Clinical features of HIV-seropositive and HIV-seronegative patients with tuberculous pleural effusion in Dar es Salaam, Tanzania.

In a prospective study, we investigated whether human immunodeficiency virus (HIV) infection alters the clinical presentation in patients with tuberculous pleuritis. One hundred twelve of 118 patients who presented with pleural effusion suffered from tuberculosis (TB); 65 patients (58%) were HIV seropositive. Evidence of disseminated TB was found more often in HIV-positive than in HIV-negative patients (30.8% vs 10.6%, p < 0.02). Dyspnea, fever, night sweat, fatigue, and diarrhea, severe tachypnea, hepatomegaly, splenomegaly, and lymphadenopathy were significantly more common in HIV-infected than in HIV-negative patients with TB. The same applied to a negative Mantoux reaction, lower hemoglobin, higher beta 2-microglobulin values, and in pleural fluid, lower albumin and higher gamma-globulin levels. Among HIV-infected patients, PPD skin test anergy was significantly associated with relative low albumin and gamma-globulin levels of pleural fluid. However, the radiographic features did not differ with respect to HIV status; they were predominantly those of primary pleuritis (78% in each group). We conclude that coexisting HIV infection affects clinical and laboratory features, but not the radiographic presentation of patients with TB pleuritis in Tanzania.

Mapping of the delayed-type hypersensitivity-inducing epitope of secreted protein MPT64 from Mycobacterium tuberculosis.

The gene encoding the immunogenic protein MPT64 found in culture filtrates of Mycobacterium tuberculosis H37Rv was expressed in Escherichia coli K-12 and purified as a recombinant protein. The purified recombinant MPT64 elicited delayed-type hypersensitivity (DTH) in outbred guinea pigs sensitized with Mycobacterium bovis BCG Tokyo. The skin reactions were comparable to those obtained with native MPT64. No skin reactions were observed when either recombinant MPT64 or native MPT64 was used in guinea pigs sensitized with M. bovis BCG Danish 1331. Amino- and carboxy-terminal deletion mutants of MPT64 were purified as fusion proteins for the mapping of DTH-inducing epitopes on recombinant MPT64 by use of the guinea pig skin test model. The part of the molecule responsible for the biological activity was located at the carboxy-terminal end. Further studies with overlapping synthetic peptides have pinpointed the biological activity at a single DTH-inducing epitope consisting of 15 residues between amino acids Gly-173 and Ala-187. Screening by PCR of 56 clinical isolates of M. tuberculosis from Danish and Tanzanian patients demonstrated the presence of mpt64 in all of the strains. These results point to MPT64 as a possible candidate for a skin test reagent specific for diagnosis of human tuberculosis.

PCR detection of mycobacteraemia in tanzanian patients with extrapulmonary tuberculosis.

In 191 Tanzanian patients admitted to hospital with suspected extrapulmonary tuberculosis (TB), TB was diagnosed in 158 patients; the remaining 33 patients had neither microbiological nor clinical evidence of TB. Mycobacterium tuberculosis was detected in the blood of 25 patients, in 92% by a polymerase chain reaction (PCR) technique and in 52% by culture of buffy coat cells. The presence of mycobacterial DNA or Mycobacterium tuberculosis bacteria in peripheral blood (positive culture) was significantly associated with HIV infection; it was detected in 22 (21.4%) of 103 HIV-seropositive patients compared to only 3 (3.5%) of 55 HIV-seronegative patients (p < 0.009). In two-thirds of the patients with mycobacteraemia, TB can be detected by simple smears from other organ sites. In patients with suspected extrapulmonary tuberculosis in whom smears from the infected site are negative or not available, PCR on blood will confirm the diagnosis within 24 hours in one third of the cases.

Influence of HIV status on pathological changes in tuberculous pleuritis.

SETTING: The AIDS epidemic has been associated with an increase in the incidence of tuberculosis, pulmonary or extrapulmonary. OBJECTIVE: To compare morphological changes in tuberculous pleurisy, and response to therapy in HIV-positive and-negative patients. DESIGN: 57 consecutive patients admitted between January and August 1991 with tuberculous pleurisy who were biopsy proven were studied. 36 were HIV-positive and 21 were HIV-negative. RESULTS: 3 types of morphological changes were observed: reactive, hyporeactive and non-reactive. Hypo- and non-reactive patterns were found in 14 of 36 HIV-positive patients but in only 2 of 21 HIV-negative patients (P < 0.02). In the HIV-positive group, 10 of the 14 with hypo- or non-reactive patterns had other HIV-related complications, compared to 6 of 22 with reactive patterns (P < 0.01). When HIV-positive patients' response to therapy was investigated, 2 of 5 patients with hypo- and non-reactive patterns improved compared to all 13 with reactive patterns (P < 0.05). CONCLUSION: A hypo- or non-reactive tissue reaction in HIV-positive patients with tuberculous pleuritis seems to indicate a less favourable prognosis.

