JAK2V617F drives gut microbiota differences in patients with myeloproliferative neoplasms

BACKGROUND

Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (MF) are myeloproliferative neoplasms (MPN). Inflammation is involved in the initiation, progression, and symptomology of the diseases. The gut microbiota impacts the immune system, infection control, and steady-state hematopoiesis.

METHODS

We analyzed the gut microbiota of 227 MPN patients and healthy controls (HCs) using next-generation sequencing. We expanded our previous results in PV and ET patients with additional PV, pre-MF, and MF patients which allowed us to compare MPN patients collectively, MPN sub-diagnoses, and MPN mutations (separately and combined) vs. HCs (N = 42) and compare within MPN sub-diagnoses and MPN mutation.

RESULTS

MPN patients had a higher observed richness (median, 245 [range, 49-659]) compared with HCs (191.5 [range, 111-300; p = .003]) and a lower relative abundance of taxa within the Firmicutes phylum; for example, Faecalibacterium (6% vs. 14%, p < .001). The microbiota of CALR-positive patients (N = 30) resembled that of HCs more than that of patients with JAK2V617F (N = 177). In JAK2V617F-positive patients, only minor differences in the gut microbiota were observed between MPN sub-diagnoses, illustrating the importance of this mutation.

CONCLUSION

The gut microbiota in MPN patients differs from HCs and is driven by JAK2V617F, whereas the gut microbiota in CALR patients resembles HCs more.

Pronounced gut microbiota signatures in patients with JAK2V617F-positive essential thrombocythemia

Essential thrombocythemia (ET) is part of the Philadelphia chromosome-negative myeloproliferative neoplasms. It is characterized by an increased risk of thromboembolic events and also to a certain degree hypermetabolic symptoms. The gut microbiota is an important initiator of hematopoiesis and regulation of the immune system, but in patients with ET, where inflammation is a hallmark of the disease, it is vastly unexplored. In this study, we compared the gut microbiota via amplicon-based 16S rRNA gene sequencing of the V3-V4 region in 54 patients with ET according to mutation status Janus-kinase 2 (JAK2V617F)-positive vs JAK2V617F-negative patients with ET, and in 42 healthy controls (HCs). Gut microbiota richness was higher in patients with ET (median-observed richness, 283.5; range, 75-535) compared with HCs (median-observed richness, 191.5; range, 111-300; P < 0.001). Patients with ET had a different overall bacterial composition (beta diversity) than HCs (analysis of similarities [ANOSIM]; R = 0.063, P = 0.004). Patients with ET had a significantly lower relative abundance of taxa within the Firmicutes phylum compared with HCs (51% vs 59%, P = 0.03), and within that phylum, patients with ET also had a lower relative abundance of the genus Faecalibacterium (8% vs 15%, P < 0.001), an important immunoregulative bacterium. The microbiota signatures were more pronounced in patients harboring the JAK2V617F mutation, and highly similar to patients with polycythemia vera as previously described. These findings suggest that patients with ET may have an altered immune regulation; however, whether this dysregulation is induced in part by, or is itself inducing, an altered gut microbiota remains to be investigated. IMPORTANCE Essential thrombocythemia (ET) is a cancer characterized by thrombocyte overproduction. Inflammation has been shown to be vital in both the initiation and progression of other myeloproliferative neoplasms, and it is well known that the gut microbiota is important in the regulation of our immune system. However, the gut microbiota of patients with ET remains uninvestigated. In this study, we characterized the gut microbiota of patients with ET compared with healthy controls and thereby provide new insights into the field. We show that the gut microbiota of patients with ET differs significantly from that of healthy controls and the patients with ET have a lower relative abundance of important immunoregulative bacteria. Furthermore, we demonstrate that patients with JAK2V617F-positive ET have pronounced gut microbiota signatures compared with JAK2V617F-negative patients. Thereby confirming the importance of the underlying mutation, the immune response as well as the composition of the microbiota.

First molecular documented case of a rarely reported parasite: Plasmodium knowlesi infection in Denmark in a traveller returning from Malaysian Borneo

Plasmodium knowlesi has been reported as an emerging infection throughout the Southeast Asian region, especially in the Malaysian state of Sabah, where it accounts for the majority of the malaria cases reported. This is in contrast to Europe, where imported P. knowlesi is a rarely reported infection. We present a case of P. knowlesi infection in a Danish woman returning from a short trip to Malaysian Borneo. Microscopy of blood smears revealed 0.8% infected erythrocytes, but due to the atypical morphological presentation, a conclusive species identification was made by molecular methods. Plasmodium knowlesi is a potentially fatal infection and taking the increasing travel activity into consideration after the coronavirus disease 2019 (COVID-19) pandemic, P. knowlesi should be a differential diagnosis in patients with travel-associated illness returning from highly endemic Southeast Asian areas.

Fatal Aberrant Parasite Migration of Echinuria uncinata in Two African Pygmy Geese (Nettapus auritus)

Two adult African pygmy geese (Nettapus auritus) were found dead with minimal clinical disease signs. Necropsy revealed aberrant migration of the nematode parasite Echinuria uncinata, as confirmed morphologically and through DNA sequencing. This common waterfowl parasite typically lives in the proventriculus, burying headfirst into the mucosa and laying eggs into the gastrointestinal lumen. In these geese, the parasites tunneled through the gastrointestinal tract wall to invade the coelomic cavity; from which, a substantial quantity of eggs found their way into the coelomic space and into the air sacs and lungs. This potential parasite migration should be monitored for in Anseriformes species that present with similar disease conditions, and the use of Daphnia species, the intermediate host, as a waterfowl feed source is not recommended.

Zoonotic pathogens in wild muskoxen (Ovibos moschatus) and domestic sheep (Ovis aries) from Greenland

The present study aimed to estimate the prevalence of zoonotic pathogens Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Erysipelothrix in muskoxen (Ovibos moschatus) and sheep (Ovis aries) from Greenland. In 2017 and 2018, faecal samples were collected from wild muskoxen from three distinct populations (Zackenberg, Kangerlussuaq, and Ivittuut) and from domestic sheep from southwest Greenland. Blood samples were collected from muskoxen from Kangerlussuaq and Ivittuut and from sheep. Faecal samples were tested for specific DNA of G. duodenalis and Cryptosporidium spp., and blood samples were tested for antibodies against T. gondii and Erysipelothrix. The estimated prevalence of G. duodenalis was 0% (0/58), 17% (7/41) and 0% (0/55) in muskoxen from Zackenberg, Kangerlussuaq and Ivittuut, respectively, and 37% (16/43) in sheep. The estimated prevalence of Cryptosporidium was 0% (0/58), 2% (1/41), 7% (4/55) in muskoxen from Zackenberg, Kangerlussuaq, Ivittuut, respectively, and 2% (1/43) in sheep. Neither Giardia nor Cryptosporidium were detected in winter samples (0/78). Of the positive samples, Giardia from one muskox sample only was successfully typed as G. duodenalis assemblage A, and Cryptosporidium from two muskoxen was successfully typed as C. parvum, subtype IIdA20G1e. The estimated T. gondii seroprevalence was 2% (1/44) and 0% (0/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 1% (1/155) in sheep. The estimated Erysipelothrix seroprevalence was 2% (1/45) and 13% (1/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 7% (10/150) in sheep. The results of this study add to the scarce knowledge on zoonotic pathogens in the Arctic.

