Elevation of CSF adenosine deaminase in HIV patient with meningitis from retroviral rebound syndrome, a case report.

Adenosine deaminase (ADA) in cerebrospinal fluid (CSF) is considered to be a useful biomarker in differentiating tuberculous meningitis (TBM) from other meningitis in non-HIV patients. However, its specificity decreases in patients with HIV, and other diseases such as cytomegalovirus encephalitis, toxoplasmosis or meningeal lymphomatosis can also elevate ADA in CSF. We here report a rare case of retroviral rebound syndrome in a HIV patient, whose ADA in CSF was elevated.

Matrix Metalloproteinases in Pulmonary and Central Nervous System Tuberculosis-A Review.

Tuberculosis (TB) remains the single biggest infectious cause of death globally, claiming almost two million lives and causing disease in over 10 million individuals annually. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes with various physiological roles implicated as key factors contributing to the spread of TB. They are involved in the breakdown of lung extracellular matrix and the consequent release of Mycobacterium tuberculosis bacilli into the airways. Evidence demonstrates that MMPs also play a role in central nervous system (CNS) tuberculosis, as they contribute to the breakdown of the blood brain barrier and are associated with poor outcome in adults with tuberculous meningitis (TBM). However, in pediatric TBM, data indicate that MMPs may play a role in both pathology and recovery of the developing brain. MMPs also have a significant role in HIV-TB-associated immune reconstitution inflammatory syndrome in the lungs and the brain, and their modulation offers potential novel therapeutic avenues. This is a review of recent research on MMPs in pulmonary and CNS TB in adults and children and in the context of co-infection with HIV. We summarize different methods of MMP investigation and discuss the translational implications of MMP inhibition to reduce immunopathology.

Raised adenosine deaminase in the cerebrospinal fluid: A tool for the diagnosis of tuberculous meningitis in developing countries.

CONTEXT: The rapid diagnosis followed by the early treatment of tuberculous meningitis (TBM) is important in preventing fatal outcomes. The mainstay of diagnosis lies in cerebrospinal fluid (CSF) analysis, radiological investigations, and clinical findings. AIM: The present study was conducted to determine the efficacy, sensitivity, and specificity of raised adenosine deaminase (ADA) level in CSF to differentiate TBM from non-TBM cases as a rapid, cost-effective, and noninvasive test. PATIENTS AND METHODS: This was a retrospective study conducted over a 1-year period in a tertiary teaching institute of Malwa region, India. A total of 143 patients presented with symptoms and signs of meningitis were included and divided into TBM and non-TBM groups on the basis of the diagnostic criteria. CSF ADA estimation was drafted and analyzed by using ≥10 U/L as a cutoff value. A statistical comparison of the ADA levels between the study groups was made by using unpaired Student's t-test. RESULTS: Out of the 143 cases, 40 were TBM, and 103 were non-TBM. The mean ADA level in TBM and non-TBM cases was 17.18 ± 9.59 and 6.33 ± 2.48, respectively, and the difference was statistically significant. Using a cutoff level ≥10 U/L, CSF ADA had a sensitivity of 92.5% and a specificity of 89.32%. Positive and negative likelihood ratios of the test were 8.66 and 0.08, respectively, and positive and negative predictive values, were 77.08 and 96.84%, respectively. CONCLUSION: The present study reflects the importance of a CSF ADA level ≥10 U/L in the diagnosis of TBM. Thus, it can be used as an adjunctive diagnostic tool to differentiate TBM from other non-TBM cases, when there is a diagnostic dilemma.

[Cerebrospinal fluid adenosine deaminase and its dynamic changes in tuberculous meningitis].

