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PubMed2000

Induction of lepromin positivity and immunoprophylaxis in household contacts of multibacillary leprosy patients: a pilot study with a candidate vaccine, Mycobacterium w.

We screened 487 household contacts of multibacillary (MB) patients for evidence of disease and their lepromin status. From the 444 results available, 302 (68.02%) were lepromin positive and 142 (31.98%) were lepromin negative on initial testing. The initial lepromin status as assessed in the group of 54 contacts having disease at the outset showed 24 out of 46 (52.2%) to be lepromin positive and 22 of 46 (47.8%) to be lepromin negative. In the same group, among 24 lepromin positives, 22 (91.7%) had paucibacillary (PB) and 2 (8.3%) had multibacillary (MB) disease; among the lepromin negatives, 12 (54.5%) had PB and 10 (45.5%) had MB disease. Out of 72 initially lepromin-negative contacts administered Mycobacterium w vaccine and followed up, the cumulative percentages show that 53 (73.6%) converted to positivity after a single dose, 10 (87.5%) after a second dose and 67 (93.1%) after the third dose. The incidence of new cases with leprosy was 8 out of 231 (3.46%) among lepromin-positive contacts and 5 out of 93 (5.38%) among lepromin-negative contacts administered Mycobacterium w vaccine. Among 231 lepromin-positive contacts, the new cases occurred in those with a 1+ and 2+ lepromin response only, and no case occurred among 51 contacts with a 3+ lepromin response. The incidence among lepromin-positive contacts in this study (3.46%) was similar to the observations in two other studies: 3.2% by Dharmendra, et al. and 6.9% by Chaudhary, et al. However, the incidence among lepromin-negative contacts administered Mycobacterium w vaccine was significantly lower than that observed among lepromin-negative contacts not administered any vaccination in the other two studies (14.1% by Dharmendra, et al. and 29.0% by Chaudhary, et al.). To conclude, although a study of small sample size, the preliminary evaluation indicates that administration of Mycobacterium w vaccine seems to have the potential to reduce the incidence of leprosy among household contacts of leprosy patients. More explicit results about the vaccine will be available from the ongoing field trials in Kanpur Dehat in the near future.

Bacterial Vaccines↗
PubMedDate not supplied

Comparison of reactions to human and armadillo lepromins in leprosy.

To assess the usefulness of Mycobacterium leprae-infected armadillo tissue as a substitute for human lepromas for the manufacture of lepromin, we compared skin reactions to preparations from these two sources in 115 leprosy patients. The patient sample represented all the primary clinical forms of leprosy. Lepromin derived from the armadillo (lepromin-A) provoked the same pattern of responses as human derived lepromin (lepromin-H), i.e., lepromatous patients gave the weakest reactions. Lepromin-A reactions were consistently more intense than those to lepromin-H. We conclude that lepromin-A is a promising alternative to lepromin-H and may make the worldwide distribution of a standardized skin testing reagent feasible.

Adolescent↗
PubMed1986

The lepromin test in rhesus monkeys.

The lepromin test was studied in rhesus monkeys. Six control monkeys which had not been inoculated with Mycobacterium leprae, six monkeys with experimentally induced leprosy, and nine monkeys which had been inoculated with M. leprae but had not developed leprosy were evaluated with 1X, 10X, and 15X lepromin A, with 1X and 10X lepromin M (mangabey monkey derived), with 1X and 25X purified inactivated M. leprae, and with an armadillo mock lepromin. We found that the lepromin test is useful in rhesus monkeys, but that a higher concentration of antigen than is used in humans is required to induce a response in monkeys. Control monkeys appear to be lepromin negative. Animals which have been inoculated and which develop lepromatous leprosy are also negative. Monkeys which are experimentally inoculated with M. leprae and do not develop leprosy become lepromin positive. Monkeys with indeterminate leprosy have reactions intermediate between lepromatous and resistant animals. No monkeys reacted to armadillo tissue. Our results indicate that 10X lepromin A is a useful preparation for the lepromin testing of rhesus monkeys.