Plasmodium cynomolgi as Cause of Malaria in Tourist to Southeast Asia, 2018

We report human infection with simian Plasmodium cynomolgi in a tourist from Denmark who had visited forested areas in peninsular Malaysia and Thailand in August and September 2018. Because P. cynomolgi may go unnoticed by standard malaria diagnostics, this malaria species may be more common in humans than was previously thought.

[Suspected toxoplasmosis in pregnancy]

Primary infection with Toxoplasma gondii in pregnant women can lead to vertical transmission of the parasites resulting in congenital toxoplasmosis. The frequency of foetal infection increases with gestational age at maternal infection, but the risk of developing clinical sequelae decreases. Data on antiparasitic treatment suggest, that maternal treatment reduces the risk of serious neurological sequelae or death in congenitally infected offspring. Aspects of diagnosis and antimicrobial treatment of T. gondii infection during pregnancy are summarised in this review.

Clinical/serological outcome in humans bitten by Babesia species positive Ixodes ricinus ticks in Sweden and on the Åland Islands

The risk of contracting babesiosis after a tick bite in Sweden and on the Åland Islands, Finland, is unknown. We investigated clinical and serological outcomes in people bitten by Ixodes ricinus ticks positive for Babesia species. Ticks, blood and questionnaires were obtained from study participants in Sweden and on the Åland Islands. Sixty-five of 2098 (3.1 %) ticks were positive by real-time PCR. Three Babesia species were detected, Babesia microti (n = 33), B. venatorum (n = 27) and B. capreoli (n = 5), the latter species not known to cause human infection. Half (46 %) of the Babesia PCR-positive ticks also contained Borrelia spp. Fifty-three participants bitten by a Babesia PCR-positive tick and a control group bitten by a Babesia PCR-negative tick were tested for B. microti IgG antibodies by IFA. The overall seroprevalence was 4.4 %, but there was no significant difference between the groups. None of the participants seroconverted and no participant with a Babesia PCR-positive tick sought medical care or reported symptoms suggestive of babesiosis. Given the prevalence of Babesia in I. ricinus ticks in southern Sweden and on the Åland Islands, babesiosis should be considered a possible diagnosis in symptomatic residents who seek medical care following tick exposure.

Parasites modulate the gut-microbiome in insects: A proof-of-concept study

Host-parasite interactions may be modulated by host- or parasite-associated microbes, but the role of these are often overlooked. Particularly for parasites with intestinal stages (either larval or adult), the host gut microbiome may play a key role for parasite establishment; moreover, the microbiome may change in response to invading parasites. Hypothesis testing at the organismal level may be hampered, particularly in mammalian definitive hosts, by ethical, logistical, and economical restrictions. Thus, invertebrates naturally serving as intermediate hosts to parasites with complex life cycles may inform the development of mammalian models as an early-stage host-parasite model. In addition, several important pathogens are vectored by insects, and insect gut microbiome-pathogen interactions may provide essential base-line knowledge, which may be used to control vectorborne pathogens. Here, we used the grain beetle, Tenebrio molitor, a host of the tapeworm Hymenolepis diminuta, to explore interactions between infection status and resident gut microbiota at two pre-determined time points (day two and seven) post infection. Using 16S/18S microbial profiling, we measured key parameters of the composition, relative abundance, and diversity of the host gut bacteriome and mycobiome. In addition, we quantified the systemic beetle immune response to infection by Phenoloxidase activity and hemocyte abundance. We found significant changes in the gut bacteriome and mycobiome in relation to infection status and beetle age. Thus, the relative abundance of Proteobacteria was significantly higher in the gut of infected beetles and driven mostly by an increased abundance of Acinetobacter. In addition, the mycobiome was less abundant in infected beetles but maintained higher Shannon diversity in infected compared with non-infected beetles. Beetles treated with a broad-spectrum antibiotic (Tetracycline) exhibited significantly reduced parasite establishment compared with the untreated control group, indicating that the host microbiome may greatly influence hatching of eggs and subsequent establishment of H. diminuta larvae. Our results suggest that experimental work using invertebrates may provide a platform for explorative studies of host-parasite-microbe interactions and their underlying mechanisms.

Direct genetic characterization of Toxoplasma gondii from clinical samples from Denmark: not only genotypes II and III

Genetic variation within Toxoplasma gondii can have both clinical and epidemiological significance, while the genotypes circulating in many parts of the world, including the Nordic country Denmark, are still unknown. We genetically characterized T. gondii strains that had been detected in human clinical samples in Denmark in 2011-2016. Samples that had tested positive for T. gondii DNA and had a quantification cycle value <33 were included in this study and subjected to direct genetic characterization of T. gondii based on length-polymorphism of 15 microsatellite markers. A total of 23 DNA samples from 22 individual patients were analyzed. The results were consistent with genotype II with 15/15 markers amplified from seven samples from the central nervous system (CNS) including two samples from one patient, four ocular samples, and one unspecified sample; with genotype III with 15/15 markers amplified from two ocular samples; with genotype Africa 1 with 15/15 markers amplified from one amniotic fluid sample and from one CNS-sample; with atypical genotype with 15/15 markers amplified from one CNS-sample and with 11/15 markers amplified from one CNS-sample; and with HG12-like genotype with 9/15 markers amplified from one CNS-sample. Genotype II, which is endemic in Europe, was predominant, but more than a third of the successfully genotyped strains were non-type-II. The possibility that clinical toxoplasmosis is caused by a strain that is not considered endemic to the region is definitely not negligible.

The Follicular Skin Microbiome in Patients With Hidradenitis Suppurativa and Healthy Controls

Importance

Although the pathogenesis of hidradenitis suppurativa (HS) remains enigmatic, several factors point to potential involvement of the cutaneous microbiome. Insight into the cutaneous microbiome in HS using next-generation sequencing may provide novel data on the microbiological diversity of the skin.

Objective

To investigate the follicular skin microbiome in patients with HS and in healthy controls.

Design, Setting, and Participants

This case-control study obtained punch biopsy specimens from patients with HS (lesional and nonlesional) and healthy controls between October 1, 2014, and August 1, 2016. Data were analyzed from March to November 2016. Patients with HS were recruited from the Department of Dermatology, Zealand University Hospital, Roskilde, Denmark. Biopsy specimens were analyzed at the Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark. None of the participants received any antibiotics (systemic or topical therapy) within 1 month before the study. In patients with HS, biopsy specimens were obtained from lesional skin (axilla or groin) and nonlesional skin. Only nodules containing at least 1 visible hair follicle were biopsied. Biopsy specimens from healthy controls were obtained from the axilla only.

Main Outcomes and Measures

The different microbiomes were investigated using next-generation sequencing targeting 16S and 18S ribosomal RNA.

Results

The skin microbiome was characterized in 30 patients with HS (mean [SD] age, 46.9 [14.0] years; 19 [63% female]) and 24 healthy controls (mean [SD] age, 32.2 [12.0] years; 13 [54% female]). The next-generation sequencing data provided a previously unreported (to our knowledge) characterization of the skin microbiome in HS. The study demonstrated that the microbiome in HS differs significantly from that in healthy controls in lesional and nonlesional skin. Overall, the following 5 microbiome types were identified: Corynebacterium species (type I), Acinetobacter and Moraxella species (type II), Staphylococcus epidermidis (type III), Porphyromonas and Peptoniphilus species (type IV), and Propionibacterium acnes (type V). In lesional skin, microbiome types consisted predominantly of type I or type IV. Microbiome type IV was not detected in healthy controls. Several taxa, including Propionibacterium, showed a significantly higher relative abundance in healthy controls vs HS skin, indicating that Propionibacterium may be part of the pathogenesis in HS.

