Role of estrogen receptor alpha in human cervical cancer-associated fibroblasts: a transcriptomic study.

Cancer-Associated Fibroblasts (CAFs) are crucial in genesis and progression of tumors; however, cervical CAFs (C-CAFs) are not well characterized. Estradiol (E2) has been implicated as a cofactor in human papillomavirus (HPV)-mediated cervical cancer (CxCa), both in animal models and in women using oral contraceptives; however, the exact role of the hormone is unclear. Human C-CAFs have recently been shown to express estrogen receptor alpha (ER-α). We investigated gene expression patterns in ex vivo cultured early and late stage C-CAFs in the context of E2. CAFs were isolated from four patients with early and two patients with late stage CxCa. ER-α expression in CxCa tissues was localized to stromal fibroblast-like cells and confirmed in ex vivo cultured C-CAFs. Two ER antagonists (ICI 182,780 and Methyl Piperidino Pyrazole) were used to unravel ER signaling in CAFs. Microarray technology was used for expression profiling and validated by quantitative reverse transcription PCR. The transcriptomes of C-CAFs across stages indicated their activated state. C-CAFs had gene expression patterns associated with both pro-tumorigenic and pro-inflammatory signaling. Late-stage C-CAFs compared to those of early stage appeared to be more actively metabolizing and cycling but expressed fewer genes related to immune function. We report differential expression profiles between C-CAFs: early vs. late stage and in the presence of ER antagonists. Both ER antagonists seemed to modulate C-CAF function by down regulating genes associated with cell cycle and metabolism, affecting angiogenesis and cancer progression. This study characterized C-CAFs from early and late stage disease, and experiments with ER inhibitors emphasized the probable importance of canonical ER-α signaling. Interfering with paracrine signaling through fibroblast ER-α is worth exploiting as a targeted therapy in CxCa management.

Risk of hepatitis B infection in pediatric acute lymphoblastic leukemia in a tertiary care center from South India.

BACKGROUND: The prevalence of hepatitis B virus (HBV) infection is high in Asian countries. Little is known about outcome of leukemia in HBV infected patients in these regions. Hence, we conducted this study in two cohorts of patients. PROCEDURE: We retrospectively evaluated mortality, reduction in dose intensity and duration of therapy (intensive phase and maintenance phase) in children with acute lymphoblastic leukemia (ALL) who developed HBV infection. Sixty-three patients with ALL were included in the retrospective cohort of the study. These were followed up for a minimum of 5 years. We prospectively investigated the prevalence of anti-HBc antibodies in 105 treatment naïve pediatric patients with ALL and negative for HbsAg. RESULTS: Twenty of the 63 patients developed hepatitis, of which 10 were attributed to HBV. All the 10 patients with HBV hepatitis had significantly reduced dose intensity during maintenance therapy with an average delay in completion of therapy of 140 ± 83 days and also a high mortality (40%). In the prospective cohort of the study, 39% of treatment naive patients who were HBsAg negative were anti-HBc positive at presentation, possibly reflecting occult HBV infection. CONCLUSIONS: HBV infection poses a serious problem in patients with ALL. Hence we propose that in India, in addition to screening for HBsAg, patients with leukemia should also be screened for anti-HBc. Improved hepatitis B vaccine coverage in the community under the universal immunization programme and introduction of HBV nucleic acid test (NAT) for blood donations should also help in addressing the problem.

Toll-like receptors 7, 8, and 9 expression and function in primary human cervical cancer Langerhans cells: evidence of anergy.

