HIV-positive men who have sex with men are at high risk of development of significant liver fibrosis after an episode of acute hepatitis C

Acute hepatitis C virus infection remains a major health concern in human immunodeficiency virus(HIV)-infected men who have sex with men (MSM). New direct-acting antiviral agent (DAA) combination therapy has not yet been approved for the treatment for acute hepatitis C virus(HCV), thereby potentially causing deferral of HCV treatment. Therefore, we aimed to study the course of liver disease after an episode of acute HCV. This study is a retrospective single-centre cohort of HIV-positive MSM with acute HCV infection. Liver fibrosis was estimated by Fibroscan^® and Fibrotest^® . Liver-related and non-liver-related outcomes were documented. Overall 213 episodes of acute HCV infection in 178 men were documented. Median follow-up for all included patients was 38.7 months. Spontaneous HCV clearance was found in 10.8% of patients, which was significantly associated with older age, lower HCV RNA levels, and higher ALT levels upon initial acute HCV diagnosis. Treatment with interferon-based therapy was initiated in 86.3% of cases, resulting in a sustained virological response(SVR) rate of 70.7%. After 3 years' follow-up, significant liver fibrosis of METAVIR F2 stage or higher was found in 39.4% of patients after first acute HCV diagnosis. Higher age, physician-declared alcoholism, and nonresponse to acute HCV therapy were independently associated with higher fibrosis stages. Ten patients died during the observation period (IR 1.4/100 patient-years) and four during interferon treatment. Significant liver fibrosis is a common finding in HIV-positive MSM following acute HCV infection despite high treatment uptake and cure rates, suggesting the need for close liver disease monitoring particularly if HCV treatment is deferred.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Evidence of a large, international network of HCV transmission in HIV-positive men who have sex with men

BACKGROUND & AIMS

Since 2000, there has been a marked rise in acute hepatitis C virus (HCV) in human immunodeficiency virus (HIV)-positive men who have sex with men (MSM). We conducted an international phylogenetic study to investigate the existence of an HCV transmission network among MSM.

METHODS

HIV-positive MSM diagnosed with recent HCV (n = 226) in England (107), The Netherlands (58), France (12), Germany (25), and Australia (24) between 2000 and 2006 were enrolled into a molecular phylogenetic study. Using real-time polymerase chain reaction (PCR), the NS5B region of the HCV genome (436 base pair) was amplified, sequenced, and compared with unrelated NS5B sequences.

RESULTS

NS5B sequences were obtained from 200 (89%) cases. Circulating HCV genotypes were 1a (59%), 4d (23%), 3a (11%), 1b (5%), and 2b/c (3%). Phylogenetic analysis revealed 156 (78%) sequences that formed 11 clusters (bootstrap value > 70%) containing between 4 and 37 individual sequences. Country mixing was associated with larger cluster size (17 vs 4.5 sequences; P = .03). "Molecular clock" analysis indicated that the majority (85%) of transmissions occurred since 1996.

CONCLUSIONS

Phylogenetic analysis revealed a large international network of HCV transmission among HIV-positive MSM. The rapid spread of HCV among neighboring countries is supported by the large proportion (74%) of European MSM infected with an HCV strain co-circulating in multiple European countries, the low evolutionary distances among HCV isolates from different countries, and the trend toward increased country mixing with increasing cluster size. Temporally, this epidemic coincides with the introduction of highly active antiretroviral therapy and associated increases in sexual risk behaviors. International collaborative public health efforts are needed to mitigate HCV transmission among this population.

[Evaluation of an enzyme immunoassay for the determination of the status of immunity against diphtheria before and after vaccination]

VACCINATION

PURPOSE

Assessment of an Easy-to-Perform Immunoenzymatic Assay for Detecting Diphtheria Immunity in the Population. Can an immunoassay replace or support the toxin neutralisation test? SERA AND METHODS: Sera of 75 adults were collected before and after vaccination and tested in the vero cell neutralisation test and the immunoassay.

RESULTS

The sensitivity of the EIA was 73 and 94%, specificity was 74 and 67% before and after vaccination, respectively. Positive or negative predictive value was 70 and 96% or 78 and 49% before and after vaccination, respectively. The correlation coefficient changed from 0.43 to 0.77 after vaccination. A comparison of the quantitative results of the test showed differences up to 19 times in individual cases.

