiosis and one lipoid pneumonia) and 30/93 (32.3%) non-specific benign lesions. CT-guided biopsy had an overall diagnostic yield of 60% (59/98) with a correct diagnosis for 50/51 malignant lesions (diagnostic yield of 98% for malignancy) and for 9/47 benign lesions (diagnostic yield of 19% for benign conditions). Major complications occurred in 4/98 (4%) of lung biopsies (four pneumothoraxes requiring chest tube placement).

CONCLUSION

Percutaneous CT-guided biopsy is an alternative to endoscopic or surgical biopsy for the diagnosis of persistent consolidation with a low risk of severe complication.

Assessment of Bronchiectasis in HIV Patients among an Urban Population

Bronchiectasis is characterized by permanent destruction of the airways that presents with productive cough, as well as bronchial wall thickening and luminal dilatation on computed tomographic (CT) scan of the chest; it is associated with high mortality. Accumulating data suggests higher rates of bronchiectasis among the HIV-positive population. This case series involves 14 patients with bronchiectasis and HIV followed at two major urban institutions from 1999 to 2018. Demographics, clinical presentation, microbiology, radiographic imaging, and outcomes were collected and compiled. Mean age was 42 years (range 12-77 years). 36% had a CD4 count greater than 500 cells/mm3, 28% had a CD4 count between 200 and 500 cells/mm3, and 36% had AIDS. 43% were treated for Pneumocystis jiroveci pneumonia (PJP) and 50% for Mycobacterium avium complex (MAC) infection. 21% had COPD, 7% had asthma, and 7% had a history of pulmonary aspergillosis. Two patients were followed up by pulmonary services after diagnosis of bronchiectasis on CT. The timeline of the follow-up in these cases was within months and after three years respectively. It is posited that the prevalence of bronchiectasis in HIV patients may be underestimated. Improving recognition and management of bronchiectasis could help diminish rehospitalization rates.

Diagnostic accuracy of magnetic resonance imaging in the evaluation of pulmonary infections in immunocompromised patients

Purpose

To evaluate the accuracy of magnetic resonance imaging (MRI) for diagnosing pulmonary infections in immunocompromised adults.

Material and methods

Computed tomography (CT) and MRI chest were performed in 35 immuno-compromised patients suspected of pulmonary infection. The MRI sequences that were performed included axial and coronal T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE), spectrally attenuated inversion recovery (SPAIR), true fast imaging with steady-state free precession (TRUFI), and three-dimensional fast low angle shot (3D FLASH) using breath-hold and respiratory triggered BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction). The presence of nodules, consolidations, and ground-glass opacities was evaluated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for MRI using CT scan as a reference standard.

Results

The sensitivity of MRI in nodule detection was 50% overall and 75% for nodules measuring more than 5 mm. Consolidation was detected with 100% sensitivity. Sensitivity and PPV for the detection of ground-glass opacities (GGOs) were 77.7% and 53.8%, respectively. T2 HASTE axial had the fewest image artefacts. Respiratory triggered MR pulse sequence did not add any significant diagnostic information as compared to the non-respiratory triggered MR pulse sequences.

Conclusions

Sensitivity for detecting small nodules and GGOs on MR is poor; CT scan remains the imaging modality of choice for the evaluation of pulmonary infections in immunocompromised patients. However, MRI can be used in the follow-up imaging of these patients.

Utility of bronchoalveolar lavage in the management of immunocompromised patients presenting with lung infiltrates

Background

Bronchoalveolar lavage (BAL) is utilized for diagnosing lung infiltrates in immunocompromised. There is heterogeneity in the data and reported diagnostic yields range from 26 to 69%. Therefore, selection criteria for BAL to maximize yield and minimize complications are unclear.

Objectives of this study were to determine the diagnostic yield and complication rate of BAL in immunocompromised patients presenting with lung infiltrates, and identify factors impacting these outcomes. Exploratory aims included characterization of pathogens, rate of treatment modification and mortality.

Methods

Retrospective study from January 2012 to December 2016. Patients on mechanical ventilation were excluded. Positive diagnostic yield was defined as confirmed microbiological or cytological diagnosis.

Results

A total of 217 patients were recruited (70.1% male and mean age: 51.7 ± 14.6 years). Diagnostic yield was 60.8% and complication rate 14.7%. Complications (hypoxemia and endobronchial bleeding) were all sell-limiting. Treatment modification based on BAL results was 63.3%. In 97.0% an infectious aetiology was identified. HIV infection (OR 5.304, 95% CI 1.611–17.458, p = 0.006) and severe neutropenia (OR 4.253, 95% CI 1.288–14.045, p = 0.018) were associated with positive yield. Leukemia (OR 0.317, 95% CI 0.102–0.982, p = 0.047) was associated with lower yield. No factors impacted complication rate. Overall mortality (90-day) was 17.5% and in those with hematologic malignancy, it was 28.3%.

