Persistent T cell unresponsiveness associated with chronic visceral leishmaniasis in HIV-coinfected patients.

A large proportion of HIV-coinfected visceral leishmaniasis (VL-HIV) patients exhibit chronic disease with frequent VL recurrence. However, knowledge on immunological determinants underlying the disease course is scarce. We longitudinally profiled the circulatory cellular immunity of an Ethiopian HIV cohort that included VL developers. We show that chronic VL-HIV patients exhibit high and persistent levels of TIGIT and PD-1 on CD8+/CD8- T cells, in addition to a lower frequency of IFN-γ+ TIGIT- CD8+/CD8- T cells, suggestive of impaired T cell functionality. At single T cell transcriptome and clonal resolution, the patients show CD4+ T cell anergy, characterised by a lack of T cell activation and lymphoproliferative response. These findings suggest that PD-1 and TIGIT play a pivotal role in VL-HIV chronicity, and may be further explored for patient risk stratification. Our findings provide a strong rationale for adjunctive immunotherapy for the treatment of chronic VL-HIV patients to break the recurrent disease cycle.

Evaluation of Less Invasive Sampling Tools for the Diagnosis of Cutaneous Leishmaniasis.

Background: Diagnosis of cutaneous leishmaniasis (CL) usually relies on invasive samples, but it is unclear whether more patient-friendly tools are good alternatives for diverse lesions when used with polymerase chain reaction (PCR). Methods: Patients with suspected CL were enrolled consecutively in a prospective diagnostic accuracy study. We compared dental broach, tape disc, and microbiopsy samples with PCR as index tests, using PCR with skin slit samples as reference test. Subsequently, we constructed a composite reference test including microscopy, the 3 index tests and skin slit PCR, and we compared these same tests with the composite reference test. We assessed diagnostic accuracy parameters with 95% confidence intervals for all comparisons. Results: Among 344 included patients, 282 (82.0%) had CL diagnosed, and 62 (18.0%) CL absence, by skin slit PCR. The sensitivity and specificity by PCR were 89.0% (95% confidence interval, 84.8%-92.1%) and 58.1% (45.7%-69.5%), respectively, for dental broach, 96.1% (93.2%-97.8%) and 27.4% (17.9%-39.6%) for tape disc, and 74.8% (66.3%-81.7%) and 72.7% (51.8%-86.8%) for microbiopsy. Several reference test-negative patients were consistently positive with the index tests. Using the composite reference test, dental broach, and skin slit had similar diagnostic performance. Discussion: Dental broach seems a less invasive but similarly accurate alternative to skin slit for diagnosing CL when using PCR. Tape discs lack specificity and seem unsuitable for CL diagnosis without cutoff. Reference tests for CL are problematic, since using a single reference test is likely to miss true cases, while composite reference tests are often biased and impractical as they require multiple tests.

PCR for detection of Leishmania donovani from microscopically negative tissue smears of suspected patients in Gondar, Ethiopia.

BACKGROUND: As untreated visceral leishmaniasis (VL) is fatal, reliable diagnostics are pivotal for accurate treatment allocation. The current diagnostic algorithm for VL in Ethiopia, which is based on the rK39 rapid diagnostic test and microscopy of tissue smears, lacks sensitivity. This probably leads to missed cases and patients not receiving treatment. METHODOLOGY: We conducted a retrospective study on stored microscopically negative spleen and bone marrow smears from suspected VL patients collected at the Leishmaniasis Research and Treatment Center (LRTC) in Gondar, northern Ethiopia between June 2019 and November 2020. Sociodemographic, clinical and treatment data were collected and samples were tested by real-time PCR targeting kinetoplast DNA. PRINCIPLE FINDINGS: Among the 191 eligible samples (135 spleen and 56 bone marrow) with a microscopically negative and valid PCR result, 119 (62.3%) were positive by PCR, although Ct values for some were high (median 33.0). Approximately three quarters of these undiagnosed primary VL (77.3%) and relapse (69.6%) patients did not receive antileishmanial treatment. Of the 56 microscopically negative bone marrow samples, 46 (82.1%) were PCR positive, which is considerably higher compared to the microscopically negative spleen samples, for which 73 out of 135 (54.1%) were PCR positive. The odds of being PCR positive were significantly higher for bone marrow aspirates and higher when white blood cell values were lower and splenomegaly (in cm) was more pronounced. CONCLUSIONS: This study demonstrates that a lot of suspected VL patients remain undiagnosed and untreated. This indicates the urgent need for better diagnostics for VL in the East-African region. The outcomes of PCR positive should be closely monitored and treatment should be provided if the patient deteriorates. In resource limited settings, implementation of PCR on bone marrow aspirate smears of patients with low WBC values and splenomegaly could lead to considerable improvements in patient management.

Hematological profiles of visceral leishmaniasis patients before and after treatment of anti-leishmanial drugs at University of Gondar Hospital; Leishmania Research and Treatment Center Northwest, Ethiopia.