CONCLUSIONS

Only cases with relatively high antibody titres (e.g. after booster vaccination) show EIA high sensitivity. Linear correlation is also high in such cases. If you expect low antitoxin levels as is the case before booster vaccination, EIA will then often be false positive or negative. Such studies should be limited to the neutralisation method.

[High percentage of isolated anti-HBc-positive persons among prisoners]

PURPOSE

Is the result "isolated Anti-HBc" higher among prisoners than in the normal population and can testing for HBV-DNA clarify the results?

PATIENTS AND METHODS

In Berlin, 519 prisoners were serologically tested in 1994 for hepatitis-B and -C because of intravenous drug abuse and alcohol disease or signs of hepatitis. Beside virus antigen and antibodies, HBV-DNA was also measured by hybridisation technique or PCR.

RESULTS

50.3% of all individuals showed markers of hepatitis-B and 36.8% of hepatitis-C. 19.2% of persons with hepatitis B markers were positive for anti HBc only, i.e. more than twice as many than in the normal population. 90% of the isolated anti-HBc-positive Persons were also anti-HCV positive, which is nearly double the number of individuals with other patterns of HBV markers. Half of them were tested for HBV-DNA. Whereas the hybridisation technique failed to detect HBV-DNA, 36% of sera were found positive by HBV-PCR.

CONCLUSION

This study shows again that the result "anti-HBc alone" is relatively frequent especially among prisoners. This pattern often seems associated with concurrent HCV-infection and in one third of the cases correlated with a chronic hepatitis-B. The result of an isolated anti-HBc should therefore always lead to further testing of anti-HCV and HBV-DNA by PCR.

Routine immunizations in adult renal transplant recipients

BACKGROUND

Vaccination guidelines for transplant recipients include regular boosters of tetanus, diphtheria, and inactivated polio vaccine, but there are few published data on the efficacy of these vaccines in patients receiving immunosuppressive therapy.

METHODS

Serum antibody values were evaluated before and 4 weeks after tetanus, diphtheria, and inactivated polio vaccination in 164 renal transplant recipients compared with healthy controls. Twelve months later, antibody levels were evaluated in 55 patients.

RESULTS

Prebooster tetanus antitoxin values were lower in transplant recipients than in controls. All patients developed protective tetanus antibody levels (> or = 0.01 IU/ml) after vaccination. After 12 months, serum antibodies had decreased, but all patients maintained protective values. Diphtheria antitoxin titers before and after booster vaccination were lower in patients than in controls: 88.5% of patients and 96.2% of controls developed protective diphtheria antibody values. Twelve months after vaccination, diphtheria antitoxin values were below the protective level (0.1 IU/ml) in 38% of patients. Prebooster antibody values to poliovirus types 1 and 3 were comparable in patients and controls, whereas antibodies to poliovirus type 2 were lower in transplant recipients. Seroprotection rates and geometric mean antibody titers after vaccination were equivalent between the two groups for all three poliovirus types. No difference was observed in antibody levels between patients on different immunosuppressive drug regimens. Adverse reactions were significantly less often reported by transplant recipients.

CONCLUSIONS

In transplant recipients, tetanus and inactivated polio vaccinations are well tolerated and induce protective antibody levels; diphtheria vaccination as currently recommended is less effective and protective antitoxin values decrease rapidly in these patients within 1 year after vaccination.

Upregulation of ICAM-1, IL-1 and reactive oxygen intermediates (ROI) by exogenous antigens from Plasmodium falciparum parasites in vitro, and of sICAM-1 in the acute phase of malaria

After 4 hours of stimulation of human mononuclear leukocytes in the presence of 300 ng/ml exogenous Plasmodium falciparum antigens, the ICAM-1 expression increased variably from 15% to 375%. Simultaneously, an increase of IL-1 mRNA production could be observed in Northern blot hybridizations with a specific cDNA gene probe for human IL-1 alpha labelled with digoxigenin. Furthermore, the reactive oxygen intermediates (ROI) production was also found to be enhanced in similar conditions. Additionally, when the levels of soluble ICAM-1 (sICAM-1) in plasma of 122 patients with P. falciparum or Plasmodium vivax malaria were analyzed in an enzyme immunoassay (EIA), significant sICAM-1 increases were found, more pronounced in patients with P. falciparum malaria, in comparison with healthy controls and with the same patients 4 weeks after chemotherapy. The presented results indicate that the expression of ICAM-1 may also be upregulated by exogenous Plasmodium antigens besides cytokines like IL-1 during the acute phase of malaria, with subsequently elevated sICAM-1 concentrations in blood.

