HLA B-27 Subtypes in Turkish Patients with Spondyloarthropathy and Healthy Controls

The frequency and the distribution of HLA-B27 subtypes in spondylarthropathy (SpA) patients and controls were investigated in a sample Turkish population. B27 subtyping was performed by PCR-SSP method in two groups: 49 unrelated HLA-B27 positive Turkish patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group Criteria, and 55 HLA-B27 positive healthy controls. The frequency of HLA-B(∗)27 was 2.6% in the Turkish population, and B(∗)2705 was the predominant allele among patients with SpA. The difference was mainly between male patients and male controls The proportion of B(∗)2705 among B27-positive patients and controls was significantly different (P = 0.02). Our study supports other reports from different populations which showed that B(∗)2705 and B(∗)2702 were more frequent in Caucasian patients with SpA

Natural infection of Plasmodium brasilianum in humans: Man and monkey share quartan malaria parasites in the Venezuelan Amazon

AbstractBackgroundThe quartan malaria parasite Plasmodium malariae is the widest spread and best adapted human malaria parasite. The simian Plasmodium brasilianum causes quartan fever in New World monkeys and resembles P. malariae morphologically. Since the genetics of the two parasites are nearly identical, differing only in a range of mutations expected within a species, it has long been speculated that the two are the same. However, no naturally acquired infection with parasites termed as P. brasilianum has been found in humans until now.MethodsWe investigated malaria cases from remote Yanomami indigenous communities of the Venezuelan Amazon and analyzed the genes coding for the circumsporozoite protein (CSP) and the small subunit of ribosomes (18S) by species-specific PCR and capillary based-DNA sequencing.FindingsBased on 18S rRNA gene sequencing, we identified 12 patients harboring malaria parasites which were 100% identical with P. brasilianum isolated from the monkey, Alouatta seniculus. Translated amino acid sequences of the CS protein gene showed identical immunodominant repeat units between quartan malaria parasites isolated from both humans and monkeys.InterpretationThis study reports, for the first time, naturally acquired infections in humans with parasites termed as P. brasilianum. We conclude that quartan malaria parasites are easily exchanged between humans and monkeys in Latin America. We hypothesize a lack of host specificity in mammalian hosts and consider quartan malaria to be a true anthropozoonosis. Since the name P. brasilianum suggests a malaria species distinct from P. malariae, we propose that P. brasilianum should have a nomenclatorial revision in case further research confirms our findings. The expansive reservoir of mammalian hosts discriminates quartan malaria from other Plasmodium spp. and requires particular research efforts

A Randomized Controlled Phase Ib Trial of the Malaria Vaccine Candidate GMZ2 in African Children

BACKGROUND: GMZ2 is a fusion protein of Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate rich protein (GLURP) that mediates an immune response against the blood stage of the parasite. Two previous phase I clinical trials, one in naïve European adults and one in malaria-exposed Gabonese adults showed that GMZ2 was well tolerated and immunogenic. Here, we present data on safety and immunogenicity of GMZ2 in one to five year old Gabonese children, a target population for future malaria vaccine efficacy trials. METHODOLOGY/PRINCIPAL FINDINGS: Thirty children one to five years of age were randomized to receive three doses of either 30 µg or 100 µg of GMZ2, or rabies vaccine. GMZ2, adjuvanted in aluminum hydroxide, was administered on Days 0, 28 and 56. All participants received a full course of their respective vaccination and were followed up for one year. Both 30 µg and 100 µg GMZ2 vaccine doses were well tolerated and induced antibodies and memory B-cells against GMZ2 as well as its antigenic constituents MSP3 and GLURP. After three doses of vaccine, the geometric mean concentration of antibodies to GMZ2 was 19-fold (95%CI: 11,34) higher in the 30 µg GMZ2 group than in the rabies vaccine controls, and 16-fold (7,36) higher in the 100 µg GMZ2 group than the rabies group. Geometric mean concentration of antibodies to MSP3 was 2.7-fold (1.6,4.6) higher in the 30 µg group than in the rabies group and 3.8-fold (1.5,9.6) higher in the 100 µg group. Memory B-cells against GMZ2 developed in both GMZ2 vaccinated groups. CONCLUSIONS/SIGNIFICANCE: Both 30 µg as well as 100 µg intramuscular GMZ2 are immunogenic, well tolerated, and safe in young, malaria-exposed Gabonese children. This result confirms previous findings in naïve and malaria-exposed adults and supports further clinical development of GMZ2. TRIAL REGISTRATION: ClinicalTrials.gov NCT00703066

Naturally acquired immune responses to malaria vaccine candidate antigens MSP3 and GLURP in Guahibo and Piaroa indigenous communities of the Venezuelan Amazon

