VL Patients Research Articles

The Phenotypic Expression of Homozygous and Compound Heterozygous Factor V R506Q (Factor V Leiden, FVL) and Factor II A20210G: Ten Years Experience At a Referral Center

Abstract 5252Heterozygous Factor V Leiden, the most common inherited thrombotic disorder with an estimated incidence of about 5% in Caucasian population, poses a moderate risk of first venous thromboembolic (VTE) event. The homozygous and compound heterozygous states are comparatively rare but are thought to be associated with high risk of recurrent VTE. This report describes ten years experience with homozygous and compound heterozygous FVL and Factor II A20210G at a major referral center in central Pennsylvania, USA. Between January 2000 and December 2010, 31 homozygous F VL patients, 2 homozygous FII A20210G, 10 compound heterozygous FVL and F II A20210G and 6 compound heterozygous F VL and protein C (PC), protein S (PS) or antithrombin (AT) deficiency were encountered. The reasons for referral were personal or family history of VTE or a first degree relative diagnosed with any of these conditions. Among these patients, 5 homozygous F VL, 1 compound heterozygous F VL and F II A20210G, and 1 compound heterozygous factor VL and PC deficiency remained free of VTE at age 17–64 years, even though they were exposed to prothrombotic conditions, e.g., surgery, hormones or pregnancy. Two compound heterozygous F VL and PS deficient patients suffered ischemic strokes, one at age 3 ½ years and the other at age 45 years, but no VTE. The other patients suffered lower extremity deep vein thrombosis and/or pulmonary embolism or visceral thrombosis. Most had recurrent events. Our experience highlights the serious thrombotic risks associated with homozygous and compound heterozygous F VL and F II A20210G status but also indicates that some patients remain thrombosis free despite exposure to additional prothrombotic conditions. However, because of referral bias this series of patients may not truly reflect the overall occurrence of VTE in patients with homozygous or compound heterozygous inherited thrombophilia. Disclosures:No relevant conflicts of interest to declare.

Studies on the arginase, 5'-nucleotidase and lysozyme activity by monocytes from visceral leishmaniasis patients.

Intracellular pathogenic protozoan infection like visceral leishmaniasis is considered in terms of the overall inflammatory response and the complex cellular interactions leading to formation of the activated macrophage. Analysis of the development of activation is facilitated when operationally defined stage of activation are characterized using a library of objective markers. There is a role of arginase in the immune response supporting its involvement in macrophage effector mechanism in vitro and in vivo. 5'-Nucleotidase a plasma membrane component has been cited as a biochemical correlate of macrophage function in an altered morphological and biochemical state of activation and stimulation. Depression in 5'-nucleotidase activity has been generally referred to as a characteristic marker of activated macrophages. Lysozyme or lysosomal enzymes are released into the endocytic or autophagic vacuole macrophage where they serve the purpose of intracellular digestion of engulfed or segregated materials. In the present study, we have studied levels of arginase and 5'-nucleotidase (marker for macrophage activation) in monocytes of active VL patients and healthy controls. Lysozyme a secretary product of macrophages was also measured in supernatants collected from monocytes of active VL patients and healthy controls. Elevated levels of 5'-nucleotidase were observed in supernatants of monocytes from active VL patients as compared to healthy controls. Low levels of arginase and lysozyme production by monocytes isolated from VL patients were observed as compared to healthy controls. Our studies suggest that low levels of arginase and elevated 5'-nucleotidase activity could be one of the mechanisms in the pathology of VL infection. Low lysozyme activity in patients may account for persistence of Leishmania parasites in VL infections.

