Integration of female genital schistosomiasis into HIV/sexual and reproductive health and rights and neglected tropical diseases programmes and services: a scoping review

Female genital schistosomiasis (FGS) affects approximately 56 million women and girls across sub-Saharan Africa and is associated with up to a threefold increased prevalence of HIV. Integrating FGS with HIV programmes as part of comprehensive sexual and reproductive health (SRH) services may be one of the most significant missed opportunities for preventing HIV incidence among girls and women. A search of studies published until October 2021 via Scopus and ProQuest was conducted using PRISMA guidelines to assess how FGS can be integrated into HIV/SRH and neglected tropical diseases (NTDs) programmes and services. Data extraction included studies that integrated interventions and described the opportunities and challenges. A total of 334 studies were identified, with 22 eligible for analysis and summarised conducting a descriptive numerical analysis and qualitative review. We adapted a framework for integrated implementation of FGS, HIV, and HPV/cervical cancer to thematically organise the results, classifying them into five themes: awareness and community engagement, diagnosis, treatment, burden assessment, and economic evaluation. Most activities pertained to awareness and community engagement (n = 9), diagnosis (n = 9) and were primarily connected to HIV/AIDS (n = 8) and school-based services and programming (n = 8). The studies mainly described the opportunities and challenges for integration, rather than presenting results from implemented integration interventions, highlighting an evidence gap on FGS integration into HIV/SRH and NTD programmes. Investments are needed to realise the potential of FGS integration to address the burden of this neglected disease and improve HIV and SRH outcomes for millions of women and girls at risk.

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semi-automatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Development and Introduction of the Filariasis Test Strip: A New Diagnostic Test for the Global Program to Eliminate Lymphatic Filariasis

A key component to achieving the global goal of elimination of lymphatic filariasis (LF) is the availability of appropriate tools for disease mapping, monitoring, and surveillance. However, the development of these tools for a neglected disease such as LF can be a challenge. The lack of a commercial market and low familiarity with these diseases leave little incentive for diagnostic manufacturers to invest in this space. The Filarial Test Strip (FTS) development story provides a case study on how a multi-stakeholder, public-private partnership model facilitated the development, evaluation, and introduction of a new monitoring and surveillance tool for LF. This paper will reflect on the experience with the FTS and document the process from development of the target product profile to adoption and scale-up in country programs. Lessons learned from both the successes and challenges experienced during this process may help inform future efforts to develop and introduce new diagnostic or surveillance tools for neglected diseases.

Addressing a silent and neglected scourge in sexual and reproductive health in Sub-Saharan Africa by development of training competencies to improve prevention, diagnosis, and treatment of female genital schistosomiasis (FGS) for health workers

Background

Schistosomiasis is an acute and chronic disease caused by parasitic worms, that can take two main forms: intestinal or urogenital. If left untreated, the urogenital form can lead to female genital schistosomiasis (FGS) in women and girls; frequently resulting in severe reproductive health complications which are often misdiagnosed as sexually-transmitted infections (STIs) or can be confused with cervical cancer. Despite its impact on women’s reproductive health, FGS is typically overlooked in medical training and remains poorly recognized with low awareness both in affected communities and in health professionals. FGS has been described as the one of the most neglected sexual and reproductive health issues in sub-Saharan Africa (Swai in BMC Infect Dis 6:134, 2006; Kukula in PLoS Negl Trop Dis 13:e0007207; Joint United Nations Programme on HIV/AIDS (UNAIDS) 2019). Increased knowledge and awareness of FGS is required to end this neglect, improve women’s reproductive health, and decrease the burden of this preventable and treatable neglected tropical disease.

Methods

We conducted interactive virtual workshops, in collaboration with the World Health Organization (WHO), engaging 64 participants with medical and public health backgrounds from around the world to establish standardized skills (or competencies) for prevention, diagnosis, and treatment of FGS at all levels of the health system. The competencies were drafted in small groups, peer-reviewed, and finalized by participants.