Animals↗
PubMed1982

Tissue response to lepromin, an index of susceptibility of the armadillo to M. leprae infection--a preliminary report.

In this preliminary report the histopathological appearance of the lepromin reaction in armadillos was correlated with their response to infection with M. leprae. Three different types of lepromin response were described, namely the lepromatous, the borderline, and the tuberculoid lepromin reactions. It was found that 10 out of the 11 animals with a lepromatous lepromin reaction and the one animal with a borderline lepromin reaction developed disseminated disease. The two with a tuberculoid lepromin reaction and one of the 11 with a lepromatous lepromin reaction failed to develop leprosy. It is suggested that by using the lepromin response it is possible to assess, to a great extent, the susceptibility of armadillos to infection by M. laprae. The pros and cons of using the armadillo as an animal model for a vaccine trial are briefly discussed.

Animals↗
PubMed1997

Immunotherapy of lepromin-negative borderline leprosy patients with low-dose Convit vaccine as an adjunct to multidrug therapy; a six-year follow-up study in Calcutta.

The present report, which describes management of lepromin-negative borderline leprosy patients with low-dose Convit vaccine, is an extension of our earlier study on the treatment of lepromatous leprosy patients with low-dose Convit vaccine as an adjunct to multidrug therapy (MDT). The test Group I, consisting of 50 lepromin-negative, borderline leprosy patients, were given low-dose Convit vaccine plus MDT. The control group II consisted of 25 lepromin-negative, borderline leprosy patients given BCG vaccination plus MDT and 25 lepromin-negative, borderline leprosy patients given killed Mycobacterium leprae (human) vaccine plus MDT. The control group III consisted of 50 lepromin-positive, borderline leprosy patients not given any immunostimulation but given only MDT. Depending upon the lepromin unresponsiveness, the patients were given one to four inoculations of the various antileprosy vaccines and were followed up every 3 months for 2 years for clinical, bacteriological and immunological outcome. All patients belonging to the test and control groups showed clinical cure and bacteriological negativity within 2 years. However, immunologic potentiation, assessed by lepromin testing and the leukocyte migration inhibition test (LMIT), was better in the test patients receiving low-dose Convit vaccine plus MDT than in the control patients receiving BCG vaccine plus MDT or killed M. leprae vaccine plus MDT or MDT alone. But the capacity of clearance bacteria (CCB) test from the lepromin granuloma showed poor bacterial clearance in the test patients. However, there was no relapse during 6 years of follow up. Two mid-borderline (BB) patients had severe reversal reactions with lagophthalmos and wrist drop during immunotherapy despite being given low-dose Convit vaccine.

Adult↗
PubMed1999

Induction of lepromin positivity following immuno-chemotherapy with Mycobacterium w vaccine and multidrug therapy and its impact on bacteriological clearance in multibacillary leprosy: report on a hospital-based clinical trial with the candidate antileprosy vaccine.

A vaccine based on autoclaved Mycobacterium w was administered, in addition to standard multidrug therapy (MDT), to 157 bacteriologically positive, lepromin-negative, multibacillary (LL, BL and BB) leprosy patients. The vaccinees were supported by a well-matched control group of 147 patients with similar type of disease who received a placebo injection in addition to MDT. The MDT was given for a minimum period of 2 years and continued until skin-smear negativity, while the vaccine was given at 3-month intervals up to a maximum of 8 doses. The lepromin response evaluated in terms of percentage of subjects converting to positivity status, measurement in millimeters, and duration of lepromin positivity sustained, reflected a statistically significant better outcome in the vaccine group patients (especially LL and BL leprosy) in comparison to those in the placebo group. The data indicate that lepromin-positivity status seems to have an impact on accelerating the bacteriological clearance, as is evident by the statistically significant accelerated decline in the BI of those patients who converted to lepromin positivity as compared to those remaining lepromin negative throughout therapy and post-therapy follow up. To conclude, the addition of the Mycobacterium w vaccine to standard MDT induces a lepromin response of a statistically significant higher magnitude than that observed with MDT alone.

