Pulmonary tuberculosis in HIV infection: radiographic appearance is related to CD4+ T-lymphocyte count

Radiographic characteristics of rifampicin-resistant tuberculosis in the STREAM stage 1 trial and their influence on time to culture conversion in the short regimen

BACKGROUND

Stage 1 of the STREAM trial demonstrated that the 9 month (Short) regimen developed in Bangladesh was non-inferior to the 20 month (Long) 2011 World Health Organization recommended regimen. We assess the association between HIV infection and radiographic manifestations of tuberculosis and factors associated with time to culture conversion in Stage 1 of the STREAM trial.

METHODS

Reading of chest radiographs was undertaken independently by two clinicians, and films with discordant reading were read by a third reader. Recording of abnormal opacity of the lung parenchyma included location (right upper, right lower, left upper, and left lower) and extent of disease (minimal, moderately-advanced, and far advanced). Time to culture conversion was defined as the number of days from initiation of treatment to the first of two consecutive negative culture results, and compared using the log-rank test, stratified by country. Cox proportional hazards models, stratified by country and adjusted for HIV status, were used to identify factors associated with culture conversion.

RESULTS

Of the 364 participants, all but one had an abnormal chest X-ray: 347 (95%) had opacities over upper lung fields, 318 (87%) had opacities over lower lung fields, 124 (34%) had far advanced pulmonary involvement, and 281 (77%) had cavitation. There was no significant association between HIV and locations of lung parenchymal opacities, extent of opacities, the presence of cavitation, and location of cavitation. Participants infected with HIV were significantly less likely to have the highest positivity grade (3+) of sputum culture (p = 0.035) as compared to participants not infected with HIV. Cavitation was significantly associated with high smear positivity grades (p < 0.001) and high culture positivity grades (p = 0.004) among all participants. Co-infection with HIV was associated with a shorter time to culture conversion (hazard ratio 1.59, 95% CI 1.05-2.40).

CONCLUSIONS

Radiographic manifestations of tuberculosis among the HIV-infected in the era of anti-retroviral therapy may not differ from that among those who were not infected with HIV. Radiographic manifestations were not consistently associated with time to culture conversion, perhaps indicating that the Short regimen is sufficiently powerful in achieving sputum conversion across the spectrum of radiographic pulmonary involvements.

TRIAL REGISTRATION

ISRCTN ISRCTN78372190. Registered 14/10/2010. The date of first registration 10/02/2016.

Prospective evaluation of radiographic manifestations of tuberculosis in relationship with CD4 count in patients with HIV/AIDS

A major risk factor to develop active tuberculosis (TB) is the infection with the human immunodeficiency virus (HIV). Chest radiography is the first-line imaging modality used to rule out TB. Coinfected individuals present often with atypical imaging patterns, due to the immunosuppression caused by the virus, making diagnosis difficult. In this prospective observational study 268 TB and HIV coinfected patients were included. During a follow-up period of 24 weeks, the predominant patterns on chest radiography were analyzed and compared to the cluster of differentiation 4 (CD4) count under antiretroviral and anti-TB therapy. Patients with low CD4 counts (<200 cells//µL) showed more often lymphadenopathy (62% vs 38%;P = .08) and a miliary pattern (64% vs 36%;P = .04) but less likely cavitation (32% vs 68%;P = .008) or consolidation (47% vs 63%;P = .002) compared to individuals with higher CD4 counts. Over the follow-up period, partial response to therapy was the most frequent radiological evolution (62%), mainly accompanied by an increase of CD4 cells (92%). Patients with a decrease in CD4 count mostly presented with a worsening in radiological findings (53%). Radiographic TB manifestation correlated with the immune status of patients coinfected with HIV. Low CD4 counts often showed atypical manifestation.

Respiratory symptoms and lung function in patients treated for pulmonary tuberculosis in Malawi: a prospective cohort study

Rationale

Pulmonary tuberculosis (PTB) can cause post-TB lung disease (PTLD) associated with respiratory symptoms, spirometric and radiological abnormalities. Understanding of the predictors and natural history of PTLD is limited.

Objectives

To describe the symptoms and lung function of Malawian adults up to 3 years following PTB-treatment completion, and to determine the evolution of PTLD over this period.

Methods

Adults successfully completing PTB treatment in Blantyre, Malawi were followed up for 3 years and assessed using questionnaires, post-bronchodilator spirometry, 6 min walk tests, chest X-ray and high-resolution CT. Predictors of lung function at 3 years were identified by mixed effects regression modelling.

Measurement and main results

We recruited 405 participants of whom 301 completed 3 years follow-up (mean (SD) age 35 years (10.2); 66.6% males; 60.4% HIV-positive). At 3 years, 59/301 (19.6%) reported respiratory symptoms and 76/272 (27.9%) had abnormal spirometry. The proportions with low FVC fell from 57/285 (20.0%) at TB treatment completion to 33/272 (12.1%), while obstruction increased from and 41/285 (14.4%) to 43/272 (15.8%) at 3 years. Absolute FEV₁ and FVC increased by mean 0.03 L and 0.1 L over this period, but FEV₁ decline of more than 0.1 L was seen in 73/246 (29.7%). Higher spirometry values at 3 years were associated with higher body mass index and HIV coinfection at TB-treatment completion.

Conclusion

Spirometric measures improved over the 3 years following treatment, mostly in the first year. However, a third of PTB survivors experienced ongoing respiratory symptoms and abnormal spirometry (with accelerated FEV₁ decline). Effective interventions are needed to improve the care of this group of patients.

CheXaid: deep learning assistance for physician diagnosis of tuberculosis using chest x-rays in patients with HIV

Tuberculosis (TB) is the leading cause of preventable death in HIV-positive patients, and yet often remains undiagnosed and untreated. Chest x-ray is often used to assist in diagnosis, yet this presents additional challenges due to atypical radiographic presentation and radiologist shortages in regions where co-infection is most common. We developed a deep learning algorithm to diagnose TB using clinical information and chest x-ray images from 677 HIV-positive patients with suspected TB from two hospitals in South Africa. We then sought to determine whether the algorithm could assist clinicians in the diagnosis of TB in HIV-positive patients as a web-based diagnostic assistant. Use of the algorithm resulted in a modest but statistically significant improvement in clinician accuracy (p = 0.002), increasing the mean clinician accuracy from 0.60 (95% CI 0.57, 0.63) without assistance to 0.65 (95% CI 0.60, 0.70) with assistance. However, the accuracy of assisted clinicians was significantly lower (p < 0.001) than that of the stand-alone algorithm, which had an accuracy of 0.79 (95% CI 0.77, 0.82) on the same unseen test cases. These results suggest that deep learning assistance may improve clinician accuracy in TB diagnosis using chest x-rays, which would be valuable in settings with a high burden of HIV/TB co-infection. Moreover, the high accuracy of the stand-alone algorithm suggests a potential value particularly in settings with a scarcity of radiological expertise.