Conclusions and Relevance

The study findings suggest a link between a dysbiotic cutaneous microbiome and HS.

Enteroaggregative Escherichia coli in Daycare-A 1-Year Dynamic Cohort Study

Enteroaggregative Escherichia coli (EAEC) has been associated with persistent diarrhea, reduced growth acceleration, and failure to thrive in children living in developing countries and with childhood diarrhea in general in industrialized countries. The clinical implications of an EAEC carrier-status in children in industrialized countries warrants clarification. To investigate the pathological significance of an EAEC carrier-state in the industrialized countries, we designed a 1-year dynamic cohort study and performed follow-up every second month, where the study participants submitted a stool sample and answered a questionnaire regarding gastrointestinal symptoms and exposures. Exposures included foreign travel, consumption of antibiotics, and contact with a diseased animal. In the capital area of Denmark, a total of 179 children aged 0–6 years were followed in a cohort study, in the period between 2009 and 2013. This is the first investigation of the incidence and pathological significance of EAEC in Danish children attending daycare facilities. Conventional microbiological detection of enteric pathogens was performed at Statens Serum Institute, Copenhagen, Denmark, and at Hvidovre Hospital, Copenhagen, Denmark. Parents completed questionnaires regarding gastrointestinal symptoms. The EAEC strains were further characterized by serotyping, phylogenetic analysis, and susceptibility testing. EAEC was detected in 25 (14%) of the children during the observational period of 1 year. One or more gastrointestinal symptoms were reported from 56% of the EAEC-positive children. Diarrhea was reported in six (24%) of the EAEC positive children, but no cases of weight loss, and general failure to thrive were observed. The EAEC strains detected comprised a large number of different serotypes, confirming the genetic heterogeneity of this pathotype. EAEC was highly prevalent (n = 25, 14%) in Danish children in daycare centers and was accompanied by gastrointestinal symptoms in 56% of the infected children. No serotype or phylogenetic group was specifically linked to children with disease.

Low and Declining Risk for Malaria in Visitors to Indonesia: A Review of Local Indonesian and European Travelers' Data and a Suggestion for New Prophylactic Guidelines

INTRODUCTION

The world's malaria map is constantly changing and with it the risk for travelers to contract malaria. While some efforts to appreciate the malaria situation for indigenous populations in Indonesia have been made recently, there is only sparse data in the literature on the risk for travelers to Indonesia.

METHODS

Data were collected from the Indonesian Ministry of Health (MoH), the World Health Organization (WHO), the Indonesian official statistics website Badan Pusat Statistik (BPS), and from the different European national surveillance bodies. Finally, a comparison between recent official guidelines for prevention of malaria in travelers from Germany, the United States, the UK, and from WHO was done.

RESULTS

Data from Denmark, Germany, Sweden and Switzerland show a steady decline of imported cases of malaria from Indonesia from 1997 to 2013, with a leveling off during the last few years. In our study material, the Plasmodium falciparum incidence 2009 to 2013 was 0.35 cases per 100,000 visits and the Plasmodium vivax incidence 1.3 cases per 100,000 visits, with a 95% confidence interval of 0.1-0.9 and 0.7-2.2, respectively. Indonesian data also show a decline of malaria cases-the Annual Parasite Index (API) for all species of malaria has decreased from 4.68 cases per 1,000 inhabitants in 1990 to 1.38 cases per 1,000 inhabitants in 2013.

CONCLUSION

Based on these data updated recommendations for malaria prophylaxis in travelers to Indonesia are suggested.

Metronidazole therapy for treating dientamoebiasis in children is not associated with better clinical outcomes: a randomized, double-blinded and placebo-controlled clinical trial

BACKGROUND

There is a paucity of evidence documenting the pathogenicity of Dientamoeba fragilis, an intestinal protozoan common in children. As case reports on successful treatment are numerous, many authors advocate treatment, despite no placebo-controlled trials being available. Metronidazole is often used for treatment, though eradication rates are relatively low (60%-80%). In the present study we determined the clinical and microbiological efficacy of metronidazole in Danish children.

METHODS

In this parallel placebo-controlled double-blinded trial, children aged 3-12 years with >4 weeks of gastrointestinal symptoms were allocated using block randomization in a 1:1 ratio to a 10-day course of oral metronidazole or placebo. Primary outcome was change in level of gastrointestinal symptoms, measured on a visual-analog-scale (VAS), and secondary outcome was eradication of D. fragilis infection. Participants, caregivers, investigators, and sponsor were all blinded to group assignment. The trial was registered with clinicaltrials.gov (NCT01314976) prior to start.

RESULTS

Of 96 participants, 48 were allocated to the metronidazole and placebo group each. Mean VAS change from pre- to post-treatment did not differ significantly (P = .8) between the metronidazole (-1.8 CI, [-2.5, -1.1]) and the placebo group (-1.6 CI, [-2.3, -.9]). Eradication of D. fragilis was significantly greater in the metronidazole group, although it declined rapidly from 62.5% 2 weeks after end of treatment to 24.9% 8 weeks after end of treatment.

CONCLUSIONS

These findings do not provide evidence to support routine metronidazole treatment of D. fragilis positive children with chronic gastrointestinal symptoms. Study funded by Statens Serum Institut.

CLINICAL TRIALS REGISTRATION

Trial was registered with clinicaltrials.gov (NCT01314976).

Treatment of Dientamoeba fragilis in patients with irritable bowel syndrome

The role of Dientamoeba fragilis in irritable bowel syndrome (IBS) is incompletely known. We aimed to investigate whether eradication of D. fragilis alleviates symptoms in IBS. Twenty-five D. fragilis-positive IBS patients were treated with Metronidazole (MZ) or Tetracycline. The patients were mostly female (89%), and mean age (SD) was 35.1 (8.2) years. Microbiological response, evaluated 2 weeks post-treatment, was observed in 15 of 25 patients (60%), all by MZ. Clinical response, defined as adequate relief of symptoms, was observed in 7 of 22 patients (32%), all by MZ. In a logistic regression analysis, we found no significant association between clinical and microbiological response. This case study did not support our hypothesis of a simple association between D. fragilis and IBS. Some D. fragilis-infections were insufficiently treated by MZ. Further studies into the prevalence and effect of eradication of D. fragilis in IBS and into efficient treatments of D. fragilis are warranted.

Cystic echinococcosis of the liver: experience from a Danish tertiary reference center (2002-2010)

BACKGROUND

Cystic echinococcosis (CE) of the liver can be treated with ultrasound-guided puncture, aspiration, injection, and re-aspiration (PAIR), with surgery and with benzimidazole derivatives. The aim of this study was to review available data concerning treatment modality and outcome for patients treated for CE of the liver in a Danish tertiary reference center.

METHODS

A search was made for patients treated for CE infection between January 1, 2002 and January 1, 2010. All relevant patient records and radiology exams were scrutinized and all cysts were re-classified according to the WHO-IWGE, blinded as to which treatment the patient had received. PAIR was performed as a first choice treatment and surgery was reserved for cases where PAIR was impossible. Inactive cyst stages received medical treatment only.