Bacterial Vaccines↗
PubMed1989

The post-lepromin scar and its significance in the control of HD.

In the past little attention has been paid to the post-lepromin scar (PLS) and its use in controlling Hansen's disease (HD), particularly in the prognosis, classification and measurement of CMI response. The immuno-information of the Mitsuda reaction is thought to be informative only in the extreme range of 10 + mm or in its absence. Previous studies have shown that the range of PLS formation increases proportionally to the degree of lepromin positivity. PLS positive HD patients have a stable form of the disease with good prognosis. Those unable to form a PLS have a marked tendency to downgrade towards the lepromatous form of HD. PLS formation appears to indicate a CMI response to M. leprae implying immunity. It is thought that there exists a correlation between the PLS and the lymphocyte transformation test (LTT), both reaching their optimum measurement three months after the M. leprae injection, either with lepromin or M. leprae suspension used for the anti-HD vaccine. It is proposed to study the use of the PLS in HD control programs on a trial basis with the objective of its general introduction as part of the management of HD control. Considerable improvements in the prognosis, classification and application of treatment can be expected from such a measure. The discovery of the armadilo as a source of M. leprae by Kirchheimer and Storrs facilitates the availability of lepromin A and its purified version, lepromin Ap. The relevant studies have shown that a 40 M/bact/ml lepromin A suspension should be used for the application of lepromin in control programs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cicatrix↗
PubMed1988

Vaccination of human volunteers with heat-killed M. leprae: local responses in relation to the interpretation of the lepromin reaction.

The early (Fernandez) and late (Mitsuda) lepromin reactions were closely examined in a group of healthy, BCG-vaccinated individuals who were given four doses of a heat-killed, armadillo-derived vaccine, i.e., 1.5 X 10(7), 5 X 10(7), 1.5 X 10(8), and 5 X 10(8) bacilli. There was a clear dose-response relationship for both the early and late reactions with no leveling of the responses within the range of doses examined. While the early response was negative in most of the volunteers, the late response was positive in all of the volunteers. No association was found between the early lepromin test and the pre-vaccination skin test to PPD. There was also no association between the early lepromin test and the pre-vaccination skin test response to a soluble Mycobacterium leprae antigenic preparation (MLSA) in general, but there was a good correlation between these two parameters at the highest vaccine dose. The late lepromin response showed no association with either the prevaccination or post-vaccination skin test response to PPD. However, there was a significant correlation between the late lepromin response and the post-vaccination skin test response to MLSA. In general, no association could be found between the in vivo skin tests and the in vitro lymphocyte transformation test (LTT). Thus, the lepromin test is essentially a vaccination which elicits a specific response to M. leprae antigens provided that the dose of armadillo lepromin given is higher than 5 X 10(7). Therefore, it is unsuitable as a diagnostic test for leprosy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Effect of repeated lepromin testing on experimental nine-banded armadillo leprosy.

Twenty-eight armadillos were lepromin tested and infected with M. leprae; 18 intravenously and 10 intradermally. The lepromin test was repeated after 3 months and at intervals of 6 months thereafter until their death or sacrifice up to 30 months. The one animal with tuberculoid lepromin was resistant and 14 of the 16 with lepromatous lepromin developed generalized disease. Of the 11 with borderline lepromin, 6 developed disseminated disease and 5 were resistant. There is a definite relationship between resistance and tuberculoid lepromin in the armadillo. Repeated lepromin testing had no effect in the rate of infection and the course of the disease in animals infected intravenously. In the intradermally infected animals the results were inconclusive. Whereas all the 20 animals with disseminated disease showed lesions in the liver, spleen and lymph nodes, only 4 animals had sciatic nerve involvement. Peripheral nerve trunk is not necessarily the preferred site in the armadillo. Lung lesions were an important cause of death in lepromatous armadillos.

Animals↗
PubMed1970

Studies towards the standardization of lepromin. Progress and prospects.