Correlation Between Clinical Manifestation and Radiological Findings In Pulmonary Tuberculosis-Human Immunodeficiency Virus Coinfection Patients In Sanglah Hospital, Bali, Indonesia

BACKGROUND

Tuberculosis (TB) mono-infection has radiological features and typical clinical manifestations that are easily recognized by clinicians. These radiological features and clinical manifestations are often found to show atypical features in subjects coinfected with Tuberculosis- Human Immunodeficiency Virus (HIV), making TB diagnosis and early management challenging to establish.

OBJECTIVE

The aim of this study was to determine the relationship between the clinical and radiological presentation of pulmonary TB patients with HIV coinfection at the Central General Hospital Sanglah, Bali.

METHODS

This research was an observational analytic study with a cross-sectional method. A total of 54 TB-HIV coinfected patients were analyzed to their sociodemographic characteristics, clinical manifestations and chest radiographic features.

RESULTS

The majority of subjects were of productive age (26-61 years), male (64.8%) and belonged to the heterosexual group (90.7%). Weight loss (75.9%), cough (64.8%) and oral candidiasis (53.7%) are the most common clinical manifestations found in subjects, especially in subjects with CD4+ >200 cells/mm3. Atypical radiological features such as infiltration/consolidation (59.3%), fibrosis (16.7%) and hillar lymphadenopathy (14.8%) are the most commonly obtained radiological features of the subjects. From the results of the bivariate analysis, it was found that radiological features in the form of infiltration/consolidation were more commonly found in subjects with CD4+ <200 cells/mm3 (OR=1.254; 95% CI 1.059-1.568).

CONCLUSION

Based on the research that has been done, it can be concluded that there are no typical radiological features and clinical manifestations in patients with TB-HIV infection.

Comparison of Löwenstein-Jensen and BACTEC MGIT 960 culture for Mycobacterium tuberculosis in people living with HIV

OBJECTIVES

The aim of the study was to clarify how HIV infection affects tuberculosis liquid and solid culture results in a resource-limited setting.

METHODS

We used baseline data from the Study on Outcomes Related to Tuberculosis and HIV Drug Concentrations in Uganda (SOUTH), which included 268 HIV/tuberculosis (TB)-coinfected individuals. Culture results from Löwenstein-Jensen (LJ) solid culture and mycobacteria growth indicator tube (MGIT) liquid culture systems and culture-based correlates for bacillary density from the sputum of HIV/TB-coinfected individuals at baseline were analysed.

RESULTS

Of 268 participants, 243 had a CD4 cell count available and were included in this analysis; 72.2% of cultures showed growth on solid culture and 82.2% in liquid culture systems (P < 0.015). A higher CD4 cell count was predictive of LJ positivity [adjusted odds ratio (OR) 1.14; 95% confidence interval (CI) 1.03-1.25 per 50 cells/μL increase; P = 0.008]. The same, but insignificant trend was observed for MGIT positivity (adjusted OR 1.09; 95% CI 0.99-1.211 per 50 cells/μL increase; P = 0.094). A higher CD4 cell count was associated with a higher LJ colony-forming unit grade (adjusted OR 1.14; 95% CI 1.05-1.25 per 50 cells/μL increase; P = 0.011) and a shorter time to MGIT positivity [adjusted hazard ratio (HR) 1.08; 95% CI 1.04-1.12 per 50 cells/μL increase; P < 0.001].

CONCLUSIONS

In a resource-limited setting, the MGIT liquid culture system outperformed LJ solid culture in terms of culture yield and dependence on CD4 cell counts in HIV/TB-coinfected individuals. We therefore suggest considering an adaptation of diagnostic algorithms: when resources allow only one culture method to be performed, we recommend that MGIT liquid culture should be used exclusively in HIV-positive individuals as a first-line culture method, to reduce costs and make TB culture results accessible to more patients in resource-limited settings.

Type I interferons in tuberculosis: Foe and occasionally friend

Tuberculosis remains one of the leading causes of mortality worldwide, and, despite its clinical significance, there are still significant gaps in our understanding of pathogenic and protective mechanisms triggered by Mycobacterium tuberculosis infection. Type I interferons (IFN) regulate a broad family of genes that either stimulate or inhibit immune function, having both host-protective and detrimental effects, and exhibit well-characterized antiviral activity. Transcriptional studies have uncovered a potential deleterious role for type I IFN in active tuberculosis. Since then, additional studies in human tuberculosis and experimental mouse models of M. tuberculosis infection support the concept that type I IFN promotes both bacterial expansion and disease pathogenesis. More recently, studies in a different setting have suggested a putative protective role for type I IFN. In this study, we discuss the mechanistic and contextual factors that determine the detrimental versus beneficial outcomes of type I IFN induction during M. tuberculosis infection, from human disease to experimental mouse models of tuberculosis.

Tuberculosis in immunosuppressed patients

Tuberculosis (TB) is one of the most significant infections in immunosuppressed patients due to its high frequency and high morbidity and mortality. TB is the leading cause of death among HIV-infected patients. The diagnosis and early treatment of latent tuberculosis infection is vital to preventing it progression to disease. Similarly, the early diagnosis of TB is key to improving the prognosis of patients and preventing its transmission. The clinical expression of TB in immunosuppressed patients is conditioned by the patient's degree of immunosuppression. It is important to keep this peculiarity in mind so as not to delay the diagnosis of suspected TB. TB treatment is basically the same in immunosuppressed patients as in the general population and any differences mainly derive from pharmacological interactions. We examined the diagnosis and treatment of TB and latent tuberculosis infection in immunosuppressed patients.

Infection

Community-Acquired Pneumonia (CAP) is the first leading cause of death due to infection worldwide.Many gram-positive, gram-negative bacteria, funguses and viruses can cause the infectious pulmonary disease, and the severity of pneumonia depends on the balance between the microorganism charge, the body immunity defenses and the quality of the underlying pulmonary tissue. The microorganisms may reach the lower respiratory tract from inhaled air or from infected oropharyngeal secretions. The same organism may produce several different patterns that depend on the balance between the microorganism charge and the body immunity defenses.CAP is classified into three main groups: lobar pneumonia, bronchopneumonia and interstitial pneumonia.Lobar pneumonia is characterized by the filling of alveolar spaces by edema full of white and inflammatory cells. Necrotizing pneumonia consists of a fulminant process associated with focal areas of necrosis that results in abscesses. Bronchopneumonia or lobular pneumonia, is characterized by a peribronchiolar inflammation with thickening of peripheral bronchial wall, the diffusion of inflammation to the centrilobular alveolar spaces and development of nodules.The interstitial pneumonia represents with the destruction and esfoliation of the respiratory ciliated and mucous cells. The interstitial septa, the bronchial and bronchiolar walls become thickened for the inflammation process and lymphocytes interstitial infiltrates.Chest radiography represents an important initial examination in all patients suspected of having pulmonary infection and for monitoring response to therapy.Its role is to identify the pulmonary opacities, their internal characteristics and distribution, pleural effusion and presence of other complications as abscesses and pneumothorax.High spatial CT resolution allows accurate assessment of air space inflammation.The CT findings include nodules, interlobular septal thickening, intralobular reticular opacities, ground-glass opacities, tree-in-bud pattern, lobar-segmental consolidation, lobular consolidation, abscesses, pneumatocele, pleural effusion, pericardial effusion, mediastinal and hilar lymphoadenopaties, airway dilatation and emphysema.