Conclusion

BAL retains utility in diagnosis of immunocompromised patients with lung infiltrates. However, patients with hematologic malignancy have a high mortality and alternative sampling should be considered because of poor results with BAL.

Trial registration

ClinicalTrials.gov identifier NCT01374542. Registered June 16, 2011.

Evaluation of cationic channel TRPV2 as a novel biomarker and therapeutic target in Leukemia-Implications concerning the resolution of pulmonary inflammation

Patients treated during leukemia face the risk of complications including pulmonary dysfunction that may result from infiltration of leukemic blast cells (LBCs) into lung parenchyma and interstitium. In LBCs, we demonstrated that transient receptor potential vanilloid type 2 channel (TRPV2), reputed for its role in inflammatory processes, exhibited oncogenic activity associated with alteration of its molecular expression profile. TRPV2 was overexpressed in LBCs compared to normal human peripheral blood mononuclear cells (PBMCs). Additionally, functional full length isoform and nonfunctional short form pore-less variant of TRPV2 protein were up-regulated and down-regulated respectively in LBCs. However, the opposite was found in PBMCs. TRPV2 silencing or pharmacological targeting by Tranilast (TL) or SKF96365 (SKF) triggered caspace-mediated apoptosis and cell cycle arrest. TL and SKF inhibited chemotactic peptide fMLP-induced response linked to TRPV2 Ca²⁺ activity, and down-regulated expression of surface marker CD38 involved in leukemia and lung airway inflammation. Challenging lung airway epithelial cells (AECs) with LBCs decreased (by more than 50%) transepithelial resistance (TER) denoting barrier function alteration. Importantly, TL prevented such loss in TER. Therefore, TRPV2 merits further exploration as a pharmacodynamic biomarker for leukemia patients (with pulmonary inflammation) who might be suitable for a novel [adjuvant] therapeutic strategy based on TL.

Role of bronchoalveolar lavage in the management of immunocompromised patients with pulmonary infiltrates

Pulmonary infiltrates are a significant cause of morbidity and mortality in immunocompromised patients and remain a diagnostic challenge due to the broad range of etiologies that include infection and malignancy. Empiric therapy may be sub-optimal and can adversely impact outcome. Therefore, a confirmed diagnosis is necessary and flexible bronchoscopy with bronchoalveolar lavage (BAL) may be a useful diagnostic tool. Samples are obtained for microbiological and cytological testing, but the procedure carries risk of complications including the adverse events related to moderate sedation. A review of published literature on BAL in immunocompromised patients from the year 2000 was undertaken focusing on diagnostic yield, complication rate, mortality as well as factors impacting these outcomes. Studies in which the majority of patients were supported on mechanical ventilation were excluded. A total of 23 studies (7 prospective and 16 retrospective) met inclusion criteria. This covered 3,395 procedures in 3,192 patients with a mean age of 47.4 years; 60.3% male gender. Diagnostic yield ranged from 26% to 69% with no clear association between diagnostic yield and etiology of immunosuppression or clinical/radiological presentation. Post BAL modification of treatment as an indicator for clinical utility ranged from 11% to 84%; and complication rate ranged from 1% to 52%. No specific factors were associated with increased adverse event rate. This review provides a summary of the data on the use of BAL for diagnosis of pulmonary infiltrates in immunocompromised patients, highlighting the heterogeneity of patients, significant variation in findings reported and the need for more data to optimize patient selection.

Pulmonary infiltrates in acute myeloid leukemia during induction treatment: how much do we know?

BACKGROUND

During induction treatment, acute myeloid leukemia patients may develop pulmonary infiltrates due to infectious or noninfectious etiologies. The risk association and the clinical outcome of such pulmonary infiltrates are poorly characterized in the literature.

METHODS

We retrospectively reviewed 363 cases of acute myeloid leukemia patients who received induction therapy as inpatients over a period of 11 years at William Beaumont Health System. Of these 363 patients, 120 developed pulmonary infiltrates during induction therapy, those patients were divided into 2 groups based on distribution of the infiltrate presenting as localized or diffuse in nature. Data on patients characteristics, leukemia subtype, cytogenetic risk, microorganism type, white blood cell count at diagnosis, neutrophil count at the time the infiltrate was reported, response to antibiotic and/or antifungal therapy, using respiratory support, and mortality rate were retrieved through chart review.