Objective: To explore the diagnostic value of cerebrospinal fluid (CSF) adenosine deaminase (ADA) level in tuberculous meningitis. Methods: We retrospectively analyzed 139 patients (73 males, 66 females) who visited Beijing Chest Hospital for suspected TBM from January 2010 to June 2015. Of them, 99 patients were diagnosed to have TBM, with 45 males and 54 females, and a mean age of (33±15) years. Forty patients were diagnosed as having Non-TBM, with 28 males and 12 females, and a mean age of (35±18) years. All patients underwent lumbar puncture, and CSF ADA, routine, biochemical and bacteriological tests were performed. Thirty-five TBM patients reviewed CSF ADA test after treatment for 4 weeks, 8 weeks and 6 months. Results: The level of CSF ADA in TBM group was higher than that in the non-TBM group, the difference being statistically significant (5.6 U/L vs 2.3 U/L, P=0.000). When the cut-off value of the CSF ADA was 3.8 U/L , the sensitivity and specificity for diagnosis of TBM were 60.6% (95%CI 50.3%-70.1%) and 87.5% (95%CI 72.4%-95.3%), respectively, and the area under the ROC curve was 0.734.The CSF ADA level was (6.7±4.2) U/L in the 35 cases of TBM before treatment. After 4 weeks, 8 weeks and 6 months of anti-tuberculosis treatment, the CSF ADA levels were (4.5±3.3) U/L, (3.7±2.7) U/L and (2.0±1.5) U/L, respectively; all significantly decreased as compared to that before treatment (P<0.001). There was no significant change in the ADA level between 8 weeks and 4 weeks (P=0.128). After 6 months of treatment, the level of CSF ADA was significantly lower than those after 4 and 8 weeks' treatment (P<0.001). Conclusions: CSF ADA in TBM patients was significantly higher than in non-TBM patients. The sensitivity of CSF ADA level in the diagnosis of TBM was poor, but the specificity was better. CSF ADA was significantly reduced and showed dynamic changes with effective anti-tuberculosis treatment and maybe helpful in evaluating the effect of treatment.

Diagnostic test accuracy of adenosine deaminase for tuberculous meningitis: A systematic review and meta-analysis.

INTRODUCTION: The measurement of adenosine deaminase (ADA) level in cerebrospinal fluid (CSF) has generated as a suitable test for tuberculous meningitis (TBM) diagnosis. The main objective in the present meta-analysis focused on analyzing the ADA test accuracy in order to diagnose TBM. METHODS: We searched several databases including Medline, Embase and Cochrane databases to identify studies addressing the diagnosis of TBM. The quality of included reports were assessed by RevMan5 software (via QUADS2 checklist). Accuracy measures of ADA test (sensitivity, specificity and others) pooled with random effects models. In addition, the data was elicited by using midas and metan packages in stata (version 12). RESULT: Twenty studies were eligible for inclusion within the meta-analysis. The pooled sensitivity and specificity for TBM diagnosis hallmarks were 89% (95% CI: 0.84-0.92) and 91% (95% CI: 0.87-0.93), respectively. The positive likelihood ratio was 9.4 (95% CI: 7-12.8), negative likelihood ratio was 0.12 (95% CI: 0.09-0.17), and diagnostic odds ratio was 77 (95% CI: 45-132). Indeed, the area under the summary receiver operating characteristic (SROC) was 0.96. CONCLUSION: It was magnificently attained that ADA test had a relatively high accuracy for TBM diagnosis.

Title: role of matrix metalloproteinase -9 in progression of tuberculous meningitis: a pilot study in patients at different stages of the disease.

BACKGROUND: TBM (Tuberculous meningitis) is severe form of tuberculosis causing death of one third of the affected individuals or leaving two-third of the survivors disabled. MMP-9 (Matrix metalloproteinase-9) is produced by the central nervous system in a variety of inflammatory conditions and has a role in the breakdown of extracellular matrix and blood-brain barrier. METHODS: In this study, the levels of MMP-9 and its inhibitor, TIMP-1 (tissue inhibitor of metalloproteinases-1), were screened using zymography and reverse zymography in cerebrospinal fluid and serum of tuberculous meningitis patients at different stages of the disease. Further, role of MMP-9 as therapeutic target was studied in C6 glioma cells infected with Mycobacterium tuberculosis H37Rv. Cells were treated with dexamethasone or SB-3CT (specific inhibitor of MMP-9) in combination with conventional antitubercular drugs. RESULTS: MMP-9 levels in patients were increased as the disease progressed to advanced stages. The infection led to increased MMP-9 levels in C6 glioma cells and specific inhibition of MMP-9 by SB-3CT augmented bacillary clearance when used along with antitubercular drugs. CONCLUSION: MMP-9 plays a prominent role in progression of tuberculous meningitis from initial to advanced stages. Increased levels of MMP-9 during advancement of the disease leads to degeneration of nervous tissue and blood brain barrier disruption. Hence, MMP-9 can be considered as a therapeutic target for efficient management of TBM and can be explored to inhibit further progression of the disease if used at an early stage.