Matrix Metalloproteinases in Tuberculosis-Immune Reconstitution Inflammatory Syndrome and Impaired Lung Function Among Advanced HIV/TB Co-infected Patients Initiating Antiretroviral Therapy

Background

HIV-infected patients with pulmonary TB (pTB) can have worsening of respiratory symptoms as part of TB-immune reconstitution inflammatory syndrome (TB-IRIS) following antiretroviral therapy (ART) initiation. Thus, reconstitution of immune function on ART could drive incident lung damage in HIV/TB.

Methods

We hypothesized that increases in matrix metalloproteinases (MMPs), which can degrade lung matrix, on ART are associated with TB-IRIS among a cohort of advanced, ART naïve, HIV-infected adults with pTB. Furthermore, we related early changes in immune measures and MMPs on ART to lung function in an exploratory subset of patients post-TB cure. This study was nested within a prospective cohort study. Rank sum and chi-square tests, Spearman's correlation coefficient, and logistic regression were used for analyses.

Results

Increases in MMP-8 following ART initiation were independently associated with TB-IRIS (p = 0.04; adjusted odds ratio 1.5 [95% confidence interval: 1.0–2.1]; n = 32). Increases in CD4 counts and MMP-8 on ART were also associated with reduced forced expiratory volume in one-second post-TB treatment completion (r = − 0.7, p = 0.006 and r = − 0.6, p = 0.02, respectively; n = 14).

Conclusions

ART-induced MMP increases are associated with TB-IRIS and may affect lung function post-TB cure. End-organ damage due to TB-IRIS and mechanisms whereby immune restoration impairs lung function in pTB deserve further investigation.

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Matrix metalloproteinases (MMP), capable of degrading lung collagen, can increase rapidly on ART in HIV/TB patients.

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Increases in plasma MMP-8 concentrations after ART initiation are associated with the development of paradoxical TB-IRIS.

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Increases in CD4 T-cells and MMP-8 concentrations after ART initiation are correlated with decreased lung function post-TB cure.

TB-associated pulmonary morbidity can persist after TB cure. However, causal mechanisms for lung damage, which may involve immune mechanisms and tissue proteases, in TB are unclear. Less is known in this regard among patients with HIV/TB, who are at risk for inflammatory reactions following ART initiation, otherwise known as TB-immune reconstitution inflammatory syndrome (IRIS). In this study, rapid ART-induced increases in certain tissue degrading proteins called matrix metalloproteinases (MMP) were associated with TB-IRIS. Furthermore, rapid recovery of CD4 T-cells and MMP-8 concentrations were associated with decreased lung function in an exploratory subset. In HIV/TB, robust increases in cellular immune function and MMPs on ART may underlie lung injury and long-term pulmonary deficits.

Radiographic appearance of pulmonary tuberculosis: dogma disproved

OBJECTIVE

The purpose of this article is to review the origins of the classic teaching on pulmonary tuberculosis, its evolution in the modern literature, and the evidence that led to its demise.

CONCLUSION

Use of molecular epidemiologic techniques that entail DNA finger-printing has led to the discovery that the radiographic appearance of pulmonary tuberculosis does not depend on the time since infection. It has been confirmed that the upper lobe cavitary disease typical in adults is the disease of the immunocompetent host, whereas lower lung zone disease, adenopathy, and effusions, which are uncommon in adults, are the hallmarks of tuberculosis in an immunocompromised host.

Animal models to study Mycobacterium tuberculosis and HIV co-infection

Mycobacterium tuberculosis (M.tb) and human immunodeficiency virus (HIV) co-infection has become a public health issue worldwide. Up to now, there have been many unresolved issues either in the clinical diagnosis and treatment of M.tb/HIV co-infection or in the basic understanding of the mechanisms for the impairments to the immune system by interactions of these two pathogens. One important reason for these unsolved issues is the lack of appropriate animal models for the study of M.tb/HIV co-infection. This paper reviews the recent development of research on the animal models of M.tb/HIV co-infection, with a focus on the non-human primate models.

Impact of human immunodeficiency virus and CD4 count on tuberculosis diagnosis: analysis of city-wide data from Cape Town, South Africa

BACKGROUND

The impact of human immunodeficiency virus (HIV) infection and CD4 count on the diagnosis of tuberculosis (TB) at population level is incompletely defined.

OBJECTIVE

To determine how HIV infection and CD4 count affect disease site, sputum smear status and overall rate of laboratory confirmation (sputum smear microscopy or culture) of TB cases under routine programme conditions.

DESIGN

Retrospective analysis of the 2009 electronic TB register for Cape Town, South Africa.

RESULTS

Of 29,478 TB cases notified in 2009, HIV status was known for 25,744 (87.3%) cases, of whom 13,237 (51.4%) were HIV-positive. Of these, 61.2% had CD4 cell counts of <200 cells/μl and 82.7% had counts of <350 cells/μl. Laboratory confirmation of TB (by smear or culture) was obtained less frequently in HIV-infected than non-HIV-infected adult cases (53.9% vs. 74.3%, P< 0.001). HIV infection was associated with a higher proportion of sputum smear-negative and extra-pulmonary TB and lower grades of sputum smear positivity even among those with CD4 counts of ≥ 500 cells/μl. However, the relationship between the proportion of smear-positive cases and CD4 count was non-linear.

CONCLUSION

Much TB is not laboratory-confirmed in this setting despite good laboratory services. HIV-associated TB is more difficult to diagnose even at high CD4 cell counts of >500 cells/μl, suggesting early impact after HIV seroconversion.

