Vestalia Rodríguez

Central University of Venezuela, Caracas, Distrito Capital, Venezuela

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Publications (15)14.05 Total impact

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    ABSTRACT: The study was designed for evaluating immunological reactivity to various mycobacterial protein preparations using serological and cell-mediated immunological tests in patients with clinical leprosy signs, predominantly, with the multibacillary forms. All patients were adults with ages between 20 and 30 years. Fifty eight (n = 81) percent corresponded to Lepromatous Leprosy (LL), 29% (n = 41) to Borderline Lepromatous Leprosy (BL) and 10% (n = 41) to Borderline Borderline Leprosy (BB); only 3% were Borderline Tuberculoid (BT) patients: 74% males and 26% females. The most frequent reactional phenomenon was of the Erythema Nodosum (ENL) type. The mycobacterial proteins tested were: total crude Mycobacterium leprae antigens (MISA); Mycobacterium bovis (MbSA and excretion MbSA); partially purified excretion protein antigen, with a 30 kDa relative movility (Ml30); and recombinant M. leprae proteins (Mt70, Mb 65, Ml 36, 28, 18 and 10 kDa). Two of the recombinant proteins (Ml10 and Ml 36 kDa) presented a statiscally significant higher serological reactivity, directly related with a larger bacillary load (p = 0.0051 and 0.050 respectively). The 30 kDa protein was predominantly recognized by antibodies from multibacillary patients. Results show that mean antibody values were higher in non reactional patients when tested against complete proteins (MbSA and ex MbSA) when compared with the group of patients who presented reactional phenomena (p = 0.000567 and 0.000061, respectively). Comparing reactional with non reactional patients, it was seen that mean antibody values against complete proteins (MbSA and ex MbSA) were higher in non reactional individuals (p = 0.000567 and 0.000061, respectively). This same behavior occurred towards individual mycobacterial proteins (30, 10 and 36 kDa). The T lymphocyte prolypherative response in reactional and non reactional patients towards mycobacterial proteins (MlSA, Ml 10 kDa, MbSA, ex MbSA) was negative.
    Investigación clínica 09/2010; 51(3):325-40. · 0.39 Impact Factor
  • Investigación clínica 09/2010; 51(3):325-340. · 0.39 Impact Factor
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    ABSTRACT: Different experimental murine models have shown that protective immunity against Lesihmania depends upon T cells, cytokines, and antigen presenting cells. However, the role of cytokines in naturally-infected hosts like domestic dogs is controversial. Few studies have evaluated cytokines in dogs naturally-infected with Leishmania infantum/chagasi. Since the domestic dog is the main reservoir of the parasite, a study was conducted to determine cytokines in serum of 33 dogs with Canine Visceral Lesihmaniasis from endemic areas of the State of Nueva Esparta, Venezuela. Dogs were classified as symptomatic (SD) and asymptomatic (AD), according to the expression of three or more clinical signs and levels of antibodies for rK39 and rK26. Ten non-infected, rK39 negative controls were included from an endemic area (EA) and ten dogs from a non-endemic area were used as healthy controls (HC). The following cytokines (pg/mL) were measured in serum by flow cytometry (CBA Hu Th1/Th 2, BDTM kit): IFN-γ, TNF-α, IL-10, IL-6, IL-4 and IL-2. Results show a higher concentration (P<0.05) of IFN-γ (69.93±7.46), IL-4 (7.51±2.68), TNF-α (3.86±1.46), and IL-2 (39.85±3.84) in AD when compared with SD (60.8±10.6; 5.28±0.80; 2.76± 0.72; and 36.04±3.61, respectively); and HC (51±14; 4.65±0.2; 3.21±0.89, and 32.65±5.86, respectively). The AD also showed higher levels (P<0.01) of IL-6 (4.9±0.55) compared with HC (4.02±0.64). Results show that AD exhibit a higher proportion of cellular activation and proinflammatory cytokines. Results indicate that measuring of serum cytokines could reflect the immunological status in dogs in future clinical trials oriented to either vaccination or therapy.