[Retrospective evaluation of western blot for detection of early HIV infections]

The purpose of HIV diagnosis is to establish safely whether there is an infection or not. The enzyme-linked immunosorbent assay (ELISA) as screening test, and the western blot assay for confirmation is the most widely used serologic test system to get this information. Diagnostic problems occur if the two tests yield different results. In our 1993 study 491 (4.4%) of 11,127 tested sera were reactive by ELISA. 39 (7.9%) of these samples could not be confirmed by western blot, giving negative or indeterminate results. In addition, 370 ELISA-negative samples were tested by HIV-1 western blot to detect the infection in the early stage. 115 (31%) of these sera showed indeterminate western blot patterns, the other samples were negative. Results of follow-up investigations of 26 (Table 1) or 11 (Table 2) persons with indefinite serodiagnosis were analysed. HIV infection was not detected in any of these cases. In the literature, persons whose sera were reactive according to ELISA and were indeterminate in western blot, had a 3-5% probability of an aisting HIV infection. In contrast, indeterminate western blot patterns in ELISA-negative sere were without significance for the prognosis as to whether a person was or was not HIV-infected.

Splenic interleukin 1 gene expression is associated with accumulation of macrophages and oxygen radical production in Plasmodium vinckei malaria

High levels of interleukin 1 alpha (IL-1 alpha) were detected in vitro, in murine peritoneal macrophages stimulated with Plasmodium vinckei exogenous antigens, and in vivo, in sera of P. vinckei-parasitized mice. Moreover, high production of IL-1 alpha mRNA could be detected by in situ hybridization analysis in spleen sections of mice during the course of P. vinckei malaria. The observed IL-1 alpha gene expression in the spleen was associated with the accumulation of F4/80+ macrophages in the red pulp and in the marginal zone of follicles, as well as with the relative proportions of Mac-1+ cells in the spleen and the capacity of spleen cells to produce reactive oxygen intermediates during murine malaria.

Upregulation of ICAM-I by Plasmodium falciparum: in vitro and in vivo studies

AIMS

To monitor the expression of intercellular adhesion molecule I (ICAM-I) in vitro after stimulation of human macrophages with Plasmodium falciparum antigens, as well as the plasma concentrations of soluble ICAM-I (SICAM-I) in vivo in malarial patients.

METHODS

Human mononuclear leucocytes were cultured and stimulated for four hours with 300 ng/ml exogenous P falciparum antigens. CD14 and CD54 (ICAM-I) expression was monitored using flow cytometry. Soluble ICAM-I (s ICAM-I) was also measured in the blood of 122 outpatients with malaria before and after treatment (Rio Branco, Acre, Brazil).

RESULTS

ICAM-I expression increased from 15% to 375% after four hours of stimulation. When sICAM-I was analysed in the plasma of 122 patients with P falciparum or Plasmodium vivax malaria by enzyme immunoassay, significant increases were found. These were more pronounced in patients with P falciparum malaria, compared with healthy controls, and with the same patients four weeks after treatment.

CONCLUSION

ICAM-I expression may also be upregulated in human macrophages by exogenous Plasmodium antigens as well as by cytokines during the acute phase of malaria. sICAM-I concentrations are downregulated after treatment, probably caused by the absence of circulating Plasmodium antigens.