OBJECTIVE: Human papillomavirus oncoproteins E6 and E7 down modulate Toll-like receptor (TLR) 9 expression in infected keratinocytes. We explored the status of expression and function of TLR7, TLR8, and TLR9 in primary human Langerhans cells (LCs) isolated from cervical tumors. METHODOLOGY: Single-cell suspensions were made from fresh tissues of squamous cell carcinoma (International Federation of Gynecology and Obstetrics stage IB2); myeloid dendritic cells were purified using CD1c magnetic activated cell separation kits. Langerhans cells were further flow sorted into CD1a*CD207* cells. Acute monocytic leukemia cell line THP-1-derived LCs (moLCs) formed the controls. mRNA from flow-sorted LCs was reverse transcribed to cDNA and TLR7, TLR8, and TLR9 amplified. Monocyte-derived Langerhans cells and cervical tumor LCs were stimulated with TLR7, TLR8, and TLR9 ligands. Culture supernatants were assayed for interleukin (IL) 1ß, IL-6, IL-10, IL-12p70, interferon (IFN) α, interferon γ, and tumor necrosis factor (TNF) α by Luminex multiplex bead array. Human papillomavirus was genotyped. RESULTS: We have for the first time demonstrated that the acute monocytic leukemia cell line THP-1 can be differentiated into LCs in vitro. Although these moLCs expressed all the 3 TLRs, tumor LCs expressed TLR7 and TLR8, but uniformly lacked TLR9. Also, moLCs secreted IL-6, IL-1ß, and tumor necrosis factor α to TLR8 ligand and interferon α in response to TLR9 ligand; in contrast, tumor LCs did not express any cytokine to any of the 3 TLR ligands. Human papillomavirus type 16 was one of the common human papillomavirus types in all cases. CONCLUSIONS: Cervical tumor LCs lacked TLR9 expression and were functionally anergic to all the 3: TLR7, TLR8, and TLR9 ligands, which may play a crucial role in immune tolerance. The exact location of block(s) in TLR7 and TLR8 signaling needs to be investigated, which would have important immunotherapeutic implications.

Cell-free epstein-barr viral loads in childhood hodgkin lymphoma: a study from South India.

Cell-free Epstein-Barr viral (EBV) DNA is detectable in plasma of patients with EBV-related lymphomas. The aim of this study was to evaluate the utility of plasma EBV DNA as a biomarker of EBV association in childhood Hodgkin lymphoma (HL). Furthermore, an attempt was made to evaluate the effectiveness of viral quantitation for assessing response to chemotherapy. Thirteen cases of childhood HL were included in this study. All 13 cases were EBV associated as reflected by expression of EBV LMP1 in the tumor specimen. Eighty-five percent had detectable EBV DNA levels; viral loads ranging from 2.9 to 156.2 × 10³ copies/ml (mean 29 × 10³ copies/ml); while in 2 patients and 30 controls tested, viral DNA was undetectable. In four patients, follow-up samples were available after three cycles of chemotherapy; all had EBV DNAemia prior to chemotherapy but undetectable EBV DNA posttherapy. This corroborated with complete response in these four patients. Plasma EBV viral load quantification maybe a useful tool for detecting EBV association with lymphomas and in monitoring response to treatment in childhood HL in centers with limited resources, more so in India where majority of childhood HL is likely to be EBV associated. This is the first Indian study estimating plasma EBV viral loads in HL.

Non invasive tests for diagnosis of parasitic infections of CNS.

Central nervous system (CNS) infections are among the most devastating diseases with high mortality and morbidity. In the pre-human immunodeficiency virus (HIV) era, the occurrence of CNS infections was very infrequent. However, in the past four decades or so, with a global increase in the immunocompromised population, the incidence of opportunistic infections of the CNS has changed. This includes a global increase in the incidence of parasitic infections such as Toxoplasma gondii. Infections such as neurocysticercosis and cerebral malaria are quite prevalent in developing countries. Early diagnosis of these infections is crucial for instituting accurate therapy and preventing mortality and morbidity. Despite advances in neuroimaging techniques, laboratory diagnosis remains the mainstay for confirmation of diagnosis. We present an update on the noninvasive tests available for laboratory diagnosis of parasitic infections of the CNS.

Region-wise distribution of high-risk human papillomavirus types in squamous cell carcinomas of the cervix in India.