RESULTS

Thirty-three percent of patients developed pulmonary infiltrates during their induction therapy. Sixty-three patients (52.5%) had a localized infiltrates and 57 patients (47.5%) had diffuse infiltrates. Of the 120 patients with pulmonary infiltrates, 48 (40%) had at least 1 pathogenic microorganism identified, and 58 (48.7%) required intubation and ventilatory support. Patients with localized pulmonary infiltrates were more likely to have positive pathogenic microorganisms (68.3% vs. 8.8%, P<0.001), to be neutropenic (96.8% vs. 21%, P<0.001), and tended to have potentially reversible infiltrates after treatment (87.3% vs. 21%, P<0.001). Whereas patients with diffuse infiltrates were more like to require intubation (78.9% vs. 21%, P<0.001), to have leukocytosis (white blood cell >100 billions/L) at diagnosis (54.4% vs. 0%, P<0.001), and had a higher mortality rate (70.2% vs. 9.5%, P<0.001).

CONCLUSIONS

The radiologic patterns of pulmonary infiltrates showed specific etiological and prognostic associations. Diffuse infiltrates are an unfavorable characteristic with overall dismal outcome.

Pulmonary radiological findings in patients with acute myeloid leukemia and their relationship to chemotherapy and prognosis: a single-center retrospective study

OBJECTIVE

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. Pulmonary are among the most common causes of mortality in AML. This single-center retrospective study aimed to evaluate the relationship between radiological findings of pulmonary at presentation and post chemotherapy on prognosis and clinical outcome in a group of AML patients.

MATERIAL AND METHODS

The study included 278 AML patients. Clinical and radiological findings, laboratory findings, and microbiological culture results were evaluated. Pulmonary complications at presentation and post chemotherapy were compared.

RESULTS

Pulmonary complications were observed in 53 of the patients (19%). Mean age of the patients with and without pulmonary complications was 43.1 ± 15.2 years and 38.8 ± 16.3 years, respectively (P < 0.001). Pulmonary complications were not correlated with gender, AML subtype, or the serum lactate dehydrogenase (LDH) level. The most common cause of pulmonary complications was infection. Pulmonary complications were observed in 29% and 71% of the patients at presentation and post chemotherapy, respectively.

CONCLUSION

Pulmonary complications were observed more frequently at presentation in neutropenic AML patients of advanced age. The mortality rate was higher among the AML patients that had pulmonary complications at presentation.

Pneumonia in immunocompromised patients

The diagnosis and identification of causative microorganisms of pneumonia are often difficult in immunocompromised patients. Immunosuppression can divided into three categories; neutropenia (or neutrophil dysfunction); humoral immunodeficiency and cellular immunodeficiency. Presumptive pathogen identifications of pneumonia could be made systematically based on the type of impaired immune function. Since there are a number of diseases that must be differentiated, the collection of respiratory tract specimens and appropriate serum antigen tests should be done whenever possible to identify the causative microorganisms. Empirical antibiotic therapy should be started as soon as possible. If initial treatment proves ineffective, invasive diagnostic procedures, including surgical lung biopsy, should be considered.

Diagnostic approach of pulmonary disease in the HIV negative immunocompromised host

The advances in medicine have resulted in increasing number of immunocompromised patients with complications related to their underlying disease or the treatment of these conditions. Pulmonary infectious and non-infectious conditions are a major cause of morbidity and mortality in these patients, and represent a diagnostic challenge. This article reviews the major conditions causing pulmonary symptoms in the HIV negative immunocompromised host. It also discusses the role of the different diagnostic methods, including the recent advances in non-invasive studies, in reaching a diagnosis of pulmonary disease in this patient population.

The Outcome of Haematological Malignancy in Scottish Intensive Care Units

To study the prognostic indicators and outcome in patients with haematological malignancy requiring intensive care, we identified 714 adult patients and analysed their clinical audit data. Mean APACHE II score was 24. Main admitting diagnoses were acute lymphoma (43%) and acute leukaemia (28%). There was a high requirement for acute organ support. Intensive care unit (ICU) mortality was 39% and hospital mortality 55%, with a standardised mortality rate of 1.05 (0.98–1.13). Factors predictive of outcome after multivariate analysis were: cardiopulmonary resuscitation (CPR) in the 24-hours before ICU admission, inotropic support in the first 24-hours, APACHE II score and requirement for ventilatory support immediately prior to, or at admission to the ICU. Neutropaenia was not an independent predictor. Patients with neutropaenic septic shock and multiorgan failure left hospital. Hospital mortality for this group is comparable to that of non-cancer patients admitted with multi-organ system failure. The reluctance to admit such patients to ICU may be unjustified.