Clindamycin in combination with chloroquine or quinine is an effective therapy for uncomplicated Plasmodium falciparum malaria in children from Gabon

Multidrug resistance of Plasmodium falciparum is becoming common in Africa. In a randomized trial, four short-term regimens were compared for treating uncomplicated P. falciparum malaria in children 4-15 years old in Gabon. One hundred thirty patients received chloroquine (25 mg/kg over 48 h; group C), chloroquine (as above) plus clindamycin (5 mg/kg every 12 h for 6 doses; group CCl), quinine (12 mg/kg every 12 h for 6 doses; group Q), or quinine (as above) plus clindamycin (as above; group QCl). In group C, only 9% of patients were cured by day 28, 44% showed recrudescent malaria (RI), and 47% showed intermediate or high-grade resistance (RII/RIII). In group CCl, 70% of patients were cured and 30% showed recrudescences. In group Q, 32% were cured and 68% showed recrudescences. In group QCl, 88% were cured and 12% showed recrudescences after day 14. All treatment regimens were well tolerated. Thus, the combination of clindamycin with chloroquine or quinine enhances parasite clearance and improves response to therapy.

Tumour necrosis factor-alpha and macrophages in Plasmodium berghei-induced cerebral malaria

The effect of tumour necrosis factor-alpha on malaria-infected mice was studied. C57Bl/6J mice infected with Plasmodium berghei K173 exhibited an increased sensitivity to exogenous TNF. Injection of 15 micrograms TNF was lethal to some of the animals when given 5-7 days after infection, while when given later on in the infection (i.e. days 8-10) amounts as low as 2.5 micrograms TNF appeared to be lethal in all mice. The pathology in infected mice treated with TNF resembled that found in the brains of infected mice dying with cerebral malaria. Infected mice treated with TNF, however, also developed severe pathological changes in other organs. On the contrary, treatment with sublethal amounts of TNF (1.0 micrograms or less) given on days 8 and 9 after infection, protected mice against the development of cerebral malaria. In addition, infected mice exhibited and enhanced sensitivity for treatment with lipopolysaccharide (LPS). Sublethal amounts of LPS, however, did not prevent mortality as in TNF-treated mice (LPS-treated mice died at about the same time as infected mice that developed cerebral malaria), but no cerebral haemorrhages were found in the majority of LPS treated, infected animals. Treatment with dexamethasone during infection protected mice against the development of cerebral malaria, but did not suppress their increased sensitivity to exogenous TNF. Treatment of mice with liposome-encapsulated dichloromethylene diphosphonate (lip-Cl2MDP), used to eliminate macrophages (an important source of TNF), prevented the development of cerebral malaria, but only when given before day 5 of infection. Mice protected by treatment with lip-Cl2MDP, however, remained sensitive for LPS on the eighth day of infection.

Production of interleukin-6 by human and murine mononuclear leukocytes stimulated with Plasmodium antigens is enhanced by pentoxifylline, and tumor necrosis factor secretion is reduced

When pentoxifylline was present during stimulation of human mononuclear leukocytes with Plasmodium falciparum exogenous antigens, an increase in interleukin-6 production was observed simultaneously with a reduction of tumor necrosis factor secretion. Similar results were obtained in murine macrophages stimulated with P. vinckei antigens. This indicates the independence of interleukin-6 and tumor necrosis factor secretion in response to malaria antigens.

Interference by antimalarial drugs with the in-vitro production of reactive nitrogen intermediates by murine macrophages

The production of reactive oxygen intermediates (ROI) by host macrophages has long been recognized as an important defense mechanism against microorganisms. More recently, reactive nitrogen intermediates (RNI), also produced by activated macrophages, have been shown to be part of the host's first line of defense against malaria. In the present in-vitro study we have investigated the effects of antimalarial drugs on RNI production by murine macrophages stimulated by interferon-gamma (IFN-gamma) and/or malaria antigen, and on ROI production induced by phorbol myristate acetate. At concentrations exceeding the peak serum levels achieved with therapeutic dosages, chloroquine, in a dose-dependent manner, inhibited IFN-gamma- and malaria antigen-induced RNI production. Quinine, at a concentration of 10 mg/L also caused a significant reduction in IFN-gamma and malaria antigen-induced RNI synthesis; this concentration was well within the therapeutic range. High concentrations of artelinate significantly inhibited IFN-gamma-induced RNI production but clindamycin had no effect on RNI synthesis. In contrast, halofantrine, in concentrations attainable with therapeutic dosages, significantly enhanced IFN-gamma-induced RNI production. ROI production by murine macrophages was unaffected by the antimalarial drugs over the same concentration ranges. It remains to be determined whether these in-vitro effects of antimalarial drugs on RNI production also influence the clinical and parasitological response in patients with malaria.

