Mycobacterium indicus pranii vaccine immunoprophylaxis in anti-phenolic glycolipid-1-positive leprosy contacts – A pilot study from a tertiary care center in North India

Background: Contacts of leprosy patients have an increased risk of infection with Mycobacterium leprae. Contact tracing and chemo- or immunoprophylaxis are important means of preventing leprosy transmission. Aims: We aimed to evaluate the efficacy of immunoprophylaxis with Mycobacterium indicus pranii vaccine in reducing anti-phenolic glycolipid-1 titers in household contacts of leprosy patients. Methods: This prospective single-center study was conducted in a tertiary care center in North India from January 2015 to December 2016. Contacts of leprosy patients (both paucibacillary and multibacillary) were screened for anti-phenolic glycolipid-1 antibodies with enzyme-linked immunosorbent assay. Those found positive were given immunoprophylaxis with a single dose of Mycobacterium indicus pranii vaccine, and anti-phenolic glycolipid-1 titers were evaluated at six and 12 months. All contacts were clinically followed for three years. Results: Of the 135 contacts of 98 leprosy patients that were screened, 128 were recruited. Seventeen of these contacts were positive for anti-phenolic glycolipid-1 antibodies and were given Mycobacterium indicus pranii vaccine. Two contacts were lost to follow-up. After immunoprophylaxis, anti-phenolic glycolipid-1 titers were negative in all patients at all intervals, and no contact developed any clinical signs or symptoms of leprosy during the three-year follow-up. Limitations: The small number of contacts studied, the short follow-up period and the absence of a control group were limitations of this study. Dicussion: We could not find any papers on natural decline of PGL 1 titres in contacts, although in leprosy patients, these titres may even increase after completion of treatment. However the titres do correlate with bacterial load (reference: Int J Lepr Other Mycobact Dis. 1998 Sep;66(3):356-64) so if the tires decrease or become negative it may be considered as an indirect evidence of bacillary clearance. Hence we may suggest the protective efficacy. Furthermore, as the editor mentioned, considering the small number of positive patients, a control group was not possible in the present pilot study, but such studies may be carried out in the future. Conclusion: Immunoprophylaxis with Mycobacterium indicus pranii vaccine is effective and safe in preventing disease in contacts of leprosy patients. However, these findings need to be replicated in larger studies.

Diagnóstico de lepra en niños mediante seguimiento serológico de anticuerpos contra el glicolípido fenólico I / Leprosy diagnosis in children by antibodies serologic follow up against the phenolic glycolipid I

Introducción: Los niños contactos de pacientes con lepra se consideran las personas con mayores posibilidades de desarrollar la enfermedad. Objetivo: Valorar la utilidad del seguimiento serológico de anticuerpos contra el glicolípido fenólico I para el diagnóstico de lepra en niños. Métodos: Investigación prospectiva. Se incluyeron todos los niños contactos de pacientes diagnosticados con lepra en las provincias de La Habana, Santiago de Cuba y Guantánamo entre enero 2013-junio 2015. Los menores se evaluaron clínicamente mediante examen dermatoneurológico y se determinó la presencia de anticuerpos contra el glicolípido fenólico I de Mycobacterium leprae para el estudio serológico. Los niños con serología positiva se siguieron, con estos dos métodos, cada seis meses durante dos años. La confirmación de un caso nuevo de lepra se realizó mediante baciloscopía y biología molecular. Resultados: Se estudiaron 151 niños, de ellos 44 (29,13 por ciento) resultaron positivos al glicolípido fenólico I. Se diagnosticaron durante el período 12 casos, de los cuales 11 tuvieron serología positiva. Presentaron sospecha clínica 10 niños de los estudiados, solo se confirmó un caso nuevo, el cual tuvo serología negativa. En ocho de los niños diagnosticados se detectó presencia de bacilos ácido alcohol resistente en la lámina de baciloscopía. En los restantes cuatro niños el diagnóstico se confirmó por la reacción en cadena de la polimerasa. Conclusiones: Los resultados de esta investigación denotan la utilidad del seguimiento serológico de anticuerpos contra el glicolípido fenólico I en el diagnóstico de lepra en niños, en apoyo a la vigilancia clínica(AU)