RESULTS

The search revealed 26 cases with confirmed CE of the liver. Nine patients underwent PAIR and nine patients surgery as a first choice treatment. Three patients were treated with PAIR secondary to surgery and one patient was treated with surgery secondary to PAIR. For all PAIR treatments, the success rate was 58% regardless of cyst stage and for surgery the success rate was 70%. The difference between the rates was not statistically significant (p = 0.67).

CONCLUSION

CE is a rare disease in Denmark and our study is the first describing clinical management of CE in our institution.

Separation of DNA-containing organelles from Toxoplasma gondii by CZE

Toxoplasma gondii and other members of the family Apicomplexa have two organelles, in addition to the nucleus, that contain DNA. Herein is reported the separation of the DNA-carrying organelles from T. gondii tachyzoites, i.e. the mitochondrion and the apicoplast, by CZE. The cells were stained with SYTO9, a dye that exhibit fluorescence when interacting with double stranded nucleic acids (e.g. DNA) and disrupted by nitrogen cavitation. Following careful removal of the heavier cellular material, the remaining lysate was injected on a CE instrument and the DNA-containing organelles were detected by LIF. The mitochondrion had longer migration time than the apicoplast, and the migration times were comparable in the replicates. This method should potentially also work for other members of the Apicomplexa including Plasmodium falciparum.

Subtype analysis of Blastocystis isolates from Blastocystis cyst excreting patients

To determine the distribution of Blastocystis sp. subtypes from Blastocystis cyst excreters, 1,000 fecal samples from patients suspected of enteroparasitic disease were scored for stool consistency, submitted to xenic in vitro culture (XIVC), formol ethyl acetate concentration (FECT) with subsequent isopycnic centrifugation, and polymerase chain reaction (PCR) with subtype (ST) analysis. Blastocystis was significantly more prevalent in specimens from patients with travel-associated diarrhea (15.6%) than those with persistent diarrhea (8.3%) (P = 0.005). Overall, 115 (11.5%) and 35 (3.5%) specimens were positive by XIVC and FECT, respectively. Blastocystis cysts were detected in 33 (28.7%) of the XIVC-positive specimens. A positive FECT result was associated with ST3 (P = 0.05). The presence of Blastocystis in general or Blastocystis cysts was independent of stool consistency, and no particular ST was significantly associated with cyst identification. In view of these data, the present study indicates that Blastocystis cyst formation is independent of Blastocystis sp. subtype and gastrointestinal transit time.

Pursuing the clinical significance of Blastocystis--diagnostic limitations

The clinical significance of one of the most prevalent single-celled intestinal parasites worldwide, Blastocystis, remains unsettled. A plethora of clinical and epidemiological studies have been undertaken to generate data on its prevalence in different populations and investigate the role of the parasite as a cause of gastro- and extra-intestinal disease. In this article, we pinpoint limitations of studies that seek to determine the clinical significance of Blastocystis, based on shortcomings in our understanding of Blastocystis diagnosis and biology, and identify methodologies for further studies aimed at determining the molecular epidemiology and clinical impact of this parasite.

Subtype distribution of Blastocystis isolates from synanthropic and zoo animals and identification of a new subtype

Blastocystis isolates from 56 Danish synanthropic and zoo animals, 62 primates primarily from United Kingdom (UK) collections and 16 UK primate handlers were subtyped by PCR, sequencing and phylogenetic analysis. A new subtype (ST) from primates and artiodactyls was identified and designated as Blastocystis sp. ST10. STs isolated from non-human primates (n=70) included ST3 (33%), ST8 (21%), ST2 (16%), ST5 (13%), ST1 (10%), ST4 (4%) and ST10 (3%). A high prevalence of ST8 was seen among primate handlers (25%). This ST is normally very rare in humans, suggesting that acquisition of Blastocystis ST8 infections from primates by their handlers had occurred in these cases. Data from published studies of non-human primates, other mammals and birds were collected and interpreted to generate a comprehensive overview on the ST distribution in such animals. On the basis of information on 438 samples, it was found that Blastocystis from primates belong mainly to ST1, ST2, ST3, ST5 and ST8, ungulates and dogs mainly ST1, ST2, ST3, ST5 and ST10, rodents ST4 and birds mainly ST6 and ST7. The data indicate moderate host specificity, most clearly exemplified by the fact that STs isolated from avian and non-avian hosts rarely overlap.

Detecting Blastocystis using parasitologic and DNA-based methods: a comparative study

Few studies have targeted the relative performance of diagnostic methods used for the detection of Blastocystis, a unicellular organism often present in fecal specimens from individuals with and without gastrointestinal symptoms. Aims of this study included a comparison of the formol ethyl acetate concentration technique (FECT), permanent trichrome staining of feces fixed in sodium acetate-acetic acid-formalin (SAF-PST), xenic in vitro culture (XIVC), and polymerase chain reaction (PCR) regarding Blastocystis screening of 107 samples from 93 patients with suspected enteroparasitic disease. Compared with PCR, the sensitivity/specificity of XIVC, SAF-PST, and FECT was 89%/100%, 82%/100%, and 50%/100%, respectively. False-negative results generated by the FECT and SAF-PST appeared to be associated with Blastocystis sp. subtype 3. A comparison of results obtained by dideoxy sequencing of positive PCR products amplified from DNA extracted directly from feces and DNA extracted from 5- and 28-day-old XIVC of 10 randomly chosen Blastocystis isolates showed no disparities, indicating that XIVC has very little or no impact on subtype distribution or variation within a given specimen. It is recommended that short-term XIVC be used for cost-effective screening of fresh fecal specimens for Blastocystis infection to generate valid prevalence estimates and to identify isolates for molecular characterization in studies aiming to illuminate the molecular epidemiology of Blastocystis.

A case of trichinellosis in Denmark, imported from Poland, June 2007

A 59-year-old Danish woman presented to her general practitioner (GP) at the end of June. A few weeks earlier, during a meal at home in Denmark, she had consumed a slice of pork sausage (‘teewurst’, German sausage) brought to her by three Polish visitors.

The prevalence of Dientamoeba fragilis in patients with suspected enteroparasitic disease in a metropolitan area in Denmark

The prevalence of Dientamoeba fragilis in patients from a metropolitan area in Denmark was determined by examination of paired stool samples using two techniques: a formol ethyl-acetate concentration technique with unpreserved faeces and a permanent staining technique on faeces preserved with sodium acetate-acetic acid-formalin (SAF). Using the SAF permanent staining technique and the formol ethyl-acetate concentration technique, 25% and 15% of the specimens, respectively, were parasite-positive. D. fragilis was detected in 12 of the 103 patients, only two of whom harboured other recognised pathogenic parasites. Overall, D. fragilis had a remarkably high prevalence in the metropolitan area of Denmark investigated.