CD4 T cell depletion exacerbates acute Mycobacterium tuberculosis while reactivation of latent infection is dependent on severity of tissue depletion in cynomolgus macaques

CD4 T cells are believed to be important in protection against Mycobacterium tuberculosis, but the relative contribution to control of initial or latent infection is not known. Antibody-mediated depletion of CD4 T cells in M. tuberculosis-infected cynomolgus macaques was used to study the role of CD4 T cells during acute and latent infection. Anti-CD4 antibody severely reduced levels of CD4 T cells in blood, airways, and lymph nodes. Increased pathology and bacterial burden were observed in CD4-depleted monkeys during the first 8 weeks of infection compared to controls. CD4-depleted monkeys had greater interferon (IFN)-γ expression and altered expression of CD8 T cell activation markers. During latent infection, CD4 depletion resulted in clinical reactivation in only three of six monkeys. Reactivation was associated with lower CD4 T cells in the hilar lymph nodes. During both acute and latent infection, CD4 depletion was associated with reduced percentages of CXCR3(+) expressing CD8 T cells, reported to be involved in T cell recruitment, regulatory function, and effector and memory T cell maturation. CXCR3(+) CD8 T cells from hilar lymph nodes had more mycobacteria-specific cytokine expression and greater coexpression of multiple cytokines compared to CXCR3(-) CD8 T cells. CD4 T cells are required for protection against acute infection but reactivation from latent infection is dependent on the severity of depletion in the draining lymph nodes. CD4 depletion influences CD8 T cell function. This study has important implications for human HIV-M. tuberculosis coinfection.

Survival among patients with HIV infection and smear-negative pulmonary tuberculosis - United States, 1993-2006

BACKGROUND

In patients with HIV and tuberculosis (TB) in resource-constrained settings, smear-negative disease has been associated with higher mortality than smear-positive disease. Higher reported mortality may be due to misdiagnosis, diagnostic delays, or because smear-negative disease indicates more advanced immune suppression.

METHODS

We analyzed culture-confirmed, pulmonary TB among patients with TB and HIV in the United States from 1993-2008 to calculate prevalence ratios (PRs) for smear-negative disease by demographic and clinical characteristics. Allowing two years for treatment outcome to be reported, we determined hazard ratios (HRs) for survival by smear status, adjusted for significant covariates on patients before 2006.

RESULTS

Among 16,710 cases with sputum smear results, 6,739 (39%) were sputum smear-negative and 9,971 (58%) were sputum smear-positive. The prevalence of smear-negative disease was lower in male patients (PR: 0.89, 95% confidence interval [CI]: 0.86-0.93) and in those who were homeless (PR: 0.92, CI: 0.87-0.97) or used alcohol excessively (PR: 0.91, CI: 0.87-0.95), and higher in persons diagnosed while incarcerated (PR: 1.20, CI: 1.13-1.27). Patients with smear-negative disease had better survival compared to patients with smear-positive disease, both before (HR: 0.82, CI: 0.75-0.90) and after (HR: 0.81, CI: 0.71-0.92) the introduction of combination anti-retroviral therapy.

CONCLUSIONS

In the United States, smear-negative pulmonary TB in patients with HIV was not associated with higher mortality, in contrast to what has been documented in high TB burden settings. Smear-negative TB can be routinely and definitively diagnosed in the United States, whereas high-burden countries often rely solely on AFB-smear microscopy. This difference could contribute to diagnostic and treatment delays in high-burden countries, possibly resulting in higher mortality.

Clinical significance of normal chest radiographs among HIV-seropositive patients with suspected tuberculosis in Uganda

BACKGROUND AND OBJECTIVE

The frequency, aetiologies and outcomes of normal chest radiographs (CXRs) among HIV-seropositive patients with suspected pulmonary tuberculosis (TB) have been infrequently described.

METHODS

Consecutive HIV-seropositive adults hospitalized for cough of ≥2 weeks duration at Mulago Hospital (Kampala, Uganda), between September 2007 and July 2008, were enrolled. Baseline CXRs were obtained on admission. Patients with sputum smears that were negative for acid-fast bacilli (AFB) were referred for bronchoscopy with bronchoalveolar lavage (BAL). BAL fluid was examined for mycobacteria, Pneumocystis jirovecii and other fungi. Patients were followed for 2 months after enrolment.

RESULTS

Of the 334 patients, 54 (16%) had normal CXRs. These patients were younger (median age 30 vs 34 years, P = 0.002), had lower counts of CD4+ T lymphocytes (median 13 vs 57 cells/µL, P < 0.001), and were less likely to be smear positive for AFB (17% vs 39%, P = 0.002) than those with abnormal CXRs. Pulmonary TB was the most frequent diagnosis (44%) among those with normal CXRs, followed by unknown diagnoses, pulmonary aspergillosis and pulmonary cryptococcosis. The frequency of normal CXRs was 12% among pulmonary TB patients. There was a trend towards increased 2-month mortality among patients with normal CXRs compared to those with abnormal CXRs (40% vs 29%, P = 0.15).

CONCLUSIONS

Normal CXR findings were common among HIV-seropositive patients with suspected TB, especially those who were young, those with low CD4+ T cell counts and those with sputum smears that were negative for AFB. Mortality was high among those with normal CXRs. Normal CXR findings should not preclude further diagnostic evaluation in this population.

Tuberculosis in antiretroviral treatment services in resource-limited settings: addressing the challenges of screening and diagnosis

The high burden of tuberculosis (TB) among patients accessing antiretroviral treatment (ART) services in resource-limited settings is a major cause of morbidity and mortality and is associated with nosocomial transmission risk. These risks are greatly compounded by multidrug-resistant disease. Screening and diagnosis of TB in this clinical setting is difficult. However, progress has been made in defining a high-sensitivity, standardized symptom screening tool that assesses a combination of symptoms, rather than relying on report of cough alone. Moreover, newly emerging diagnostic tools show great promise in providing more rapid diagnosis of TB, which is predominantly sputum smear–negative. These include culture-based systems, simplified versions of nucleic acid amplification tests (such as the Xpert MTB/RIF assay), and detection of lipoarabinomannan antigen in urine. In addition, new molecular diagnostics now permit rapid detection of drug resistance. Further development and implementation of these tools is vital to permit rapid and effective screening for TB in ART services, which is an essential component of patient care.

Manifestações clínicas, radiológicas e laboratoriais em indivíduos com tuberculose pulmonar: estudo comparativo entre indivíduos HIV positivos e HIV negativos internados em um hospital de referência

OBJETIVO: Comparar as manifestações clínicas, radiológicas e laboratoriais de indivíduos com tuberculose pulmonar coinfectados com HIV com aqueles sem a coinfecção. MÉTODOS: Estudo transversal, no qual sinais e sintomas foram analisados por meio de anamnese e exame físico em pacientes internados com tuberculose pulmonar. A baciloscopia, a cultura para Mycobacterium tuberculosis, a dosagem de hemoglobina e a contagem de células T CD4+ foram obtidas de registros dos prontuários, assim como os laudos das radiografias de tórax. RESULTADOS: Foram incluídos 50 pacientes com tuberculose pulmonar, que foram divididos em dois grupos (HIV positivo e HIV negativo; n = 25 por grupo). A média de idade dos participantes foi de 38,4 ± 10,5 anos, 46 (92%) eram do sexo masculino, e 27 (54%) eram caucasianos. Apresentaram expectoração 21 (84%) e 13 (52%) dos pacientes nos grupos HIV negativo e HIV positivo, respectivamente (p = 0,016). Achados radiológicos de cavitação estavam presentes em 10 (43%) e 2 (10%) dos pacientes nos grupos HIV negativo e HIV positivo, respectivamente (p = 0,016), ao passo que padrão intersticial estava presente em 18 (78%) e 8 (40%) dos pacientes nesses grupos (p = 0,012). O nível médio de hemoglobina foi de 11,1 ± 2,9 g/dL e 9,3 ± 2,2 g/dL nos grupos HIV negativo e HIV positivo, respectivamente (p = 0,015). CONCLUSÕES: Entre pacientes coinfectados com tuberculose e HIV desta amostra, houve menor prevalência de expectoração, foram menos frequentes os achados radiológicos de cavitação e de padrão intersticial, e os níveis de hemoglobina foram mais baixos do que naqueles sem essa coinfecção.