BACKGROUND: Visceral leshimaniasis is a parasitic disease characterized by systemic infection of phagocytic cells and an intense inflammatory response. The progression of the disease or treatment may have an effect on hematological parameters of these patients'. Thus, the current study sought to compare the hematological profiles of visceral leishmaniasis patients before and after treatment with anti-leishmaniasis drugs. METHOD: An institutional-based retrospective cohort study was conducted among visceral leishmaniasis patients admitted to the University of Gondar comprehensive specialized referral hospital leishmaniasis research and treatment centre between September 2013 and August 2018. Hematological profiles were extracted from the laboratory registration book before and after treatment. Data were entered to Epi-info and exported to SPSS for analysis. Descriptive statistics were summarized using frequency and percentage to present with the table. The mean, standard deviation, median, and interquartile range were used to present the data. Furthermore, using the paired t-test and the Wilcoxon Signed rank test, the mean difference for normally and non-normally distributed data was compared. Spearman and Pearson correlation analysis were used to describe the relationship between hematological parameters and various variables. A P value of 0.05 was considered statistically significant. RESULT: With the exception of the absolute neutrophil count, all post-treatment hematological parameters show a significant increase when compared to pre-treatment levels. Prior to treatment, the prevalence of anemia, leukopenia, and thrombocytopenia was 85.5, 83.4, and 75.8%, respectively, whereas it was 58.3, 38.2, and 19.2% following treatment. Furthermore, parasite load was found to have a statistically significant negative correlation with hematological profiles, specifically with white blood cell and red blood cell parameters. CONCLUSION: According to our findings, patients with visceral leishmaniasis had improved hematological profiles after treatment. The effect of treatment on parasite proliferation and concentration within visceral organs, in which the parasite load could directly affect the patient's hematological profiles, may be associated with the change in hematological profiles.

Case Report: Atypical Presentation of Visceral Leishmaniasis: Two Cases from Northwest Ethiopia.

Human visceral leishmaniasis (VL) is a life-threatening disease caused by protozoan parasites belonging to the Leishmania donovani complex. Atypical cases of leishmaniasis and HIV coinfection have been documented in case reports, mostly associated with gastrointestinal tract, kidney, and skin involvement. We report two VL cases with atypical localizations not reported from east Africa before, both diagnosed and treated at the Leishmaniasis Research and Treatment Center, Gondar, Ethiopia. The first case was an HIV-infected patient with scrotal and penile involvement. Leishmania parasites were detected in the spleen and the scrotum. The second case was an immunocompetent individual with esophageal, laryngeal, and pharyngeal involvement and facial lesions. Leishmania parasites were detected in the spleen, skin, and esophageal biopsies. Current evidence suggests atypical presentation can occur in patients irrespective of their HIV status. Therefore, we suggest a high index of suspicion for VL among clinicians working in endemic areas of Ethiopia.

A Ten-Year Trend of Cutaneous Leishmaniasis at University of Gondar Hospital, Northwest Ethiopia: 2009-2018.

BACKGROUND: Cutaneous leishmaniasis (CL), which is one form of leishmaniasis, may show variations over years across regions, and epidemiological studies are crucial to estimate the cases of the disease status over a long time. This study is aimed at determining the trend of CL among patients at the University of Gondar Leishmaniasis Research and Treatment Center, northwest Ethiopia between 2009 and 2018 years. METHODS: A ten-year data were extracted retrospectively. We included all patients who were visiting the center for CL diagnosis during the last ten years. Giemsa-stained skin slit microscopy was used to diagnose the disease. A chi-square test was used to compare the proportions of patients infected across years, seasons, months, sex, and age groups. RESULT: During the 10 years, a total of 1079 samples were requested for the diagnosis of CL. The cumulative average annual prevalence was found to be 55.4% (598/1079). The highest and lowest proportions of CL cases were recorded in 2014 (69.5%) and 2018 (35.4%), respectively. However, the percentage of CL cases did not show any significant differences over the study period. The number of suspected patients was significantly increased over the years (being lowest in 2009 and highest in 2017). The proportion of CL cases showed a remarkable difference across months but not seasons. CL was the highest within 15-49 years of age and males. CONCLUSION: The prevalence of CL did not show any significant differences over the last ten years. However, a remarkable increase of CL suspected cases was observed across the years. The disease showed significant association with age, sex, and months, but not seasons.

Diagnostic accuracy of direct agglutination test, rK39 ELISA and six rapid diagnostic tests among visceral leishmaniasis patients with and without HIV coinfection in Ethiopia.