Adenosine deaminase activity in cerebrospinal fluid and serum for the diagnosis of tuberculous meningitis.

OBJECTIVE: To evaluate the usefulness of serum and CSF adenosine deaminase (ADA) activity for the diagnosis of tuberculous meningitis (TBM) from other meningitis. METHODS: We studied CSF and serum ADA activity for 83 cases of TBM, 148 of bacterial meningitis (BM), and 262 of viral or aseptic meningitis. RESULTS: The mean ADA activities (IU/L) in CSF and serum were higher in TBM (11.80 ± 2.50, 30.28 ± 7.30) than in other types of meningitis (8.52 ± 3.60, 17.90 ± 9.20 in BM; 5.26 ± 1.90, 8.56 ± 5.9 in viral or aseptic meningitis). When we accepted a serum ADA activity cut-off value of 15 IU/L for the differential diagnosis of TBM and non-TBM with ROC analysis, the sensitivity was 84% and specificity was 82%. Combining CSF (≥ 10) and serum (≥ 15) ADA activity significantly increased overall specificity from 92% to 97% for the diagnosis of TBM. CONCLUSIONS: The determination of CSF and serum ADA activity is a simple and reliable test for differentiating TBM from other types of meningitis.

Evaluation of cerebrospinal fluid adenosine deaminase activity for the differential diagnosis of tuberculous and nontuberculous meningitis.

INTRODUCTION: The diagnosis value of adenosine deaminase (ADA) activity in cerebrospinal fluid (CSF) of tuberculous meningitis (TBM) has been well documented. However, the cutoff point of CSF ADA has not been fully assessed. In the current study, the authors set to calculate the cutoff points of ADA and monitor the changes of CSF ADA activities in patients with TBM after antitubercular therapy. METHODS: CSF ADA activity in patients with different types of meningitis was measured by Trinder enzyme-coupled assay. RESULTS: The mean CSF ADA values in the patients with TBM, bacterial meningitis, viral meningitis, cryptococcal meningitis and noninfectious neurologic disorders were 14.1 ± 5.4, 9.6 ± 5.5, 4.3 ± 2.5, 7.8 ± 3.4 and 2.6 ± 1.3 U/L, respectively. CSF ADA activity was significantly higher in TBM compared with patients with non-TBM (P < 0.05). Moreover, the best cutoff point for differentiating between TBM and non-TBM was 9.5 U/L. In addition, CSF ADA activity was decreased in patients with TBM after antitubercular therapy in a time-dependent manner. CONCLUSIONS: The determination of ADA with a cutoff value of 9.5 U/L in CSF is a useful aid for the differential diagnosis of TBM and non-TBM. Moreover, dynamic monitoring of CSF ADA activity may be an indicator for evaluating antitubercular therapy in TBM.

Adenosine deaminase in CSF and pleural fluid for diagnosis of tubercular meningitis and pulmonary tuberculosis.