Results

This participatory process led to identification of 27 skills needed for FGS prevention, diagnosis, and management for two categories of health workers; those working in a clinical setting, and those working in a community setting. Among them, ten relate to the diagnosis of FGS including three that involve a pelvic exam and seven that do not. Six constitute the appropriate behaviors required to treat FGS in a clinical setting. Eleven address the community setting, with six relating to the identification of women at risk and five relating to prevention.

Conclusion

Defining the skills necessary for FGS management is a critical step to prepare for proper diagnosis and treatment of women and girls in sub-Saharan Africa by trained health professionals. The suggested competencies can now serve as the foundation to create educative tools and curricula to better train health care workers on the prevention, diagnosis, and management of FGS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-021-01252-2.

Schistosomiasis belongs to the group of neglected tropical diseases (NTDs) found in tropical and subtropical countries, disproportionately affecting poor populations with limited access to safe water and adequate sanitation. Female genital schistosomiasis (FGS) is a chronic disease caused by parasitic worms, schistososomes, transmitted by contact with infested fresh water. When left untreated, FGS can lead to severe reproductive health complications, such as sub-or infertility and ectopic pregnancy. FGS is a leading neglected issue in sexual and reproductive health in sub-Saharan Africa; however, health professionals are not familiar with it, leading to misdiagnosis and improper treatment. A critical challenge in addressing the burden of FGS is the knowledge gap about the disease in communities and health professionals in endemic areas and the world at large. As part of an FGS Accelerated Scale Together (FAST) package, and in an attempt to address the knowledge gap in health professionals, we organized an interactive workshop bringing together a group of 64 participants working in sexual and reproductive health generally, and/or FGS specifically. Together, we developed a comprehensive set of required skills for health workers training on FGS. The workshop participants drafted 27 skills (or competencies) to diagnose, treat, and prevent FGS. Establishing what health workers must know is a crucial first step towards the integration of FGS into women’s health care. The competencies are now available and can be used as a framework in the development of training for health professionals, opening the doors to better reproductive health for women.

Design and synthesis of bis-biotin-containing reagents for applications utilizing monoclonal antibody-based pretargeting systems with streptavidin mutants

Previous studies have shown that pretargeting protocols, using cancer-targeting fusion proteins, composed of 4 anti-CD20 single chain Fv (scFv) fragments and streptavidin (scFv(4)-SAv), followed by a biotinylated dendrimeric N-acetyl-galactosamine blood clearing agent (CA), 1, then a radiolabeled DOTA-biotin derivative (a monobiotin), 3a, can provide effective therapy for lymphoma xenografts in mouse models. A shortcoming in this pretargeting system is that endogenous biotin may affect its efficacy in patients. To circumvent this potential problem, we investigated a pretargeting system that employs anti-CD20 scFv(4)-SAv mutant fusion proteins with radioiodinated bis-biotin derivatives. With that combination of reagents, good localization of the radiolabel to lymphoma tumor xenografts was obtained in the presence of endogenous biotin. However, the blood clearance reagents employed in the studies were ineffective, resulting in abnormally high levels of radioactivity in other tissues. Thus, in the present investigation a bis-biotin-trigalactose blood clearance reagent, 2, was designed, synthesized, and evaluated in vivo. Additionally, another DOTA-biotin derivative (a bis-biotin), 4a, was designed and synthesized, such that radiometals (e.g., (111)In, (90)Y, (177)Lu) could be used in the pretargeting protocols employing scFv(4)-SAv mutant fusion proteins. Studies in mice demonstrated that the CA 2 was more effective than CA 1 at removing [(125)I]scFv(4)-SAv-S45A mutant fusion proteins from blood. Another in vivo study compared tumor targeting and normal tissue concentrations of the new reagents (2 and [(111)In]4b) with standard reagents (1 and [(111)In]3b) used in pretargeting protocols. The study showed that lymphoma xenografts could be targeted in the presence of endogenous biotin when anti-CD20 fusion proteins containing SAv mutants (scFv(4)-SAv-S45A or scFv(4)-SAv-Y43A) were employed in combination with CA 2 and [(111)In]4b. Importantly, normal tissue concentrations of [(111)In]4b were similar to those obtained using the standard reagents (1 and [(111)In]3b), except that the blood and liver concentrations were slightly higher with the new reagents. While the reasons for the higher blood and liver concentrations are unknown, the differences in the galactose structures of the clearance agents 1 and 2 may play a role.