Introduction: Children having contact with leprosy patients are considered the contacts with greater possibilities of developing the disease. Objective: To assess the usefulness of antibodies´ serologic follow up against the phenolic glycolipid I (PGL-1) for the diagnosis of leprosy in children. Methods: Prospective study in which were included all children contacts of patients diagnosed with leprosy in Havana, Santiago de Cuba and Guantanamo provinces between January 2013 and June 2015. They were evaluated clinically by the dermato-neurological examination and the presence of antibodies against the PGL-1 of M. leprae was determined. Children with positive serology were followed up using these same two methods every six months for two years. The confirmation of a new case of leprosy was made by smear microscopy and molecular biology / PCR-Rlep. Results: A total of 151 children were studied. Of these, 44 children (29.13 percent) were positive for phenolic glycolipid I. A total of 12 children were diagnosed during this period, of which 11 had positive serology. Only 10 children of the studied ones presented clinical suspicion and of these only one new case was confirmed, which had negative serology. In eight of the diagnosed children, the presence of acid-fast bacilli was detected in the smear microscopy. In the remaining four children, the diagnosis was confirmed by the PCR result. Conclusion: The results of this investigation show the usefulness of the antibodies´ serologic follow up against the phenolic glycolipid I in the diagnosis of leprosy in children as a support to clinical surveillance(AU)

Salivary anti-PGL-1 IgM may indicate active transmission of Mycobacterium leprae among young people under 16 years of age

Abstract Considering that the main route of Mycobacterium leprae transmission is the upper respiratory tract, detection of salivary antibodies can be a useful tool for diagnosing early infection. The study aimed to analyze salivary anti-PGL-1 IgA and IgM antibodies in 169 children aged 4-16 years old, who lived nearby or inside the house of multibacillary or paucibacillary leprosy patients in two endemic cities in Alagoas State - Brazil. Salivary anti-PGL-1 antibodies were quantified by modified ELISA method. The frequency of contact and clinical form of the index case were significantly associated with salivary antibody levels. High frequency of IgM positivity strongly suggests active transmission of M. leprae in these communities. We suggest in the present work that salivary anti-PGL IgA and IgM are important biomarkers to be used for identifying communities with probable active transmission of M. leprae.

Zinc supplementation could modulate T cell to maintain interleukin-2 level in seropositive contact of leprosy patients.

Background: WHO classified the number of leprosy cases in Indonesia as number three in the world after India and Brazil. The number of new leprosy patients tends to increase since there is a possibility that seropositive leprosy is turning into manifest leprosy. The aim of this study was to analyze the influence of zinc supplementation on interleukin-2 (IL-2) level of seropositive contact of leprosy patients with marginal zinc deficiency. Methods: Twenty two subjects aged 20-40 years were recruited for this study. The zinc-supplemented group received 40 mg elemental Zn/d orally for 3 months. Seropositive leprosy was determined by examining IgM anti Phenolic Glycolipid–1 level and concentration of IL-2 in lymphocyte cell culture supernatant fluid were measured by Elisa method. Results: The IL-2 concentration in the subject in the zinc group was relatively not changed (p= 0.721), whereas that in placebo group tended to be significantly lower (p= 0.025) at the end of the study. Conclusion: There was a significant change of IL-2 level between both groups (p= 0.037).

Enzyme-linked immunosorbent assay of phenolic glycolipid-I in patients with Hansen’s disease / Inmunoensayo ligado a enzimas (ELISA) a glicolípido fenólico -1 en pacientes con enfermedad de Hansen