Blastocystis: subtyping isolates using pyrosequencing technology

Blastocystis is a prevalent single-celled enteric parasite of unresolved clinical significance. Efforts based on molecular methodologies to establish whether pathogenicity is linked to specific isolates of the genetically diverse genus of Blastocystis have been scarce and so far yielded ambiguous results which can be difficult to interpret. To alleviate some of the problems related to unravelling the molecular epidemiology of Blastocystis infections we developed and evaluated a simple and high-throughput sequence analysis (SQA) pyrosequencing technique based on the detection of genotype-specific nucleotide polymorphisms in the 18S small subunit rRNA gene for a rapid and cost-effective post-PCR screening of Blastocystis genotypes. The method was effectively capable of genotyping 48/48 isolates positive by nested PCR in approximately one hour, and in 94% of the cases the isolate detected by PCR and pyrosequencing was also detected by one of two different PCR assays with subsequent dideoxy sequencing.

Usefulness of Toxoplasma gondii recombinant antigens (GRA1, GRA7 and SAG1) in an immunoglobulin G avidity test for the serodiagnosis of toxoplasmosis

The precise diagnosis of an acute and recent Toxoplasma infection in pregnant women and the newborn child is important before treatment. This study describes a new Toxoplasma gondii IgG avidity test based on a combination of recombinant GRA1, GRA7 and SAG1 antigens and shows that this test is useful for diagnostic purposes and may replace the lysed, whole-cell antigens. Although more sera need to be tested, the results obtained here suggest that the IgG avidity test performed with rec-antigens correlated more with the stage of a T. gondii infection than the IgG avidity results obtained with the lysed, whole-cell antigen test, the VIDAS Toxo IgG avidity (bioMérieux).

Toxoplasma gondii: DNA vaccination with bradyzoite antigens induces protective immunity in mice against oral infection with parasite cysts

Infection of the host by Toxoplasma gondii leads to an acute systemic dissemination of tachyzoites, followed by a chronic phase, in which bradyzoites, enclosed in cysts, persist in the brain, the heart, and other tissues. Among putative vaccine candidates, the bradyzoite antigens BAG1 and MAG1 look promising since they are preferentially expressed during the chronic stage of the parasite. This work focused on studying the immunogenicity of bradyzoite antigens in a mouse model of chronic toxoplasmosis. A mixture of plasmids directing the cytoplasmic expression of MAG1 and BAG1 in mammalian cells was used to immunize mice. We show here that immunized mice developed, preferentially, specific anti-MAG1 and anti-BAG1 IgG2a subclass antibodies, indicating a shift towards a Th1-like response after DNA immunization. We then demonstrated that DNA immunization followed by challenge infection elicited effective protection in mice, suggesting that bradyzoite antigens should be considered in the design of vaccines against toxoplasmosis.

A combination of antigenic regions of Toxoplasma gondii microneme proteins induces protective immunity against oral infection with parasite cysts

Infection with Toxoplasma gondii causes morbidity and mortality in congenitally infected and immunocompromised individuals. Both humoral and cell-mediated immunity are involved in host resistance to invasion of the parasite. Among putative vaccine candidates, the T. gondii microneme proteins appear to be promising, because they are responsible for the invasion process. The present work focused on studying the immunogenicity of microneme proteins in infected individuals and in a mouse model of chronic toxoplasmosis. We identified 5 distinct antigenic regions within MIC2, MIC4, MIC2-associated protein, and apical membrane antigen 1 gene products, which were recognized by (1) T cells from both adults with acquired infection and children with congenital infection and (2) antibodies from all patients. Finally, we demonstrated that DNA immunization with microneme fragments elicited effective protection in mice (84% reduction in brain-cyst burden), suggesting that a combination of these antigenic regions should be considered in the design of potential vaccines against toxoplasmosis.

Usefulness of Toxoplasma gondii-specific recombinant antigens in serodiagnosis of human toxoplasmosis

Toxoplasma gondii SAG1, GRA1, and GRA7 recombinant antigens may be regarded as tools for the detection of T. gondii immunoglobulin G antibodies in persons with chronic and acute toxoplasmosis. GRA7 is more correlated with acute toxoplasmosis. A combination of these antigens will increase the sensitivity of enzyme-linked immunosorbent assays.

DNA vaccination with the immunodominant tachyzoite surface antigen (SAG-1) protects against adult acquired Toxoplasma gondii infection but does not prevent maternofoetal transmission

We examined the ability of a DNA vaccine comprising the Toxoplasma gondii tachyzoite immunodominant surface antigen, SAG-1, to both protect adult BALB/c mice against infection with the avirulent Beverly type-2 strain of T. gondii and also to inhibit the incidence of congenital disease. Vaccination induced an enhanced type-1 immune response as measured by IgG2a antibody production and increased splenocyte IFN-gamma production. Vaccination also limited disease following infection via either the oral or peritoneal routes as measured by mortality, pathology or brain cyst burden. While vaccination with plasmid alone also increased splenocyte IFN-gamma production, this afforded no protection and following infection mortality rates and cyst burden counts were similar in this group to that of non-vaccinated animals. Although, vaccination with SAG-1 DNA did protect against adult acquired T. gondii infection, it did not prevent maternofoetal transmission in previously vaccinated dams infected during pregnancy. The results indicate differences in the protective mechanisms operating between adult acquired disease and congenital transmission and have significant implications for future vaccine development.

Transurethral interstitial laser coagulation of the prostate and transurethral microwave thermotherapy vs transurethral resection or incision of the prostate: results of a randomized, controlled study in patients with symptomatic benign prostatic hyperplasia

OBJECTIVE

To compare the efficacy and frequency of complications of transurethral interstitial laser coagulation (ILC) and transurethral microwave thermotherapy (TUMT) with transurethral resection or incision of the prostate (TURP/TUIP) in patients with symptomatic benign prostatic hyperplasia (BPH).

PATIENTS AND METHODS

Forty-eight patients were randomized to undergo ILC, 46 to TUMT and 24 to TURP/TUIP; they were followed for 6 months and the outcome analysed on an intention-to-treat basis.

RESULTS

At 6 months the symptom scores and maximum urinary flow rate (Qmax) had improved significantly in all groups. At 6 months the mean symptom score was 9.2 in both experimental groups and 6.8 in the control group (P > 0.05); the mean Qmax was 20.6 mL/s in the control group, 16.2 in the ILC group (P > 0.05 vs control) and 13.2 in the TUMT group (P < 0.05 vs. the control group). In the TUMT group patients developing urinary retention afterward had a significantly greater increase in Qmax than those who did not. The types of complications in the three groups varied. Urinary tract infection occurred frequently in the experimental groups, especially after ILC, whereas the 'well-known' complications of TURP occurred in the control group. Overall, 36% in the ILC, 54% in the TUMT and 73% in the control group had no complications (retrograde ejaculation excluded) during the first 6 months. One patient in the TUMT group underwent TURP after 3 months, whereas no patients in the ILC or the con-trol group were re-treated for BPH within the first 6 months.

CONCLUSION

In the short term both ILC and TUMT are reasonable alternatives to standard transurethral surgery for symptomatic BPH, where the reduction of symptoms is the primary goal of treatment. However, both ILC and TUMT were associated with morbidity, although the complication profiles differed from those after TURP/TUIP. Both ILC and TUMT seem advantageous in some patients because of the reduced risk of bleeding and the eliminated risk of TUR syndrome, and because TUMT only requires local anaesthesia. Thus, as neither treatment is better in all aspects, the advantages of one technique over the other must be weighed when deciding how to treat each patient.