HYPOTHESIS: Assessment of the prevalence and type distribution of human papillomavirus (HPV) in squamous cell carcinomas (SCC) of the cervix across India was undertaken to estimate the impact of available prophylactic HPV-L1 vaccines in the country and to find out additional types that might be needed to be incorporated in second-generation vaccines. METHODS: High-risk (HR) HPVs were genotyped from 667 histopathologically confirmed cases of SCC from 6 different centers representing 4 regions across India: Advanced Centre for Treatment, Research and Education in Cancer, Mumbai; All India Institute of Medical Sciences, New Delhi; Cancer Foundation of India, Kolkata; Christian Medical College, Vellore; Kidwai Memorial Institute of Oncology, Bangalore; and Regional Cancer Center, Thiruvananthapuram. Human papillomaviruses in tumor biopsies were analyzed by Xcytonscreen HPV based on PGMY09/11 multiplex polymerase chain reaction and reverse dot blot assay. RESULTS: Overall viral prevalence across India was not different; 92.1% of 667 cases harbored HPV; 8% were negative. Infection with single HR type was seen in 86.8%: predominant types being HPV-16 followed by HPV-18, -45, -73, -31, -56, -52, -58, -59, -33, -68, -51, -35, -26, and -39. Human papillomavirus types 16/18-positive fraction formed 79.6%; other types comprised 12.4%. CONCLUSIONS: Prophylactic HPV-16/18-L1 vaccines would provide greater than 75% protection against SCC in India. Ranking and frequencies of non-16/18 types were different from earlier reports. Hence, considering the possibility of promotion of persistence of nonvaccine types in the vaccinees due to original antigenic sin and the lack of organized screening programs in India, a broad-based vaccine approach would be appropriate.

Molecular variants of HPV-16 associated with cervical cancer in Indian population.

Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose.

Cell intrinsic & extrinsic factors in cervical carcinogenesis.

Human papillomavirus (HPV) infection is a common sexually transmitted infection which a majority of infected women are able to clear by mounting an effective immune response. Individuals with a suboptimal immune response may be at increased risk of persistent HPV infection leading to sequelae of various grades of dysplasias and / or associated malignancy. Both cell intrinsic and extrinsic phenomena work in concert to bring about oncogenesis. Cell intrinsic factors for cervical carcinogenesis are: integration of the viral genome into the genome of the host's cell which correlates with the progression of low grade lesions into high grade ones, inactivation of tumor suppressor genes like p53 and pRB by HPV oncoproteins particularly E6 and E7, deregulation of cell cycle regulators, host DNA synthesis and apoptosis. Cell extrinsic elements include factors contributing towards immune tolerance; some incriminated in the multistep carcinogenesis of HPV induced cervical cancer are: immunoregulatory enzyme indoleamine 2,3-dioxygenase expressing antigen presenting cells, low numbers of invariant Natural Killer T cells, anergic cytotoxic T lymphocytes, regulatory T cells (Tregs), an immunoregulatory microenvironment comprising of increased IL10, TGF and reduced IL2; reduced intralesional ratios of effectors (CD4 and CD8) vs. Tregs; and different types of Tregs in the lesions of invasive squamous cell carcinoma. Notch signaling plays a crucial role in regulating T cell differentiation and activation including induction of Tregs. Increased expression of Notch receptor-Jagged 1 and number of Tregs were seen in invasive disease when compared to precancer in cervical cancer. Tregs impart their function either through cytokines or by cell to cell contact. Investigation of the consequences of interference of Notch signaling in terms of the dynamics of intratumoral Tregs in cervical cancer would be interesting.

Pro-oncogenic, intra host viral quasispecies in Diffuse large B cell lymphoma patients with occult Hepatitis B Virus infection.