Proteome mapping of overexpressed membrane‐enriched and cytosolic proteins in sodium antimony gluconate (SAG) resistant clinical isolate of Leishmania donovani

This study aimed to identify differentially overexpressed membrane-enriched as well as cytosolic proteins in SAG sensitive and resistant clinical strains of L. donovani isolated from VL patients which are involved in the drug resistance mechanism. The proteins in the membrane-enriched as well as cytosolic fractions of drug-sensitive as well as drug-resistant clinical isolates were separated using two-dimensional gel electrophoresis and overexpressed identified protein spots of interest were excised and analysed using MALDI-TOF/TOF. Six out of 12 overexpressed proteins were identified in the membrane-enriched fraction of the SAG resistant strain of L. donovani whereas 14 out of 18 spots were identified in the cytosolic fraction as compared with the SAG sensitive strain. The major proteins in the membrane-enriched fraction were ABC transporter, HSP-83, GPI protein transamidase, cysteine-leucine rich protein and 60S ribosomal protein L23a whereas in the cytosolic fraction proliferative cell nuclear antigen (PCNA), proteasome alpha 5 subunit, carboxypeptidase, HSP-70, enolase, fructose-1,6-bisphosphate aldolase, tubulin-beta chain have been identified. Most of these proteins have been reported as potential drug targets, except 60S ribosomal protein L23a and PCNA which have not been reported to date for their possible involvement in drug resistance against VL. This study for the first time provided a cumulative proteomic analysis of proteins overexpressed in drug resistant clinical isolates of L. donovani indicating their possible role in antimony resistance of the parasite. Identified proteins provide a vast field to be exploited for novel treatment strategies against VL such as cloning and overexpression of these targets to produce recombinant therapeutic/prophylactic proteins.

Anti- Leishmania chagasi immunoglobulin G3 detected by flow cytometry for early cure assessment in American visceral leishmaniasis

We have previously reported a novel flow cytometric based methodology to access the reactivity of seric anti-live (FC-ALPA) and fixed (FC-AFPA) L. chagasi IgG antibodies applicable for cure assessment after specific therapy of VL. Both, FC-ALPA-IgG and FC-AFPA-IgG are promising targets to be used for early cure assessment. However, our finding suggested that further refinements were still required to improve the performance of FC-AFPA IgG for early cure assessment in VL. In the present investigation, we have established and evaluated the performance of FC-AFPA-IgG1/IgG2/IgG3/IgG4 aiming to increase the performance index of the previously reported for FC-AFPA-IgG. The data was expressed as percentage of fluorescent positive parasites after incubation of pre-fixed L. chagasi promastigotes with the test sera samples and addition of second-step FITC-labeled anti-human IgG subclasses conjugates. The analysis of anti- L. chagasi IgG reactivity in polled sera samples from VL patients demonstrated that, before the etiological treatment, the IgG subclass profile was characterized by IgG1 > IgG3 with the absence of IgG2 and IgG4 at the specific sera dilution tested. Following the establishment of specific PPFP cut-off-edges to segregate negative and positive results (PPFP of 50% for FC-AFPA-IgG1 and PPFP of 40% for FC-AFPA-IgG3), the analysis of IgG1 and IgG3 reactivity demonstrated good performance for early cure assessment in VL. The analysis of individual samples indicated that despite at 2 mAT, most treated VL patients (81%) still displayed positive results in FC-AFPA-IGg1 analysis, an increased fraction of treated patients (76%) presented negative in FC-AFPA-IgG1 analysis at 6 mAT. Interestingly, the data from FC-AFPA-IgG3 demonstrated an outstanding performance of this method to early cure assessment in VL with increased frequency of treated patients displaying negative results at 2 mAT (90.5%) as well as at 6 mAT (95.2%). The analysis of likelihood ratio (LR) further confirmed the remarkable performance of FC-AFPA-IgG3 as an early complementary biomarker useful to monitor the post-therapeutic cure in human VL.