Diagnosis & treatment of tuberculosis in HIV co-infected patients

Human immunodeficiency virus (HIV) associated tuberculosis (TB) remains a major global public health challenge, with an estimated 1.4 million patients worldwide. Co-infection with HIV leads to challenges in both the diagnosis and treatment of tuberculosis. Further, there has been an increase in rates of drug resistant tuberculosis, including multi-drug (MDR-TB) and extensively drug resistant TB (XDRTB), which are difficult to treat and contribute to increased mortality. Because of the poor performance of sputum smear microscopy in HIV-infected patients, newer diagnostic tests are urgently required that are not only sensitive and specific but easy to use in remote and resource-constrained settings. The treatment of co-infected patients requires antituberculosis and antiretroviral drugs to be administered concomitantly; challenges include pill burden and patient compliance, drug interactions, overlapping toxic effects, and immune reconstitution inflammatory syndrome. Also important questions about the duration and schedule of anti-TB drug regimens and timing of antiretroviral therapy remain unanswered. From a programmatic point of view, screening of all HIV-infected persons for TB and vice-versa requires good co-ordination and communication between the TB and AIDS control programmes. Linkage of co-infected patients to antiretroviral treatment centres is critical if early mortality is to be prevented. We present here an overview of existing diagnostic strategies, new tests in the pipeline and recommendations for treatment of patients with HIV-TB dual infection.

Chest radiographic findings of pulmonary tuberculosis in severely immunocompromised patients with the human immunodeficiency virus

OBJECTIVE

We describe chest radiograph (CXR) findings in a population with a high prevalence of human immunodeficiency virus (HIV) and tuberculosis (TB) in order to identify radiological features associated with TB; to compare CXR features between HIV-seronegative and HIV-seropositive patients with TB; and to correlate CXR findings with CD4 T-cell count.

METHODS

Consecutive adult patients admitted to a national referral hospital with a cough of duration of 2 weeks or longer underwent diagnostic evaluation for TB and other pneumonias, including sputum examination and mycobacterial culture, bronchoscopy and CXR. Two radiologists blindly reviewed CXRs using a standardised interpretation form.

RESULTS

Smear or culture-positive TB was diagnosed in 214 of 403 (53%) patients. Median CD4+ T-cell count was 50 cells mm(-3) [interquartile range (IQR) 14-150]. TB patients were less likely than non-TB patients to have a normal CXR (12% vs 20%, p = 0.04), and more likely than non-TB patients to have a diffuse pattern of opacities (75% vs 60%, p = 0.003), reticulonodular opacities (45% vs 12%, p < 0.001), nodules (14% vs 6%, p = 0.008) or cavities (18% vs 7%, p = 0.001). HIV-seronegative TB patients more often had consolidation (70% vs 42%, p = 0.007) and cavities (48% vs 13%, p < 0.001) than HIV-seropositive TB patients. TB patients with a CD4+ T-cell count of ≤ 50 cells mm(-3) less often had consolidation (33% vs 54%, p = 0.006) and more often had hilar lymphadenopathy (30% vs 16%, p = 0.03) compared with patients with CD4 51-200 cells mm(-3).

CONCLUSION

Although different CXR patterns can be seen in TB and non-TB pneumonias there is considerable overlap in features, especially among HIV-seropositive and severely immunosuppressed patients. Providing clinical and immunological information to the radiologist might improve the accuracy of radiographic diagnosis of TB.

Pretreatment and posttreatment radiography in patients with pulmonary tuberculosis with and without human immunodeficiency virus infection

PURPOSE

The purpose of this study was to determine differences in pretreatment and posttreatment radiographic findings in pulmonary tuberculosis (PTB) patients with and without human immunodeficiency virus (HIV) infection.

MATERIALS AND METHODS

All patients were reviewed in terms of pre- and posttreatment radiographic findings comparing non-HIV-related versus HIV-related PTB.

RESULTS

Among 177 PTB patients, 38 (22%) were HIV seropositive and 139 (78%) were HIV-seronegative. The most common radiographic finding in non-HIV-related TB was reticular infiltration (66.2%), whereas the miliary pattern was the most common radiographic finding in HIV-related TB (34.2%). Radiographic findings in HIV related TB significantly presented with higher prevalence of the miliary pattern (P < 0.0001) and lower prevalence of reticular infiltration (P < 0.0001), cavitation (P = 0.003), and mass-like lesions (P = 0.039) compared to non-HIV-related TB. During the posttreatment period, normal chest radiographs were significantly present in the patients who had HIV-seropositivity, the miliary pattern, and sputum negative for acid-fast bacilli during the pretreatment period (P < 0.05).

CONCLUSION

Pretreatment radiographic features of HIV-related TB had a significantly higher prevalence of the miliary pattern and lower prevalence of reticular infiltration, cavitation, and mass-like lesions. HIV-related TB and the miliary pattern seen by pretreatment radiography were significantly associated with normal chest radiographs during the posttreatment period.

HIV and tuberculosis: a deadly human syndemic

A syndemic is defined as the convergence of two or more diseases that act synergistically to magnify the burden of disease. The intersection and syndemic interaction between the human immunodeficiency virus (HIV) and tuberculosis (TB) epidemics have had deadly consequences around the world. Without adequate control of the TB-HIV syndemic, the long-term TB elimination target set for 2050 will not be reached. There is an urgent need for additional resources and novel approaches for the diagnosis, treatment, and prevention of both HIV and TB. Moreover, multidisciplinary approaches that consider HIV and TB together, rather than as separate problems and diseases, will be necessary to prevent further worsening of the HIV-TB syndemic. This review examines current knowledge of the state and impact of the HIV-TB syndemic and reviews the epidemiological, clinical, cellular, and molecular interactions between HIV and TB.

The role of IL-10 in immune regulation during M. tuberculosis infection

During gaseous exchange the lungs are exposed to a vast variety of pathogens, allergens, and innocuous particles. A feature of the lung immune response to lung-tropic aerosol-transmitted bacteria such as Mycobacterium tuberculosis (Mtb) is a balanced immune response that serves to restrict pathogen growth while not leading to host-mediated collateral damage of the delicate lung tissues. One immune-limiting mechanism is the inhibitory and anti-inflammatory cytokine interleukin (IL)-10. IL-10 is made by many hematopoietic cells and a major role is to suppress macrophage and dendritic cell (DC) functions, which are required for the capture, control, and initiation of immune responses to pathogens such as Mtb. Here, we review the role of IL-10 on bacterial control during the course of Mtb infection, from early innate to adaptive immune responses. We propose that IL-10 is linked with the ability of Mtb to evade immune responses and mediate long-term infections in the lung.