Cost-effectiveness of new treatments for benign prostatic hyperplasia: results of a randomized trial comparing the short-term cost-effectiveness of transurethral interstitial laser coagulation of the prostate, transurethral microwave thermotherapy and standard transurethral resection or incision of the prostate

OBJECTIVES

To compare the short-term cost-effectiveness of ILC and TUMT with that of transurethral resection or incision of the prostate in patients with symptomatic benign prostatic hyperplasia.

MATERIAL AND METHODS

One hundred and eighteen patients were randomized to ILC, TUMT and TUR-P/TUI-P in 2:2:1 fashion. The use of resources within the first 6 months of follow-up were measured and the cost of treatment for each patient were calculated. A few parameters, primarily related to the time spent by the staff, were measured only in a subgroup of patients. A cost-effectiveness analysis was performed based on the average calculated cost and change in I-PSS found in each group. For costly resources a sensitivity analysis was performed.

RESULTS

At 6 months the cost was lowest in the TUMT group and highest in the ILC group. The cost-effectiveness ratio (C/E) was 763 DKK/point reduction in I-PSS in the control group and 1.200 and 938 in the ILC and TUMT group, respectively. An incremental analysis demonstrated that TUR-P/TUI-P dominated ILC. In a similar comparison of the TUMT and the TUR-P/TUI-P group an incremental ratio of 170 DKK/extra point of reduction in I-PSS was found in the TUR-P/TUI-P group.

CONCLUSION

In the short-term TUMT and TUR-P has comparable cost-effectiveness. TUR-P was slightly more effective than TUMT, but the cost was also slightly higher. In our set-up of ILC the short-term cost-effectiveness of ILC was inferior to that of TUR-P. Conclusions should be made with caution, since the follow-up at present is short.

Characterisation of the allelic variation in the rpoS gene in thirteen K12 and six other non-pathogenic Escherichia coli strains

The nucleotide sequence of rpoS, the gene for the stress sigma factor, was determined in 13 different K12 strains of Escherichia coli. The results indicate that the original K12 isolate carried an amber mutation at codon 33, which in 50% of the derivatives is mutated by a single base substitution to a coding triplet, in most cases to CAG encoding glutamine. The six non-K12 strains examined here had GAG, encoding glutamate, in position 33. The two most divergent strains had three and seven neutral substitutions in rpoS and carried insertions of 2100 and 2900 bp, respectively, just downstream of the gene. The genetic variations in rpoS were compared with the variation in RpoS-related phenotypes, by measuring catalase (KatE) activity, glycogen accumulation and acid phosphatase levels, and a katEp-gfp fusion was used to visualise katE gene transcription. The RpoS phenotypes of the six rpoS(33E) strains varied significantly more than that of the K12 rpoS(33Q) strains, especially with respect to acid phosphatase levels. This was due to the absence of the gene for the transcriptional activator AppY from four of the rpoS(33E) strains, while all the K12 derivatives carried this gene. When cloned into a LacI-controlled vector and compared in a rpoS::Tn 10 background, the RpoS(33Q) and RpoS(33E) variants showed the same activity.

Calreticulin is an interleukin-3-sensitive calcium-binding protein in human basophil leukocytes

BACKGROUND

IL-3 enhances basophil histamine release upon stimulation with any known secretagogue. The molecular mechanism behind this regulation is not known, although some observations suggest that IL-3 modulates the calcium part of the signal transduction mechanism. The inhibitory action of glucocorticoids on basophils can be reversed by stimulation with IL-3.

METHODS

Calcium-binding proteins in the basophil cell line KU812 were identified by two-dimensional gel electrophoresis, Calcium-overlay assay, N-terminal sequence analysis, and mass spectometry. The presence of the same proteins in purified human basophil leukocytes was established by comigration of KU812 and human basophil proteins on the two-dimensional gels. The expression of the calcium-binding proteins in the absence and presence of IL-3 and/or anti-IgE was determined by densitometric measurement of the spots on the two-dimensional gels.

RESULTS

Calreticulin was identified on the two-dimensional gel of KU812 proteins. A protein with exactly the same migration pattern was found on the gels of proteins from purified human basophils. Immunoblotting with a specific antihuman calreticulin antibody confirmed that this protein was calreticulin. Subsequent analysis showed that the expression of calreticulin in the basophils is upregulated twofold upon stimulation with rhIL-3, even in doses below those needed for enhancement of histamine release.

CONCLUSIONS

The expression of calreticulin in human basophil leukocytes is regulated by IL-3. Calreticulin is known to modulate IP3-dependent Ca2+ influx in different cell systems, and calreticulin overexpression inhibits steroid-induced transcriptional activation. Therefore, modulation of calreticulin expression may be one mechanism by which IL-3 exerts its effects on human basophils.

Construction, biological activity, and immunogenicity of synthetic envelope DNA vaccines based on a primary, CCR5-tropic, early HIV type 1 isolate (BX08) with human codons

So far codon-optimized HIV-1 envelope genes have been investigated for the T cell line-adapted strain MN, which differs in several aspects from primary isolates. Envelopes of primary isolates may be more relevant for vaccine purposes. This article describes for the first time the engineering and characterization of four "humanized" genes encoding the secreted gp120/gp140, or the membrane-bound gp150/gp160, of a primary CCR5 tropic, clade B, clinical isolate HIV-1(BX08). The genes were built in fragments for easy cassette exchange of regions important for immunogenicity, function, and expression. The transcription and expression of the synthetic genes in mammalian cell lines were Rev independent and highly increased. Increased expression of membrane-bound gp160 induced a high cytopathic effect in U87.CD4.CCR5 cells. Gene gun and intramuscular DNA vaccination in mice induced a strong specific cytotoxic T lymphocyte response independent of the gene construct, expression level, or DNA immunization route. In contrast, the highest anti-gp120 antibody levels were induced by synthetic genes encoding the secreted glycoproteins followed by gp160/gp150. Unlike HIV-1(MN), HIV-1(BX08) V3 was not immune dominant. Despite the high antibody response only low and inconsistent neutralizing titers to the homologous HIV-1 isolate were measured. However, neutralization of SHIV89.6P could be obtained. Thus, the neutralizing epitopes on the cell line-adapted SHIV89.6P and HIV-1(MN) may be more antigenically available for the cross-neutralizing antibodies induced. In conclusion, complete "humanization" of the DNA vaccine genes failed to induce a consistent neutralizing antibody response, albeit expression and immunogenicity of the primary HIV-1 glycoproteins were greatly improved. Optimization in terms of improving neutralization may require further modifications of the DNA vaccine gene. The synthetic cassette construct described is a convenient tool developed to investigate this further.

Histamine immunocytochemistry: a new method for detection of basophils in peripheral blood

We report that basophils in peripheral blood can be stained using histamine immunocytochemistry. The staining is based on the fixation of leucocytes with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (CDI) and the subsequent incubation of these cells with antisera raised against histamine conjugated to different carrier proteins using CDI. The staining appears to be specific for basophils and stained cells can be examined using both fluorescence microscopy and flow cytometry. In addition, histamine immunocytochemistry can be combined with conventional immunocytochemistry by incubating leucocytes with antibodies to cell surface antigens prior to or following fixation of the cells with CDI. Thus, histamine immunocytochemistry may be a valuable tool in future studies of human basophils.