Differentiation of C2D macrophage cells after adoptive transfer

C2D macrophage cells protect immunocompromised mice from experimentally induced pneumonias after intraperitoneal (i.p.) adoptive transfer. These macrophage cells are immature and display minimal activity in vitro. Therefore, we wanted to understand how adoptive transfer affected these cells. We believe that the in vivo environment affects the phenotypic and functional characteristics of macrophages that help maintain the physiological integrity of the host. To test this hypothesis, we characterized the trafficking patterns and cellular changes of the established macrophage C2D cell line after adoptive transfer. We examined phenotypic changes of the C2D macrophage cells in vivo with and without stimulation with gamma interferon (IFN-gamma). After in vivo i.p. adoptive transfer, C2D macrophage cells trafficked to the lungs, spleen, lymph nodes, and bone marrow of recipient mice. The cells were detected for as long as 2 months, and the cells expressed increased levels of CD11b, c-fms, and F4/80 on their surface, becoming more differentiated macrophages compared to cells maintained in vitro. Upon in vivo stimulation with IFN-gamma, c-fms levels decreased while Gr-1 levels increased compared to in vivo, unstimulated, phosphate-buffered saline-injected controls. These responses were independent of the genetic backgrounds of the recipient mice. These data support the hypothesis and indicate that C2D macrophage cells respond to in vivo signals that are absent during in vitro culture.

Fiberoptic bronchoscopy and bronchoalveolar lavage for the evaluation of pulmonary disease in children with primary immunodeficiency and cancer

BACKGROUND

Patients with childhood cancer or primary immunodeficiencies (PID) are at high risk for developing pulmonary infections and non-infectious complications. The broad differential diagnoses and the critical condition of these patients often drive physicians to start broad-spectrum antibiotic therapy before a definite diagnostic procedure is performed. A definite diagnosis may be achieved in these situations by fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL).

PATIENTS AND METHODS

The records of 58 PIDs and cancer (immunocompromised group) pediatric patients who underwent 62 fiberoptic bronchoscopies between 2000 and 2004 were retrospectively reviewed and compared to 158 non-cancer patients who underwent 182 fiberoptic bronchoscopies during the same period.

RESULTS

The overall diagnostic rate achieved by macroscopic inspection of purulent secretions or hemorrhage, abnormal cell count, and infectious agent isolation in the immunocompromised patients was 84%. A definite organism was recovered in 53.2% of the patients. Probable infection defined as purulent secretions or abnormal cell count without infectious agent isolation was diagnosed in another 21% of the patients. The rate of complications was 30.6%. In the control group, the overall diagnostic rate was 76.9% (n.s) and an infectious agent was demonstrated in 12.1% (P < 0.001). Probable infection was diagnosed in 24.2% (n.s) while the rate of complications was lower (15%) (P < 0.01).

CONCLUSIONS

Rapid and accurate diagnoses were achieved in most procedures performed on immunocompromised patients. Although the rate of complications was higher in the immunocompromised group, they were usually very mild with no mortality. Based on these results, broncoalveolar lavage should be considered as an initial diagnostic tool in pediatric immunocompromised patients with pulmonary complications.

Bronchoscopic diagnosis of pulmonary infiltrates in granulocytopenic patients with hematologic malignancies: BAL versus PSB and PBAL

BACKGROUND

Treatment of patients with hematologic malignancies is often complicated by severe respiratory infections. Bronchoscopy is generally to be used as a diagnostic tool in order to find a causative pathogen.

OBJECTIVES

In a prospective study the combination of protected specimen brush (PSB) and protected bronchoalveolar lavage (PBAL) was compared with bronchoalveolar lavage (BAL) for evaluated feasibility and diagnostic yield in granulocytopenic patients with hematologic malignancies and pulmonary infiltrates.

METHODS

All specimens from 63 bronchoscopic procedures (35 BAL and 28 PSB-PBAL) were investigated by cytological examination and various microbiological tests. If clinically relevant and feasible, based on the clinical condition and/or the presence of thrombocytopenia, lung tissue samples were obtained.

RESULTS

The majority of the 58 included patients were diagnosed as having acute myeloid leukaemia and developed a severe neutropenia (BAL-group: 27 days; PSB-PBAL group: 30 days). Microbiological and cytological examination of 63 bronchoscopic procedures (35 BAL and 28 PSB-PBAL) yielded causative pathogens in 9 (26%) patients of the BAL-group and 8 (29%) patients of the PSB-PBAL group (PSB and PBAL 4 each). Aspergillus fumigatus was the pathogen most frequently (13%) detected. Using all available examinations including the results of autopsy, a presumptive diagnosis was established in 43% of the patients in the BAL group and 57% of those in the PSB-PBAL group; in these cases microbial aetiology was correctly identified in 67% and 57%, respectively. The complication rate was of these procedures were low, and none of the patients experienced serious complications due to the invasive techniques.

CONCLUSIONS

Our results showed that modern bronchoscopic techniques such as PSB and PBAL did not yield better diagnostic results compared to BAL in granulocytopenic patients with hematologic malignancies and pulmonary infiltrates. In approximately half of the cases a presumptive diagnosis was made by bronchoscopic procedures.

