Rama Prosad Goswami

Enhanced Lesional Foxp3 Expression and Peripheral Anergic Lymphocytes Indicate a Role for Regulatory T Cells in Indian Post-Kala-Azar Dermal Leishmaniasis

Indian post-kala-azar dermal leishmaniasis (PKDL) is a low-frequency (5-10%) dermal sequela of visceral leishmaniasis (VL) caused by Leishmania donovani; importantly, affected individuals are speculated to be parasite reservoirs. Insight into its immunopathogenesis could translate into rational immunomodulatory therapeutic approaches against leishmaniases. In patients with PKDL (n=21), peripheral lymphocytes were analyzed for surface markers, intracellular cytokines, and lymphoproliferative responses using flow cytometry. In lesional tissue biopsies (n=12), expression of counter-regulatory cytokines (IFN-gamma and IL-10) and the T-regulatory transcription factor forkhead box protein 3 (Foxp3) was analyzed using reverse transcriptase-PCR, along with immunohistochemical detection (n=8) of CD3 and Foxp3 positivity. In patients with PKDL, circulating CD8(+)CD28(-) and antigen-induced IL-10(+)CD3(+) lymphocytes were increased and receded with treatment. CD8(+) lymphocytes showed impaired proliferative responses to L. donovani antigen (LDA) and phytohemagglutinin, which were reinstated after treatment. At presentation, the upregulated lesional IFN-gamma and IL-10 messenger RNA (mRNA), Foxp3 mRNA, and protein were curtailed after treatment. In Indian patients with PKDL, increased frequency of the CD8(+)CD28(-) phenotype, enhanced antigen-specific IL-10 production, and accompanying anergy of circulating lymphocytes suggest their regulatory nature. Furthermore, the concomitantly elevated lesional expression of Foxp3 suggests their possible recruitment into the lesional site, which would sustain disease pathology.

Monitoring of intracellular nitric oxide in leishmaniasis: Its applicability in patients with visceral leishmaniasis

Nitric oxide (NO) has been demonstrated to be a principal effector molecule responsible for mediating intracellular killing of Leishmania parasites, the causative organism of leishmaniasis. As measurement of intracellular NO remains a challenge to biologists, we have developed a flow cytometric approach to perform real time biological detection of NO within Leishmania parasites and parasitized macrophages using a membrane permeable derivative of diaminofluorescein [4,5‐diaminofluorescein diacetate (DAF‐2DA)]. Initially, assay optimization was performed in Leishmania donovani promastigotes, assay specificity being confirmed using both a NO donor [S‐nitroso‐N‐acetyl‐penicillamine (SNAP)] and a NO scavenger [2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, C‐PTIO]. Using 40 μM DAF‐2DA, basal levels of intracellular NO were measured which varied in different Leishmania species; addition of conventional anti‐leishmanial drugs, antimony and miltefosine translated into a dramatic increase in DAF‐2T fluorescence. Furthermore, the assay also measured levels of NO in macrophages, but needed a 20 fold lower concentration of DAF‐2DA, being 2 μM. Following parasitization, levels of NO decreased which was normalized following treatment with anti‐leishmanial drugs. Similarly monocytes of patients with visceral leishmaniasis at disease presentation showed decreased levels of NO which too reverted on completion of treatment. Taken together, this study opens new perspectives of research regarding monocyte function and provides a real time approach for monitoring the effect of anti‐leishmanial compounds.

Histoplasmosis in eastern India: The tip of the iceberg?

Systemic histoplasmosis has various clinical presentations and is of especially concern in immunocompromised patients. A high index of suspicion is required for its diagnosis. A total of 38 cases had been reported from India up to 1996. The most frequent occurrence of cases was around Calcutta in eastern India where the previous case was detected 20 years earlier. However, we have diagnosed 5 cases in the past 2 years from eastern India which are reported here. These cases may indicate under-diagnosis and under-reporting of histoplasmosis in India. All 5 patients had disseminated disease with multisystem involvement including 2 with bilateral adrenal enlargement. Two were diabetic and only 1 patient was infected with HIV.