Non Hodgkin lymphoma, predominantly Diffuse Large B-cell Lymphoma (DLBCL) has been reported to have a significant association with Hepatitis B virus (HBV). We investigated the presence of different gene segments of HBV in plasma, B-cells and tumor tissues from DLBCL patients and explored the genetic variability of HBV within and across different compartments in a host using Next Generation Sequencing. Despite all 40 patients being HBV seronegative, 68% showed evidence of occult HBV. Sequencing of these gene segments revealed inter-compartment viral variants in 26% of them, each with at least one non-synonymous mutation. Between compartments, core gene variants revealed Arg94Leu, Glu86Arg and Ser41Thr while X gene variants revealed Phe73Val, Ala44Val, Ser146Ala and Ser147Pro. In tumor compartments per se, several mis-sense mutations were detected, notably the classic T1762A/A1764G mutation in the basal core promoter. In addition, a virus surface antigen mis-sense mutation resulting in M125T was detected in all the samples and could account for surface antigen negativity and occult HBV status. It would be interesting to further explore if a temporal accumulation of viral variants within a favored niche, like patients' lymphocytes, could bestow survival advantage to the virus, and if certain pro-oncogenic HBV variants could drive lymphomagenesis in DLBCL.

Restriction Fragment Length Polymorphism-based Genotyping of Toxoplasma gondii from Autopsy-Proven Cases of Acquired Immunodeficiency Syndrome-associated Cerebral Toxoplasmosis.

CONTEXT: Published data on genetic characterization of Toxoplasma gondii (T.gondii) from clinical cases of toxoplasmosis from India is lacking. AIMS: The present study was aimed at identifying genetic types of T. gondii in fatal cases of cerebral toxoplasmosis (CT) associated with HIV, from India. SETTINGS AND DESIGN: Archived tissues of CT were obtained postmortem from 25 acquired immunodeficiency syndrome patients between 2000 and 2014. SUBJECTS AND METHODS: Direct amplification of eight different loci, namely, SAG1, 5'-3'SAG2, Alt. SAG2, SAG3, BTUB, GRA6, C22-8, and L358 followed by restriction fragment length polymorphism was used to genotype the parasite. RESULTS: The canonical Types I, II, or III were not found in our study. More than 96% of the cases harbored atypical genotypes-likely recombinants of the canonical types; one case closely corresponded to Type II genotype. CONCLUSIONS: Thus, a majority of T. gondii causing CT in South India belonged to a noncanonical lineage. These nonarchetypal genotypes differed from the conventional Types I, II, and III and caused devastating severity in patients with CT in the background of HIV. These results are a step further to deciphering the population genetics of this important zoonotic parasitic infection in Indian patients, information that has thus far been lacking.

Toxoplasma seroprevalence in healthy voluntary blood donors from urban Karnataka.

BACKGROUND & OBJECTIVES: Although many infections can be transmitted through blood transfusion, it is not possible to carry out screening tests for all. Among the protozoal diseases transmitted by blood transfusion in India the most important is malaria, followed by toxoplasmosis. Screening for malaria is mandatory in India. We evaluated the seroprevalence of Toxoplasma gondii in healthy adult population of blood donors in Karnataka, south India. METHODS: A total of 1000 serum samples collected in two batches (500 each) in the years 2004 and 2005 from healthy voluntary blood donors were tested for T. gondii antibodies by ELISA method, in addition to the other five mandatory tests. RESULTS: Overall 20.3 per cent were positive for T. gondii IgG antibody, of which, 63 per cent had high and 7 per cent low avidity, 3.6 per cent IgM positive. IgG titre ranged from 18-362 IU/ml. INTERPRETATION & CONCLUSION: Our study showed a high prevalence of T. gondii antibodies in healthy voluntary blood population. It may be appropriate to include screening for T. gondii also in the pretransfusion blood testing schedule.