Tuberculosis (TB) is one of the most common infectious diseases in developing countries including Nepal. Delay in diagnosis and treatment of tuberculosis results in poor prognosis of the disease. This study was conducted to estimate diagnostic cut off values of Adenosine Deaminase (ADA) in cerebrospinal fluid (CSF) and pleural fluid and to evaluate the sensitivity, specificity, positive and negative predictive values ofADA in pleural fluid and CSF from patients with tuberculous and non-tuberculous disease. A total of 98 body fluid (CSF: 24, Pleural fluid: 74) specimens were received for the estimation of ADA. ADA activity was measured at 37 degrees C by spectrophotometric method of Guisti and Galanti, 1984 at 625nm wavelength. Among the patients enrolled for the study subjects for which CSF were received (n = 24) included 8 tuberculous meningitis (TBM), and 16 non-tubercular meningitis (NTM). Pleural fluid samples (n = 74) were received from 19 pulmonary TB with pleural effusion, 17 PTB without pleural effusion and 37 of non-tuberculous disease patients. CSF ADA activity were (11. 1 +/- 2.03 IU/L) and (5.3 +/- +1.89 IU/L) (p <00001) in TM and non-NTM groups and Pleural fluid ADA activity were (10 +/- 22.18 IU/L) and (23.79 +/- 11.62 IU/L) (p < 0.001) in PTB and non-TB groups respectively. ADA test in body fluids, which is simple, cost-effective and sensitive, specific for the tubercular disease is recommended to perform before forwarding the cumbersome and expensive procedures like culture and PCR for TB diagnosis.

Comparative analysis of cerebrospinal fluid adenosine deaminase activity in meningitis.

AIM: The purpose is to determine the cut-off value of adenosine deaminase (ADA) activity in cerebrospinal fluid (CSF) of patients with tuberculous and non-tuberculous meningitis, and to assess its value in differential diagnosis. MATERIAL AND METHODS: This study was conducted in 91 patients with meningitis in two university hospitals in Turkey. 24 patients had tuberculous meningitis (TBM), 25 purulent meningitis (PM), 25 aseptic meningitis (AM) and 17 neurobrucellosis (BM). ADA activity of CSF was quantified by colorimetry. RESULTS: In our study, mean ADA values in CSF were 28.34 ± 14.83 IU/L in TB cases, 8.71 ± 5.83 IU/L in BM, 6.18 ± 2.54 IU/L in PM and 3.43 ± 3.48 U/L in AM cases. If we accept for CSF ADA an activity cut-off value of 12.5 IU/L for differential diagnosis of TBM and BM, its sensitivity was 92% and specificity was 88%. If we accept 12.35 IU/L for differential diagnosis of TBM and PM, its sensitivity was 92% and specificity was 100%. If we accept 6.45 IU/L for differential diagnosis of TBM and AM, its sensitivity was 100% and specificity was 92%. Additionally, we examined the cases after dividing them into two groups, viz. TB and non-TB. If we accept an ADA activity cut-off level of 11 IU/L for differential diagnosis of TB and non-TB by applying ROC analysis, its sensitivity was 92% and specificity was 90%. CONCLUSION: The sensitivity and specificity for CSF ADA activity are markedly high in differential diagnosis of TB from non-TB. Hence CSF ADA activity may be used as a simple, cost-effective and reliable test for early differential diagnosis of TB.

Comparative analysis of cerebrospinal fluid adenosine deaminase in tuberculous and non-tuberculous meningitis.

OBJECTIVE: To calculate cut-off point for the adenosine deaminase (ADA) activity in the CSF of patients with tuberculous meningitis (TBM). PATIENTS AND METHODS: The ADA assay was based on the automatic indirect method in which ADA catalyzes adenosine to inosine. ADA activity in the CSF was calculated based on ammonia liberated from adenosine and quantified spectrophotometrically. Arithmetic mean values and standard deviation of each variable were measured. Mann-Whitney U and Fisher exact tests were applied to compare continuous and dichotomous variables between tuberculous and non-tuberculous groups. A receiver operating characteristic curve was plotted to identify various cut-off points to determine the best level for ADA activity. RESULTS: Totally 42 patients were enrolled into the study. The median of ADA activity in the TBM group was 22 and in the non-TBM group was 8.0. The mean CSF-ADA activity was found to be significantly higher in TBM group (23.05+/-13.1IU/L) than in the CSF from non-TBM patients (9.39+/-5.18IU/L). The highest accuracy is at the cut-off value of 10.5IU/L. The sensitivity and specificity of the test at this cut-off to differentiate TBM from non-tuberculous meningitis is 81% and 86% respectively. CONCLUSION: Considering that a high positive value of ADA activity cannot confirm TBM, however, in suspected patients it may lead the physician to treat patient earlier before the confirmatory diagnostic reports will be received. The suggested cut-off value in this pilot study is 10.5IU/L with high sensitivity and specificity.