Because of the wide range of concentrations of Mycobacterium leprae in existing lepromins the authors studied methods of producing a standardizable lepromin containing 160 million bacilli/ml. The effects of using different dilutions of lepromin on the incidence of false-positive reactions were also studied.Progress reported includes a convenient method for preparing large batches of non-sedimenting lepromin, which is directly suitable for microscopic counting of Myco. leprae cells; and a validation of current methods for microscopic enumeration of Myco. leprae. Skin tests with diluted lepromins have demonstrated that dilutions up to 1:16 increase progressively the ability to distinguish between lepromatous and tuberculoid leprosy. This work has provided further evidence that 20 million bacilli/ml (a 1:8 dilution of the initial lepromin) should produce adequate Mitsuda reactions in general populations, provided that 3-mm reactions are taken as the criterion for 1+ positivity. The net effect of these findings is equivalent to expanding the world supply of lepromin by 8 times.Recommendations for further research are proposed.

Antigens↗
PubMed1963

IMMUNOLOGICAL IDENTIFICATION OF FOOT-PAD ISOLATES AS MYCOBACTERIUM LEPRAE BY LEPROMIN REACTIVITY IN LEPROSY PATIENTS.

Lepromin, a product containing Mycobacterium leprae from patients' tissues, fails to elicit skin reactions in lepromatous patients; this non-reactivity was utilized as a means of identifying the mycobacterium isolated in mouse foot-pads from leprosy patients. To do this a suspension of acid-fast bacilli prepared from mouse foot-pads infected with a typical isolate was compared to human lepromin. The isolate was in fourth passage, and the multiplication since first isolation had diluted the original inoculum to insignificant levels. Three preparations were tested: A, A foot-pad preparation containing 1.6 x 10(7) organisms/ml, B, lepromin diluted to the same bacillary content, and C, undiluted lepromin containing 4.2 x 10(7) organisms/ml. The reactions were compared in 34 lepromatous and 30 tuberculoid patients. All 34 lepromatous patients were negative in both early (Fernandez) and late (Mitsuda) reactions to all 3 antigens. In the tuberculoid patients the late reactions were positive in 66.7, 70.0 and 90.0 per cent to antigens A, B, and C, respectively. The size of the reactions to A and B were closely correlated in the individual patients. Experience in leprosy patients with suspensions prepared from 16 other mycobacterial cultures is reported or reviewed. None of them produced reactions that correlated with those of lepromin. Thus the lack of reactivity to lepromin of lepromatous patients appears to be a specific phenomenon. The results provide evidence that the foot-pad isolates and M. leprae are immunologically identical.

Animals↗
PubMed1995

Ultraviolet radiation decreases the granulomatous response to lepromin in humans.

Ultraviolet radiation (UVR) modulates cellular immunity in humans and experimental animals and can interfere with immune responses against infectious agents in animal models. We used the lepromin reaction, a cell-mediated immune response to antigens of Mycobacterium leprae, to determine whether UVR affects the cellular immune response to an infectious agent in humans. We selected 29 healthy, lepromin-positive contacts of leprosy patients and determined their minimal erythema dose (MED) of UVR. Immediately afterward, each subject was injected with 0.1 ml of lepromin in two areas of the buttocks: one at the site that had received twice the MED of UVR and the other on the contralateral, unirradiated site. The irradiated site was given twice the MED every 4 d for a total of five treatments. One week after the last irradiation, both lepromin reactions were measured and biopsied. The size of the lepromin-induced granulomas was significantly reduced in the irradiated site, as was the number of lymphocytes. Immunohistochemical analysis showed a depletion in the number of infiltrating cells and a lower percentage of T cells, particularly the CD4+ subpopulation, in granulomas formed in UV-irradiated skin. This study demonstrates that local UV irradiation reduces the granulomatous reaction to lepromin in sensitized individuals. These findings are of clinical relevance because of the fundamental role played by the delayed-type hypersensitivity response in defense against intracellular pathogens and because of potential increases in the amount of UVR in sunlight reaching the earth's surface.

Adolescent↗