Evaluation of the 2007 WHO guideline to improve the diagnosis of tuberculosis in ambulatory HIV-positive adults

Background

In 2007 WHO issued a guideline to improve the diagnosis of smear-negative and extrapulmonary tuberculosis (EPTB) in HIV-positive patients. This guideline relies heavily on the acceptance of HIV-testing and availability of chest X-rays.

Methods and Findings

Cohort study of TB suspects in four tuberculosis (TB) clinics in Phnom Penh, Cambodia. We assessed the operational performance of the guideline, the incremental yield of investigations, and the diagnostic accuracy for smear-negative tuberculosis in HIV-positive patients using culture positivity as reference standard. 1,147 (68.9%) of 1,665 TB suspects presented with unknown HIV status, 1,124 (98.0%) agreed to be tested, 79 (7.0%) were HIV-positive. Compliance with the guideline for chest X-rays and sputum culture requests was 97.1% and 98.3% respectively. Only 35 of 79 HIV-positive patients (44.3%) with a chest X-ray suggestive of TB started TB treatment within 10 days. 105 of 442 HIV-positive TB suspects started TB treatment (56.2% smear-negative pulmonary TB (PTB), 28.6% smear-positive PTB, 15.2% EPTB). The median time to TB treatment initiation was 5 days (IQR: 2–13 days), ranging from 2 days (IQR: 1–11.5 days) for EPTB, over 2.5 days (IQR: 1–4 days) for smear-positive PTB to 9 days (IQR: 3–17 days) for smear-negative PTB. Among the 34 smear-negative TB patients with a confirmed diagnosis, the incremental yield of chest X-ray, clinical suspicion or abdominal ultrasound, and culture was 41.2%, 17.6% and 41.2% respectively. The sensitivity and specificity of the algorithm to diagnose smear-negative TB in HIV-positive TB suspects was 58.8% (95%CI: 42.2%–73.6%) and 79.4% (95%CI: 74.8%–82.4%) respectively.

Conclusions

Pending point-of-care rapid diagnostic tests for TB disease, diagnostic algorithms are needed. The diagnostic accuracy of the 2007 WHO guideline to diagnose smear-negative TB is acceptable. There is, however, reluctance to comply with the guideline in terms of immediate treatment initiation.

Diagnosis of tuberculosis in an era of HIV pandemic: a review of current status and future prospects

HIV and tuberculosis co-infection interact in fundamentally important ways. This interaction is evident patho-physiologically, clinically and epidemiologically. There are several differences between HIV-infected and HIV-uninfected patients with tuberculosis (TB) that have practical diagnostic implications. TB is more likely to be disseminated in nature and more difficult to diagnose by conventional diagnostic procedures as immunosuppression progresses. As TB rates continue to increase in HIV-endemic regions, improved diagnostic techniques merit consideration as TB-control strategies. There is a need to develop more user friendly techniques, which can be adapted for use in the high-burden and low-income countries. This review focuses on the diagnostic challenges in HIV-TB co-infection with an update on the current techniques and future prospects in an era of HIV pandemic.

Changing concepts of "latent tuberculosis infection" in patients living with HIV infection

One third of the world's population is estimated to be infected with Mycobacterium tuberculosis, representing a huge reservoir of potential tuberculosis (TB) disease. Risk of progression to active TB is highest in those with HIV coinfection. However, the nature of the host-pathogen relationship in those with “latent TB infection” and how this is affected by HIV coinfection are poorly understood. The traditional paradigm that distinguishes latent infection from active TB as distinct compartmentalised states is overly simplistic. Instead the host-pathogen relationship in “latent TB infection” is likely to represent a spectrum of immune responses, mycobacterial metabolic activity, and bacillary numbers. We propose that the impact of HIV infection might better be conceptualised as a shift of the spectrum towards poor immune control, higher mycobacterial metabolic activity, and greater organism load, with subsequent increased risk of progression to active disease. Here we discuss the evidence for such a model and the implications for interventions to control the HIV-associated TB epidemic.

Tuberculosis: global approaches to a global disease

Mycobacterium tuberculosis is a remarkably successful human pathogen. The interaction with the human host is complex and much remains unknown. Recent advances in systems biology have allowed the integration of data from humans and animal models into computational approaches. For example, mathematical models provide a platform for in silico manipulation of host-pathogen interactions to gain insight into this infection across temporal and biologic scales. Here, we review recent studies on global approaches toward identifying comprehensive responses of both host and bacillus during infection, and the potential for incorporation of these data into many types of useful computational systems. Systems biology approaches provide a unique opportunity to study interventions that may improve therapy and vaccines against this major killer.

Reactivation of latent tuberculosis in cynomolgus macaques infected with SIV is associated with early peripheral T cell depletion and not virus load

HIV-infected individuals with latent Mycobacterium tuberculosis (Mtb) infection are at significantly greater risk of reactivation tuberculosis (TB) than HIV-negative individuals with latent TB, even while CD4 T cell numbers are well preserved. Factors underlying high rates of reactivation are poorly understood and investigative tools are limited. We used cynomolgus macaques with latent TB co-infected with SIVmac251 to develop the first animal model of reactivated TB in HIV-infected humans to better explore these factors. All latent animals developed reactivated TB following SIV infection, with a variable time to reactivation (up to 11 months post-SIV). Reactivation was independent of virus load but correlated with depletion of peripheral T cells during acute SIV infection. Animals experiencing reactivation early after SIV infection (<17 weeks) had fewer CD4 T cells in the periphery and airways than animals reactivating in later phases of SIV infection. Co-infected animals had fewer T cells in involved lungs than SIV-negative animals with active TB despite similar T cell numbers in draining lymph nodes. Granulomas from these animals demonstrated histopathologic characteristics consistent with a chronically active disease process. These results suggest initial T cell depletion may strongly influence outcomes of HIV-Mtb co-infection.

Approaches to tuberculosis screening and diagnosis in people with HIV in resource-limited settings

Tuberculosis is the main cause of morbidity and mortality in people living with HIV/AIDS worldwide. Early diagnosis and treatment is essential to addressing the dual epidemic of tuberculosis and HIV. Increasing recognition of the importance of integrating tuberculosis services--including screening--into HIV care has led to global policies and the beginnings of implementation of joint activities at the national level. However, debate remains about the best methods of screening for pulmonary tuberculosis among people living with HIV/AIDS in resource-limited settings. Mycobacterial culture, the gold standard for tuberculosis diagnosis, is too slow and complex to be a useful screening test in such settings. More widely available methods, such as symptom screening, sputum smear microscopy, chest radiography, and tuberculin skin testing have important shortcomings, especially in people living with HIV/AIDS. However, until simpler, cheaper, and more sensitive diagnostics for tuberculosis are available in peripheral healthcare settings, a strategy must be developed that uses current evidence to combine available screening tools.