BACKGROUND: Malaria transmission in most of Latin America can be considered as controlled. In such a scenario, parameters of baseline immunity to malaria antigens are of specific interest with respect to future malaria eradication efforts. METHODS: A cross-sectional study was carried out in two indigenous population groups in Amazonas/Venezuela. Data from the regional malaria documentation system were extracted and participants from the ethnic groups of the Guahibo (n = 180) and Piaroa (n = 295) were investigated for the presence of Plasmodium parasites and naturally acquired antibodies to Plasmodium falciparum antigens in serum. The GMZ2 vaccine candidate proteins MSP3 and GLURP were chosen as serological markers. RESULTS: The incidence of P. falciparum in both communities was found to be less than 2%, and none of the participants harboured P. falciparum at the time of the cross-sectional. Nearly a quarter of the participants (111/475; 23,4%) had positive antibody titres to at least one of the antigens. 53/475 participants (11.2%) were positive for MSP3, and 93/475 participants (19.6%) were positive for GLURP. High positive responses were detected in 36/475 participants (7.6%) and 61/475 participants (12.8%) for MSP3 and GLURP, respectively. Guahibo participants had significantly higher antibody titres than Piaroa participants. CONCLUSIONS: Considering the low incidence of P. falciparum, submicroscopical infections may explain the comparatively high anti-P. falciparum antibody concentrations

The challenges for women's health in sub-Saharan Africa: Lessons learned from an integrative multistakeholder workshop in Gabon.

The sub-Saharan African (SSA) region is home to more than 230 million females of reproductive age who face multiple intersecting health, social, gender and economic challenges [1]. Neglected tropical diseases (NTDs) are a group of chronic disabling, almost exclusively communicable diseases affecting the poorest of the poor, especially in Africa, which alone bears about 40% of the global burden of NTDs [2- 4]. While both men and women are impacted, biological and sociocultural biases mean that NTDs disproportionately affect women and girls [5]. In recent decades, there has been a global shift from communicable toward non-communicable diseases (NCDs), which cause almost 32 million deaths in low-and lower- middle- income countries (LMIC) [6]. It is expected that by 2030, 85% of NCD-related deaths among women will occur in LMICs, including many countries of SSA region [7]. For women older than 50, NCDs are the leading cause of both death and disability-adjusted life years (DALYs) [8]. Important disparities persist in access to maternal and reproductive health services both within and between countries in SSA [9]; it is estimated that almost half of the women in SSA do not have access to essential health care during pregnancy and childbirth. In 2017, SSA accounted for roughly two-thirds of all maternal deaths in the world [10]. Hence, it is evident that many, if not most, women and girls in SSA carry a triple burden of vulnerability to NTDs, NCDs and poor reproductive health outcomes. Here, we report on the outcomes of an integrative, multistakeholder workshop held in Gabon, Central Africa, to help develop a framework for synergistic, sustainable and gender- and context-appropriate interventions to manage the NTD-NCD complex and additionally reproductive health

Direct venous inoculation of Plasmodium falciparum sporozoites for controlled human malaria infection: a dose-finding trial in two centres

BACKGROUND: Controlled human malaria infection (CHMI) accelerates development of anti-malarial interventions. So far, CHMI is done by exposure of volunteers to bites of five mosquitoes carrying Plasmodium falciparum sporozoites (PfSPZ), a technique available in only a few centres worldwide. Mosquito-mediated CHMI is logistically complex, exact PfSPZ dosage is impossible and live mosquito-based interventions are not suitable for further clinical development. METHODS: An open-labelled, randomized, dose-finding study in 18-45 year old, healthy, malaria-naive volunteers was performed to assess if intravenous (IV) injection of 50 to 3,200 aseptic, purified, cryopreserved PfSPZ is safe and achieves infection kinetics comparable to published data of mosquito-mediated CHMI. An independent study site verified the fully infectious dose using direct venous inoculation of PfSPZ. Parasite kinetics were assessed by thick blood smear microscopy and quantitative real time PCR. RESULTS: IV inoculation with 50, 200, 800, or 3,200 PfSPZ led to parasitaemia in 1/3, 1/3, 7/9, and 9/9 volunteers, respectively. The geometric mean pre-patent period (GMPPP) was 11.2 days (range 10.5-12.5) in the 3,200 PfSPZ IV group. Subsequently, six volunteers received 3,200 PfSPZ by direct venous inoculation at an independent investigational site. All six developed parasitaemia (GMPPP: 11.4 days, range: 10.4-12.3). Inoculation of PfSPZ was safe. Infection rate and pre-patent period depended on dose, and injection of 3,200 PfSPZ led to a GMPPP similar to CHMI with five PfSPZ-infected mosquitoes. The infectious dose of PfSPZ predicted dosage of radiation-attenuated PfSPZ required for successful vaccination. CONCLUSIONS: IV inoculation of PfSPZ is safe, well tolerated and highly reproducible. It shall further accelerate development of anti-malarial interventions through standardization and facilitation of CHMI. Beyond this, rational dose selection for whole PfSPZ-based immunization and complex study designs are now possible. TRIAL REGISTRATION: ClinicalTrials.gov NCT01624961 and NCT01771848

Epidemiology of dengue fever in Gabon: Results from a health facility-based fever surveillance in Lambaréné and its surroundings.