Clinical features of HIV seropositive and HIV seronegative patients with tuberculous lymphadenitis in Dar es Salaam.

SETTING: The medical wards of a referral hospital in Dar es Salaam, Tanzania. OBJECTIVE: To investigate the impact of HIV infection on clinical features in tuberculous lymphadenitis. DESIGN: A prospective clinical study of HIV seropositive and HIV seronegative patients with lymphadenopathy. RESULTS: Of 128 patients with peripheral lymphadenopathy, 24 had no tuberculosis (TB) and in 10 patients TB was found only in other organs. The remaining 94 patients, of whom 76% were HIV seropositive, formed our study population. TB lymphadenitis was considered proven in 89 and probable in 5 patients. Disseminated TB (both TB adenitis and TB in other organs) was diagnosed more often in HIV seropositive than in HIV seronegative patients (52% versus 26%, P < 0.03). 59% of the 71 HIV-infected patients compared to only 4% of the 23 patients without HIV infection were over 30 years of age (P < 0.02). The following clinical features were significantly associated with HIV infection: dyspnoea, respiratory rate > 20/min, low motility score (bedridden), neurological abnormalities, hepatomegaly, splenomegaly, lymph node size < 2.5 cm, negative PPD skin test, lymphopenia (< 1000/cm3) and presence of pleural fluid. CONCLUSION: Co-infection with HIV influences several clinical and laboratory features in patients with tuberculous lymphadenitis.

Humoral response to Mycobacterium tuberculosis-specific antigens in African tuberculosis patients with high prevalence of human immunodeficiency virus infection.

SETTING: The applicability of serodiagnosis of tuberculosis using Mycobacterium tuberculosis-complex-specific antigens in a Tanzanian population with high prevalence of HIV. OBJECTIVE: This study was performed to evaluate the usefulness, sensitivity and specificity of serology using M. tuberculosis-specific antigens in the diagnosis of tuberculosis in patients with and without HIV co-infection. DESIGN: Patients with proven pulmonary and extrapulmonary tuberculosis at a major referral centre in Tanzania were enrolled in the study. The control group consisted of patients without a history of previous tuberculosis admitted to the trauma ward and of healthy volunteers. Sera were analysed by an enzyme linked immunoassay (ELISA) using two M. tuberculosis specific proteins as antigen: the 38 kDa protein [3T] and a 17 kDa protein. In addition was recorded presence or absence of BCG scar and tuberculin sensitivity and the sera were tested for HIV and analysed for beta-2-microglobulin content. RESULT: Sensitivity and specificity were markedly reduced in tuberculosis patients with HIV co-infection compared to patients without this disease (73% and 70% versus 52% and 50% respectively). CONCLUSION: Serology for diagnosis of tuberculosis is not feasible in an HIV endemic region.

Mannan-binding lectin in the sub-Saharan HIV and tuberculosis epidemics.

Inherited deficiency of mannan-binding lectin (MBL) has been shown to predispose to infections. Conversely, it has also been suggested that MBL might facilitate the uptake of certain intracellular microbes. The aim of this study was to investigate whether MBL plays a role in the HIV and tuberculosis epidemics in Africa. Thus, the authors determined the MBL serum concentration in 173 HIV infected patients (150 with concomitant tuberculosis), 94 patients with tuberculosis without being HIV infected, and 113 controls from Tanzania. The frequency of MBL deficiency was significantly increased in HIV infected patients compared with controls (12.1% and 3.5%, respectively). The frequency of patients deficient of MBL did not differ between controls and HIV negative patients with tuberculosis. However, HIV negative patients with tuberculosis had significantly higher MBL levels than both controls and HIV infected patients with or without tuberculosis. These results indicate that low levels of MBL are associated with increased risk of sexually transmitted HIV infection in Africans. By contrast, high levels of MBL may be involved in the pathogenesis of tuberculosis in immunocompetent individuals.

Diagnosis of tuberculous lymphadenitis in an area of HIV infection and limited diagnostic facilities.