Visceral Leishmaniasis Relapse in Southern Sudan (1999–2007): A Retrospective Study of Risk Factors and Trends

BackgroundRisk factors associated with L. donovani visceral leishmaniasis (VL; kala azar) relapse are poorly characterized.MethodsWe investigated patient characteristics and drug regimens associated with VL relapse using data from Médecins Sans Frontières - Holland (MSF) treatment centres in Southern Sudan. We used MSF operational data to investigate trends in VL relapse and associated risk factors.ResultsWe obtained data for 8,800 primary VL and 621 relapse VL patients treated between 1999 and 2007. Records of previous treatment for 166 VL relapse patients (26.7%) were compared with 7,924 primary VL patients who had no record of subsequent relapse. Primary VL patients who relapsed had larger spleens on admission (Hackett grade ≥3 vs0, odds ratio (OR) for relapse = 3.62 (95% CI 1.08, 12.12)) and on discharge (Hackett grade ≥3 vs 0, OR = 5.50 (1.84, 16.49)). Age, sex, malnutrition, mobility, and complications of treatment were not associated with risk of relapse, nor was there any trend over time. Treatment with 17-day sodium stibogluconate/paromomycin (SSG/PM) combination therapy vs 30-day SSG monotherapy was associated with increased risk of relapse (OR = 2.08 (1.21, 3.58)) but reduced risk of death (OR = 0.27 (0.20, 0.37)), although these estimates are likely to be residually confounded. MSF operational data showed a crude upward trend in the proportion of VL relapse patients (annual percentage change (APC) = 11.4% (−3.4%, 28.5%)) and a downward trend in deaths (APC = −18.1% (−22.5%, −13.4%)).ConclusionsSplenomegaly and 17-day SSG/PM vs 30-day SSG were associated with increased risk of VL relapse. The crude upward trend in VL relapses in Southern Sudan may be attributable to improved access to treatment and reduced mortality due to SSG/PM combination therapy.

Proteases Secreted by the Infective Larvae of Toxocara canis and Partial Purification of a 50 kDa Protease

with subclinical leishmaniasis, and 100 seronegative healthy controls were measured by enzyme-linked immunosorbent assay. Genotyping of CD 28 gene polymorphism was performed by polymerase chain reaction based allotyping method using allele-specific primers for C or T at intron 3 position +17 in three groups. Results: The frequency of CC genotype was significantly higher in subclinical VL patients (42.4%) than active VL group (27.3%) and healthy controls (16%) (p < 0.001). Also, the frequency of allele C among subclinical VL group (57.6%) was significantly higher than active VL (40.9%) and control groups (34%) (p = 0.003). No significant differences were observed between the plasma levels of sCD 28 in three groups. Conclusion: Our findings suggest that the CD 28 gene may have significant role in the protection of active VL in the Iranian population.

Serum soluble markers in the evaluation of treatment in human visceral leishmaniasis.

Visceral leishmaniasis (VL) has a fatal course if not properly treated. Recovery from VL is linked to cellular immune response. Unresponsiveness to antimonial therapy reinforces the importance of determining parameters for treatment assessment. We analysed the pre- and post-treatment serum levels of soluble CD4 (sCD4), sCD8, sIL-2R, soluble intercellular adhesion molecule-1 (sICAM-1) and neopterin in groups of VL patients either responsive or not to standard antimonial therapy. Pretreatment serum levels of all markers except for sICAM-1 were significantly higher in VL patients than in healthy subjects from the same area (P < 0.05). sICAM-1 levels were similar in healthy controls and in VL patients refractory to antimonial therapy (P = 0.25), but significantly higher in patients responsive to treatment (P = 0.02). The comparison of pre- and post-treatment concentrations showed that all markers, except sCD4 and sICAM-1, presented a significant fall (P < 0.05) in patients responsive to antimonial therapy. However, only neopterin presented with levels compatible with those of healthy subjects at the end of treatment (P = 0.30). In refractory patients sICAM-1 presented with post-treatment levels significantly higher than the pretreatment determinations (P = 0.03), while sCD4 experienced a significant drop (P = 0.01). All markers displayed clearly distinct behaviour according to the patient's response to therapy. This makes all soluble molecules studied suitable for use as indicators of antimonial therapy response. Additionally the comparison of pretreatment levels of the markers between responders and refractory patients to antimonial therapy showed that serum concentrations of sIL-2R and sICAM-1 significantly differed among these two groups (P = 0.02 in each case), suggesting that they may be used in future as predictors of antimonial therapy response.