Non invasive tests for diagnosis of parasitic infections of CNS

Central nervous system (CNS) infections are among the most devastating diseases with high mortality and morbidity. In the pre-human immunodeficiency virus (HIV) era, the occurrence of CNS infections was very infrequent. However, in the past four decades or so, with a global increase in the immunocompromised population, the incidence of opportunistic infections of the CNS has changed. This includes a global increase in the incidence of parasitic infections such as Toxoplasma gondii. Infections such as neurocysticercosis and cerebral malaria are quite prevalent in developing countries. Early diagnosis of these infections is crucial for instituting accurate therapy and preventing mortality and morbidity. Despite advances in neuroimaging techniques, laboratory diagnosis remains the mainstay for confirmation of diagnosis. We present an update on the noninvasive tests available for laboratory diagnosis of parasitic infections of the CNS.

Oestrogen Receptor-α binds the FOXP3 promoter and modulates regulatory T-cell function in human cervical cancer.

Oestrogen controls Foxp3 expression in regulatory T cells (Treg cells) via a mechanism thought to involve oestrogen receptor alpha (ERα), but the molecular basis and functional impact of ERα signalling in Treg cells remain unclear. We report that ERα ligand oestradiol (E2) is significantly increased in human cervical cancer (CxCa) tissues and tumour-infiltrating Treg cells (CD4+CD25hiCD127low), whereas blocking ERα with the antagonist ICI 182,780 abolishes FOXP3 expression and impairs the function of CxCa infiltrating Treg cells. Using a novel approach of co-immunoprecipitation with antibodies to E2 for capture, we identified binding of E2:ERα complexes to FOXP3 protein in CxCa-derived Treg cells. Chromatin immunoprecipitation analyses of male blood Treg cells revealed ERα occupancy at the FOXP3 promoter and conserved non-coding DNA elements 2 and 3. Accordingly, computational analyses of the enriched regions uncovered eight putative oestrogen response elements predicted to form a loop that can activate the FOXP3 promoter. Together, these data suggest that E2-mediated ERα signalling is critical for the sustenance of FOXP3 expression and Treg cell function in human CxCa via direct interaction of ERα with FOXP3 promoter. Overall, our work gives a molecular insight into ERα signalling and highlights a fundamental role of E2 in controlling human Treg cell physiology.

Microscopic, cultural and molecular evidence of disseminated invasive aspergillosis involving the lungs and the gastrointestinal tract.

A patient with acute promyelocytic leukaemia developed invasive aspergillosis post chemotherapy during a pancytopenic episode, clinically involving the lungs and the gastrointestinal tract. Dichotomously branched septate fungal hyphae were demonstrated microscopically in stools and sputa. Cultures of the samples yielded Aspergillus flavus, which were identical by RFLP and random amplification of polymorphic DNA analyses and antifungal MICs, proving disseminated disease. To the best of the author's knowledge, this is the first time that boluses of fungal hyphae have been demonstrated microscopically in the stools of a patient with gastrointestinal aspergillosis.

Genetic characterization of Toxoplasma gondii from autopsy proven cases of AIDS associated cerebral toxoplasmosis in South India.

Toxoplasma gondii (T.gondii) infection can be devastating in the immunodeficient causing high morbidity and mortality. Due to limited availability of both diagnostic facilities and Highly Active Antiretroviral Therapy (HAART), toxoplasmosis continues to be a significant problem amongst Acquired Immuno Deficiency Syndrome (AIDS) patients in India. While scanty literature is available on T. gondii isolates in animals in India, little is known about the genetic diversity of the parasite in humans. Therefore, the present study investigated the genetic diversity of T. gondii in 25 confirmed cases of cerebral toxoplasmosis developing on the background of human immunodeficiency virus (HIV) infection/AIDS. PCR DNA sequencing was performed at four important genetic loci of T. gondii: BTUB, GRA6, alternative SAG2 (alt SAG2) and SAG3 on DNA from tissues obtained at postmortem. The amplified products from all the cases were successfully sequenced except at one locus for one case. Results of the present study suggest that majority of the patients (22/25; 88%) in South India are infected with strains that are recombinants of type II/III and/or strains representing T. gondii different from the archetypal lineages I, II, and III. In addition, clonal types III, MAS, and MAS variant genotypes were encountered. No clonal type I or II was seen in the present study. In addition, variants were observed at alt SAG2 and SAG3 but BTUB and GRA6 were highly conserved. Single nucleotide polymorphisms were observed mainly at two loci which are coding for surface antigens at alt SAG2 and SAG3. In conclusion, the present study reveals genetic diversity in India amongst strains of T. gondii from clinical cases of toxoplasmosis which is in accordance with other recent studies showing a high rate of genetic diversity in this parasite across the globe. There is a need to genotype T. gondii from different forms of toxoplasmosis in humans in India.