[Value of assaying adenosine deaminase level in patients with neuromeningeal tuberculosis]. / Intérêt du dosage de l'adénosine désaminase dans les infections tuberculeuses neuro-méningées.

Neuromeningeal tuberculosis is a rare extrapulmonary location in France. Delayed diagnosis can lead to therapeutic failure and severe sequels. However early diagnosis is a major challenge that requires the proper epidemiological, clinical, radiological and biological resources. Problems related to diagnosis of mycobacteria infection and to shortcomings in certain healthcare systems can hinder early diagnosis. The purpose of this review was to describe the diagnostic value of assaying adenosine deaminase activity in cerebrospinal fluid from patients with neuromeningeal tuberculosis. Evidence from studies published over the last 25 years indicate that the sensitivity and specificity of measuring adenosine deaminase activity range from 36 to 92% and 71 to 100% respectively depending of cutoff values used. Before performing this assay, it is necessary to rule out obvious or frequent etiologies such as purulent bacterial meningitis or cryptococcosis in HIV patients. Taken together these studies show that this simple, inexpensive technique is a valuable tool for early diagnosis and management of tuberculosis patients and that it can be easily implemented in hospital labs regardless of technical or financial resources.

Secretory phospholipase A2 plays an essential role in microglial inflammatory responses to Mycobacterium tuberculosis.

In previous studies, we have shown that reactive oxygen species (ROS)-mediated inflammatory signaling is essential for microglial proinflammatory responses to Mycobacterium tuberculosis (Mtb). To further investigate the molecular mechanisms governing these processes, we sought to describe the role of phospholipase A(2) (PLA(2)) in Mtb-induced ROS generation and inflammatory mediator release by microglia. Inhibition of secretory PLA(2) (sPLA(2)), but not cytosolic PLA(2) (cPLA(2)), profoundly abrogated Mtb-mediated ROS release, the generation of various inflammatory mediators (tumor necrosis factor, interleukin-6, cyclooxygenase-2, inducible nitric oxide synthase, and matrix metalloproteinase-2 and -9), and the activation of nuclear factor (NF)-kappaB and MAPKs (ERK1/2, p38, and JNK/SAPK) by murine microglial BV-2 cells or primary mixed glial cells. Interruption of the Ras/Raf-1/MEK1/ERK1/2 pathway abolished Mtb-induced sPLA(2) activity, whereas the blockage of JNK/SAPK or p38 activity had no effect. Specific inhibition of sPLA(2), but not cPLA(2), suppressed the upregulation of ERK1/2 phosphorylation by Mtb stimulation, suggesting the existence of a mutual dependency between the ERK1/2 and sPLA(2) pathways. Moreover, examination of the protein kinase C (PKC) family revealed that classical PKCs are involved in Mtb-induced sPLA(2) activation by microglia. Taken together, our results demonstrate for the first time that sPLA(2), either through pathways comprising Ras/Raf-1/MEK1/ERK1/2 or the classical PKC family, plays an essential role in Mtb-mediated ROS generation and inflammatory mediator release by microglial cells.

Comparative study of cerebrospinal fluid adenosine deaminase activity in patients with meningitis.