Pretargeted Radioimmunotherapy for B-Cell Lymphomas

Relapsed or treatment refractory B-cell lymphomas are currently incurable with conventional chemotherapy and radiation treatments. High-dose chemoradiotherapy and stem cell transplantation can cure some patients with relapsed or refractory lymphoma, but the majority of such patients die of progressive disease. We have investigated the potential utility of pretargeted radioimmunotherapy using monoclonal antibody-streptavidin, immunoconjugates, and fusion proteins in combination with N-acetylgalactosamine dendrimeric clearing agent and radiometal-labeled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid biotin for treatment of lymphomas using mouse and primate models. We have targeted a variety of cell surface antigens, including CD20, CD22, CD45, and HLA-DR, using conventional and pretargeted radioimmunotherapy. These studies showed the marked superiority of pretargeted radioimmunotherapy for each of the antigenic targets in terms of superior biodistributions, more complete tumor regressions, and longer survival. We are optimistic that this novel approach will provide a meaningful prolongation of survival for patients with relapsed or refractory lymphomas.

Evaluation of CD20, CD22, and HLA-DR Targeting for Radioimmunotherapy of B-Cell Lymphomas

Despite the promise of radioimmunotherapy using anti-CD20 antibodies (Ab) for the treatment of relapsed patients with indolent non-Hodgkin lymphoma (NHL), most patients treated with conventional doses of (131)I-tositumomab or (90)Y-ibritumomab eventually relapse. We did comparative assessments using conventional radioimmunotherapy targeting CD20, CD22, and HLA-DR on human Ramos, Raji, and FL-18 lymphoma xenografts in athymic mice to assess the potential for improving the efficacy of radioimmunotherapy by targeting other NHL cell surface antigens. Results of biodistribution studies showed significant differences in tumor localization consistent with variable antigenic expression on the different lymphoma cell lines. Interestingly, the radioimmunoconjugate that yielded the best tumor-to-normal organ ratios differed in each tumor model. We also explored administering all three (111)In-1,4,7,10-tetra-azacylododecane N,N',N'',N'''-tetraacetic acid antibodies in combination, but discovered, surprisingly, that this approach did not augment the localization of radioactivity to tumors compared with the administration of the best single radiolabeled Ab alone. These data suggest that conventional radioimmunotherapy using anti-CD20, anti-HLA-DR, or anti-CD22 Abs is effective when used singly and provides targeted uptake of radiolabel into the tumor that is dependent on the levels of antigen expression. Improvements in tumor-to-normal organ ratios of radioactivity cannot be achieved using directly labeled Abs in combination but may be afforded by novel pretargeting methods.

Comparative biodistributions of pretargeted radioimmunoconjugates targeting CD20, CD22, and DR molecules on human B-cell lymphomas

Pretargeted radioimmunotherapy (PRIT) using streptavidin (SA)-conjugated antibodies (Abs), followed by clearing agent and radiolabeled biotin is a promising method that can increase the effectiveness of RIT, while decreasing the toxicities associated with directly labeled Abs. Although CD20 has been the traditional target antigen for RIT of non-Hodgkin lymphoma (NHL), studies targeting HLA DR and CD22 have yielded promising results. Targeting all 3 antigens at once may further augment the effect of PRIT. This study compares the targeting of Ramos, Raji, and FL-18 lymphoma xenografts with either anti-CD20 Ab/SA (1F5/SA), anti-HLA DR Ab/SA (Lym-1/SA), anti-CD22 Ab/SA (HD39/SA), or all 3 conjugates in combination, followed 24 hours later by a biotin-N-acetyl-galactosamine clearing agent, and 3 hours after that by (111)In-DOTA-biotin. The Ab/SA conjugate yielding the best tumor uptake and tumor-to-normal organ ratios of radioactivity varied depending on the target antigen expression on the cell line used, with 1F5/SA and Lym-1/SA yielding the most promising results overall. Also, the best tumor-to-normal organ ratios of absorbed radioactivity were obtained using single conjugates optimized for target tumor antigen expression rather than the combination therapy. This study highlights the importance of screening the antigenic expression on lymphomas to select the optimal reagent for PRIT.