Introduction: Hansen’s disease or leprosy is a contagious-infection entity produced by the Hansen bacillus or Mycobacterium leprae. The phenolic glycolipid is a special trisaccharide found in the bacillus cell wall and proved to be specific and immunogenic species during M. leprae.Objective: To determine the presence of the Hansen bacillus enzyme-linked immunoassay (ELISA) method glycolipid phenolic I in a group of patients in Dermatology Consultation at the Valle del Cauca Health Services; these patients were classified as cures or under watch according to criteria established by the World Health Organization (WHO).Methodology: From the data base of the Dermatology Consultation at the Valle del Cauca Health Services, we studied 159 patients with Hansen’s disease who were tested with the enzyme-linked immunoassay (ELISA) with the phenolic glycolipid I to cross reference information and observe if they were or were not positive to this test. A positive ELISA indicates the bacillus is still present in the patient.Results: As an important fact, we found that of 78 patients cured, when bearing in mind the monitoring period, 9 were positive for the ELISA. When this period was discarded, 81 sick individuals were classified as cured according to WHO criteria but the same 9 continued positive for ELISA.Conclusion: It may be concluded that in spite of meeting WHO criteria, these patients still show presence of the bacillus and the monitoring period is not required as a criterion to discharge a patient. We recommend adding to WHO criteria a negative ELISA, to obtain additional information that helps to certify that a patient is or is not cured.

Introducción: La enfermedad de Hansen o lepra es una entidad infecto-contagiosa producida por el bacilo de Hansen o Mycobacterium leprae. El glicolípido fenólico I es un trisacárido especial que se encuentra en la pared celular del bacilo y ha demostrado ser específico de especie e inmunogénico durante la infección de M. leprae.Objetivo: Determinar la presencia del bacilo de Hansen por el método de inmunoensayo ligado a enzimas (ELISA) a glicolípido fenólico I en un grupo de pacientes del Consultorio Dermatológico del Servicio de Salud del Valle del Cauca clasificados como curados o en vigilancia, según criterios preestablecidos por la Organización Mundial de la Salud (OMS).Metodología: De la base de datos del Consultorio Dermatológico del Servicio de Salud del Valle del Cauca se estudiaron en total 159 pacientes con enfermedad de Hansen a los cuales se les practicó examen de inmunoensayo ligado con enzimas (ELISA) con el glicolípido fenólico I a fin de cruzar información y observar si eran o no positivos a esta prueba. El ELISA positivo dice que el bacilo aún existe en el paciente.Resultados: Se encontró como dato importante que de 78 pacientes curados, al tener en cuenta además el período de vigilancia, 9 fueron positivos para el ELISA. Cuando se descartó este período, a 81 enfermos se les clasificó como curados según criterios de la OMS pero siguieron positivos para ELISA los mismos 9.Conclusión: Se concluye que a pesar de cumplir los criterios de la OMS, estos pacientes aún muestran presencia de bacilo y que el período de vigilancia no se necesita como criterio para dar de alta a un paciente. Se recomienda agregar a los criterios de la OMS el ELISA negativo, con el fin de tener una información más que ayude a certificar que un paciente está curado o no.

Evaluation of an Immunochromatography Assay Kit for the Detection of Antibodies to the Mycobacterium leprae-specific Phenolic Glycolipid-I Antigen / 나학회지

Among the many reported applications of the detection of antibodies to phenolic glycolipid-I (PGL-I) of Mycobacterium leprae, the use of seroprevalence as an indicator of the magnitude of the leprosy problem may turn out to be very useful in leprosy control programs. In order to facilitate the use of PGL-I based serology in leprosy control programs, however, a simple test system for the detection of antibodies to PGL-I has been required. For being searched the meaning of qualitative analysis for PGL-I antibodies, we examined enzyme-linked immunosorbent assay and immunochromatographic assay kit using PGL-I neoglycoconjugate antigens. The sensitivity was 91.7%, and the specificity was 78.1%.

Comparison of DNA fragment patterns between the phenolic glycolipid-Tb producers and non-producers of Mycobacterium tuberculosis

Differences in ability to produce the specific phenolic glycolipid-Tb (PGL-Tb) antigen among Mycobacterium tuberculosis strains have been reported. One of the explanations would be the genotypic variation between the strains. In this study, we compared the DNA fragment patterns after digestion of DNA with various restriction enzymes between the PGL-Tb producing and non-producing strains of M. tuberculosis. Three clinical isolates of M. tuberculosis producing the PGL-Tb antigen detectable by thin-layer chromatography, and M. tuberculosis H37Rv and M. bovis BCG not producing the antigen were grown in Sauton medium. The chromosomal DNA was digested with the restriction endonucleases, Eco RI, Sau3A I, BamH I, Xho I, Sma I, Pst I, Hinc II, and Bst EII. Most of the restriction enzymes used gave no clear DNA bands or no DNA fragment common just to the PGL-Tb producing strains. When DNAs were digested with Bst EII, however, there was a 13 kb DNA fragment common to the PGL-Tb producing isolates of M. tuberculosis and not present in the H37Rv strain and M. bovis BCG. This study thus suggests that there might be differences in DNA fragment patterns between the PLG-Tb producing and non-producing strains of M. tuberculosis.