    Revista de la Facultad de Ciencias Veterinarias. 06/2010; 51(1):43-50.
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    ABSTRACT: Different experimental murine models have shown that protective immunity against Lesihmania depends upon T cells, cytokines, and antigen presenting cells. However, the role of cytokines in naturally-infected hosts like domestic dogs is controversial. Few studies have evaluated cytokines in dogs naturally-infected with Leishmania infantum/chagasi. Since the domestic dog is the main reservoir of the parasite, a study was conducted to determine cytokines in serum of 33 dogs with Canine Visceral Lesihmaniasis from endemic areas of the State of Nueva Esparta, Venezuela. Dogs were classified as symptomatic (SD) and asymptomatic (AD), according to the expression of three or more clinical signs and levels of antibodies for rK39 and rK26. Ten non-infected, rK39 negative controls were included from an endemic area (EA) and ten dogs from a non-endemic area were used as healthy controls (HC). The following cytokines (pg/mL) were measured in serum by flow cytometry (CBA Hu Th1/Th 2, BD TM kit): IFN-g, TNF-a, IL-10, IL-6, IL-4 and IL-2. Results show a higher concentration (P<0.05) of IFN-g (69.93±7.46), IL-4 (7.51±2.68), TNF-a (3.86±1.46), and IL-2 (39.85±3.84) in AD
    Revista de la Facultad de Ciencias Veterinarias UCV Venezuela. 05/2010; 51(1):43-50.
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    ABSTRACT: Human visceral leishmaniasis is a serious public health problem in endemic countries because of its high potential lethality, particularly in children. Rapid diagnosis is essential to early treatment and control of visceral leishmaniasis. The aim was to compare three serodiagnostic tools for human visceral leishmaniasis. Three methods were compared: the rK39 dipstick (Kalazar detection test, Inbios International Inc.), ELISA rK26 and direct agglutination test (DAT) (KIT Biomedical Research). Fifty serum samples from patients positive for rK39 ELISA were compared from four endemic provinces in Venezuela: Nueva Esparta (Margarita island), Lara, Anzoátegui and Trujillo. Additional serum samples from 17 healthy volunteers and 25 patients with other diseases were included. The rK39 ELISA served as the baseline standard method. Sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratio were calculated for each test. All methods had a positive correlation with rK39 ELISA (p<0.0001). They showed high sensitivity and specificity. The direct agglutination test and the rK39 dipstick showed high sensitivity values, 89.7% (95% CI: 81.34.0-98.2%) and 94.2% (95% CI: 87.7-100%), respectively, and high specificity, 81.0% (95% CI: 80.0-99.5%) and 100%. The rK26 ELISA showed good specificity, 99% (95% CI: 95.2-100%), but a very low sensitivity, 37% (95% CI: 23.4-50.2%). Overall results indicated that DAT and rK39 dipstick have the highest specificity and sensitivity. Both are simple, cost-effective and field applicable tests. Therefore, they are recommended for early and accurate diagnosis of visceral leishmaniasis.
    Biomédica: revista del Instituto Nacional de Salud 01/2010; 30(1):39-45. · 0.32 Impact Factor
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    ABSTRACT: Visceral leishmaniasis is the most severe clinical form of leishmaniasis and is often fatal without proper treatment. Therefore, early and accurate diagnosis is important, but often difficult in endemic areas. The aim was to evaluate a direct agglutination test as a potential visceral leishmaniasis diagnostic method in endemic areas of Venezuela. The performance of the direct agglutination test, based on freeze-dried Leishmania donovani antigen was evaluated under laboratory conditions using serum samples of humans and dogs from several Venezuelan visceral leishmaniasis endemic areas: Nueva Esparta (Margarita Island), Lara, Anzoátegui and Trujillo Status. The study included confirmed visceral leishmaniasis patients (n=30), visceral leishmaniasis suspected subjects (n=4), healthy controls (n=19) and patients with other confirmed diseases (n=20). In addition, 24 serum samples from dogs with confirmed visceral leishmaniasis and 18 healthy control dogs were tested. All serum samples of visceral leishmaniasis patients, either active or recovered, were positive. They showed anti-L. donovani titers above 1:1600. Three out of four suspected visceral leishmaniasis cases were also positive, while serum samples from endemic controls and patients with other diseases had titers lower than 1:800. A sensitivity of 100% was obtained for all threshold levels under consideration and 100% specificity at the threshold titer of 1:800 (95% confidence interval: 91-100%). A 93% sensitivity (95% confidence interval: 76-99%) was observed in dog samples, with 100% specificity (95% confidence interval: 79-100%) at the threshold titer of 1:200. The direct agglutination test seems suitable for use in epidemiological studies and for serological diagnosis of human visceral leishmaniasis and canine visceral leishmaniasis.