Diferenças na apresentação clínico-radiológica da tuberculose intratorácica segundo a presença ou não de infecção por HIV

OBJETIVO: Descrever as diferenças na apresentação clínico-radiológica da tuberculose segundo a presença ou não de infecção por HIV. MÉTODOS: Examinou-se uma amostra consecutiva de 231 adultos com tuberculose pulmonar bacilífera internados em hospital de tisiologia. A presença de infecção por HIV, AIDS e fatores associados foi avaliada e as radiografias de tórax foram reinterpretadas. RESULTADOS: Havia 113 pacientes HIV-positivos (49%). Estes pacientes apresentavam maior freqüência de tuberculose pulmonar atípica (lesões pulmonares associadas a linfonodomegalias intratorácicas), tuberculose de disseminação hemática e tuberculose pulmonar associada a linfonodomegalias superficiais e menor freqüência de lesões pulmonares escavadas do que os pacientes HIV-negativos. Isto também ocorreu entre os pacientes HIV-positivos com AIDS e os HIV-positivos sem AIDS. Não se observaram diferenças entre os pacientes HIV-positivos sem AIDS e os HIV-negativos. Os valores medianos de CD4 foram menores nos pacientes HIV-positivos com linfonodomegalias intratorácicas e lesões pulmonares em comparação aos com lesões pulmonares exclusivas (47 vs. 266 células/mm³; p < 0,0001), nos pacientes HIV-positivos com AIDS em comparação aos HIV-positivos sem AIDS (136 vs. 398 células/mm³; p < 0,0001) e nos pacientes com tuberculose pulmonar atípica em comparação aos com outros tipos de tuberculose (31 vs. 258 células/mm³; p < 0,01). CONCLUSÃO: Há um predomínio de formas atípicas e doença disseminada entre pacientes com imunossupressão avançada. Em locais com alta prevalência de tuberculose, a presença de tuberculose pulmonar atípica ou de tuberculose pulmonar associada a linfonodomegalias superficiais é definidora de AIDS.

Alterações radiográficas em pacientes com a co-infecção vírus da imunodeficiência humana/tuberculose: relação com a contagem de células TCD4+

OBJETIVO: Correlacionar os padrões radiológicos com a contagem de células TCD4+ em pacientes co-infectados por tuberculose e vírus da imunodeficiência humana. MÉTODO: Foram avaliados os pacientes admitidos no Hospital Nereu Ramos, Florianópolis (SC), co-infectados por tuberculose e vírus da imunodeficiência humana, no período de janeiro de 2000 a dezembro de 2003. RESULTADOS: Foram incluídos no estudo 87 pacientes, com média de idade de 34 ± 8 anos, sendo 6,8% não caucasianos. A média de linfócitos TCD4+ foi de 220,2 células/mm³ e a mediana foi de 144 células/mm³, sendo que 56,4% dos pacientes possuíam menos de 200 células/mm³. Os padrões radiográficos isolados foram relacionados com a contagem de células TCD4+. O padrão de consolidação alveolar estava presente em 50,6% dos casos (56,8% TCD4+ < 200); o intersticial em 32,2% (53,6% TCD4+ < 200); derrame pleural em 24,1% (47,6% TCD4+ < 200); cavitação em 24,1% (57,1% TCD4+ < 200); linfonodomegalia mediastinal e/ou hilar em 11,5% (90% TCD4+ < 200); e sem alterações radiológicas em 11,5% deles (60% TCD4+ < 200). A média dos linfócitos para cada padrão radiológico foi de 235,2/mm³ (consolidação alveolar); 208,8/mm³ (intersticial); 243,3/mm³ (derrame pleural); 265/mm³ (cavitação); 115,1/mm³ (linfonodomegalia mediastinal e/ou hilar) (p < 0,05); e 205,5/mm³ (sem alteração radiológica). A linfonodomegalia mediastinal e/ou hilar foi o único padrão que se correlacionou de forma estatisticamente significativa com o grau de imunidade celular. CONCLUSÃO: Com exceção da linfonodomegalia mediastinal e/ou hilar, as alterações radiológicas distribuíram-se aleatoriamente em relação à contagem de células TCD4+.

Peripheral tuberculous lymphadenitis: epidemiology, diagnosis, treatment, and outcome

We reviewed 106 patients referred to our institution for treatment of peripheral tuberculous adenitis to establish the epidemiologic, clinical, and pathologic manifestations of this disease. Tuberculous lymphadenitis occurred predominantly in young, foreign-born women a mean of 5 years after arrival in the United States. Tuberculin skin tests were positive in 94% of cases. Lymphadenopathy occurred most frequently in the neck (57%) or supraclavicular area (26%) and involved 1-3 nodes. Forty (38%) patients had an abnormal chest radiograph consistent with granulomatous infection. Culture-positive pulmonary tuberculosis was diagnosed in 41% of those patients with abnormal chest radiographs. Fine needle aspiration was an essential step in the evaluation and diagnosis of tuberculous lymphadenitis. Granulomas were seen in 61% of fine needle aspirates and 88% of surgical biopsies. Positive cultures for Mycobacterium tuberculosis were obtained from 62% of fine needle aspirate samples and 71% of excisional biopsies. The presence of necrosis and/or neutrophilic inflammation in tissue samples correlated with culture positivity. Given the high yield of positive cultures from fine needle aspirates, surgery was rarely indicated as an initial step in immunocompetent adults. In this cohort, 101 patients received a final diagnosis of peripheral tuberculous lymphadenitis. Eighty-two percent received their entire therapy under direct observation, and response to antituberculous therapy was uniformly successful. Paradoxical expansion of adenopathy was seen in 20% of all patients and was more commonly noted in human immunodeficiency virus-seropositive patients. We present a diagnostic algorithm based on our experience.

How effectively does HAART restore immune responses to Mycobacterium tuberculosis? Implications for tuberculosis control

Use of highly active antiretroviral treatment (HAART) has had a major impact on HIV-associated morbidity and mortality in industrialized countries. Access to HAART is now expanding in low-income countries where tuberculosis (TB) is the most important opportunistic disease. The incidence of TB has been fueled by the HIV epidemic and in many countries with high HIV prevalence current TB control measures are failing. HAART reduces the incidence of TB in treated cohorts by approximately 80% and therefore potentially has an important role in TB control in such countries. However, despite the huge beneficial effect of HAART, rates of TB among treated patients nevertheless remain persistently higher than among HIV-negative individuals. This observation raises the important question as to whether immune responses to Mycobacterium tuberculosis (MTB) are completely or only partially restored during HAART. Current data suggest that full restoration of circulating CD4 cell numbers occurs only among a minority of patients and that, even among these, phenotypic abnormalities and functional defects in lymphocyte subsets often persist. Suboptimal restoration of MTB-specific immune responses may greatly reduce the extent to which HAART is able to contribute to TB control at the community level because patients receiving HAART live much longer and yet would maintain a chronically heightened risk of TB.