Pulmonary Infiltration from Chronic Lymphocytic Leukemia

We present 2 patients with chronic lymphocytic leukemia infiltration of the lung resulting in centrilobular nodularity on computed tomography. We present the x-ray and computed tomography patterns with pathological findings in these cases.

Role of flexible bronchoscopy in immunocompromised patients with lung infiltrates

STUDY OBJECTIVE

To study the diagnostic role of flexible bronchoscopy (FB) in immunocompromised patients with pulmonary infiltrates.

DESIGN

Prospective, observational study.

SETTING

Tertiary care hospital.

PATIENTS

A total of 104 consecutive non-HIV-infected immunocompromised patients with lung infiltrates in whom FB was performed.

METHODS

The primary outcome measure was the diagnostic yield of FB, which was derived as the number of the diagnoses made using FB results divided by all final diagnoses. Final diagnoses were established using data from FB, surgical lung biopsy (SLB), and microbiology and serology testing, and by the clinical response to empiric therapy. We also studied the diagnostic yields of individual sampling procedures such as BAL, transbronchial biopsy (TBB), and protected-specimen brush (PSB) sampling.

RESULTS

Overall, 128 diagnoses were made in 104 patients. The overall diagnostic yield of FB was 56.2% (95% confidence interval [CI], 47 to 64%). FB provided at least one diagnosis in 53 of 104 patients (51%; 95% CI, 40 to 62%). FB was more likely to establish the diagnosis when the lung infiltrate was due to an infectious agent (81%; 95% CI, 67 to 90%) than to a noninfectious process (56%; 95% CI, 43 to 67%; p = 0.011). The diagnostic yields of BAL (38%; 95% CI, 30 to 47%) and TBB (38%; 95% CI, 27 to 51%) were similar (p = 0.94). The diagnostic yield of PSB sampling was lower (13%; 95% CI 6 to 24%; p = 0.001) than that of BAL. The combined diagnostic yield of BAL and TBB (70%; 95% CI, 57 to 80%) was higher than that of BAL alone (p < 0.001). Finally, the diagnostic yield of FB with PSB sampling, BAL, and TBB was similar to that of FB with BAL and TBB. The complication rate from FB was 21% (95% CI, 15 to 31%). Minor bleeding (13%) and pneumothorax (4%) were the most common complications.

CONCLUSIONS

FB has a high diagnostic yield in immunocompromised patients with pulmonary infiltrates. Based on our results, we recommend performing TBB in these patients, whenever possible.

Acute myelogenous leukemia with splenic infarcts presenting as fulminant multi-organ failure

A 60-year-old male was admitted with leukopenia, thrombocytopenia, splenic infarcts and a normal peripheral smear. Within few hours he rapidly deteriorated with fatal multi-organ failure. Autopsy revealed massive infiltration of leukemic cells in several organs. Acute myelogenous leukemia should be considered in a patient presenting with unexplained multiorgan failure.

Pulmonary complications in chronic lymphocytic leukemia

BACKGROUND

Although pulmonary complications account for significant morbidity and mortality in patients with chronic lymphocytic leukemia (CLL), to the authors' knowledge there are sparse data available in published literature. The authors evaluated pulmonary complications in patients with CLL and identified prognostic variables that predict hospital mortality in these patients.

METHODS

Clinical data were analyzed retrospectively from patients with CLL who required hospitalization for a respiratory illness at a tertiary care institution from January 1993 to December 2001. A logistic regression analysis with a backward elimination procedure was carried out to determine prognostic variables that predict hospital mortality.

RESULTS

There were 110 patients who were admitted on 142 occasions with a pulmonary complication. The median age was 75 years (range, 43-97 years), and the male:female ratio was 1.7:1.0. Among 142 admissions, 68% were high risk according to the Rai criteria, 68% of patients admitted had received prior therapy for CLL, and 35% had received treatment within 3 months of admission. The most common pulmonary complications were pneumonias (75%), malignant pleural effusion/and or lung infiltrate due to CLL (9%), pulmonary leukostasis (4%), Richter transformation or nonsmall cell lung carcinoma (3%), and upper airway obstruction (2%). Forty-four of 110 patients (40%) died. In multivariate analysis, admission absolute neutrophil counts </= 0.5 x 10(9)/L (odds ratio, 4.6; 95% confidence interval [95% CI], 1.3-16.6) and blood urea nitrogen (BUN) levels >/= 20 mg/dL (odds ratio, 3.0; 95% CI, 1.1-8.3) were correlated significantly with mortality.

CONCLUSIONS

Pneumonia was the major pulmonary complication in hospitalized patients with CLL. Severe neutropenia and high BUN levels were correlated significantly with increased mortality.