    Biomédica: revista del Instituto Nacional de Salud 10/2007; 27(3):447-53. · 0.32 Impact Factor
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    ABSTRACT: To report recent data on the distribution of human and canine visceral leishmaniasis (VL) in Venezuela, and to highlight problems associated with effective control measures. We report the number of cases, incidence rate, age and sex distribution, and mortality rates for human VL (HVL) for the period of 1995 through 2000, based on National Registry of Leishmaniasis data. We carried out serological studies on a total of 3 025 domestic dogs from the 12 states in Venezuela reporting cases of human VL in this 1995-2000 period and also from the state of Yaracuy, where cases were reported earlier during the decade of the 1990s. From 1995 through 2000, 242 cases of HVL were reported from 12 states, in various sections of Venezuela. There was a relatively stable national incidence rate of 0.2 cases per 100 000 persons per year. Of the 242 cases, 26.0% were from Margarita Island, one of the three islands that make up the state of Nueva Esparta (Margarita Island was the only one of the Nueva Esparta islands that had HVL cases). Over the 1995-2000 period, the annual incidence rates for Nueva Esparta ranged from 1.7 to 3.8 cases per 100 000 population. Males in Venezuela were more frequently affected (59.5%) than were females (40.5%). In terms of age, 67.7% of the VL patients were </= 4 years of age, and 80.6% were younger than 15 years. The mortality rate among the persons with VL was 7.85% during the 1995-2000 period. Serological screening with rK39 antigen of 1 217 dogs from Margarita Island found a 28.5% positivity rate (testing of dogs was not done on the two other islands of Nueva Esparta). In contrast, the rate was 2.8% in the 1 808 samples from dogs from 12 states on the mainland. Human and canine VL are unevenly distributed in Venezuela. The distribution may reflect such factors as differences among the states in human population density, vector density, and the presence or absence of other trypanosomatidae. Particularly high infection rates in very young children as well as in domestic dogs occur in semiurban communities of Nueva Esparta, where other human-infecting trypanosomatidae have not been reported. Control measures related to limiting canine infection might contribute to disease control where VL infections are frequent. Reducing VL mortality requires increased awareness among medical professionals of the possibility of VL in the differential diagnosis of hepato-splenic syndromes, particularly in children.
    Revista Panamericana de Salud Pública 04/2003; 13(4):239-45. · 0.85 Impact Factor
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    ABSTRACT: Sixty-five patients were diagnosed with visceral leishmaniasis (VL) on Margarita Island in the decade from 1990 to1999; 86.2% were <= 3 years old. All were leishmanin-negative at diagnosis. Evaluation of 23 cured patients in 1999 revealed that 22/23 had converted to leishmanin-positive; five had persisting antibodies to rK39 antigen, with no clinical evidence of disease. Leishmanin tests were positive in 20.2% of 1,643 healthy individuals from 417 households in endemic areas. Of the positive reactors, 39.8% were identified in 35 (8.4%) of the households, 15 of which had an antecedent case of VL, a serologically positive dog or both. Weak serological activity to rK39 antigen was detected in 3 of 488 human sera from the endemic areas. The presence of micro-foci of intense peri-urban transmission and the apparent absence of other Trypanosomatidae causing human disease offer a unique opportunity for the study of reservoirs, alternative vectors and evaluation of control measures on the Island.