The significance of serum soluble IL-2 receptor as a marker for active visceral leishmaniasis in Sicilian patients.

Sera from nine Sicilian patients with confirmed visceral leishmaniasis (Leishmania donovani infantum; VL), at the moment of the diagnosis, during the course of the disease and after clinical recovery, were analysed for the concentration of soluble IL-2 receptor (sIL-2R). The results show that sIL-2R is a marker of disease activity, since it is in high concentration at the beginning of infection and returns to the normal range following successful chemotherapy. At the same time of serum analysis for sIL-2R, peripheral blood mononuclear cells (PBMC) of VL patients were stimulated with phytohaemagglutinin (PHA) or antigen and supernatant tested for IL-2 and interferon-gamma (IFN-gamma) production. Data demonstrate that there is an inverse relation between concentration of IL-2 and IFN-gamma in the supernatants and sIL-2R secretion in the sera.

Kinesin Motor Domain ofLeishmania donovanias a Future Vaccine Candidate

Visceral leishmaniasis (VL) is one of the important parasitic diseases, with approximately 350 million people at risk. Due to the nonavailability of an ideal drug, development of a safe, effective, and affordable vaccine could be a solution for control and prevention of this disease. The present study was carried out to examine the immunological potential of kinesin protein from the microtubule locus of Leishmania donovani as a suitable vaccine candidate. In silico analysis of this region revealed clusters of major histocompatibility complex class I and II binding epitopes in its motor domain region. A recombinant protein was expressed from this region and named rLvacc. The antigenicity and immunogenicity studies of this protein by Western blot analysis revealed that rLvacc is strongly recognized by sera from acute VL patients. To evaluate its immunogenicity, peripheral blood mononuclear cells from cured VL patients were separated, and a lymphocyte proliferation assay was carried out in the presence of rLvacc. After lymphocyte proliferation, the pooled culture supernatant was assayed for anti-rLvacc antibody titers using an enzyme-linked immunosorbent assay. The results showed that immunoglobulin G2 (IgG2) subtype antibodies were predominant, while IgG1 subtype antibodies were produced in very low titers. On the basis of these ex vivo preliminary findings, its immunogenicity was studied in BALB/c mice. Vaccination with the DNA construct generated a good cellular immune response with significant increases in gamma interferon and interleukin-2 (IL-2) cytokine levels (Th1), but no increase in IL-4 levels (Th2). Taken together, our findings suggest the kinesin motor domain region of L. donovani as a potential vaccine candidate against visceral leishmaniasis.

IL-10- and TGF-β-Mediated Susceptibility in Kala-azar and Post-kala-azar Dermal Leishmaniasis: The Significance of Amphotericin B in the Control of Leishmania donovani Infection in India

Visceral leishmaniasis (VL) or kala-azar is known to be associated with a mixed Th1-Th2 response, and effective host defense requires the induction of IFN-gamma and IL-12. We address the role of the differential decline of IL-10 and TGF-beta in response to sodium antimony gluconate (SAG) and amphotericin B (AmB), the therapeutic success of SAG and AmB in Indian VL, and the significance of IL-10 and TGF-beta in the development and progression of post-kazla-azar dermal leishmaniasis (PKDL). In the active disease, PBMC from VL patients showed suppressed Ag-specific lymphoproliferation, IFN-gamma and IL-12 production, and elevation of IL-10 and TGF-beta. Cure corresponded with an elevation in IFN-gamma and IL-12 production and down-regulation of IL-10 and TGF-beta. Both CD4(+) and CD8(+) T cells were involved in IFN-gamma and IL-10 production. Interestingly, the retention and maintenance of residual IL-10 and TGF-beta in some SAG-treated individuals and the elevation of IL-10 and TGF-beta in PKDL, a sequel to kala-azar, probably reflects the role of these cytokines in reactivation of the disease in the form of PKDL. Contrastingly, AmB treatment of VL resulted in negligible TGF-beta levels and absolute elimination of IL-10, reflecting the better therapeutic activity of AmB and its probable role in the recent decline in PKDL occurrences in India. Moreover, elucidation of immune responses in Indian PKDL patients revealed a spectral pattern of disease progression where disease severity could be correlated inversely with lymphoproliferation and directly with TGF-beta, IL-10, and Ab production. In addition, the enhancement of CD4(+)CD25(+) T cells in active VL, their decline at cure, and reactivation in PKDL suggest their probable immunosuppressive role in these disease forms.