Cavitary pulmonary tuberculosis HIV-related

INTRODUCTION

It was usually assumed that pulmonary tuberculosis (TB) in HIV-seropositive patients represents reactivation TB, despite the radiographic appearance frequently consistent rather with a recent disease. Hence, these radiographic features were considered "atypical". We have hypothesised that the so called "atypical" radiographic features could be due to a greater proportion of primary TB among these patients, representing the typical appearance of primary radiological pattern.

MATERIAL AND METHODS

We reviewed chest imaging of 219 HIV+ patients with microbiological proven pulmonary tuberculosis, who were assessed for the presence, number, distribution of cavitations and for associated pulmonary parenchymal abnormalities, adenopathies and pleural effusion, and were classified as a primary or post-primary pattern.

RESULTS

The patients with post-primary pattern were 50%, and the rate of cavitation was 63%, not wandering off the general population. Cavities still occurred with similar proportion in groups with CD4 <200 or >200cells/mm(3).

CONCLUSION

We suggest that HIV-related pulmonary tuberculosis is typical in its radiological appearances, consistent with those of the general population, and this could be confirmed by the most recent molecular epidemiological techniques that allow to definitely classify the tuberculosis episodes as either primary or post-primary disease.

Tuberculosis and HIV disease: two decades of a dual epidemic

The HIV epidemic is currently in its third decade without any sign of abating. Tuberculosis (TB) is responsible for a third of all AIDS deaths, 99% of which occur in developing countries. The two epidemics fuel each other, together making up the leading infectious causes of mortality worldwide. Tuberculosis-HIV coinfection presents special diagnostic and therapeutic challenges and constitutes an immense burden on the health care systems of heavily infected countries. Despite major gains that have been made in the past two decades, important questions still remain. To cope with the challenge of TB-HIV coinfection, further research in the design of diagnostic tests for tuberculosis, detection of drug resistant Mycobacterium tuberculosis strains in HIV-positive people, as well as development of more effective therapeutic agents and vaccines are urgently needed. It has become evident that this dual epidemic will persist unless comprehensive measures are instituted through the provision of sufficient funding in addition to expanding and strengthening current control strategies adopted by governments and international organizations.

Radiological patterns in HIV-associated pulmonary tuberculosis: comparison between HAART-treated and non-HAART-treated patients

AIM

To evaluate whether highly active antiretroviral therapy (HAART) modifies radiographic appearances of pulmonary tuberculosis (TB), in terms of patterns and their relative frequencies, among patients with human immunodeficiency virus (HIV) infection.

MATERIALS AND METHODS

Chest radiographs were obtained in 209 HIV-infected patients with culture confirmed pulmonary TB. Computed tomography (CT) images were also reviewed for 42 patients whose chest radiographs were normal or showed questionable abnormalities. Imaging was evaluated for the presence and distribution of consolidation, cavitation, interstitial changes, pleural disease, adenopathy, and were classified as a primary or post-primary pattern.

RESULTS

A post-primary pattern was more frequent after 1996 when HAART came into clinical use. Forty-four percent (77/176) of patients not on HAART had a post-primary pattern in comparison with 82% (27/33) of patients receiving HAART (p<0.001). A primary pattern was significantly more frequent (p<0.001), in patients with more severe immunosuppression (CD4 lymphocyte less than 200/mm(3)).

CONCLUSION

HIV patients receiving HAART with pulmonary TB, had a post-primary pattern more frequently than those not receiving this treatment. This observation is consistent with the partial restoration of cell-mediated immunity that can be induced by HAART.

Tuberculosis in the tropics

Tropical countries bear the brunt of the global TB burden. Young children are at high risk and suffer the most severe forms of TB; adults with pulmonary cavities are the main sources of transmission. The incidence in sub-Saharan Africa is increasing as a consequence of the HIV pandemic. Smear-negative TB, which is common in children and patients who have HIV infection, is becoming a major problem in resource-poor settings where access to mycobacterial culture and histopathology is limited. Clinical case definitions are being developed to address this problem. Short courses of rifampin-based therapy are not universally available, but access is increasing. DOTS is the main strategy that the WHO is promoting to improve TB control. This is particularly important for sputum smear-positive patients. Unfortunately, the DOTS targets set by the WHO have not yet been met. Innovative, low-cost ways of supervising therapy have been developed using family members or lay supervisors. Preventive therapy in tropical countries is limited to high-risk cases (young children and HIV-infected patients who are tuberculin skin test-positive). An improved TB vaccine would dramatically improve TB control.

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.

How does tuberculosis relate to HIV positive and HIV negative drug users?

OBJECTIVES

(1) To compare the incidence of active tuberculosis in HIV positive and HIV negative drug users. (2) To describe the main characteristics of the tuberculosis cases.

DESIGN

A prospective study was performed from 1986 to 1996 as part of an ongoing cohort study of HIV infection in Amsterdam drug users.

METHODS

Data from the cohort study, including HIV serostatus and CD4-cell numbers, were completed with data from the tuberculosis registration of the tuberculosis department of the Amsterdam Municipal Health Service. Analyses were carried out with person time and survival methods.

RESULTS

Of 872 participants, 24 persons developed culture confirmed tuberculosis during a total follow up period of 4000 person years (0.60 per 100 py, 95% CI: 0.40, 0.90). Nineteen cases were HIV positive (1.54 per 100 py, 95% CI: 0.86, 2.11) and five HIV negative (0.18 per 100 py, 95% CI: 0.08, 0.43). Multivariately HIV infection (relative risk: 12.9; 95% CI: 3.4, 48.8) and age above 33 years (RR: 6.8; 95% CI: 1.3, 35.0, as compared with age below 27) increased the risk for tuberculosis substantially. Additional findings were: (1) 13 of 22 pulmonary tuberculosis cases (59%) were detected by half yearly radiographic screening of the chest; (2) tuberculosis occurred relatively early in the course of HIV infection at a mean CD4 cell number of 390/microliter; (3) an estimated two thirds of the incidence of tuberculosis observed among HIV positive cases was caused by reactivation; (4) all but one patient completed the tuberculosis treatment.

CONCLUSION

HIV infection increases the risk for active tuberculosis in Amsterdam drug users 13-fold. The incidence of tuberculosis in HIV negative drug users is still six times higher than in the overall Amsterdam population. In the absence of contact tracing and screening with tuberculin skin tests, periodic chest radiographic screening contributes substantially to early casefinding of active tuberculosis in Amsterdam drug users.