    Memórias do Instituto Oswaldo Cruz 12/2002; 97(8):1079-83. · 1.36 Impact Factor
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    ABSTRACT: The frequency of American visceral leishmaniasis affecting humans on Margarita Island, Venezuela, has increased in recent years, and infected dogs appear to constitute the principal source of infection. ELISA tests with Leishmania donovani promastigotes and rK39 antigen from L. chagasi in serum from 541 dogs were positive in 33.1% and 21.6% of the samples, respectively. A second blood sample taken from 50 animals after 8-10 months revealed an increase from 24% to 40% of ELISA positivity to both antigens, suggesting high susceptibility and transmission in the canine population. Among 42 serologically positive dogs, 33% of which showed clinical signs of disease, 79% were positive in polymerase chain reactions using primers specific for the L. donovani complex. Control measures including epidemiological hypersurveillance, the humane sacrifice of infected dogs, and rapid diagnosis and treatment of human cases have been initiated.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 01/2000; 94(5):484-7. · 1.82 Impact Factor
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    ABSTRACT: An endemic focus of American visceral leishmaniasis (AVL) in eastern Venezuela has been evaluated in terms of patients (n = 48), immunologic reactivity to Leishmania in household contacts (n = 187) and neighborhood controls (n = 170), detection of Leishmania (L. donovani complex) in dogs and wild animals by the polymerase chain reaction (PCR) and characteristics of the sandfly population. The male:female ratio of patients was 1.18:1; 89.6% were < or =12 years old. Serologic reactivity was significantly higher in household contacts than in controls (P = 0.0008), as was the size of leishmanin reactions in contacts < or =10 years of age (P = 0.0141). Leishmania donovani complex-specific PCRs were positive in dogs, an opossum (Didelphis marsupialis), and a black rat (Rattus rattus). Lutzomyia longipalpis and Lu. evansi, both implicated in the transmission of AVL, were identified among the 386 sand flies examined. These observations provide the bases for an active control program as well as further studies of reservoirs and vector-host relationships in this area.
    The American journal of tropical medicine and hygiene 12/1999; 61(6):945-50. · 2.53 Impact Factor
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    ABSTRACT: Multibacillary (MB) leprosy patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT) with BCG + heat-killed Mycobacterium leprae were tested annually for their ability to proliferate in vitro to the mycobacterial antigens BCG, M. leprae soluble extract, and intact M. leprae. IgM antibody responses to phenolic glycolipid I (PGL-I) were measured, as well as serum nitrite levels in patients' sera, before, during and after treatment. Patients who received only MDT did not present cellular reactivity to intact M. leprae antigens, in contrast to the results obtained with BCG, which elicited reactivity at time zero, that increased after treatment. Regarding PGL-I antibody variations in relation to the initial value, we observed a statistically significant marked decrease at the end of 2 years which continued to fall in successive evaluations. MB patients showed high initial serum nitrite concentrations which dropped drastically with treatment. This decay was apparently associated with the bacillary load present in these patients. The group submitted to IMT + MDT showed high and long-lasting T-cell responses to mycobacterial antigens in a significant number of initially unresponsive MB patients. There was a marked increase to M. leprae soluble extract and BCG, as well as a more variable response to whole bacilli. The antibody levels in this group of patients are sustained for a somewhat longer period and decreased more slowly during the 5-year follow up.
    International Journal of Leprosy and Other Mycobacterial Diseases 10/1997; 65(3):320-7. · 0.22 Impact Factor
  • V Rodríguez, M Centeno, M Ulrich
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    ABSTRACT: American cutaneous leishmaniasis (ACL) presents a spectrum of clinical and immunological manifestations. Since the nature of the cellular response appears to play a fundamental role in determining the characteristics of the immunoglobulin isotype of specific antibody responses, we have compared the relative levels of specific antibodies of the four IgG isotypes against Leishmania in sera from patients with different clinical manifestations of ACL. Using a specific antibody capture assay, significant levels of antibodies of the IgG1, 2 and 3 isotypes were detected in localized cutaneous leishmaniasis (LCL); the average level of IgG4 antibodies was low and they were not detected in 10/20 sera. Sera from muco-cutaneous leishmaniasis (MCL) gave a comparatively strong IgG1 response. Sera from diffuse cutaneous leishmaniasis (DCL), the rare form characterized by antigen-specific anergy of cell-mediated immunity, showed highly significant levels of IgG4 antibodies compared to antibody levels of this isotype in the other groups; IgG1 and IgG2 levels were also elevated. Based on other studies of the relationship between the IgG isotype response and cell-mediated immunity, these results confirm a Th1-like CD4+ T cell response in LCL and MCL and a significant Th2-like response in DCL.