Cerebrospinal fluid (CSF) adenosine deaminase (ADA) activity in tubercular meningitis (TBM) patients (n=20), non-tubercular meningitis (NTBM) patients (n=10) and non-tubercular non-meningitis (NTBNM) cases (n=15) were measured by the method based on Berthlot's reaction. The mean CSF ADA activity in TBM (13.62 +/- 8.45 IU/L) was found to be significantly higher as compared to NTBM (6.51 +/- 2.41 IU/ L, p<0.001) and NTBNM (2.35 +/- 1.16 IU/L, p<0.0001) respectively. The sensitivity and specificity of CSF ADA activity was 85.0% and 88.0% respectively at cut-off value of 6.97 IU/L to diagnose tubercular meningitis. The specificity and sensitivity of CSF ADA for TBM was found to be 85.0% and 70.0% as compared to NTBM and 85.0% and 100.0% as compared to NTBNM. We propose that estimation of that ADA activity in CSF of TBM patients, using a cut off value 6.97 IU/L can diagnose differentially tubercular meningitis. Since, most developing countries have the dubious distinction of having higher prevalence and incidence of tubeculosis and lack of well equipped laboratory services for proper diagnosis of tubercular meningitis, measurement of CSF ADA activity can be a better and reliable approach for the rapid diagnosis and management of tubercular meningitis vis a vis other types of meningitis.

Comparison of an adenosine deaminase assay with ELISA for the diagnosis of tuberculous meningitis infection.

BACKGROUND: Diagnosing tuberculous meningitis (TBM) remains problematic despite many new advanced diagnostic methods. Adenosine deaminase (ADA) assays have emerged as novel alternatives to other costly and time-consuming methods for TBM diagnosis. In the present study the usefulness of the ADA method was assessed for the diagnosis of TBM and compared with an in-house developed ELISA method for detecting the antigen 85 (Ag 85) complex of M. tuberculosis in cerebrospinal fluid (CSF) samples of suspected and culture-confirmed TBM patients. MATERIAL/METHODS: ADA activity in CSF was determined at 37 degrees C according to the method of Guisti and Galanti. ELISA, employing monoclonal antibodies against the purified Ag 85 complex, was used to demonstrate Ag 85 complex in CSF from TBM patients. CSF samples were obtained from 153 patients in three different groups: confirmed TBM (n=27), clinically suspected TBM (n=39), and non-TBM (n=87). RESULTS: The ADA method yielded sensitivity and specificity of 83% and 86%, which are similar to those of the ELISA method (89% and 90%). The correlation between the Ag 85 complex activity in absorbance by ELISA and the ADA activity obtained in units per liter per minute (U/l/min) was also positive and significant. (Pearson's correlation coefficient r=0.3234, 95%CI: 0.1621-0.4679, p<0.001). CONCLUSIONS: This study suggests that the ADA method can be performed for TBM diagnosis in low-income TB-affected regions where more sophisticated facilities are generally not available.

Evaluation of enzymes in pyogenic and tuberculous meningitis.

OBJECTIVES: Lactic dehydrogenase (LDH), creatine kinase (CK) and gamma glutamyl transpeptidase (GGTP) were measured serially in cerebrospinal fluid (CSF) and serum in twenty five cases of meningitis and an equal number of age and sex matched healthy control subjects with an aim to find out their diagnostic and prognostic significance in cases of meningitis. METHODS: The enzymatic activity was measured serially (day 0, 4th and 7th) in cerebrospinal fluid (CSF) and serum in twenty-five cases of meningitis consisting of fifteen cases of pyogenic meningitis (PM) and ten of tuberculous meningitis (TBM) and an equal number of age and sex matched healthy control. The clinical details including the level of consciousness and neurological deficit were correlated with the enzymatic activity and prognosis. RESULTS: The levels of these enzymes were significantly elevated in all the cases of meningitis in serum as well as CSF as compared to control subjects. The activity was significantly higher in pyogenic than tuberculous meningitis (p<0.001) and it was higher in CSF than in serum (p<0.001). The maximum elevation in activity of GGTP and LDH were seen on the first day whereas CK was highest on 4th day and thereafter, the activity of all the enzymes declined in the majority of cases who had shown clinical improvement. However, in three cases of pyogenic and five cases of tuberculous meningitis, the enzymatic activity on subsequent estimation, increased serially. All these eight cases died. Further, the basal enzymatic activity in all these eight cases that died was higher as compared to those who survived. Of all the enzymes, CSF GGTP levels correlated best with the clinical picture. CONCLUSIONS: It is concluded that GGTP, CK and LDH were significantly elevated in cases of meningitis. It was not possible to differentiate the type of meningitis on the basis of enzymatic activity in any of them. However, it was possible to predict prognosis because higher basal activity and serial rise were associated with poor prognosis.