Predictors of mortality in leptospirosis: an observational study from two hospitals in Kolkata, eastern India

BACKGROUND Leptospirosis has a mortality rate of 5-20%. Poor prognostic factors are older age; oliguria; elevated potassium, creatinine and/or bilirubin levels; and altered mental status. We conducted this retrospective study to analyse the predictors of mortality among Indian patients with leptospirosis. METHODS Clinical, biochemical, demographic and treatment related data (time between onset of symptoms and commencement of leptospira specific antibiotics) of 101 leptospirosis patients were reviewed. Predictors identified by univariate analysis were analysed by multivariable Cox regression for survival analysis. RESULTS Prominent clinical features were: fever (101/101, 100%), jaundice (62, 62.4%), vomiting (42, 41.6%), oliguria (35, 34.7%), cough (18, 17.8%) and dyspnoea (10, 10.0%). Common complications were acute kidney injury (22, 21.8%), cardiovascular collapse (13, 12.9%), haemorrhages (10, 10.0%), meningitis (7, 6.9%), acute respiratory distress syndrome and pancreatitis (5, 5.0% each). Seventeen patients died (16.8%). Univariate predictors of mortality were older age, delayed antibiotic therapy, higher bilirubin, aspartate aminotransferase, alkaline phosphatase, leucocyte count and aspartate/alanine aminotransferase ratio (AAR). Only AAR (HR 1.208, 95% CI 1.051-1.388) and number of days the patient was symptomatic before access to specific antibiotic therapy (HR 1.304, 95% CI 1.081-1.574) remained significant predictors after Cox regression. CONCLUSIONS Multivariate analysis showed high AAR and delayed antibiotic therapy might be associated with fatality.

Induction of IL-10 and TGFβ from CD4+CD25+FoxP3+ T Cells Correlates with Parasite Load in Indian Kala-azar Patients Infected with Leishmania donovani.

Background Visceral leishmaniasis (VL) is distinguished by a complex interplay of immune response and parasite multiplication inside host cells. However, the direct association between different immunological correlates and parasite numbers remains largely unknown. Methodology/Principal Findings We examined the plasma levels of different disease promoting/protective as well as Th17 cytokines and found IL-10, TGFβ and IL-17 to be significantly correlated with parasite load in VL patients (r = 0.52, 0.53 and 0.51 for IL-10, TGFβ and IL-17, respectively). We then extended our investigation to a more antigen-specific response and found leishmanial antigen stimulated levels of both IL-10 and TGFβ to be significantly associated with parasite load (r = 0.71 and 0.72 for IL-10 and TGFβ respectively). In addition to cytokines we also looked for different cellular subtypes that could contribute to cytokine secretion and parasite persistence. Our observations manifested an association between different Treg cell markers and disease progression as absolute numbers of CD4+CD25+ (r = 0.55), CD4+CD25hi (r = 0.61) as well as percentages of CD4+CD25+FoxP3+ T cells (r = 0.68) all correlated with parasite load. Encouraged by these results, we investigated a link between these immunological components and interestingly found both CD4+CD25+ and CD4+CD25+FoxP3+ Treg cells to secrete significantly (p<0.05) higher amounts of not only IL-10 but also TGFβ in comparison to corresponding CD25- T cells. Conclusions/Significance Our findings shed some light on source(s) of TGFβ and suggest an association between these disease promoting cytokines and Treg cells with parasite load during active disease. Moreover, the direct evidence of CD4+CD25+FoxP3+ Treg cells as a source of IL-10 and TGFβ during active VL could open new avenues for immunotherapy towards cure of this potentially fatal disease.

