Mass screening for hepatitis B and C viruses in a population of persons with disabilities with and without HIV status in Cameroon.

Hepatitis viral infections are one of major threat to public health worldwide. The vast majority of people infected with viral hepatitis are found in resources limited countries of Africa and Asia. There is a lack of accurate data to better determine the burden of this disease in Cameroon, moreover among vulnerable people. The aim of this study was to estimate the seroprevalence of HBV and HCV viruses among persons with disabilities (PwD) with or without HIV status.

Alarming rates of virological failure and HIV-1 drug resistance amongst adolescents living with perinatal HIV in both urban and rural settings: evidence from the EDCTP READY-study in Cameroon.

OBJECTIVES: Adolescents living with perinatal HIV infection (ALPHI) experience persistently high mortality rates, particularly in resource-limited settings. It is therefore clinically important for us to understand the therapeutic response, acquired HIV drug resistance (HIVDR) and associated factors among ALPHI, according to geographical location. METHODS: A study was conducted among consenting ALPHI in two urban and two rural health facilities in the Centre Region of Cameroon. World Health Organization (WHO) clinical staging, self-reported adherence, HIVDR early warning indicators (EWIs), immunological status (CD4 count) and plasma viral load (VL) were assessed. For those experiencing virological failure (VF, VL ≥ 1000 copies/mL), HIVDR testing was performed and interpreted using the Stanford HIV Drug Resistance Database v.8.9-1. RESULTS: Of the 270 participants, most were on nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimens (61.7% urban vs. 82.2% rural), and about one-third were poorly adherent (30.1% vs. 35.1%). Clinical failure rates (WHO-stage III/IV) in both settings were < 15%. In urban settings, the immunological failure (IF) rate (CD4  < 250 cells/µL) was 15.8%, statistically associated with late adolescence, female gender and poor adherence. The VF rate was 34.2%, statistically associated with poor adherence and NNRTI-based antiretroviral therapy. In the rural context, the IF rate was 26.9% and the VF rate was 52.7%, both statistically associated with advanced clinical stages. HIVDR rate was over 90% in both settings. EWIs were delayed drug pick-up, drug stock-outs and suboptimal viral suppression. CONCLUSIONS: Poor adherence, late adolescent age, female gender and advanced clinical staging worsen IF. The VF rate is high and consistent with the presence of HIVDR in both settings, driven by poor adherence, NNRTI-based regimen and advanced clinical staging.

Mobile health clinic for the medical management of clinical sequelae experienced by survivors of the 2013-2016 Ebola virus disease outbreak in Sierra Leone, West Africa.

An Ebola survivor Mobile Health Clinic (MHC) was established to implement lasting changes in communities it operates by providing effective and efficient mobile healthcare. After months of development, the MHC solution was operationalised in February 2015, aiming to provide integrated primary healthcare services to address the medical and psychosocial needs of Ebola virus (EBOV) survivors living in areas with low medical coverage. A total of 910 medical consultations for 246 EBOV survivors were performed between 7 February 2015 and 10 June 2016. Females constituted 148 (60.2%) whereas 6 (2.44%) were children under 5 years of age. The most common complication was arthralgia 185 (75.2%), headache 98 (39.8%), abdominal pain 167 (68%), myalgia 182 (73.6%), and skin disease 25 (10%). Moreover, ocular problems were diagnosed in 84 survivors (34.1%), and 60 (24.4%) suffered from psycho-trauma. Some 16 female survivors (10.8%) had miscarriages, whereas 9 (6.1%) had complaints of oligomenorrhea, 7 (4.7%) loss of sexual desire and 4 (2.7%) premature menopause. Five male survivors (5.1%) reported erectile dysfunction and 10 (10.2%) loss of sexual desire. At least 221 (89.8%) reported more than one complication. Other infectious diseases were common and no clinically relevant differences were established from haematology and clinical biochemistry laboratory results. Ibuprofen, paracetamol, anti-malaria drugs and antibiotics were the most common medicines prescribed. Community participation is critical for implantation of MHC among EBOV survivors. Future strategies for the mobile clinics should include enrolment of survivors at discharge from treatment centres with close monitoring follow-up activities, to address sequelae as they arise, to reduce the potential for development of long-term disabilities.