Malaria antigen and cytokine-induced production of reactive nitrogen intermediates by murine macrophages: no relevance to the development of experimental cerebral malaria

The in vitro production of reactive nitrogen intermediates (RNI) by murine macrophages was evaluated in response to heat-stable malaria antigen and cytokines. Malaria antigen, interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) induced RNI production in macrophages in a dose-dependent way. RNI production steadily increased over a 2-day period and was enhanced when the malaria antigen was co-incubated with IFN-gamma and/or TNF. RNI production induced by either IFN-gamma or malaria antigen or a combination of the two was suppressed by pentoxifylline in a dose-dependent manner. Pentoxifylline did not significantly influence TNF-induced RNI production. L-N-monomethyl arginine reduced malaria antigen, IFN-gamma and TNF-induced RNI production when these reagents were used in combination or alone. An anti-TNF monoclonal antibody (mAb) reduced IFN-gamma-induced RNI production, but did not significantly alter the malaria antigen-induced RNI synthesis by macrophages. The influence of inhibitors of nitric oxide synthase, L-N-monomethyl arginine and N omega-nitro-L-arginine, was studied in experimental cerebral malaria. They did not exert any significant effect on the development of cerebral malaria in Plasmodium berghei ANKA-infected CBA/J mice.

Selective damage of hippocampal neurons in murine cerebral malaria prevented by pentoxifylline

The effect of pentoxifylline, a phosphodiesterase inhibitor, was investigated on the development of cerebral malaria in Plasmodium berghei K 173 infected C57/B16 mice. No significant differences occurred in the course of parasitemia and survival time after infection between control mice and pentoxifylline treated mice. Moreover, no differences were observed between the groups with respect to the occurrence of cerebral malaria. The only striking difference was that pentoxifylline treatment selectively prevented neuronal cell damage in the sector CA1 of the hippocampus. These findings are in contrast to previous studies, where pentoxifylline prevented cerebral malaria in P. berghei ANKA infected CBA/Ca mice, another widely used model of cerebral malaria. Obvious differences exist between these models.

Interferon-gamma induced lethality in the late phase of Plasmodium vinckei malaria despite effective parasite clearance by chloroquine

A combination therapy was tested consisting of chloroquine and interferon-gamma (IFN-gamma) in the late phase of blood-stage Plasmodium vinckei malaria in BALB/c mice. When mice were treated with three times 300 micrograms chloroquine at 24-h intervals starting at a parasitemia of 30%-50%, only 5 of 14 mice (36%) died 2-4 days after initiation of therapy. However, when infected mice received chloroquine plus 1 microgram IFN-gamma at the same time, 14 of 18 mice (78%) died 0.5-3 days after start of therapy (p < 0.05) despite clearance of parasitemia. The histopathology from mice dying after combination therapy revealed interstitial leukocyte infiltration of lung tissue, severe liver cell necrosis and kidney tubular necrosis. Pretreatment of P. vinckei-infected mice with pentoxifylline, a phosphodiesterase inhibitor, led to a significant decrease of IFN-gamma-induced lethality (p < 0.05). In contrast, pretreatment with neutralizing antibodies to tumor necrosis factor or with L-N-monomethyl arginine, the latter an inhibitor of the nitric oxide synthase, significantly increased lethality (p < 0.05).

Soluble tumor necrosis factor receptors correlate with parasitemia and disease severity in human malaria

Elevated serum or plasma concentration of immunoreactive tumor necrosis factor (TNF) is consistently detected in patients with malaria. TNF levels correlate with high parasitemia and clinical severity but not always with outcome. Since the effects of TNF may be neutralized by soluble TNF receptors, sera of 30 nonimmune patients with malaria were analyzed before and during antimalarial therapy. High concentrations of receptors R1 (55 kDa) and R2 (75 kDa) were detected immunologically in all sera of untreated patients. Levels of immunoreactive TNF correlated closely with levels of soluble TNF R1 and R2 (r = .75 and .59, respectively). In contrast, sera lacked cytotoxic activity against target cells in the TNF bioassays. Soluble TNF receptor levels remained elevated for days after treatment. These results suggest that excessive release of TNF induced by the asexual stage of malaria parasites is controlled by a subsequent shedding of soluble TNF receptors that may bind and deactivate biologically functional TNF.