Short-Course Treatment Regimen of Indian Visceral Leishmaniasis with an Indian Liposomal Amphotericin B Preparation (Fungisome™)

India bears the burden of about half of global visceral leishmaniasis (VL) cases with emerging problems of stibanate resistance. Liposomal preparations have improved treatment outcome through shorter duration of therapy and lower toxicity compared with conventional amphotericin B. We report the efficacy of two short-course regimens of an Indian preparation of liposomal amphotericin B (Fungisome™) for VL caused by Leishmania donovani in India. An open-label, randomized, single-center comparative study was undertaken from 2008 to 2011, involving 120 treatment naive non-human immunodeficiency virus VL patients randomly allocated to two groups. Fungisome™ was given, in groups A (N = 60), 5 mg/kg daily for 2 days and B (N = 60), 7.5 mg/kg daily for 2 days, as intravenous infusion. Initial cure rate was 100% in both the groups after 1 month posttreatment. At 6 months after completion of treatment, definitive cure rate was group A 90% (54/60, 95% confidence interval (CI): 80.55-95.72%); group B: 100% (95% CI: 95.92-100%); (P = 0.027). No serious adverse events occurred in either group. The short-course, 2-day regimen of 15 mg/kg Fungisome™ infusion is easy to administer, effective, and safe for treatment of VL caused by L. donovani in India.

Easy Test for Visceral Leishmaniasis and Post–Kala-azar Dermal Leishmaniasis

To the Editor: Diagnosis of visceral leishmaniasis (VL), fatal if untreated, is complex because the symptoms are the same for many fever-associated ailments. Despite limitations, diagnosis remains based on finding Leishmania amastigotes in spleen and/or bone marrow aspirates (1). Sophisticated laboratory methods, although sensitive, are costly. The immunochromatographic strip test that uses recombinant K39 antigen (rK39), although satisfactory in India, is less sensitive in Africa, Latin America, and Mediterranean regions (2). Post–kala-azar dermal leishmaniasis (PKDL), a sequel to VL in India and Africa, is often confused with other skin diseases (3,4). Diagnosis of VL in dogs in Latin America and Mediterranean countries remains confusing because of rampant asymptomatic infections and elevated antibodies against Leishmania spp (5). Earlier we reported the diagnostic potential of L. donovani (MHOM/IN/83/AG83) promastigote membrane antigens (LAg) (3,6). Here we report applicability of LAg-based ELISA and dipstick systems even at primary health centers. Using randomized sampling, we tested samples from 122 kala-azar patients from India, 20 PKDL patients from India, and 40 VL patients from Brazil. VL was confirmed by finding parasites in aspirates. Serum samples were collected before chemotherapy was given. PKDL was diagnosed as described (3). Control samples were collected from 24 healthy persons from non–disease-endemic areas in India; 15 healthy persons from disease-endemic areas in India; 20 healthy persons from disease-endemic areas in Brazil; and 21 persons with Hansen disease, 7 with filariasis, 4 with tuberculosis, 1 with lymphoma, 1 with leukemia, 2 with virus-induced fever, and 5 with malaria. Consent was obtained from all human donors. This study was approved by Ethical Committee on Human Subjects at Indian Institute of Chemical Biology and the Ethical Board for Human Subjects and Animal Experimentation of the Federal University of Piaui. We developed a diagnostic ELISA with modifications of our previous method (6). Microtiter plates were coated with 2.5 μg LAg at pH 7.5 (100 μL/well) and kept at 4°C overnight, after which they were blocked with 1% bovine serum albumin, dried, and stored at 4°C as precoated plates. The assay performed at room temperature took ≈2.5 h. Test and control serum samples (1:1,000 dilution, 100 μL/well) were applied to the plates for 45 min and shaken occasionally. Horseradish peroxidase–conjugated goat anti-human immunoglobulin (Ig) G (Genei, Bangalore, India) was applied at 1:5,000 (100 μL/well) for 45 min. Color development with ortho-phenylenediamine (Sigma-Aldrich, St. Louis, MO, USA) was allowed for 5–10 min. Positive results were determined by comparing colors with those on a card previously prepared for positive and negative wells. ELISA, performed for the VL and PKDL patients from India, was 100% sensitive (percentage of patients with confirmed disease and positive test results) and 96.3% specific (percentage of negative controls with negative test results) (Figure, panel A); sensitivity and specificity were higher than that reported earlier (6) and by other studies that used crude leishmanial antigens (2). One sample from each of filariasis, lymphoma, and disease-endemic area controls was marginally false positive. Seropositivity was diagnosed for 1 patient who had a negative spleen aspirate but clinical signs of VL and for 1 patient who refused spleen or bone marrow aspiration. Figure Representative results of ELISA and dipstick testing. A) Samples underwent ELISA in duplicate. Upper panel, positive samples in duplicate (1–2 and 3–4) in wells A–H, except A1–A2 (blank), and G3–G4 and H3–H4 ... To avoid any visible cross-reaction in the dipstick assay, we optimized LAg concentration, test serum dilution, and control serum dilution. Optimum concentration for human studies is 500 μg/mL LAg, 1:2,000 serum dilutions, 1:2,000 horseradish peroxidase–conjugated goat anti-human IgG, and 15 mg 3,3′-diaminobenzidine (Sigma-Aldrich) as substrate in 30 mL Tris-buffered saline. LAg was bound to a long nitrocellulose piece at the test line (line on which LAg is coated). Goat anti-human IgG (Genei) at 1:25 was coated as an internal control line. Free sites were blocked with 2% bovine serum albumin containing 0.01% NaN3 and were air dried. LAg-coated membranes were affixed to the end of a plastic support (with a free end as handle) with double-adhesive tape, cut into 4-mm–wide sticks, and stored at room temperature. During the testing process at room temperature, dipsticks were incubated in diluted serum for 30 min, washed 2×, incubated for 30 min with secondary antibody, washed 3×, and incubated in substrate solution for 1 min. Finally, dipsticks were washed in water, dried on tissue paper, and examined for specific reaction. When stored at room temperature without desiccation, dipsticks performed consistently for 12 months. Dipsticks appeared equally sensitive and specific (100%) for VL from India and Brazil and for PKDL. Because internal control lines remained positive, analyses were considered valid (Figure, panel B). LAg dipsticks are more sensitive for diagnosing VL in Brazil than rK39 (7) and cost ≈70× less (8). Although further validation with a larger sample size and healthy controls from disease-endemic areas and controls for other diseases is warranted, these easy, simple, and low-cost methods could emerge as efficient tools for diagnosis of VL and PKDL.