English

&nbsp; One of the important immunological factors in diseases is mannose binding lectin(MBL).&nbsp;The aim of present study is to determine the distribution of the alleles of mannose-binding lectin gene codon 52, 54, 57 and promoter variants H/L, X/Y, P and Q in confirmed VL patients as an intracellular pathogen while compares with extracellular pathogens (in renal infection) and seek correlation between these variants and intracellular and extracellular infections. Fifty eight confirmed VL patients&rsquo; blood samples were compared with fifty eight blood samples of patients received renal in results of renal infections. MBL genotypes were investigated by polymerase chain reaction and restriction fragment length polymorphism.&nbsp;Frequency of defective allele B in extracellular pathogens was more than intracellular pathogens (P = 0.0001), and in contrary prevalence of wild type allele A in intracellular pathogens was more than extracellular pathogens (P = 0.0001), and in&nbsp;other alleles and variants there was not any significant difference. In conclusion, there was more prevalence of alleles with low mannose binding lectin serum level in extrallelular pathogens which can be consider as a risk factor for these infections. In other hand prevalence of high concentration alleles in intracellular pathogens indicate the role of mannose binding lectin level for susceptibility to intracellular pathogens.&nbsp; &nbsp; Key words:&nbsp;Extracellular, genotype, infection, intracellular, mannose binding lectin, pathogen.

Protective immunization against visceral leishmaniasis using Leishmania sterol 24- c-methyltransferase formulated in adjuvant

We present here the identification and characterization of Leishmania sterol 24- c-methyltransferase (SMT), as well as data on protection of mice immunized with this Ag formulated in MPL ®-SE. Serological evaluation revealed that SMT is recognized by VL patients. C57BL/6 mice immunized with this vaccine candidate plus MPL ®-SE showed Ag-specific Th1 immune responses characterized by robust production of IFN-γ upon specific Ag re-exposure in vitro. Upon challenge with L. infantum, mice immunized with SMT plus MPL ®-SE showed significant lower parasite burdens in both spleens and livers compared with non-immunized mice or mice injected with adjuvant alone. The results indicate that SMT/MPL ®-SE can be an effective vaccine candidate for use against VL.

Mannose-Binding Lectin Gene and Promoter Polymorphism in Visceral Leishmaniasis Caused by Leishmania infantum

Visceral leishmaniasis is an infectious disease caused by various species of Leishmania and Leishmania infantum is known to be associated with VL in Iran. Different factors can consider risk factors for VL that some remain unknown. The aim of present study is to determine the distribution of the alleles ofmannose-binding lectin gene codon 52, 54, 57 and promoter variants H/L, X/Y, P and Q in confirmed VL patients while compares then with normal controls and seek correlation between these variants and confirmed VL patients. Fifty eight confirmed VL patients blood samples were compared with one hundred and twenty normal controls from Azarbaijan population of Iran. MBL genotypes were investigated by polymerase chain reaction and restriction fragment length polymorphism. Allelic and genotypic frequency of the polymorphism at promoters and genes didn't show statistical differences in patients and normal controls, but frequency of alleles with high MBL concentration in VL patients was higher than controls (p = 0.03). We can conclude that normal alleles with high MBL serum level are risk factor for VL and defective alleles have protective role in VL.