Pulmonary considerations in the immunocompromised patient

The compromised patient who presents to the emergency department with pulmonary complaints is becoming a common occurrence. An immunocompromised state can result from a disease process such as HIV or from medications used to prevent graft rejection in solid organ recipients or to treat conditions such as collagen vascular disease. The emergency department physician should be familiar with the more common complications that can afflict this unique patient group. This article addresses the presentation, evaluation, and treatment of the more common pulmonary complications that can occur in solid organ transplant recipients, cancer patients, patients suffering from collagen vascular disease, and patients with HIV disease.

Leukaemic pulmonary infiltrates in adult acute myeloid leukaemia: a high-resolution computerized tomography study

Leukaemic infiltration of the lungs may occur in acute myeloid leukaemia (AML). Pulmonary infiltrates are usually microscopic and invariably associated with hyperleucocytosis. Four AML patients with respiratory symptoms and low leucocyte counts underwent standard chest radiography, bronchoscopy with bronchoalveolar lavage and high-resolution computerized tomography (HRCT) of the lungs. HRCT scans showed pulmonary infiltrates with alveolar, interstitial, mixed and peribronchial/perivascular patterns in all patients, including one with negative standard radiographic findings. Infectious agents were excluded. Histology of the lung biopsy/autopsy specimens showed leukaemic infiltrates. Pulmonary leukaemia may be the cause of pulmonary infiltrates, even in non-hyperleucocytosic AML patients with low blast counts.

A pulmonary syndrome in patients with acute myelomonocytic leukemia and inversion of chromosome 16

Different subtypes of acute myelogenous leukemia have distinct clinical presentations and courses. The specific clinical and molecular aspects of these leukemias have helped modify and create specific strategies for their management. We observed an increased incidence of pulmonary complications in patients with acute myelomonocytic leukemias (AMML) with inversion of chromosome 16 [inv(16)] irrespective of the presence of hyperleukocytosis. We reviewed patient records available over a period of 12 years at The Cleveland Clinic Foundation of patients with AMML with inv(16) and compared the incidence of pulmonary complications to a matched control group of patients with AMML but without inv(16). We found an increased incidence of pulmonary complications in the AMML with inv(16)group when compared to the control group. Two of these patients demonstrated brochiolitis obliterans with organizing pneumonia (BOOP) on lung biopsy. No specific etiology for the pulmonary complications was identified. These findings represent the first observation of an association between WHO-AMML with inv(16) [FAB-AML M4 with inv(16)] with a pulmonary syndrome at presentation. BOOP should be suspected in these cases. A larger prospective study to evaluate this association is warranted.

Acute respiratory failure in critically ill patients with cancer. Diagnosis and management

Respiratory failure remains a common cause of admission to the ICU for patients with cancer, regardless of the nature of malignancy. The diagnosis and management of ARF in patients with cancer poses special challenges to the intensivist. Depending on the type of cancer, the degree of immunosuppression, underlying comorbidities, the modality of cancer treatment, progression or spread of underlying cancer, and disease- or therapy-associated complications are the most common causes of ARF in these patients. Despite significant advances in antineoplastic therapies and supportive management in the ICU, the mortality rate of patients with cancer with ARF remains high. Severity-of-illness scoring systems and mortality probability models, although useful in discriminating between survivors and nonsurvivors in large groups of critically ill patients, should not be used alone to justify reluctance in admitting individual patients with cancer with potentially reversible respiratory failure to the ICU. Close collaboration between oncologists and intensivists will ensure the establishment of clear goals and direction of treatment for every patient with cancer who requires mechanical ventilation.

Role of the clinical microbiology laboratory in the diagnosis of infections

The proper use and interpretation of clinical microbiology test results may be complicated but critical to the care of cancer patients. The microbiology laboratory director is often available to offer advice concerning the differential diagnosis, choice of specimens, as well as the optimal stains and cultures to facilitate diagnosis. Additionally, the rapid interpretation of Gram-stained smears provides useful, occasionally lifesaving, information relative to the etiologic diagnosis and empiric antimicrobial therapy. The microbiology laboratory director should also provide further interpretation of culture and antimicrobial testing results that allow the clinical service to focus on the most critical data. Person-to-person or telephone conversations discussing important laboratory information should be followed up by a written summary report placed in the patient's chart so all services involved share the same interpretation (Figure 2). The clinical service has an important responsibility to communicate with the laboratory to optimize care of the patient with cancer. The laboratory compiles data collected from groups of patients that is available and useful to physicians. Review and discussion of test utilization is essential for cost-effective, quality health care. This may include analysis of blood cultures documenting an acceptable level of contamination, appropriate number collected per day, and sufficient blood volume per culture. In addition, information about changing resistance patterns or nosocomial transmission can be provided to the clinician. As patients with malignancies become more complex and their infections increasingly difficult to treat, regular interaction between the laboratory and clinician is likely to improve patient care.