Bloodstream infections in febrile neutropenic patients at a tertiary cancer institute in South India: A timeline of clinical and microbial trends through the years.

INTRODUCTION: Febrile neutropenia (FN) is an oncological emergency. The choice of empiric therapy depends on the locally prevalent pathogens and their sensitivities, the sites of infection, and cost. The Infectious Diseases Society of America guidelines are being followed for the management of FN in India. METHODS: This is a prospective observational study conducted at a tertiary care cancer centre from September 2012 to September 2014. OBJECTIVES: The objectives of this study were as follows: (1) To review the pattern of microbial flora, susceptibility pattern, and important clinical variables among bloodstream infections in febrile neutropenic patients with solid tumors and hematological malignancies. (2) As per the institutional protocol to periodically review the antibiotic policy and susceptibility pattern, and compare the findings with an earlier study done in our institute in 2010. This was a prospective study conducted from September 2012 to September 2014. RESULTS: About 379 episodes of FN were documented among 300 patients. About 887 blood cultures were drawn. Of these, 137 (15%) isolates were cultured. Isolates having identical antibiograms obtained from a single patient during the same hospitalization were considered as one. Hence, 128 isolates were analyzed. About 74 (58%) cultures yielded Gram-negative bacilli, 51 (40%) were positive for Gram-positive cocci, and 3 (2%) grew fungi. Among Gram-negative organisms, Escherichia coli followed by Acinetobacter baumannii and Klebsiella pneumoniae accounted for 78% of the isolates. Among Gram-positive cocci, Staphylococcus species accounted for 84% of the isolates. We have noted a changing trend in the antibiotic sensitivity pattern over the years. Following the switch in empirical antibiotics, based on the results of the study done in 2010 (when the empirical antibiotics were ceftazidime + amikacin), the sensitivity to cefoperazone-sulbactam has plunged from about 80% to 60%%. Similar reduction in susceptibility was noted for piperacillin-tazobactam, imipenem, and meropenem. On the contrary, there was a marked increase in sensitivity to ceftazidime (50-76%). Based on these results, we have reverted to ceftazidime + amikacin as the empirical antibiotics. CONCLUSION: Every institute must have a regular revision of antibiotic policy based on periodic assessment of the clinical and microbiological profile in FN. This will combat antibiotic resistance.

No evidence of association of xenotropic murine leukemia virus-related virus with oral cancers: Experience from a tertiary care center in South India.