Detection of Phenolic Glycolipid I of Mycobacterium leprae and Antibodies to the Antigen in Sera from Leprosy Patients and Their Contacts

Serum specimens from leprosy patients, their contacts and controls were examined for the presence of phenolic glycolipid I (PGL-I), a Mycobacterium leprae specific antigen, and antibodies to the antigen using enzyme-linked immunosorbent assays. Of 12 lepromatous patients with less than 2 years of therapy, 11(91.7%) were seropositive to PGL-l, thus indicating that new lepromatous cases can be identified by detecting anti-PGL-l antibodies. In contrast 88(56.4%) of 156 lepromatous patiens treated more than 2 years were positve. Moreover, only 69(40.8%) were seropositve among 169 lepromatous patients in the leprosy resettlement villages. The mean antibody level also declined significantly in proportion to the duration of chemotherapy. This may suggest the possibility of monitoring chemotherapy by detecting anti-PGL-l antibodies. The prevalence of anti-PGL-l antibodies among 200 controls from a high endemic area for leprosy was 5.5% and was significantly higher than that(1.5%) among 200 controls from a low endemic area. Of 103 household contacts in the resettlement villages, 10(9.7%) were seropositive, reflecting the frequent chance of exposure to M. leprae. However, PGL-l was not detected many in any of the sera from controls, contacts, and inactive lepromatous patients having the anti-PGL-l antibodies; on the other hand, 6(50%) of 12 lepromatous patients treated less than 2 years had detectable PGL-l in their sera. The results thus indicate that PGL-l detection may be more suitable for monitoring the effectiveness of chemotherapy and that it may be necessary to examine for the presence of PGL-l in sera from contacts and normal populations for confirming M. leprae infection.

Immunological unresponsiveness in leprosy and its relevance to immunoregulation in man.

The varied forms of leprosy form a clinical and immunological spectrum which offers extraordinary possibilities for insight into immunoregulatory mechanisms in man. At one pole, tuberculoid leprosy, patients develop high levels of cell-mediated immunity which ultimately results in killing of bacilli in the tissues, albeit often with damage to nerves. At the lepromatous pole, patients exhibit selective immunological unresponsiveness to antigens of Mycobacterium leprae. Even though all currently known protein species of Mycobacterium leprae and BCG are cross-reactive, lepromatous patients unreactive to Mycobacterium leprae antigens frequently respond strongly to tuberculin. In vitro experiments suggest the existence of lepromin-induced suppressor activity, mediated by both monocytes and Τ cells. The Τ suppressor cells have the T8 phenotype of which 50% express the activation markers, Ia and FcR. The one unique species of antigen of the leprosy bacillus is a phenolic glycolipid, and it appears that the Ts cells largely recognize the terminal trisaccharide of this unique antigen. Depletion of Ts cells restores in vitro reactivity of lymphocytes to lepromin in a portion of lepromatous patients, and addition of IL-2 containing supernatants partially restores responsiveness to Mycobacterium leprae antigens. Vaccination of lepromatous patients with a mixture of Mycobacterium leprae and live BCG restores cell-mediated immunity in the majority of lepromatous patients, and concomitantly reduces the in vitro suppressor activity and number of activated T8 cells. These experiments suggest the existence of stage-of-disease related suppressor cells in leprosy which appear to block the responsiveness of TH capable of responding to either specific or cross-reactive mycobacterial antigens. The mode of action of these Ts appears to be the inhibition of production of IL-2 and other lymphokines. Successful immunotherapeutic vaccination appears to overcome this block in the majority of patients.