Role of bronchoalveolar lavage in immunocompromised patients with pneumonia treated with a broad spectrum antibiotic and antifungal regimen

BACKGROUND

In a retrospective study the value of bronchoalveolar lavage (BAL) in the diagnosis of pneumonia was investigated in 95 immunocompromised patients suffering from haematological disorders and receiving a regimen of broad spectrum antibiotics and antifungal agents (BSAR).

METHODS

With the exception of four afebrile patients, all had fever, raised C reactive protein (CRP) levels, and new infiltrates visible on chest radiography. All patients underwent BAL to identify the organism causing the pneumonia and surveillance cultures were performed regularly for pathogens at different sites. Following classification of the isolates, patients with positive cultures were subdivided into two groups, pathogenic or contaminated. We investigated whether relevant pathogens were cultured only from the BAL fluid and whether they were susceptible to BSAR.

RESULTS

Although 77 of the 95 patients were thrombocytopenic, bleeding during BAL occurred in only 15% of all patients. Ten days after the procedure the fever improved in 88% of patients, radiographic findings improved in 71%, and CRP levels improved in 75% of patients; 22% of patients died within 28 days. Pathologically relevant isolates were found in 65% of all patients. Respiratory pathogens were detected only in the BAL fluid of 29 of the 95 patients (35% Gram positive species, 40% Gram negative species, 11% Mycobacterium, 11% fungi, and 3% cytomegalovirus). In 16 of these 29 patients (55%) the pathogens cultured only from the BAL fluid were resistant to treatment. Pathogens detected only in the BAL fluid were not susceptible to a standard broad spectrum antibiotic and antifungal regimen including teicoplanin, ceftriaxon, tobramycin, and amphotericin B in 12 of the 29 patients (41%).

CONCLUSIONS

Our data suggest that 12 patients were treated with broad spectrum antimicrobial agents which were not directed at the appropriate organism on in vitro sensitivity tests without BAL. BAL is a relatively safe procedure in the diagnosis of pneumonia, supplying important information in immunocompromised patients as well as in immunocompromised patients receiving BSAR.

Pulmonary infections in immunocompromised hosts: the importance of correlating the conventional radiologic appearance with the clinical setting

The lung is one of the most frequently involved organs in a variety of complications in the immunocompromised host. Among the pulmonary complications that occur in this kind of patient, infection is the most common and is associated with high morbidity and mortality. Although chest radiography and computed tomography (CT) are essential diagnostic tools, radiologists often have difficulty in establishing the correct diagnosis on the basis of radiologic findings alone. The reasons are that the immunocompromised host is potentially susceptible to infection from many different microorganisms and that radiologic findings are seldom specific for the detection of a particular pathogen. Experience has shown that a particular clinical setting predisposes patients to infection by particular pathogens. The setting comprises (a) the specific epidemiologic or environmental exposure, (b) the type of underlying immune defect, (c) the duration and severity of immune compromise, and (d) the progression rate and pattern of the radiologic abnormality. Correlating the radiologic appearance with the clinical setting can expedite diagnosis and appropriate therapy. In this review, the authors describe the clinical settings that are helpful in choosing the radiologic approach to treatment of the immunocompromised host who presents with suspected pulmonary infection.

Drug-induced respiratory disorders: incidence, prevention and management

Various drugs are associated with adverse respiratory disorders (ARDs) ranging in severity from mild, moderate to severe and even fatal. Cardioselective and nonselective beta-blockers, calcium antagonists and dipyridamole can induce asthma. ACE inhibitors are mainly associated with cough. Amiodarone is related to a form of interstitial pneumonitis (IP) which can be fatal, tocainidine and flecainidine to a form of IP, and hydrochlorothiazide to a form of IP and pulmonary oedema. Antiasthmatic drugs can be associated with a paradoxical bronchospasm, while leukotriene antagonists are linked to the development of Churg-Strauss syndrome. Nonsteroidal anti-inflammatory drugs including aspirin (acetylsalicylic acid) may induce asthma. Gold is mainly related to IP, penicillamine to IP, systemic lupus erythematosus, bronchiolitis obliterans, and Goodpasture's syndrome. Acute respiratory reactions to nitrofurantoin include dyspnoea, cough, IP, and pleural effusion while IP and fibrosis are common in chronic reactions. Other antibacterials mainly evoke pneumonitis, pulmonary infiltrates and eosinophilia, and bronchiolitis obliterans. ARDs are similar for most categories of cytotoxic agents, with chronic pneumonitis and fibrosis being the most common. Noncardiogenic pulmonary oedema occurs as the most common respiratory complication in opioid agonist addiction. Psychotropic drugs such as phenothiazides, butyrophenones and tricyclic antidepressants can also induce pulmonary oedema. Oral contraceptives may produce asthma exacerbation, while long term use and/or high doses of postmenopausal hormone replacement therapy increase the risk of asthma. Bromocriptine is mainly associated with pleural effusion, while methysergide is usually associated with pleural effusion and fibrosis. Some anorectic agents have been linked to the development of primary pulmonary hypertension. The possibility of the occurrence of ARDs should be taken into account in each individual patient. Although in most cases the adverse effects are unpredictable, they can be reduced to a minimum or prevented if some drugs are avoided or stopped in time.