BACKGROUND: Development of oral cancer, a widely prevalent cancer in India, is multifactorial with increased risk in those habituated to smoking, consuming alcohol and chewing paan and tobacco. This does not preclude other etiological factors in the causation of this cancer. Exploratory studies on several oncogenic viruses have found varied associations with oral cancers. AIM: The aim of this study was to explore the association of xenotropic murine leukemia virus-related virus, (XMRV) a retrovirus recently implicated in oncogenesis in humans, with oral cancers. SETTINGS AND DESIGN: The presence of XMRV proviral deoxyribonucleic acid (DNA) was evaluated by standard nucleic acid amplification from DNA extracted from representative bits of tumor tissues and adjacent normal tissues from surgically resected specimens sent post-operatively for routine histopathological testing. MATERIALS AND METHODS: This prospective study comprised 109 patients with a provisional diagnosis of oral cancer who were operated at the Oral Oncology Department of Kidwai Memorial Institute of Oncology, over a period of 10 months. RESULTS: XMRV was not found in any of the tumor tissues (squamous cell carcinomas - 98; verrucous carcinomas - 4) nor in any of the normal tissues. It is thus important that the absence of this oncogenic virus in all the cases makes the association of XMRV with oral cancers very unlikely. CONCLUSIONS: There is a need to investigate potentially oncogenic viruses in other solid tumors and in larger sample sizes. Any such association could have implications in detecting, preventing and treating these cancers.

Generation of reactive oxygen species by blood monocytes during acute Plasmodium knowlesi infection in rhesus monkeys.

The status and kinetics of monocyte activation during acute P. knowlesi infection was investigated by latex-induced, luminol-dependent chemiluminescence (CL) response. The contribution of various reactive oxygen species (ROS) to CL response was estimated before infection and at peak parasitaemia (day 7 post infection) by using scavengers of ROS (benzoate, catalase and superoxide dismutase). The chemiluminescence index (CLI) was not found to be significantly different from controls on day 2 postinfection, but was significantly higher on days 5 and 7 postinfection. Hydroxyl radical (OH.) production was considerably elevated, whereas superoxide anion (O2-.) and hydrogen peroxide (H2O2) production dropped following infection. These changes in generation of ROS are discussed in relation to the progression of parasitaemia to high levels, immunopathology and immunosuppression during acute P. knowlesi infection.

Oxidative metabolic response of peripheral blood monocytes of monkeys during primary and chronic Plasmodium knowlesi infection.

The oxygen free radical generation (as determined by cytochrome c reduction) and respiratory burst enzyme activities were measured in the peripheral blood monocytes before infecting normal animals, during primary Plasmodium knowlesi infection, after treatment of primary infection with chloroquine, after administration of various subcurative doses following reinfection and after establishment of chronicity. For all the parameters of the oxidative response, no significant difference was observed during primary infection and after curing of primary infection. However, the response was significantly increased in the reinfected monkeys given subcurative therapy; this was followed by a sharp decline after the 4th subcurative dose, after which the response continued to be low until the attainment of chronicity. The results of the present study exclude the possibility of the increase in oxidative metabolism being the effect of the drug (i.e. chloroquine), since no significant difference was observed during primary infection and after its cure. The sustained low grade parasitaemia in the chronic stage, in spite of the sharp decrease in the oxidative response, suggests that some nonoxidant parasitic killing mechanism might be playing a role in the regulation of parasitaemia.

Assessment of suitability & ease of performance of seven commercial assay systems for the detection of antibodies to HIV-1.

In this study, we have evaluated the suitability and ease of performance of seven HIV assays namely: Vironostika anti-HIV Uni-Form; Vironostika HIV MIXT; Elavia MIXT; Genelavia MIXT; Serodia-HIV; Immunocomb Bi-spot; and Test pack HIV-1 and 2 Abbott, for use in Indian laboratories. A panel of 41 blind coded Western blot confirmed sera were used for this purpose. Rapid assays like Immunocomb Bi-Spot, Serodia HIV and Test pack HIV-1/HIV-2 Abbott were found to be more suitable and easy to perform as compared to the ELISAs. Sensitivity of all the assays was excellent (100%). Specificity of Serodia HIV, Immunocomb Bi-spot, Test pack HIV-1 and 2 Abbott and Elavia MIXT were excellent (100%), while that of Vironostika MIXT and Vironostika anti-HIV Uni-Form was poor. Positive predictive value of the assays ranged from 64.5 to 100 per cent. Negative predictive value of six of the assays was 100 per cent and that of Vironostika anti-HIV Uni-Form was very poor.