Visceral leishmaniasis/human immunodeficiency virus co-infection in India: the focus of two epidemics

India contributes heavily to the global burden of visceral leishmaniasis (VL, kala-azar) and human immunodeficiency virus (HIV)/AIDS. The prevalence of HIV seropositivity in VL patients at a tertiary care centre in northern India, as observed during a prospective study over a period of 2 years, is presented. Of the 104 cases of VL/post-kala-azar dermal leishmaniasis, six (5.7 %) were found to be HIV positive, compared to 11 (5.5 %) seropositive for HIV of 198 patients with fever due to other causes. Four of the six (67 %) VL/HIV co-infected patients had a chronic/relapsing course, not responding to antileishmanial treatment. A CD4 T-cell count of < 200 mm(-3) was found in four of the five (80 %) co-infected patients in whom the test was done. Although the level of HIV/VL co-infection in the present study was lower than that of Mediterranean countries, there is a trend towards rising co-infection. The VL-endemic states of India have a huge population of migrant labourers, who work in high-HIV-prevalence states. The reported increase in the prevalence of HIV in the VL-endemic, populous states of India is a cause of grave concern, and co-infection may assume epidemic proportions in the coming decade if left unchecked.

Cloning, Characterization, and Serodiagnostic Evaluation ofLeishmania infantumTandem Repeat Proteins

Visceral leishmaniasis (VL) is a form of leishmaniasis, which is caused by infection with the protozoan parasite Leishmania, and is often fatal unless it is treated. Rapid and accurate diagnosis of VL is important for effective treatment. Here we report the cloning of previously undescribed tandem repeat (TR) proteins of Leishmania infantum and an evaluation of VL patient antibody responses to the corresponding proteins. By screening an L. infantum expression library with sera from human VL patients or infected hamsters, we identified 43 genes encoding B-cell antigens. Surprisingly, 19 of the 43 genes (44%) were TR proteins, and that percentage was significantly higher than that for genes picked randomly from the database. We then expressed the TR regions of LinJ16.1750, LinJ22.1590, and LinJ33.2870 and the entire LinJ28.2310 protein. These recombinant proteins were all recognized by Sudanese VL patient sera in an enzyme-linked immunosorbent assay. Recombinant LinJ16.1750 (rLinJ16.1750) showed the best performance among these antigens in terms of both sensitivity and specificity. Serological evaluation revealed that 97% (34 of 35) of Sudanese VL patients had significantly elevated antibody levels to rLinJ16.1750. Furthermore, when eight of the patient sera which had low reactivities to rK39 were tested with the novel recombinant antigens, some of the sera showed stronger antibody responses to these antigens than to rK39. Our results suggest that TR regions from the novel L. infantum proteins identified in this study are immunodominant B-cell epitopes and may represent good candidates for serodiagnosis of VL.

Sero-epidemiological assessment and diagnosis of visceral leishmaniasis in an endemic locality using Fast Agglutination Screening Test (FAST)

The Fast Agglutination Screening Test (FAST) was employed on sera obtained from an endemic area of visceral leishmaniasis in southwestern Ethiopia, in February 2000. The study involved (i) active case detection among 1575 residents of two villages; and (ii) passive case detection in an outpatient clinic. Sera of 1587 individuals, including 143 sera of previously treated VL patients, were tested. Based on the size of agglutination mat, the FAST results were read qualitatively as non-reactive (−), weakly reactive (1+), moderately reactive (2+) and highly reactive (3+). All FAST reactive sera were re-tested with the Direct Agglutination Test (DAT). After clinical screening of 1625 individuals, 61 individuals with signs and symptoms of early or late VL were found; 26 sera were FAST positive. Twenty-two of these suspected VL cases were subjected to parasitological examination using lymph node aspirates. Eighteen (81.8%) were confirmed either by demonstration of amastigotes in smears or promastigotes in NNN cultures. FAST reactive anti-leishmanial antibodies were detected in 4.5% of untreated and 70.6% of previously treated patients. Forty-five sera of 1390 previously untreated asymptomatic individuals (3.2%) were found to be FAST positive. This report demonstrates that FAST is a rapid and cost-effective screening test for the diagnosis and sero-epidemiological surveillance of visceral leishmaniasis.