Complete protection against lethal Toxoplasma gondii infection in mice immunized with a plasmid encoding the SAG1 gene

Infection with the protozoan parasite Toxoplasma gondii is transmitted to humans from infected animals by tissue cysts and oocysts excreted by cats. Immunization with inactivated parasites or recombinant proteins has at best shown partial protection. We constructed a plasmid expressing the SAG1 surface antigen of T. gondii, p1tPASAG1, and showed that animals immunized with the plasmid produce anti-SAG1 antibodies which recognize the native SAG1. Mice immunized with p1tPASAG1 showed 80 to 100% protection against challenge with the non-cyst-producing, virulent RH isolate, compared to an 80% mortality in mice immunized with empty plasmid, which is the greatest efficacy of any vaccine against T. gondii produced so far. The SAG1 molecule was analyzed for potential cytotoxic T-lymphocyte (CTL) epitopes, and four peptides with the best fit were synthesized. The ability of the peptides to stimulate gamma interferon production by CD8(+) T cells from p1tPASAG1-immunized mice was tested in an ELISPOT assay, and one new CTL epitope was identified. Adoptive transfer of CD8(+) T cells from p1tPASAG1-immunized to naïve mice showed partial protection. In conclusion, DNA vaccination with p1tPASAG1 gave effective protection in mice against T. gondii infection and the protection could be adoptively transferred by purified CD8(+) T cells.

Induction of cytotoxic T-cell responses by gene gun DNA vaccination with minigenes encoding influenza A virus HA and NP CTL-epitopes

Cytotoxic T-lymphocyte (CTL) response is an important component of anti-viral immunity. CTLs are specific to short peptides presented by MHC-I molecules and immunisation with the exact peptide sequence introduced in the cytosol is therefore a minimal approach, which potentially affords a high degree of controllability. We have examined the induction of murine CTL's by this approach using DNA plasmid minigene vaccines encoding known mouse K(k) minimal CTL epitopes (8 amino acids) from the influenza A virus hemagglutinin and nucleoprotein. We here report that such an approach is feasible and that wild type influenza virus flanking amino acid sequences can influence the CTL response but are not essential for optimal CTL induction. We also examined the effect of different new amino acid sequences flanking the CTL epitopes. In one version, two CTL epitopes were linked together as 'string of beads'. This did not improve CTL induction. In another version, one CTL epitope was inserted into a known T-helper protein (HBsAg). This did significantly augment the response probably due to immunological help from HBsAg Th epitopes. Finally, the CTL inducing minigene DNA vaccines were compared with Flu-induced CTL responses and tested for their protective effect against a lethal influenza A virus infection in mice and no effect was found. We conclude that a specific and highly directed CTL induction is possible by unlinked minigene DNA immunisation, but that CTL induction solely is not always sufficient to provide protection.

Gene gun DNA vaccination with Rev-independent synthetic HIV-1 gp160 envelope gene using mammalian codons

DNA immunization with HIV envelope plasmids induce only moderate levels of specific antibodies which may in part be due to limitations in expression influenced by a species-specific and biased HIV codon usage. We compared antibody levels, Th1/Th2 type and CTL responses induced by synthetic genes encoding membrane bound gp160 versus secreted gp120 using optimized codons and the efficient gene gun immunization method. The in vitro expression of syn.gp160 as gp120 + gp41 was Rev independent and much higher than a classical wt.gp160 plasmid. Mice immunized with syn.gp160 and wt.gp160 generated low and inconsistent ELISA antibody titres whereas the secreted gp120 consistently induced faster seroconversion and higher antibody titres. Due to a higher C + G content the numbers of putative CpG immune (Th1) stimulatory motifs were highest in the synthetic gp160 gene. However, both synthetic genes induced an equally strong and more pronounced Th2 response with higher IgG1/IgG2a and IFNgamma/IL-4 ratios than the wt.gp160 gene. As for induction of CTL, synthetic genes induced a somewhat earlier response but did not offer any advantage over wild type genes at a later time point. Thus, optimizing codon usage has the advantage of rendering the structural HIV genes Rev independent. For induction of antibodies the level of expression, while important, seems less critical than optimal contact with antigen presenting cells at locations reached by the secreted gp120 protein. A proposed Th1 adjuvant effect of the higher numbers of CpG motifs in the synthetic genes was not seen using gene gun immunization which may be due to the low amount of DNA used.

Improved immunogenicity of HIV-1 epitopes in HBsAg chimeric DNA vaccine plasmids by structural mutations of HBsAg

To improve the immunogenicity of epitopes from the envelope protein of HIV-1, we have developed gene gun-delivered subunit DNA vaccines by inserting the sequences encoding the V3 region into the hepatitis B virus (HBV) envelope gene, often called the surface antigen (HBsAg). We have examined the possibility of modifying the immune response to V3 by introducing modifications into the carrier HBsAg in gene gun DNA immunization of mice. In some plasmid constructions, the V3 sequence was introduced into the preS2 region of the HBsAg. Although this region is not present in all protein subunits of the HBsAg particles produced, abolishing the internal translational initiation site for the S protein had no effect on the immune response to V3. Expression of V3 at the N-terminal or C-terminal part of the HBsAg protein resulted in equal anti-V3 antibody and cytotoxic T-lymphocyte (CTL) responses. However, elimination of secretion by single amino-acid mutations in the HBsAg decreased the anti-HBsAg antibody response but enhanced the anti-V3 antibody response. In contrast, the CTL response to V3 was independent of the structural mutations but could be improved by a total deletion of the HBsAg sequence part. Thus, the immune response to heterologous epitopes can be altered by modifications in the carrier HBsAg protein. Modifications of the HBsAg carrier might interfere with the dominant immune response to the HBsAg epitopes, allowing better antibody induction to less immunogenic foreign epitopes. However, for induction of CTL responses, the expression of minimal epitopes may be advantageous.

Ureteropelvic junction obstruction and ureteral strictures treated by simple high-pressure balloon dilation

The long-term results of simple high-pressure balloon dilation in the treatment of ureteropelvic junction obstruction (UPJO) and ureteral strictures were evaluated. A total of 77 consecutive patients were treated: 40 had UPJO and 37 ureteral strictures. The etiology of the obstruction included congenital UPJO, previous stones, sequelae of endoscopic and open surgery, radiotherapy, and urinary tract reconstruction. A retrograde ureteroscopic approach was used. Evaluation included clinical and radiographic examinations and renal scintigraphy with diuretic wash-out. The procedure was repeated in 21 cases. The median follow-up was 29 months. The procedure was considered successful if it left the patient asymptomatic and with improved renographic function and drainage. The overall success rate was 70%. The best results were obtained in strictures secondary to stones, with a success rate of 94%, and in strictures secondary to reconstructive and ureteroscopic surgery, with a success rate of 91%. In congenital UPJO, the results were less encouraging: in patients with a symptom debut after the age of 18 years, balloon dilation was successful in 57% of cases; in patients with symptom debut before the age of 18 years, success was achieved in only 25% of cases. There were no major complications. It was concluded that simple high-pressure balloon dilation is a safe and reasonably effective technique for the management of most ureteral strictures and congenital UPJO with symptom debut in adult life. Balloon dilation seems to have no place in the treatment of primary congenital UPJO in children.