In order to evaluate procedures leading to the diagnosis of tuberculous lymphadenitis, a prospective clinical study was carried out of patients with lymphadenopathy admitted to the medical wards of a referral hospital in Tanzania. The yield of diagnostic procedures (direct auramine/Ziehl-Neelsen (ZN) stained smears, Löwenstein-Jensen (LJ) cultures, cytology and histological examinations of fine needle aspirations (FNA) and biopsy material of lymph nodes, respectively, was compared. We also tried to identify clinical diagnostic markers. One hundred and twenty-eight (99 HIV-seropositive) patients were included. In 89 (67 HIV-positive) patients TB lymphadenitis could be proven. Histology and LJ culture of a lymph node biopsy had the highest diagnostic yield, 85% and 88% respectively, followed by detection of acid-fast bacilli (AFB) in biopsy smear (53%) and in fine-needle aspirations (35%). The diagnostic yield of the several procedures was not affected by associated HIV infection. Macroscopic caseation was 100% predictive for TB with a sensitivity of 69%. Firm and matted lymph nodes, ESR > 100 mm/hr, a positive PPD skin test and pleural opacity on a chest x-ray proved to be independent predictors for TB. Retrospective testing of a stepwise diagnostic approach based on direct smears of FNA, macroscopic visible caseation and direct smear of biopsy tissue, suggests that in 93% of the patients a definite diagnosis of TB lymphadenitis could have been made. Our data suggest that in HIV/TB epidemic areas most of the cases of TB lymphadenitis can be diagnosed correctly by simple and cheap methods which are generally available at district hospitals. Our findings need further prospective validation, however.

PIP: In order to evaluate procedures leading to the diagnosis of tuberculous lymphadenitis, a prospective clinical study was carried out on patients with lymphadenopathy admitted to four medical wards of the Muhibili Medical Center, Dar es Salaam, Tanzania, from January to August 1991. The yield of diagnostic procedures (direct auramine/Ziehl-Neelsen stained smears, Lowenstein-Jensen [LJ] cultures, cytology and histological examinations of fine needle aspirations [FNA], and biopsy material of lymph nodes) was compared. Clinical diagnostic markers were also identified. 128 (99 HIV-seropositive) patients with a mean age of 30 years were included. 41% were male. In 89 (67 HIV-positive) patients, TB lymphadenitis could be demonstrated. 46 (30 HIV-positive) had TB lymphadenitis only and 43 (37 HIV-positive) had disseminated TB. In 10 patients TB was found in specimens other than the lymph node, making the total of TB patients 99. Histology and LJ culture of lymph node biopsy had the highest diagnostic yield, 85% and 88%, respectively, followed by detection of acid-fast bacilli in biopsy smears (53%) and in FNAs (35%). The diagnostic yield of the procedures was not affected by associated HIV infection. Macroscopic caseation was 100% predictive of TB with a sensitivity of 69%. Multivariate logistic regression analysis demonstrated four independent predictors of TB: 1) firm and matted lymph nodes (odds ratio [OR] 11.8); 2) erythrocyte sedimentation rate (ESR) 100 mm/hr (OR 4.6); 3) a positive purified protein derivative (PPD) skin test (OR 10.2); and 4) pleural opacity on a chest X-ray (OR 9.5). Retrospective testing of a stepwise diagnostic approach based on direct smears of FNA, macroscopic visible caseation, and direct smears of biopsy tissue suggests that in 93% of the patients a definite diagnosis of TB lymphadenitis could have been made. These data suggest that in HIV/TB epidemic areas most of the cases of TB lymphadenitis can be diagnosed correctly by simple and cheap methods which are generally available at district hospitals.

Diagnosis of tuberculosis in patients with pleural effusion in an area of HIV infection and limited diagnostic facilities.

In a prospective study of 118 patients with pleural effusion, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Löwenstein-Jensen medium) in pleural fluid or pleural tissue (obtained by closed biopsy) or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%) and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 patients and dissemination of TB to other sites in 25 patients of whom 20 were HIV positive. By logistic regression analysis we identified 2 independent diagnostic markers for TB pleuritis: pleural fluid protein > 50 g/l (Odds ratio 12.1, 95% confidence interval (CI): 1.1-128.3) and adenosine deaminase of > 10 U/l (Odds ratio 11.08, 95% CI: 1.3-96.4). We conclude that conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, for regions with overstretched health services and high prevalences of tuberculous pleurisy in patients with pleural effusion we suggest a simplified diagnostic approach based on exclusion of other causes of pleural effusion by simple means and use of these diagnostic markers.