Abusive use of antibiotics in poultry farming in Cameroon and the public health implications.

The types and methods of use of antibiotics in poultry farms in Cameroon, residual levels and potential microbial resistance were determined. A questionnaire-based survey identified the different antibiotics used and high-performance liquid chromatography (HPLC) was used to determine residual levels of antibiotics. Pathogens were isolated, identified by use of commercial API kits and minimum inhibition concentration (MIC) was determined. Oxytetracyclin, tylocip and TCN (oxytetracycline, chloramphenicol and neomycin) were the most frequently used antibiotics. Antibiotics screened by HPLC were chloramphenicol, tetracycline and vancomycin. All of them except vancomycin were detected, and the concentration of these antibiotics was higher than the maximum residual limits (MRL) set by regulatory authorities. No residues of various antibiotics were found in egg albumen or yolk. The concentration of tetracycline was significantly higher in liver (150 ± 30 µg/g) than in other tissues. Foodborne pathogens, including Salmonella spp., Staphylococcus spp., Listeria spp., Clostridium spp. and Escherichia spp., were identified. Most of the pathogens were resistant to these various antibiotics tested. These findings imply the need for better management of antibiotic use to control sources of food contamination and reduce health risks associated with the presence of residues and the development of resistant pathogens by further legislation and enforcement of regulations on food hygiene and use of antibiotics.

In vitro anti Mycobacterium tuberculosis H37Rv activity of Lannea acida A. Rich from Burkina Faso.

The cytotoxic and anti-Mycobacterium tuberculosis H37Rv activities of hydro-alcoholic extract of Lannea acida A. Rich (Anacardiaceae) were assessed. The cytoxicity evaluation was carried out on THP1 monocytoid cell line (after 24 h at 1; 5 and 10 microg mL(-1)) and showed only a slight modification of lactate dehydrogenase (LDH) release. The rate of monocytes in different stages of mitosis had been amended in absence and presence of extract as follows: Go/G1 58.83-59.83%; synthesis 21.95-18.64%; mitosis 16.67-15.77%; necrosis 2.65-5.64%. The percentage of inhibition of Mycobacterium tuberculosis proliferation was respectively 77.6 and 36.8% at 1.2 and 0.6 mg mL(-1) of extract. This is an interesting experimental study on antimicrobial and immune-stimulating properties of Lannea acida ethanol-water (70% v/v) extract which may contain potential antibacterial and immune-stimulating agents for clinical use.

Characterization of the immune response of human cord-blood derived gamma/delta T cells to stimulation with aminobisphosphonate compounds.

Vγ9Vδ2 T lymphocytes have been shown to respond to a variety of non-peptide antigens including alkylamines and phosphoantigens. Recently, aminobisphosphonates have also been shown to stimulate this subset of γδ+ T cells. In this study we analyzed the proliferative responses of freshly isolated γδ T lymphocytes obtained from human cord blood when challenged with pyrophosphomonoesters or aminobisphosphonates. Nitrogen-containing aminobisphopsphonates, in contrast to phoshoantigens, readily stimulated expansion of Vδ2Vγ9 cells in human cord blood. Expanded cells displayed an activated mature phenotype, and were capable of producing TNFalpha and IFNgamma but not perforin following secondary stimulation, consistent with the development of a regulatory, as opposed to cytotoxic, phenotype. This approach may provide a useful strategy for a new approach to the treatment of neonatal pathologies.

Performance evaluation of an in-house human immunodeficiency virus type-1 protease-reverse transcriptase genotyping assay in Cameroon.