A genetically engineered anti-CD45 single-chain antibody-streptavidin fusion protein for pretargeted radioimmunotherapy of hematologic malignancies

Acute myelogenous leukemia (AML) currently kills the majority of afflicted patients despite combination chemotherapy and hematopoietic cell transplantation (HCT). Our group has documented the promise of radiolabeled anti-CD45 monoclonal antibodies (Ab) administered in the setting of allogeneic HCT for AML, but toxicity remains high, and cure rates are only 25% to 30% for relapsed AML. We now show the superiority of pretargeted radioimmunotherapy (PRIT) compared with conventional radioimmunotherapy using a recombinant tetravalent single-chain Ab-streptavidin (SA) fusion protein (scFv(4)SA) directed against human CD45, administered sequentially with a dendrimeric N-acetylgalactosamine-containing clearing agent and radiolabeled 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic (DOTA)-biotin. The scFv(4)SA construct was genetically engineered by fusing Fv fragments of the human CD45-specific BC8 Ab to a full-length genomic SA gene and was expressed as a soluble tetramer in the periplasmic space of Escherichia coli. The fusion protein was purified to >95% homogeneity at an overall yield of approximately 50% using iminobiotin affinity chromatography. The immunoreactivity and avidity of the fusion protein were comparable with those of the intact BC8 Ab, and the scFv(4)SA construct bound an average of 3.9 biotin molecules out of four theoretically possible. Mouse lymphoma xenograft experiments showed minimal toxicity, excellent tumor-specific targeting of the fusion protein and radiolabeled DOTA-biotin in vivo, marked inhibition of tumor growth, and cured 100% of mice bearing CD45-expressing tumors. These promising results have prompted large-scale cGMP production of the BC8 fusion protein for clinical trials to be conducted in patients with hematologic malignancies.

Comparison of a tetravalent single-chain antibody-streptavidin fusion protein and an antibody-streptavidin chemical conjugate for pretargeted anti-CD20 radioimmunotherapy of B-cell lymphomas

The efficacy of radioimmunotherapy (RIT) for patients with relapsed non-Hodgkin lymphoma (NHL) is limited by nonspecific delivery of radiation to normal tissues due to the long circulating half-life of radiolabeled anti-CD20 antibodies (Abs). Pretargeted RIT using a covalent conjugate of the 1F5 anti-CD20 Ab with streptavidin (SA) has been shown to augment the efficacy of RIT and decrease toxicity compared with a directly labeled 1F5 Ab. We have engineered a tetravalent singlechain 1F5 (scFv)4SA fusion protein and compared it to the 1F5-SA conjugate. Athymic mice bearing Ramos lymphoma xenografts received either the conjugate or fusion protein, followed 20 hours later by a biotin-N-acetyl-galactosamine clearing agent, followed 4 hours later by 111In-DOTA-biotin. After 24 hours, 11.4% +/- 2.1% of the injected dose of radionuclide was present per gram of tumor (% ID/g) using 1F5 (scFv)4SA compared with 10.8% +/- 2.5% ID/g with 1F5 Ab-SA. Superior tumor-to-normal organ ratios of radioactivity were consistently seen using the fusion protein compared with the chemical conjugate (eg, tumor-to-blood ratio > 65:1 after 48 hours with the fusion protein, but < 7:1 with the conjugate). More than 90% of lymphomabearing mice could be cured with minimal toxicity using either reagent followed by 1200 muCi (44.4 MBq) 90Y-DOTA-biotin.