Persistent increase of matrix metalloproteinases in cerebrospinal fluid of tuberculous meningitis.

Matrix metalloproteinase (MMP)-2 and MMP-9 were analyzed by gelatin zymography and an enzyme-linked immunosorbent assay (ELISA) in a cerebrospinal fluid (CSF) from patients with tuberculous meningitis (n=24), acute aseptic meningitis (n=23) and the control (n=10). The MMP-2 and MMP-9 levels were significantly higher in the samples from the tuberculous meningitis patients than those from either the aseptic meningitis patients or the controls. In tuberculous meningitis, the patients with late neurologic complications had higher MMP-2 and MMP-9 levels than those without. The persistent increase in the MMP-2 and MMP-9 levels was associated with the development of complications following tuberculous meningitis. Inhibiting the MMPs may be an effective strategy for preventing or reducing the complications in tuberculous meningitis.

Significance of cerebrospinal fluid adenosine deaminase isoenzymes in tuberculous (TB) meningitis.

Adenosine deaminase (ADA) exists as two isoenzymes, ADA(1) and ADA(2). It appears that the ADA(2) isoenzyme originates mainly from monocytes and macrophages. In tuberculous pleural effusions most of the ADA activity consists of ADA(2). The aim of this prospective study was to analyse ADA isoenzymes in the CSF of patients with meningitis to investigate whether the expected rise of the ADA(2) isoenzyme would occur in tuberculous meningitis. ADA isoenzyme analysis was performed on the CSF of 15 patients with tuberculous and 11 patients with bacterial meningitis by an automated kinetic enzyme coupled assay in the presence and absence of a specific ADA inhibitor. The ratio of ADA(2)/ADA(Total) was > 0.8 in 14/15 patients with tuberculous meningitis. In bacterial meningitis the ratio was > or =0.8 in 10/11 patients. The ADA(2) isoenzyme is the major contributor to increased ADA activity in the CSF of patients with tuberculous meningitis, probably reflecting the monocyte-macrophage origin of the ADA.

Identification of a matrix-degrading phenotype in human tuberculosis in vitro and in vivo.

Tuberculous meningitis is characterized by cerebral tissue destruction. Monocytes, pivotal in immune responses to Mycobacterium tuberculosis, secrete matrix metalloproteinase-9 (MMP-9), which facilitates leukocyte migration across the blood-brain barrier, but may cause cerebral injury. In vitro, human monocytic (THP-1) cells infected by live, virulent M. tuberculosis secreted MMP-9 in a dose-dependent manner. At 24 h, MMP-9 concentrations increased 10-fold to 239 +/- 75 ng/ml (p = 0.001 vs controls). MMP-9 mRNA became detectable at 24--48 h. In contrast, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) gene expression and secretion were similar to constitutive levels from controls at 24 h and increased just 5-fold by 48 h. In vivo investigation revealed MMP-9 concentration per leukocyte in cerebrospinal fluid (CSF) from tuberculous meningitis patients (n = 23; median (range), 3.19 (0.19--31.00) ng/ml/cell) to be higher than that in bacterial (n = 12; 0.23 (0.01--18.37) ng/ml/cell) or viral meningitis (n = 20; 0.20 (0.04--31.00) ng/ml/cell; p < 0.01). TIMP-1, which was constitutively secreted into CSF, was not elevated in tuberculous compared with bacterial meningitis or controls. Thus, a phenotype in which MMP-9 activity is relatively unrestricted by TIMP-1 developed both in vitro and in vivo. This is functionally significant, since MMP-9 concentrations per CSF leukocyte (but not TIMP-1 concentrations) were elevated in fatal tuberculous meningitis and in patients with signs of cerebral tissue damage (unconsciousness, confusion, or neurological deficit; p < 0.05). However, MMP-9 activity was unrelated to the severity of systemic illness. In summary, M. tuberculosis-infected monocytic cells develop a matrix-degrading phenotype, which was observed in vivo and relates to clinical signs reflecting cerebral injury in tuberculous meningitis.