Most commercial HIV-1 genotyping assays are hampered by high cost in resource-limited settings. Moreover, their performance might be influenced over time by HIV genetic heterogeneity and evolution. An in-house genotyping protocol was developed, and its sequencing performance and reproducibility were compared to that of ViroSeq™. One hundred ninety plasma samples from HIV-1-infected subjects in Cameroon, a resource-limited setting with a high HIV genetic variability, were processed for pol gene sequencing with an in-house protocol, ViroSeq™, or both. Only non-B subtypes were found. The in-house sequencing performance was 98.7% against 92.1% with ViroSeq™. Among 36 sequence pairs obtained using both assays, the overall rate of discordant amino acid positions was negligible (0.24%). With its high sensitivity and reproducibility, as well as its affordable cost (about half of ViroSeq™: 92 euros vs. 217 euros), this in-house assay is a suitable alternative for HIV-1 genotyping in resource-limited and/or in high-genetic-diversity settings.

Traditional medicine: past, present and future research and development prospects and integration in the National Health System of Cameroon.

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country.

Evaluation of a multi-antigen test based on B-cell epitope peptides for the serodiagnosis of pulmonary tuberculosis.

SETTING: Two sample panels: 1) 20 pulmonary tuberculosis (PTB) patients and 10 healthy subjects from a country with a low incidence of TB (Italy); and 2) 47 PTB patients and 26 healthy subjects from a country with a high incidence of TB (Morocco). OBJECTIVE: To identify a combination of Mycobacterium tuberculosis peptides useful for the serodiagnosis of active PTB. METHODS: Fifty-seven B-cell epitope peptides of M. tuberculosis were evaluated by immunoenzymatic assay and the data were analysed using logistic regression analysis and the random forest method. RESULTS: The best discriminating peptide between PTB patients and healthy subjects from the sample of the low TB incidence country was the 23 amino acid peptide of the Rv3878 protein. The sensitivity and specificity were respectively 65% and 100%. The same peptide had a sensitivity and specificity of respectively 47% and 100% for the sample from the high TB incidence country. The best combination of peptides was a pool of nine peptides which had a sensitivity of 70.2% and a specificity of 100% in the high TB incidence country. CONCLUSIONS: The 9-peptide pool can be useful in identifying patients with active PTB.

Exploiting immunotherapy in Mycobacterium tuberculosis-infected mice: sphingosine 1-phosphate treatment results in a protective or detrimental effect depending on the stage of infection.

Sphingosine 1-phosphate (S1P) is a natural lysophospholipid able to enhance antimycobacterial innate immune response. In the present study, we address the possible therapeutic role of S1P administered during primary or acute infection in mice aerogenically infected with Mycobacterium tuberculosis (MTB). Results show that the administration of S1P during primary infection significantly reduces the presence of MTB-infected cells within pulmonary granulomas and mycobacterial burden in the lung and in the spleen. However, if S1P treatment was started during acute infection, a detrimental effect was observed in terms of pulmonary histopathology and mycobacterial burden in the lung and in the spleen. Taken together, these results show that S1P can exert a therapeutic effect as a treatment of primary infection only.

Effective program against mother-to-child transmission of HIV at Saint Camille Medical Centre in Burkina Faso.