Antibody response in Plasmodium vinckei malaria after treatment with chloroquine and adjuvant interferon-gamma

The antibody response of mice infected with Plasmodium vinckei after treatment with chloroquine either alone or in combination with interferon-gamma (IFN-gamma) was determined. Sequential serum samples were drawn from BALB/c mice receiving either 240 micrograms chloroquine on the day of infection or 120 micrograms chloroquine plus 10(4) units IFN-gamma daily for 11 days beginning on day 3 prior to infection. Mice treated with additional IFN-gamma showed an early induction of IgG2a response and a reduction in IgG1 antibodies as detected by the immunofluorescence technique at between 10 and 16 days after infection as compared with mice treated with chloroquine alone. Thus, IFN-gamma may partly exert its antimalarial activity via the induction of IgG2a antibody formation. At 4-6 weeks after infection, when mice from both groups resisted homologous re-infection, the predominant antibody isotypes found in both groups were IgG1 and IgG2a. Serum samples obtained from mice in both treatment groups at 6 weeks after infection were used for serum transfer experiments. When parasitised erythrocytes were preincubated with such immune serum, a retardation of the course of parasitaemia by 2 days was observed.

Prevalence and level of antibodies to the circumsporozoite proteins of human malaria parasites, including a variant of Plasmodium vivax, in the population of two epidemiologically distinct areas in the state of Acre, Brazil

A seroepidemiological study of the prevalence of antibodies against the repeating epitopes of circumsporozoite (CS) proteins of human malaria parasites was conducted in 2 different areas in the state of Acre, Brazil in 1987 and 1990. In 1987 antibodies against the CS protein of the VK 247 variant Plasmodium vivax as well as antibodies against the CS proteins of P. falciparum and the classic P. vivax were found at relatively high rates in the 2 areas, but significant microepidemiological differences were observed. In 1990, when large scale migration in Amazonia had ceased and control measures were applied in the study areas, the malaria endemicity decreased, as determined by the declining prevalence of anti-sporozoite antibodies against all Plasmodium species, and the small number of individuals with positive blood smears. Antibodies against sporozoites of the variant P. vivax did not cross-react with the CS proteins of the classic P. vivax, nor with antibodies against sporozoites of P. falciparum and P. malariae. Sera containing antibodies against the CS protein of P. malariae were found at a very low frequency, and only in 1987. The anti-CS protein antibody response to all Plasmodium species was age-related.

Prevention of murine cerebral malaria by a stable prostacyclin analog

Iloprost, a synthetic prostacyclin analog, successfully prevents the development of cerebral malaria in mice. Malaria antigen-induced tumor necrosis factor (TNF) production could be inhibited by iloprost in vitro and in vivo. Northern analysis of TNF mRNA revealed that malaria antigen-induced TNF expression was suppressed at the transcription level.

Pentoxifylline prevents murine cerebral malaria

Pentoxifylline, a widely used methylxanthine, was tested for its capacity to prevent cerebral malaria (CM) in Plasmodium berghei ANKA-infected CBA/Ca mice. Nine of 12 control mice developed neurologic signs and died from CM approximately 2 weeks after infection. All 12 mice treated with daily intraperitoneal pentoxifylline (1 mg) for 10 days after infection did not develop CM. All surviving mice developed high parasitemia and severe anemia and died 2 weeks later without neurologic signs. In pentoxifylline-treated mice, serum tumor necrosis factor (TNF) bioactivity was nondetectable, whereas control mice had high TNF levels on day 6 after infection. These findings were supported by in vitro investigations of malaria antigen-induced TNF synthesis. Northern blot analysis of TNF mRNA from stimulated macrophages showed that pentoxifylline inhibited TNF expression at the transcription level, and TNF bioactivity in supernatants was strongly depressed. These findings make pentoxifylline a potential candidate for study as a supportive agent in human CM.