Noninvasive Diagnosis of Visceral Leishmaniasis: Development and Evaluation of Two Urine-Based Immunoassays for Detection of Leishmania donovani Infection in India.

Background Visceral Leishmaniasis (VL), a severe parasitic disease, could be fatal if diagnosis and treatment is delayed. Post kala-azar dermal leishmaniasis (PKDL), a skin related outcome, is a potential reservoir for the spread of VL. Diagnostic tests available for VL such as tissue aspiration are invasive and painful although they are capable of evaluating the treatment response. Serological tests although less invasive than tissue aspiration are incompetent to assess cure. Parasitological examination of slit-skin smear along with the clinical symptoms is routinely used for diagnosis of PKDL. Therefore, a noninvasive test with acceptable sensitivity and competency, additionally, to decide cure would be an asset in disease management and control. Methodology/principal findings We describe here, the development of antibody-capture ELISA and field adaptable dipstick test as noninvasive diagnostic tools for VL and PKDL and as a test of cure in VL treatment. Sensitivity and specificity of urine-ELISA were 97.94% (95/97) and 100% (75/75) respectively, for VL. Importantly, dipstick test demonstrated 100% sensitivity (97/97) and specificity (75/75) in VL diagnosis. Degree of agreement of the two methods with tissue aspiration was 98.83% (κ = 0.97) and 100% (κ = 1), for ELISA and dipstick test, respectively. Both the tests had 100% positivity for PKDL (14/14) cases. ELISA and dipstick test illustrated treatment efficacy in about 90% (16/18) VL cases when eventually turned negative after six months of treatment. Conclusions/significance ELISA and dipstick test found immensely effective for diagnosis of VL and PKDL through urine samples thus, may substitute the existing invasive diagnostics. Utility of these tests as indirect methods of monitoring parasite clearance can define infected versus cured. Urine-based dipstick test is simple, sensitive and above all noninvasive method that may help not only in active VL case detection but also to ascertain treatment response. It can therefore, be deployed widely for interventions in disease management of VL particularly in poor resource outskirts.