The present research was aimed to prevent mother-to-child transmission of HIV; to use RT-PCR in order to detect, 6 months after birth, infected children; and to test the antiretroviral resistance of both children and mothers in order to offer them a suitable therapy. At the Saint Camille Medical Centre, 3,127 pregnant women (aged 15-44 years) accepted to be enrolled in the mother-to-child transmission prevention protocol that envisages: (i) Voluntary Counselling and Testing for all the pregnant women; (ii) Antiretroviral therapy for HIV positive pregnant women and for their newborns; (iii) either powdered milk feeding or short breast-feeding and RT-PCR test for their children; (iv) finally, pol gene sequencing and antiretroviral resistance identifications among HIV positive mothers and children. Among the patients, 227/3,127 HIV seropositive women were found: 221/227 HIV-1, 4/227 HIV-2, and 2/227 mixed HIV infections. The RT-PCR test allowed the detection of 3/213 (1.4%) HIV infected children: 0/109 (0%) from mothers under ARV therapy and 3/104 (2.8%) from mothers treated with Nevirapine. All children had recombinant HIV-1 strain (CRF06_CPX) with: minor PR mutations (M36I, K20I) and RT mutations (R211K). Among them, two twins had Non-Nucleoside Reverse Transcriptase Inhibitor mutation (Y18CY). Both mothers acquired a major PR mutation (V8IV), investigated 6 months after a single-dose of Nevirapine. Prevention by single-dose of Nevirapine reduced significantly mother-to-child transmission of HIV, but caused many mutations and resistance to antiretroviral drugs. Based on present study the antiretroviral therapy protocol, together with the artificial-feeding, might represent the ideal strategy to avoid transmission of HIV from mother-to-child.

Sphingosine 1-phosphate interferes on the differentiation of human monocytes into competent dendritic cells.

Sphingosine 1-phosphate (S1P) is a lipidic messenger known to exert several physiological functions within the cell. We tested here whether the stimulation of human monocytes with different doses of S1P might interfere with their differentiation into competent dendritic cells (DC). Monocytes cultured with granulocyte macrophage colony stimulating factor, interleukin-4 (IL-4) and S1P differentiated into a DC population lacking CD1a molecules on the surface and acquired some aspects of mature DC (mDC), though in the absence of maturation stimuli. When stimulated with lipopolisaccharide (LPS), CD1a(-) DC produce high amounts of tumour necrosis factor-alpha and IL-10, but not IL-12. Accordingly, these CD1a(-) DC were not capable of stimulating allogenic T lymphocytes so well as CD1a(+) DC generated from untreated monocytes and maturated with LPS. S1P monocyte-derived DC lost their polarizing capacity abrogating the production of gamma-interferon/IL-4 by co-cultured naïve CD4(+)CD45RA(+) T cells. Our findings suggest a mechanism through which S1P can favour the development of immune-related pathological states.

Characterization of drug-resistance mutations in HIV-1 isolates from non-HAART and HAART treated patients in Burkina Faso.

Non-B HIV subtypes have been estimated to account for 88% of HIV infections in the world. These subtypes are particularly relevant in view of the availability of antiretroviral (ARV) drugs, since subtype-specific mutations are associated with drug-resistance in developing countries. Therefore, the pol gene sequences in HIV-1 isolates were examined from the three distinct groups of 39 infected patients from Ouagadougou in Burkina Faso: 17 patients who had not received any antiretroviral therapy (ART); 16 patients received ART, and 6 HIV-infected children, from infected mothers, received a single Nevirapine dose prophylaxis during birth. HIV-1 pol sequencing was successful for 29 samples. As expected, all patients presented the common (non-B subtype) M36I polymorphism and 26/29 (90%) the K20I mutation. Phylogenetic studies showed high predominance of recombinant HIV-1 strains: CRF06_cpx 16/29 (55.17%), CRF02_AG 9/29 (31.03%), A1 2/29 (6.89%), G 1/29 (3.44%), and CRF09_cpx 1/29 (3.44%). Two twins showed, 6 months after birth, a NNRTI-mutation (Y181C/Y). During the same period, the twin mother presented a different NNRTI-mutation (V106I), thus suggesting that the different blood drug concentration may determine a different drug-resistance pathway. Among 17 non-highly active antiretroviral therapy (HAART) patients, 3/17 (17.64%) presented virus with reverse transcriptase (RT) mutations [V118I: 1/17 patients (5.88%), V179E: 2/17 patients (11.76%)]. 10/17 (58.82%) presented virus with minor protease (PR) mutations [L63P: 5/17 patients (29.41%), V77I: 3/17 patients (17.64%), L10I: 2/17 patients (11.76%)]. 4/17 patients did not show any PR and RT mutations (23.52%). Among six HAART-treated patients, 6/6 and 3/6 had M36I and L63LP protease minor subtypes, respectively; and only two (33.33%) presented virus with K103N mutation. The low prevalence of drug-resistant associated mutations in Burkina Faso is encouraging. However, further studies with a larger cohort with a high non-B subtype prevalence are necessary to optimize ART in developing countries.