Interferon-gamma enhances the effect of antimalarial chemotherapy in murine Plasmodium vinckei malaria

Most nonimmune patients with Plasmodium falciparum infection are no longer cured by such standard antimalarial drugs as chloroquine. Thus, alternative treatment regimens are necessary. A combination therapy was tested consisting of a subcurative dose of chloroquine and interferon-gamma (IFN-gamma) in BALB/c mice with lethal Plasmodium vinckei malaria. Treatment with either agent alone prolonged median survival by 1-2 days compared with placebo-treated mice. However, a combination of 80 micrograms of chloroquine given at the time of infection plus 1 x 10(4) units of IFN-gamma/day for 11 days (starting 3 days before infection) cured 83% of infected mice. Moreover, these mice showed solid immunity when challenged with the homologous strain of P. vinckei. However, when these mice were infected with the heterologous strain of Plasmodium berghei, the same degree of parasitemia developed as did in P. berghei-infected control mice. Thus, the combination of chemotherapy with the cytokine IFN-gamma leads to substantial improvement of antimalarial treatment and to a rapid development of strain-specific immunity in murine P. vinckei malaria.

Drug susceptibility of Plasmodium falciparum in the western Amazon region, State of Acre, Brazil

Field studies in the western Amazon region (state of Acre, Brazil) indicate that the 4-aminoquinolines, as well as the combined regimen with sulfadoxine-pyrimethamine, can no longer be recommended for the treatment and prophylaxis of P. falciparum infections in this region. Quinine remains an effective drug when used correctly. However, compliance problems arise due to the often occurring side-effects during a ten day regimen. Prospects of overcoming these constraints by combining a short course of quinine with other drugs are limited, because of the lack of suitable partner compounds. For this reason quinine/clindamycin appears to be a more practical therapy of P. falciparum malaria. In vitro data from this study suggest that mefloquine is another effective alternative for the treatment of falciparum malaria in this Amazon region.

Interferon-gamma treatment in mice experimentally infected with Trichinella spiralis

Interferon-tau (IFN-tau) treatment of Trichinella spiralis-infected BALB/c mice was investigated. The therapeutic regimen consisted of daily intraperitoneal injection of 10(4) U murine IFN-tau for 7 days, starting at 2 weeks post-infection. Striated muscle samples (diaphragm, thigh) were collected at 4, 8 and 12 weeks after infection. The muscle larval burden, the degree of encystation and the digestion of T. spiralis larvae were investigated. Furthermore, immunohistochemical studies of the inflammatory cell infiltrate around encysted larvae were performed. The results demonstrated an influence of IFN-tau treatment on the CD4+ and CD8+ subset distribution during the immune response but revealed no difference in the degree of encystation or digestion of encapsulated larvae as compared with control values.

Determinants of the immune response in visceral leishmaniasis: evidence for predominance of endogenous interleukin 4 over interferon-gamma production

Accumulating evidence points toward an antagonism between TH1 and TH2 focused immune responses decisive for the outcome of parasitic infections with leishmaniae. Interferon-gamma (IFN-gamma) and interleukin 4 (IL4), the principal cytokines involved in these pathways, as well as IgE and the IgG subclasses differentially modulated by these cytokines, were therefore assessed in 18 Brazilian patients with visceral leishmaniasis. The results are compared to those of a local control group. IL4 was detected in all patient sera but in only one control. Low concentrations of IFN-gamma where detectable in 50% of the Brazilian controls but in only two patients. While group medians of mitogen-induced in vitro synthesis of IL4 and IFN-gamma were similar, release of these lymphokines correlated inversely in patients (Spearman's rho = -0.84). Elevations of serum IgE complement the lymphokine data to indicate prominent TH2 type responses in clinical infections with Leishmania donovani.

[The detection of HIV antibodies in blood stains]

Blood samples were collected on cotton wool and stored at +20 degrees C. These samples were tested in an enzyme linked immunosorbent assay and the immunoblotting test. HIV-antibodies could be detected in samples stored up to four month.