Alternative treatment approach to cerebral toxoplasmosis in HIV/AIDS: experience from a resource-poor setting

The current standard treatment for cerebral toxoplasmosis (pyrimethamine/sulfadiazine) often encounters problems of poor tolerability, adverse effects, frequent dropouts and non-availability of pyrimethamine/sulfadiazine in some parts of India. We have had to use the combination of two effective alternative agents for toxoplasmosis, cotrimoxazole and clindamycin, on compassionate grounds. This retrospective observational study reports superior efficacy and better tolerability of cotrimoxazole/clindamycin compared to the recommended regimen. Primary end-point (complete response) was defined as more than 50% improvement of clinical status or more than 50% decrease in the size of brain lesions after two weeks of treatment initiation. Complete response occurred more commonly with cotrimoxazole/clindamycin than with pyrimethamine/sulfadiazine group (80% vs. 31.25%, respectively, relative risk 2.56, 95% confidence interval: 1.21–5.43). There was a trend towards higher on-treatment mortality in the pyrimethamine/sulfadiazine group in comparison to the cotrimoxazole/clindamycin (mortality rate 37.5% in pyrimethamine/sulfadiazine vs 12% in cotrimoxazole/clindamycin, p = 0.07, relative risk = 3.125, 95% confidence interval: 0.91–10.75). Overall, 62.5% (10/16) of patients on pyrimethamine/sulfadiazine suffered drug-related adverse reactions compared to 24% (6/25) on cotrimoxazole/clindamycin (p = 0.02, relative risk = 2.60, 95% confidence interval: 1.17–5.76). The commonest complication of pyrimethamine/sulfadiazine was severe thrombocytopenia with major bleeding (4/16, 25%). We propose that the new combination chemotherapy, which is widely available, effective and safe, can be used in developing countries.

Immunoproteomic Identification and Characterization of Leishmania Membrane Proteins as Non-Invasive Diagnostic Candidates for Clinical Visceral Leishmaniasis

Visceral leishmaniasis (VL), a potentially fatal disease is an outcome of infection caused by the parasite Leishmania donovani. The clinical diagnostic tests for this disease are still related to invasive tissue aspiration or serological immunochromatography. Advancements in immunoproteomics such as two-dimensional gel electrophoresis, mass spectrometry, B cell epitope prediction, and peptide synthesis have enabled researchers to discover newer biomarkers for disease diagnosis. In this study, we have screened several urine-reactive leishmanial membrane proteins as potential biomarker candidates. In the immunoblot assay, three proteins 51, 55 and 63 kDa showed 100% reactivity to the urine of 47 VL patients and nonreactive to 18 healthy and other diseases. Mass spectrometry revealed the identity of 51, 55 and 63 kDa proteins as elongation factor 1α (EF1-α), α-tubulin, and glycoprotein 63, respectively. B cell reactive epitopes of these proteins were mapped through bioinformatic tools and one epitope from each protein that had the highest score were synthesized. All the three native electroeluted proteins and their corresponding synthetic peptides were tested through ELISA for reactivity with VL and control urine samples. While all three demonstrated good reactivity, the diagnostic performance of EF1-α was the best. Our findings illustrate the use of urine-based proteomic approach for biomarker discovery in non-invasive clinical diagnosis of VL.