Reduction of mother-to-child transmission of HIV at Saint Camille Medical Centre in Burkina Faso.

One thousand three hundred and twenty-eight pregnant women with less than 32 weeks of amenorrhea received voluntary counseling and testing at Saint Camille Medical Center from May 1, 2002 to December 30, 2004. Following informed consent and pre-test counseling, HIV screening was performed in 1,202 women. According to the prevention protocol, HIV-positive women received a single dose of Nevirapine (200 mg) during their labor, while their newborn received a single dose of Nevirapine (2 mg/kg) within 72 hr from birth. HIV seroprevalence (11.2%) was higher than in the overall population. One hundred and ninety-three children were born at the end of December 2004; 53 children (27.5%) followed a short breastfeeding protocol for 4 months, while 140 (72.5%) were fed artificially. All the children underwent RT-PCR test for HIV 5-6 months after their birth: 173 (89.6%) were HIV negative whilst 20 children (10.4%) were HIV positive. Out of the 20 positive children 5/53 (9.4%) had received breast milk for 4 months, while the remaining 15/140 (10.7%) had been fed artificially (P = 0.814). Artificially fed babies (3/140 (2.1%)) and 1/53 (1.9%) of those breast fed for 4 months deceased according to mortality rate of HIV-positive children. This shows that there is no statistically significant difference (P = 0.648) between the mortality of artificially fed (3/140 or 2.1%) and breast-fed (1/53 or 1.9%) children. Artificially fed children (20/140 (14.3%)) and 5/53 (9.4%) of breast-fed children died within 6-10 months. This figure indicates that there is no significant difference between the mortality rate of artificially and that of breast-fed children (P = 0.427). Although the HIV prevention program reduced significantly the vertical transmission of HIV at Saint Camille Medical Center, the mortality of artificially fed children was still high due to gastrointestinal diseases. The HIV diagnosis by RT-PCR technique was of great help in the early identification of HIV-infected children.

Role of mycobacteria-induced monocyte/macrophage apoptosis in the pathogenesis of human tuberculosis.

Apoptosis is a physiological programmed cell death process whose dysregulation plays an important role in different human infectious diseases. An increasing number of intracellular pathogens are known to induce target cell apoptosis, while some other parasites inhibit it. Unlike necrosis, apoptosis is a silent immunological event occurring without inflammation. Infection-induced target cell apoptosis may be a successful strategy to eliminate pathogens and assure host survival. Conversely, apoptosis inhibition could represent an adaptive mechanism for pathogen survival, while it may be beneficial for the host to initiate an effective immune response. The worldwide increase in tuberculosis has stimulated more research aimed at defining the interaction between Mycobacterium tuberculosis and the immune system. M. tuberculosis possesses sophisticated strategies to circumvent its fate within target monocytic cells. Apoptosis of alveolar macrophages and monocytes has been described as a consequence of M. tuberculosis infection. Moreover, the observation that mycobacterial lipoproteins activate macrophages through Toll-like receptor (TLR) 2 suggests that innate immune receptors contribute to defence against M. tuberculosis. There is evidence that TLR-induced apoptosis modulates inflammation and immune activation during M. tuberculosis infection. Finally, the role of apoptotic-infected cells as a source of microbial antigens for cross-priming of effector T-cells is also discussed.

Expansion of CCR5+ CD4+ T-lymphocytes in the course of active pulmonary tuberculosis.