Immunization with E. coli produced recombinant T. gondii SAG1 with alum as adjuvant protect mice against lethal infection with Toxoplasma gondii

Polyclonal rabbit antibodies against recombinant Toxoplasma gondii SAG1 antigen expressed in E.coli recognize T. gondii and the antibodies significantly reduced T.gondii adherence and/or invasion into the host cell as did a monoclonal antibody against a conformational epitope of the SAG1 antigen. Groups of outbread NMRI mice were immunized with recombinant T. gondii SAG1 antigen in alum. The antibody response to immunizations was dominated by a Th2 response with production of T.gondii specific IgG1 antibodies. Challenge with tachyzoites from the virulent RH-strain produced a Th1 response dominated by the production of specific IgG2a antibodies and moderately boosted the IgG1 response, and challenge with bradyzoites from the avirulent SSI119-strain showed the same pattern. Immunization with rSAG1 resulted in a significant increased survival after challenge with tachyzoites of the RH-strain. Immunization with E.coli expressed recombinant SAG1 in alum induce partial protective immunity against lethal infection with T. gondii in mice.

Identification of a basophil leukocyte interleukin-3-regulated protein that is identical to IgE-dependent histamine-releasing factor

This study aimed to identify basophil leukocyte proteins associated with interleukin (IL)-3 and/or anti-IgE activation by two-dimensional (2-D) gel electrophoresis. We noticed one particular protein showing increased synthesis after recombinant human (rh)IL-3 and, to a lesser extent, anti-IgE stimulation. The protein was also present in the culture medium in increased amounts after rhIL-3 stimulation. On the basis of comigration with proteins in published 2-D gel electrophoresis databases and immunoblotting with a specific monoclonal antibody, we identified this protein as translationally controlled tumor protein (TCTP), also known as p23 or IgE-dependent histamine-releasing factor. The antibody was shown to be specific for TCTP/IgE-dependent histamine-releasing factor by blotting on 2-D gels of proteins from human lymphocytes and the human basophilic cell line KU812, followed by N-terminal amino-acid sequencing of the bound protein. Densitometric analysis of the gels showed that the synthesis of IgE-dependent histamine-releasing factor in human basophil leukocytes was dose dependent upon rhIL-3 stimulation with an optimum of 100 ng/ml. The level of the protein in the medium was also highest at an optimal rhIL-3 concentration of 100 ng/ml. Supernatants from cultured basophils were able to stimulate histamine release from other basophils. This histamine release was decreased by precipitation of TCTP/IgE-dependent histamine-releasing factor from these supernatants.

Comparisons of DNA-mediated immunization procedures directed against surface glycoproteins of human immunodeficiency virus type-1 and hepatitis B virus

DNA vaccination methods were compared to examine the in vivo expression of HIV-1 gp160 and beta-galactosidase, and the resulting immune response. Beta-galactosidase plasmid showed expression rates of 2-5% of muscle fibers with or without pretreatments using bupivacaine or cardiotoxin facilitators 1 or 5 days earlier, respectively. In contrast, HIV gp160 expression was lower in untreated or bupivacaine-treated muscles, but was improved by pretreatment with cardiotoxin. Equal expression of beta-galactosidase and HIV gp160 was obtained using gene gun delivery to the epidermis. Unlike the i.m. in situ expression of gp160, the anti-HIV antibody response did not improve after muscle pretreatments but depended on the vaccination intervals. Gene gun delivery of pMN160 also resulted in a slow and low titered antibody response. In contrast, a single i.m. injection of plasmid encoding another viral envelope, HBsAg, resulted in earlier seroconversion to high titers without the need for pretreatments or boostings. Intradermal inoculation by gene gun using 100-fold less DNA resulted in the same anti-HBsAg antibody profile only after boostings. In contrast to the differences in antibody responses, a specific CTL response was obtained in all cases. Bupivacaine-treated muscles showed an extreme degree of edema with disruption of connective tissue (endo- and mesomysium) and was not well tolerated (4 of 19 mice died). Cardiotoxin created muscle necrosis and occasional (2 of 20 mice) development of fibrotic muscles. It is concluded that in vivo expression cannot be properly predicted using reporter gene experiments and that the resulting immune response does not follow directly with the expression rate. It is suggested that the antibody response may depend primarily on the nature of the antigen expressed rather than the DNA vaccination method. It is proposed that gene gun or i.m. injection be used without pretreatment in the case of DNA vaccination with plasmid encoding HIV MN gp160.

Purification of human colonic and gastric mast cells

We have developed a method to purify mast cells from enzymatic isolates of human colonic mucosa (HCM) and submucosa/muscle (HCS), and gastric mucosa (HGM) and submucosa/muscle (HGS). The purification of mast cells from these enzymatic isolates involves positive affinity-magnetic selection of mast cells using a monoclonal antibody specific for the c-kit receptor tyrosine kinase (CD117). The monoclonal antibody is coupled to Dynabeads for positive affinity selection of c-kit receptor positive cells which includes mast cells. This selection procedure generates preparations of mast cells from HCM, HCS, HGM and HGS that are 80% pure. The purified mast cells were microscopically normal and viable (> 85%). The functionality of purified mast cells was examined by studying the effect of anti-human IgE, Concanavalin A (Con A) and calcium ionophore A23187 on histamine release. These results show that this purification procedure generates microscopically normal, viable and functional mast cells. This method of purifying human gastrointestinal tissue mast cells may be a valuable tool for the further study of mast cell heterogeneity and the role of mast cells in the gastrointestinal tract.

Improved humoral and cellular immune responses against the gp120 V3 loop of HIV-1 following genetic immunization with a chimeric DNA vaccine encoding the V3 inserted into the hepatitis B surface antigen

The gp120-derived V3 loop of HIV-1 is involved in co-receptor interaction, it guides cell tropism, and contains an epitope for antibody neutralization. Thus, HIV-1 V3 is an attractive vaccine candidate. The V3 of the MN strain (MN V3) contains both B- and T-cell epitopes, including a known mouse H-2d-restricted cytotoxic T lymphocyte (CTL) epitope. In an attempt to improve the immunogenicity of V3 in DNA vaccines, a plasmid expressing MN V3 as a fusion protein with the highly immunogenic middle (pre-S2 + S) surface antigen of hepatitis B virus (HBsAg) was constructed. Epidermal inoculation by gene gun was used for genetic immunization in a mouse model. Antibody and CTL responses to MN V3 and HBsAg were measured and compared with the immune responses obtained after vaccination with plasmids encoding the complete HIV-1 MN gp160 and HBsAg (pre-S2 + S), respectively. DNA vaccination with the HIV MN gp160 envelope plasmid induced a slow and low titred anti-MN V3 antibody response at 12 weeks post-inoculation (p.i.) and a late appearing (7 weeks), weak and variable CTL response. In contrast, DNA vaccination with the HBsAg-encoding plasmid induced a rapid and high titred anti-HBsAg antibody response and a uniform strong anti-HBs CTL response already 1 week p.i. in all mice. DNA vaccination with the chimeric MN V3/HBsAg plasmid elicited humoral responses against both viruses within 3-6 weeks which peaked at 6-12 weeks and remained stable for at least 25 weeks. In addition, specific CTL responses were induced in all mice against both MN V3 and HBsAg already within the first 3 weeks, lasting at least 11 weeks. Thus, HBsAg acts as a 'genetic vaccine adjuvant' augmenting and accelerating the cellular and humoral immune response against the inserted MN V3 loop. Such chimeric HIV-HBsAg plasmid constructs may be useful in DNA immunizations as a 'carrier' of protein regions or minimal epitopes which are less exposed or poorly immunogenic.