BACKGROUND: In Africa, information on dengue is limited to outbreak reports and focused on some countries with continuing transmission in West and East Africa. To estimate the proportion of dengue-positive cases among febrile patients and identify clinical indicators of dengue cases, we conducted passive facility-based fever surveillance in a catchment area population of 70,000 residents of Lambaréné and its surroundings in Gabon. METHODS: Non-malarial febrile patients with current fever or history of fever (≤7 days) between 1 and 55 years of age, were enrolled at Albert Schweitzer Hospital (ASH). Acute (visit 1, day of enrollment) and convalescent blood samples were collected between 10 and 21 days after enrollment. Acute/convalescent samples were tested with IgM/IgG ELISA, and a selected subset of acute samples with RT-PCR. RESULTS: Among 682 non-malarial febrile patients enrolled, 119 (17.4%) were identified as dengue-positive (94 dengue-confirmed and 25 dengue-probable cases). Of these dengue-positive cases, 14 were confirmed with PCR, and based on serotyping, two infections were identified to be DENV-2 and two were DENV-3. The majority of our enrolled patients were <25 years of age and close to 80% of our dengue-positive cases were <15 years of age. In adjusted analyses, retro-orbital pain and abdominal pain were 2.7 and 1.6 times more frequently found among dengue-positive cases, compared to non-dengue cases. CONCLUSION: Lambaréné is not considered dengue-endemic. However, one in six non-malarial febrile episodes was found to be dengue-positive in the study period. Dengue should be considered more frequently in clinicians' diagnosis among non-malarial febrile patients in Lambaréné. Given the lack of data on dengue in Gabon, additional prospective and longitudinal studies would help to further define the burden and patterns of dengue for improved case detection

Plasmodium falciparum-Infected Erythrocytes Induce Granzyme B by NK Cells through Expression of Host-Hsp70

In the early immune response to Plasmodium falciparum-infected erythrocytes (iRBC), Natural Killer (NK) cells are activated, which suggests an important role in innate anti-parasitic immunity. However, it is not well understood whether NK cells directly recognize iRBC or whether stimulation of NK cells depends mainly on activating signals from accessory cells through cell-to-cell contact or soluble factors. In the present study, we investigated the influence of membrane-bound host Heat shock protein (Hsp) 70 in triggering cytotoxicity of NK cells from malaria-naïve donors or the cell line NK92 against iRBC. Hsp70 and HLA-E membrane expression on iRBC and potential activatory NK cell receptors (NKG2C, CD94) were assessed by flow cytometry and immunoblot. Upon contact with iRBC, Granzyme B (GzmB) production and release was initiated by unstimulated and Hsp70-peptide (TKD) pre-stimulated NK cells, as determined by Western blot, RT-PCR and ELISPOT analysis. Eryptosis of iRBC was determined by Annexin V-staining. Our results suggest that presence of Hsp70 and absence of HLA-E on the membrane of iRBC prompt the infected host cells to become targets for NK cell-mediated cytotoxicity, as evidenced by impaired parasite development. Contact of iRBC with NK cells induced release of GzmB. We propose that following GzmB uptake, iRBC undergo eryptosis via a perforin-independent, GzmB-mediated mechanism. Since NK activity toward iRBC could be specifically enhanced by TKD peptide and abrogated to baseline levels by blocking Hsp70 exposure, we propose TKD as an innovative immunostimulatory agent to be tested as an adjunct to anti-parasitic treatments in vivo

Evaluating dengue burden in Africa in passive fever surveillance and seroprevalence studies: protocol of field studies of the Dengue Vaccine Initiative.

INTRODUCTION: Dengue is an important and well-documented public health problem in the Asia-Pacific and Latin American regions. However, in Africa, information on disease burden is limited to case reports and reports of sporadic outbreaks, thus hindering the implementation of public health actions for disease control. To gather evidence on the undocumented burden of dengue in Africa, epidemiological studies with standardised methods were launched in three locations in Africa. METHODS AND ANALYSIS: In 2014-2017, the Dengue Vaccine Initiative initiated field studies at three sites in Ouagadougou, Burkina Faso; Lambaréné, Gabon and Mombasa, Kenya to obtain comparable incidence data on dengue and assess its burden through standardised hospital-based surveillance and community-based serological methods. Multidisciplinary measurements of the burden of dengue were obtained through field studies that included passive facility-based fever surveillance, cost-of-illness surveys, serological surveys and healthcare utilisation surveys. All three sites conducted case detection using standardised procedures with uniform laboratory assays to diagnose dengue. Healthcare utilisation surveys were conducted to adjust population denominators in incidence calculations for differing healthcare seeking patterns. The fever surveillance data will allow calculation of age-specific incidence rates and comparison of symptomatic presentation between patients with dengue and non-dengue using multivariable logistic regression. Serological surveys assessed changes in immune status of cohorts of approximately 3000 randomly selected residents at each site at 6-month intervals. The age-stratified serosurvey data will allow calculation of seroprevalence and force of infection of dengue. Cost-of-illness evaluations were conducted among patients with acute dengue by Rapid Diagnostic Test. ETHICS AND DISSEMINATION: By standardising methods to evaluate dengue burden across several sites in Africa, these studies will generate evidence for dengue burden in Africa and data will be disseminated as publication in peer-review journals in 2018