    Parasite Immunology 08/1996; 18(7):341-5. · 2.21 Impact Factor
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    M Ulrich, V Rodriguez, M Centeno, J Convit
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    ABSTRACT: Leprosy and American cutaneous leishmaniasis are tropical diseases which present a spectrum of clinical and immunological manifestations. Lepromatous leprosy and diffuse cutaneous leishmaniasis are the severe, progressive polar forms of disease characterized by persistent T cell anergy. Relative concentrations of antibodies belonging to the four IgG isotypes have been determined in these forms of disease as well as active visceral leishmaniasis, which presents transitory T cell anergy. Leishmania-specific IgG4 antibodies predominated in 19/20 sera from patients with diffuse cutaneous leishmaniasis, and IgG1 antibodies predominated in 9/10 cases of untreated visceral leishmaniasis. The predominant IgG isotype of Mycobacterium leprae-specific antibodies in untreated lepromatous leprosy was remarkably variable (IgG1, IgG2, IgG3 and IgG4 in 8, 6, 2 and 1 sera, respectively). Differing IgG antibody isotypes have been associated with distinct CD4+ T cell helper subpopulations and their characteristic lymphokine profiles in several pathologies. These results suggest that T cell anergy in chronic intracellular infections may be associated with as yet undefined mechanisms which modulate reported T helper cell-lymphokine isotype relationships.
    Clinical & Experimental Immunology 05/1995; 100(1):54-8. · 3.41 Impact Factor
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    ABSTRACT: More than 150 leprosy patients treated with multidrug therapy (MDT) plus immunotherapy (IMT) with a mixture of heat-killed Mycobacterium leprae plus live BCG were studied in relation to humoral and cell-mediated immune responses. Many previously had received prolonged sulfone monotherapy. Patients received 2 to 10 doses of IMT in a period of 1 to 3 years, depending upon their clinical form of leprosy. The patients were followed up for 5 to 10 years with repeated determinations of antibody levels to phenolic glycolipid-I; lymphoproliferative (LTT) responses to soluble extract of M. leprae, to whole bacilli and to BCG, skin-test responses and bacterial indexes (BIs). After MDT plus IMT there was a statistically significant decrease of antibody levels in the multibacillary (MB) group. The BI decreased proportionally to the ELISA results. LTT increased to M. leprae antigens, especially to soluble extract, in a high percentage of these patients (34% of LL patients positive). Lepromin positivity in MB patients increased from 5% initially positive to 75% at the cut-off during this follow up. These results show substantial early and persistent cell-mediated reactivity to M. leprae in many MB patients treated with MDT-IMT, confirming and expanding previously published data.
    International Journal of Leprosy and Other Mycobacterial Diseases 01/1995; 62(4):552-8. · 0.22 Impact Factor
  • Marian Ulrich, Vestalia Rodriguez
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    ABSTRACT: The study of the IgG subclasses of antibo-dies across the clinical spectrum of leprosy id not reveal differences that could be related to the Th1/Th2 dichotomy; the predominance of antibodies of the IgG1, 2 and 3 subclasses suggest a possible Th1 response across the spectrum in Venezuelan patients. In contrast, the anergic form of American cutaneous leishmaniasis was characterized by a strong IgG4 specific antibody response, suggesting a Th2 response, while localized forms of the disease appeared to be associated with responses of the Th1 type. Persisting antibodies to phenolic glyco-lipid-I in a small percentage of clinically inactive multibacillary patients may reflect differences in the catabolism of this unusual antigen, since persistence was not associated with a unique initial IgG subclass response to a complex extract of Mycobacterium leprae antigens.