Routine chest radiography for the evaluation of febrile neutropenic patients after autologous stem cell transplantation

Chest radiographs are routinely obtained for diagnostic evaluation of neutropenic febrile patients. We investigated the frequency of chest radiographic abnormalities during febrile episodes after autologous PBSC transplants and assessed the relationship of these abnormalities to past history of pulmonary disease, pre-transplant chest radiographic abnormalities, and pulmonary signs or symptoms at time of fever. We also studied the impact of chest radiographic findings on patient management. Sixty-one consecutive adult autologous PBSC transplant recipients were studied. Fifty-two (85%) developed fever, and 20 (38%) of these showed new chest radiographic abnormalities suggestive of pulmonary infection. Patients with pre-transplant chest radiographic abnormalities were more likely to develop additional abnormalities with fever post-transplant. Pulmonary symptoms or signs had low sensitivity or specificity for predicting radiographic abnormalities. Only 40% of patients with pulmonary symptoms or signs had an abnormal chest radiograph. Twenty-six percent of patients with abnormal chest radiographs had no clinical findings suggestive of pulmonary infection. The identification of chest radiographic abnormality did not change empiric antibiotic treatment in any patient. The role of routine chest radiography for diagnostic evaluation of febrile autologous PBSC transplant patients should be re-evaluated.

Bronchoalveolar lavage in the diagnosis of pulmonary complications of bone marrow transplant patients

Bronchoalveolar lavage (BAL) has proved valuable in the diagnosis of pulmonary complications in immunosuppressed patients. We evaluated the diagnostic yield of BAL in pulmonary complications in bone marrow transplantation (BMT) recipients. We reviewed sequentially the records of 89 patients during an 18-month period. BAL was diagnostic in 42 patients (47%). The most common pulmonary complication diagnosed by BAL was diffuse alveolar hemorrhage (n = 15); followed by bacterial pneumonia (n = 10), respiratory syncytial virus (n = 8), aspergillosis (n = 6), Pneumocystis carinii pneumonia (n = 5), cytomegalovirus (CMV) (n = 4), and others (n = 4). The final diagnoses in the BAL non-diagnostic group were: bacterial pneumonia (n = 6), CMV (n = 6), idiopathic pneumonia syndrome (n = 5), cancer recurrence (n = 4), cardiogenic pulmonary edema (n = 4), and others (n = 9). We conclude that BAL is a useful diagnostic tool in BMT-related pulmonary complications.

Successful management of pulmonary tuberculosis in renal allograft recipients in a single center

BACKGROUND

Pulmonary infections, especially tuberculosis, are responsible for significant mortality and morbidity among renal transplant recipients in developing countries. Conventional diagnostic modalities are associated with a low yield, delaying specific therapy.

METHODS

All patients transplanted within a 1.5-year period were prospectively followed-up for one year. Patients were on a cyclosporine-based triple immunosuppressive regimen. None received isoniazid prophylaxis, and those transplanted in the last seven months of the study period received daily cotrimoxazole. Patients exhibiting unequivocal evidence of pulmonary infections underwent further evaluation. Search for offending organisms was made by sputum examination and bronchoalveolar lavage (BAL).

RESULTS

. Thirty-nine infection episodes were recorded in 34 patients. M. tuberculosis was isolated during 10 episodes, pyogenic bacteria and Pneumocystis carinii in 6 each, candida in 4, aspergillus in 3, cytomegalovirus (CMV) in 3, and nocardia and mucor in one episode each. More than one organism was isolated during five episodes. Bacterial pneumonia and tuberculosis were diagnosed in another seven and two patients, respectively, on the basis of a therapeutic response to specific chemotherapy. Over two thirds of the organisms were identified by examination of BAL fluid. BAL was useful in the diagnosis of tuberculosis and P. carinii pneumonia but was relatively insensitive for CMV and bacterial infections. An increased frequency of acute rejection and higher serum creatinine were factors that predisposed to infections. All patients with pulmonary tuberculosis made a full recovery.

CONCLUSIONS

Tuberculosis and P. carinii are the most common nonpyogenic infections in the first year after transplantation in developing countries. An aggressive search for tubercle bacilli should be made using bronchoscopy and examination of BAL fluid in patients not responding to a short trial of antibiotics. A four-drug regime without rifampicin given for 18 months is effective for pulmonary tuberculosis in patients on cyclosporine. We recommend routine prophylactic use of one single-strength tablet of cotrimoxazole daily for at least six months after transplantation.