Diagnosis of a first-time visceral leishmaniasis (VL) infection in Ethiopia is established by use of a rapid diagnostic test (RDT) detecting antibodies against rK39, direct agglutination test (DAT) and microscopy according to the national algorithm. The performance of individual tests and algorithm is variable and depends on several factors, one being HIV status. Limited data are available on the performance of tests in VL-HIV coinfected patients. Assessment of the performance of DAT (ITM-A), rK39 ELISA (Serion) and six RDT (Onsite Leishmania Ab CTK, Antigen ICT Xinjier, IT Leish Biorad, Kalazar Detect Inbios, rK39 IgG1 Coris, rk28 IgG1 Coris) for the diagnosis of VL was done on a panel of 91 stored serum and plasma samples of 'first-episode' suspected VL patients, with HIV coinfection (n = 51) and without (n = 40). A combined reference standard was used: either positive microscopy on tissue aspirates, or in case of negative microscopy, positive PCR results on the aspirate slide. Additionally, endemic healthy controls (n = 20), non-endemic controls (n = 10) and patients with confirmed malaria infection (n = 10) were tested for specificity evaluation. Sensitivities ranged from 69.2% for DAT (applied cut-off ≥ 1/3200) to 92.2% for the Onsite RDT, whereas specificities ranged from 20.0% for Kalazar Antigen ICT to 100% for IT Leish and rK39 IgG1. Sensitivities from all assays decreased upon stratification according to HIV status but was only significantly different for rK39 Serion ELISA (p-value 0.0084) and the Onsite RDT (p-value 0.0159). In conclusion, performance of commercially available assays for VL on samples from Northern-Ethiopian patients varied widely with a substantial decrease in sensitivity in the VL-HIV coinfected group. Clear guidelines on minimal performance criteria of individual tests and algorithms are needed, as well as which reference standard should be used to determine the performance.

Validation of in-house liquid direct agglutination test antigen: the potential diagnostic test in visceral Leishimaniasis endemic areas of Northwest Ethiopia.

BACKGROUND: Visceral leishmaniasis in Ethiopia is a re-emerging threat to public health, with increased geographical distribution and number of cases. It is a fatal disease without early diagnosis and treatment; thus, the availability of affordable diagnostic tools is crucial. However, due to delays caused by import regulations, procurement and late delivery of imported test kits, accessibility remains a problem in the control program. Therefore, we aimed to produce and evaluate the performance of an in-house liquid (AQ) direct agglutination test (DAT) antigen. RESULT: The AQ-DAT was produced at the Armauer Hansen Research Institute, using Leishmania donovani strain (MHOM/ET/67/L82). Sera from 272 participants; 110 microscopically confirmed cases of VL, 76 apparently healthy and 86 patients who had infectious disease other than VL were tested with AQ-DAT, and standard kits: Freeze-dried DAT (FD-DAT) and rK39. Taking microscopy as a gold standard; the sensitivity and specificity of the AQ-DAT were 97.3 and 98.8%, respectively. It had high degrees of agreement (k > 0.8), with a significant (P < 0.05) correlation compared to microscopy, FD-DAT, and rK39. CONCLUSION: Although further standardization is required, the in-house AQ-DAT could improve diagnostic accessibility, minimize intermittent stock outs and strengthen the national VL control program.

A multicentric evaluation of dipstick test for serodiagnosis of visceral leishmaniasis in India, Nepal, Sri Lanka, Brazil, Ethiopia and Spain.

Visceral leishmaniasis (VL) is one of the leading infectious diseases affecting developing countries. Colloidal gold-based diagnostic tests are rapid tools to detect blood/serum antibodies for VL diagnosis. Lack of uniformity in the performance of these tests in different endemic regions is a hurdle in early disease diagnosis. This study is designed to validate a serum-based dipstick test in eight centres of six countries, India, Nepal, Sri Lanka, Brazil, Ethiopia and Spain with archived and fresh sera from 1003 subjects. The dipstick detects antibodies against Leishmania donovani membrane antigens (LAg). The overall sensitivity and specificity of the test with 95% confidence intervals were found to be 97.10% and 93.44%, respectively. The test showed good sensitivity and specificity in the Indian subcontinent (>95%). In Brazil, Ethiopia, and Spain the sensitivity and specificity of the dipstick test (83.78-100% and 79.06-100%) were better as compared to the earlier reports of the performance of rK39 rapid test in these regions. Interestingly, less cross-reactivity was found with the cutaneous form of the disease in Spain, Brazil, and Sri Lanka demonstrating 91.58% specificity. This dipstick test can therefore be a useful tool for diagnosing VL from other symptomatically similar diseases and against cutaneous form of leishmaniasis.

Visceral Leishmaniasis Patients Display Altered Composition and Maturity of Neutrophils as well as Impaired Neutrophil Effector Functions.

Immunologically, active visceral leishmaniasis (VL) is characterized by profound immunosuppression, severe systemic inflammatory responses, and an impaired capacity to control parasite replication. Neutrophils are highly versatile cells, which play a crucial role in the induction as well as the resolution of inflammation, the control of pathogen replication, and the regulation of immune responses. Neutrophil functions have been investigated in human cutaneous leishmaniasis; however, their role in human VL is poorly understood. In the present study we evaluated the activation status and effector functions of neutrophils in patients with active VL and after successful anti-leishmanial treatment. Our results show that neutrophils are highly activated and have degranulated; high levels of arginase, myeloperoxidase, and elastase, all contained in neutrophils' granules, were found in the plasma of VL patients. In addition, we show that a large proportion of these cells are immature. We also analyzed effector functions of neutrophils that are essential for pathogen clearance and show that neutrophils have an impaired capacity to release neutrophil extracellular traps, produce reactive oxygen species, and phagocytose bacterial particles, but not Leishmania parasites. Our results suggest that impaired effector functions, increased activation, and immaturity of neutrophils play a key role in the pathogenesis of VL.