Nonsyncytium inducing, macrophage tropic HIV strains predominate in the course of active tuberculosis (TB). The present study assesses the expression of CCR5 in CD4+ T-lymphocytes from blood and bronchoalveolar lavage (BAL) of TB patients, non-TB lung disease controls and healthy controls. Memory (CD45RO+), recently activated (CD69+), proliferating (Ki67+) CCR5+ or CCR3+ CD4+ T-lymphocytes were determined by multiparametric flow cytometry analysis. Results show that BAL CD4+ T-lymphocytes expressing CCR5 or CCR3 were significantly increased when compared to peripheral blood both in patients and in healthy controls. However, the data show that the proportions of peripheral blood CCR5+ CD4+ and CCR3+ CD4+ T-lymphocytes and BAL CCR5+ CD4+ T-lymphocytes, but not BAL CCR3+ CD4+ T-lymphocytes, were significantly increased in TB patients. Furthermore, the observation that BAL CCR5+ CD4+ T-lymphocytes from TB patients expressed early activation markers, were not proliferating and showed down-regulation of CCR5 expression suggests recruitment and trapping at the site of disease. Altogether, these results suggest that the lower respiratory tract mucosa may provide cellular targets accessible for efficient transmission of macrophage tropic HIV-1 variants and that tuberculosis may enhance this phenomenon.

Role of macrophage phospholipase D in natural and CpG-induced antimycobacterial activity.

The present study addresses the differential ability of macrophages to control intracellular growth of non-pathogenic Mycobacterium smegmatis (Msm) and pathogenic M. tuberculosis (MTB). Results reported herein show that 3 h post infection, intracellular Msm, but not MTB, was significantly killed by macrophages. As the role of human macrophage phospholipase D (PLD) in the activation of antimicrobial mechanisms has been documented, we hypothesised the role of such enzyme in antimycobacterial mechanisms. To this aim, macrophage PLD activity was analysed at different times after exposure with either pathogenic MTB or non-pathogenic Msm. Results showed that, starting from 15 min after mycobacterial exposure, MTB did not induce macrophage PLD activity, whereas the environmental non-pathogenic Msm stably increased it. The direct contribution of PLD in intracellular mycobacterial killing was also analysed by inhibiting enzymatic activity with ethanol or calphostin C. Results show that PLD inhibition significantly increases intracellular Msm replication. In order to see whether the innate PLD-mediated antimicrobial mechanisms against MTB are also induced after CpG ODN stimulation, the role of PLD has been analysed in the course of CpG-mediated intracellular MTB killing. CpG DNA increased PLD activity in both uninfected and MTB-infected macrophages, and the inhibition of PLD activity resulted in a significant reduction of CpG-induced MTB killing. Taken together, our data suggest a relationship between host PLD activation and the macrophage ability to control intracellular mycobacterial growth.

Detailed analysis of the effects of Glu/Lys beta69 human leukocyte antigen-DP polymorphism on peptide-binding specificity.

The polymorphism at position beta69 of the human leukocyte antigen (HLA)-DP molecule has been associated with susceptibility to several immune disorders and alloreactivity. Using molecular modeling, we have predicted a detailed structure of the HLA-DP2 molecule (carrying Glubeta69) complexed with class II associated invariant chain derived peptide (CLIP) and compared it with the form carrying Lys at beta69 (HLA-DP2K69). Major changes between the two models were observed in the shape and charge distribution of pocket 4 and of the nearby pocket 6. Consequently, we analyzed in detail the peptide-binding specificities of both HLA-DP molecules expressed as recombinant proteins. We first determined that the minimum peptide-binding core of CLIP for both HLA-DP2 and DP2K69 is represented by nine aminoacids corresponding to the sequence 91-99 of invariant chain (Ii). We then assessed the peptide-binding specificities of the two pockets and determined the role of position beta69, using competition tests with the Ii-derived peptide CLIP and its mutated forms carrying all the aminoacidic substitutions in P4 and P6. Pocket 4 of HLA-DP2 showed high affinity for positively charged, aromatic, and polar residues, whereas aliphatic residues were disfavored. Pocket 4 of the DP2K69 variant showed a reduced aminoacid selectivity with aromatic residues most preferred. Pocket 6 of HLA-DP2 showed high affinity for aromatic residues, which was increased in DP2K69 and extended to arginine. Finally, we used the experimental data to determine the best molecular-modeling approach for assessing aminoacid selectivity of the two pockets. The results with best predictive value were obtained when single aminoacids were evaluated inside each single pocket, thus, reducing the influence of the overall peptide/ major histocompatibility complex interaction. In conclusion, the HLA-DPbeta69 polymorphism plays a fundamental role in the peptide-binding selectivity of HLA-DP. Furthermore, as this polymorphism is the main change in the pocket 4 area of HLA-DP, it could represent a supertype among HLA-DP molecules significantly contributing to the selection of epitopes presented in the context of this HLA isotype.