Ethiopian visceral leishmaniasis: generic and proprietary sodium stibogluconate are equivalent; HIV co-infected patients have a poor outcome

We evaluated generic sodium stibogluconate (SSG) (International Dispensary Association, Amsterdam) versus Pentostam ® (sodium stibogluconate, GlaxoWellcome, London) under field conditions in Ethiopian patients with visceral leishmaniasis (VL; kala-azar). The 199 patients were randomly assigned to Pentostam ( n = 104) or SSG ( n = 95) in 1998/99; both drugs were given at 20 mg/kg intra-muscularly for 30 days. A clinical cure after 30-days treatment was achieved in 70·2% (Pentostam) and 81·1% (SSG). There were no significant differences between the 2 drugs for the following parameters: frequency of intercurrent events (vomiting, diarrhoea, bleeding or pneumonia) or main outcome (death during treatment and death after 6-month follow-up; relapse or post kala-azar dermal leishmaniasis at 6-months follow-up). Twenty-seven patients had confirmed co-infection with HIV. On admission, HIV co-infected VL patients were clinically indistinguishable from HIV-negative VL patients. The HIV co-infected VL patients had a higher mortality during treatment (33·3% vs 3·6%). At 6-month follow-up, HIV-positive patients had a higher relapse rate (16·7% vs 1·2%), a higher death rate during the follow-up period (14·3% vs 2·4%), and more frequent moderate or severe post kala-azar dermal leishmaniasis (27·3% vs 13·3%). Only 43·5% of the HIV-positive patients were considered cured at 6-months follow-up vs 92·1% of the HIV-negative patients. HIV-positive patients relapsing with VL could become a reservoir of antimonial-resistant Leishmania donovani.

3. Visceral leishmaniasis

From the early 1900s, visceral leishmaniasis (VL; kala-azar) has been among the most important health problems in Sudan, particularly in the main endemic area in the eastern and central regions. Several major epidemics have occurred, the most recent—in Western Upper Nile province in southern Sudan, detected in 1988 — claiming over 100000 lives. The disease spread to other areas that were previously not known to be endemic for VL. A major upsurge in the number of cases was noted in the endemic area. These events triggered renewed interest in the disease. Epidemiological and entomological studies confirmed Phlebotomus orientalis as the vector in several parts of the country, typically associated with Acacia seyal and Balanites aegyptiaca vegetation. Infection rates with Leishmania were high, but subject to seasonal variation, as were the numbers of sand flies. Parasites isolated from humans and sand flies belonged to three zymodemes (MON-18, MON-30 and MON-82), which all belong to the L. donovani sensu lato cluster. Transmission dynamics have not been elucidated fully; heavy transmission in relatively scarcely populated areas such as Dinder national park suggested zoonotic transmission whereas the large numbers of patients with post kala-azar dermal leishmaniasis (PKDL) in heavily affected villages may indicate a human reservoir and anthroponotic transmission. Clinical presentation in adults and in children did not differ significantly, except that children were more anaemic. Fever, weight loss, hepato-splenomegaly and lymphadenopathy were the most common findings. PKDL was much more common than expected (56% of patients with VL developed PKDL), but other post-VL manifestations were also found affecting the eyes (uveitis, conjunctivitis, blepharitis), nasal and/or oral mucosa. Evaluation of diagnostic methods showed that parasitological diagnosis should still be the mainstay in diagnosis, with sensitivities for lymph node, bone marrow and spleen aspirates of 58%, 70% and 96%, respectively. Simple, cheap serological tests are needed. The direct agglutination test (DAT) had a sensitivity of 72%, specificity of 94%, positive predictive value of 78% and negative predictive value of 92%. As with other serological tests, the DAT cannot distinguish between active disease, subclinical infection or past infection. The introduction of freeze-dried antigen and control sera greatly improved the practicality and accuracy of the DAT in the field. An enzyme-linked immunosorbent assay using recombinant K39 antigen had higher sensitivity than DAT (93%). The polymerase chain reaction using peripheral blood gave a sensitivity of 70–93% and was more sensitive than microscopy of lymph node or bone marrow aspirates in patients with suspected VL. The leishmanin skin test (LST) was typically negative during active VL and converted to positive in c. 80% of patients 6 months after treatment. Immunological studies showed that both Th1 and Th2 cell responses could be demonstrated in lymph nodes from VL patients as evidenced by the presence of messenger ribonucleic acid for interleukin (IL)-10, interferon γ and IL-2. Treatment of peripheral blood mononuclear cells from VL patients with IL-12 was found to drive the immune response toward a Th1 type response with the production of interferon γ, indicating a potential therapeutic role for IL-12. VL responded well to treatment with sodium stibogluconate, which is still the first line drug at a dose of 20 mg/kg intravenously or intramuscularly per day for 15–30 d. Side effects and resistance were rare. Liposomal amphotericin B was effective, with few side effects. Control measures have not been implemented. Based on observations that VL does not occur in individuals who have a positive LST, probably because of previous cutaneous leishmaniasis, a vaccine containing heat-killed L. major promastigotes is currently undergoing a phase III trial.