PIP: In a prospective study of 118 patients with pleural effusion admitted to four medical wards in Muhimbili Medical Center between January and August 1991, Dar es Salaam, Tanzania, tuberculosis (TB) was diagnosed in 112. In 84 patients the diagnosis of TB was made by detection of acid-fast bacilli by stain (auramine, Ziehl-Neelsen) or by culture of mycobacteria (Lowenstein-Jensen medium) in pleural fluid or pleural tissue obtained by closed biopsy or by the presence of caseating granulomas in histological sections. In 28 patients the diagnosis of TB was considered probable, based on good response to anti-tuberculous therapy. In the remaining 6 non-TB patients adenocarcinoma (1), bacterial infection (2), and aspecific inflammation (3) were diagnosed. 58% of the TB and 3 of the non-TB patients were infected with HIV. The diagnostic procedures were evaluated in 75 patients. The highest diagnostic yield was obtained by histology (85%), followed by culture of pleural biopsy (37%), and pleural fluid culture (36%). Pulmonary tuberculosis was found in 8 (4 HIV-positive) patients and dissemination of TB to other sites in 25 patients, of whom 20 were HIV-positive. By logistic regression analysis, two independent diagnostic markers for TB pleuritis were identified: pleural fluid protein 50 g/l (odds ratio [OR] 12.1) and pleural fluid adenosine deaminase level of 10 U/l (OR 11.08). The sensitivity of these two diagnostic tests was 82% and 97.3%, and the specificity was 83.6% and 50%, respectively. TB was the underlying cause in nearly all patients who presented with pleural effusion (94.9%). TB was confirmed in 75% of these using the referral hospital. Conventional facilities of a referral hospital are sufficient to diagnose tuberculous pleuritis as well as disseminated tuberculosis irrespective of HIV infection. However, in regions with overburdened health facilities and high prevalence of tuberculous pleurisy in patients with pleural effusion, a simplified diagnostic approach is suggested based on exclusion of other causes of pleural effusion by simple use of these diagnostic markers.

Pulmonary complications of HIV infection in Dar es Salaam, Tanzania. Role of bronchoscopy and bronchoalveolar lavage.

To determine the pulmonary complications in HIV-1-infected patients in Dar es Salaam, Tanzania, and to evaluate the diagnostic utility of bronchoscopy and bronchoalveolar lavage, we carried out a prospective study of 237 patients with acute respiratory disease who were hospitalized at Muhimbili Medical Center (MMC). Diagnoses were made using well-defined criteria. Of the total, 127 (54%) were HIV-1-seropositive and 110 (46%) were seronegative. Tuberculosis was the most common diagnosis occurring in 95 (75%) HIV-1-seropositive and 87 (79%) seronegative patients. Bacterial pneumonia was the next most common diagnosis occurring in 18 (14%) HIV-1-seropositive and 17 (15%) seronegative patients. Pneumocystis carinii pneumonia was diagnosed in one and Kaposi's sarcoma was seen in only two HIV-1-seropositive patients. Bronchoscopy with bronchoalveolar lavage was the sole source of a diagnosis in nine (8%) seropositive and six (5%) seronegative patients. We conclude that the HIV seroprevalence rate among patients hospitalized for acute respiratory disease at MMC is extremely high. Tuberculosis was the most common cause of pulmonary disease, regardless of HIV serostatus, and other HIV-associated opportunistic pulmonary infections were unusual. Bronchoscopy with bronchoalveolar lavage added little to the diagnosis and thus should not be high-priority procedures for the routine workup in resource-poor areas where tuberculosis is endemic.

DNA fingerprinting and phenotyping of Mycobacterium tuberculosis isolates from human immunodeficiency virus (HIV)-seropositive and HIV-seronegative patients in Tanzania.

With the purpose of determining whether the risk of infection with a particular clone of Mycobacterium tuberculosis is influenced by the human immunodeficiency virus (HIV) status of the host, we analyzed and compared 68 mycobacterial isolates obtained from HIV-seropositive patients with tuberculosis (TB) in Dar es Salaam, Tanzania, with 66 mycobacterial isolates obtained from HIV-seronegative patients with TB in the same geographical region by using both DNA fingerprinting and classical phenotyping methods. One hundred one different IS6110 fingerprinting patterns were observed in the 134 isolates. The level of diversity of the DNA fingerprints observed in the HIV-seropositive group was comparable to the level of the diversity observed in the HIV-seronegative group. Resistance to a single anti-TB drug was found in 8.8% of the tested isolates, and 3.2% of the isolates were resistant to more than one anti-TB drug. The drug susceptibility profiles were not significantly difference between the two groups of isolates compared in the present study. Phenotypic characteristics which classify M. tuberculosis strains as belonging to the Asian subgroup correlated with a low IS6110 copy number per isolate. However, the occurrence of Asian subgroup strains was not associated with the HIV status of the patients. The results of the study suggested an equal risk of infection with a defined M. tuberculosis clone for HIV-seropositive and HIV-seronegative individuals.