Different cytokine production and effector/memory dynamics of alpha beta+ or gamma delta+ T-cell subsets in the peripheral blood of patients with active pulmonary tuberculosis.

Immunity to M.tuberculosis (MTB) infection consists of interactions between various T-cell subsets that control the infection and prevent further reactivation. We analysed the effector/memory T-cell dynamics and cytokines production in the peripheral blood of patients with pulmonary tuberculosis (TB). We observed that the frequency of CD4+ T-cell effectors was significantly increased during active TB, confirming a major role of this T-cell subset in TB immunity. Pre-terminally differentiated CD8+ T-lymphocytes were increased in the peripheral blood as well. In contrast, we observed a reduced number of effector mycobacteria-reactive gammadelta+ T-lymphocytes with a specific defects in reacting to mycobacterial nonpeptidic antigens, suggesting that this innate response is rapidly lost during TB infection. Nevertheless, the frequency of gammadelta+ T-cells effectors in TB patients was higher than the alphabeta+ T-cell response to peptide from MTB-ESAT-6 protein and quantitatively similar to PPD reactivity. Thus, alphabeta+ and gammadelta+ T-cell differentiation and function are differently triggered by active TB infection.

Diagnosis of tuberculosis: available technologies, limitations, and possibilities.

Rapid diagnosis and treatment are important for preventing transmission of Mycobacterium tuberculosis. However, the diagnosis of tuberculosis continues to pose serious problems, mainly because of difficulties in differentiating between patients with active tuberculosis and those with healed lesions, normal mycobacterium boris BCG (Bacillus Calmette Guerin) vaccinated individuals, and unvaccinated Manteux positives. Physicians still rely on conventional methods such as Ziehl-Neelsen (ZN) staining, fluorochrome staining, sputum culture, gastric lavage, and other non-traditional methods. Although the tuberculin test has aided in the diagnosis of tuberculosis for more than 85 years, its interpretation is difficult because sensitization with nontuberculous mycobacteria leads to false-positive tests. There have been numerous unsuccessful attempts to develop clinically useful serodiagnostic kits for tuberculosis. A number of proteinaceous and nonprotein antigens (such as acyltrehaloses and phenolglycolipids) have been explored from time to time for the development of such assays but they have not proved to be clinically useful. It has been difficult to develop an ELISA utilizing a suitable antigen because M. tuberculosis shares a large number of antigenic proteins with other microorganisms that may or may not be pathogenic. With the advent of molecular biology techniques, there have been significant advances in nucleic acid-based amplification and hybridization, which are helping to rectify existing flaws in the diagnosis of tuberculosis. The detection of mycobacterial DNA in clinical samples by polymerase chain reaction (PCR) is a promising approach for the rapid diagnosis of tuberculous infection. However, the PCR results must be corrected for the presence of inhibitors as well as for DNA contamination. In the modern era of genetics, marked by proteomics and genomics, the day is not far off when DNA chip-based hybridization assays will instantly reveal mycobacterial infections.