Treatment of antimony-unresponsive Indian visceral leishmaniasis with ultra-short courses of amphotericin-B-lipid complex

High cost is the principal drawback of treating visceral leishmaniasis (VL; kala-azar) with any of the new lipid formulations of amphotericin B. The aim of the present study was to see if the costs of treatment with such drugs could be reduced by using ultra-short courses. Amphotericin-B-lipid complex (ABLC) was given to 77 Indian patients with antimony-unresponsive VL, either as a single infusion of 5 mg/kg (Group A) or two infusions, each of 5 mg/kg, given 5 days apart (Group B) or on consecutive days (Group C). Other than the anticipated higher fever and chills, treatment was well-tolerated. On day 19 after first infusion, 72 patients were considered apparent cures: 24 (89%) of the 27 in Group A; all 24 (100%) in Group B; and 24 (92%) of the 26 patients in Group C. Six months after treatment, 19 (70%) of 27 in Group A, 19 (79%) of 24 in Group B, and 21 (81%) of 26 in Group C were healthy, relapse-free and considered definitive cures. These cure rates were not statistically different. All 18 treatment failures (five initial non-responders and 13 relapses) were cured after treatment with a 5-day course of ABLC at a higher dose (10–15 mg/kg.day).In a related analysis of hospital plus drug costs for treating antimony-unresponsive VL, short-course ABLC (1–5 days) was compared with conventional amphotericin B (0.75–1.0 mg/kg on alternate days over 30–34 days). This analysis, which included the cost of re-treatment, identified one short-course ABLC regimen with an overall estimated expense which was only modestly higher than that of amphotericin B. Together, the present results provide further support for the use of ABLC in the management of VL patients who fail antimony therapy.

Humoral and cellular immune responses to synthetic peptides of the Leishmania donovani kinetoplastid membrane protein-11.

Native kinetoplastid membrane protein-11 (KMP-11), purified from crude extracts of Leishmania donovani parasites, activates T cells from individuals who have recovered from visceral leishmaniasis. In this work we used three 38-mer peptides spanning the amino acid sequence of the L. donovani KMP-11 as solid-phase ligands in enzyme-linked immunosorbent assays (ELISAs) and as stimulating antigens in lymphoproliferative assays in order to evaluate humoral and cellular immune responses to well-defined sequences of the protein. Antibody reactivity against the three peptides was measured in plasma from 63 Sudanese visceral leishmaniasis patients (VL) and the percentage of patients with anti-KMP-11 antibodies in ELISA were 37% (KMP-11-1), 30% (KMP-11-2) and 58% (KMP-11-3). The fraction of VL patients with measurable antibody reactivity in one or more of the three ELISAs was 79%. Cross-reactivity to the KMP-11 peptides was detected in plasma from Sudanese patients suffering from Leishmania major infections and in plasma from Sudanese and Danish patients infected with Plasmodium falciparum. In lymphoproliferative assays, 10 of 17 PBMC isolates from donors previously infected with L. donovani showed a response to one or more of the three KMP-11 peptides.