Specific IgG antibody responses may be used to monitor leprosy treatment efficacy and as recurrence prognostic markers.

Although curable, leprosy requires better diagnostic and prognostic tools to accompany therapeutic strategies. We evaluated the serum samples of leprosy patients from Venezuela and Brazil for reactivity against the specific recombinant proteins, ML0405 and ML2331, and the LID-1 fusion protein that incorporates both of these antigens. Antigen-specific IgG was highest in lepromatous leprosy patients (LL) and decreased across the disease spectrum, such that only a small subset of true tuberculoid patients (TT) tested positive. The impact of multidrug therapy (MDT) on these antibody responses was also examined. Several years after treatment, the vast majority of Venezuelan patients did not possess circulating anti-LID-1, anti-ML0405, and anti-ML2331 IgG, and the seropositivity of the remaining cases could be attributed to irregular treatment. At discharge, the magnitude and proportion of positive responses of Brazilian patients against the proteins and phenolic glycolipid (PGL)-I were lower for most of the clinical forms. The monthly examination of IgG levels in LL patient sera after MDT initiation indicated that these responses are significantly reduced during treatment. Thus, responses against these antigens positively correlate with bacillary load, clinical forms, and operational classification at diagnosis. Our data indicate that these responses could be employed as an auxiliary tool for the assessment of treatment efficacy and disease relapse.

Serologic response to mycobacterial proteins in hansen's patients during multidrug treatment.

Humoral immune responses were studied in 24 leprosy patients treated with multidrug therapy (MDT) and 16 contacts. The patients were monitored for 2 to 3 years with repeated determination of IgG antibody levels directed to different mycobacterial proteins (Mycobacterium tuberculosis, Mt70; M. bovis, Mb65; M. leprae, Ml36, 28, 18, 10 kDa, and the complete protein M. leprae extract, MLSA). All recombinant antigens were used at 5 micrograms/ml concentration and the complete soluble M. leprae extract at 2 micrograms/ml. The results shown in this study reveal a clear decline in IgG antibodies directed toward mycobacterial proteins in the 12 multibacillary (MB) patients when they were submitted to MDT. Initially we found strong reactivity toward complete cytosolic protein and M. leprae membrane protein. The most reactive recombinant proteins in MB patients were Ml10, Ml36, Mt70 kDa and, finally, Ml18 kDa when compared to the paucibacillary (PB) group. After treatment was completed all lepromatous and borderline lepromatous patients showed low or undetectable levels as compared with their initial values before starting treatment.

A follow-up study of multibacillary Hansen's disease patients treated with multidrug therapy (MDT) or MDT + immunotherapy (IMT).

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.

A longitudinal study of immunologic reactivity in leprosy patients treated with immunotherapy.

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.

Leprosy in women: characteristics and repercussions.

"Health is often measured in terms of low mortality; nevertheless, merely being alive is not a measure of the quality of life" H. Méndez Castellanos. Physiological, socioeconomic and cultural factors play important roles in the response of women to Mycobacterium leprae and in the impact of leprosy on their lives. They appear to develop stronger immunological responses to M. leprae than men, as suggested by lower incidence and less severe clinical forms of disease in most areas of the world, as well as stronger reactions of cell-mediated immunity after prophylactic vaccination. Genetic factors and physiological status including pregnancy, intercurrent infection and malnutrition might be among the factors which modulate this response. Women in leprosy-endemic areas of the world, with few exceptions, suffer from marked economic and social dependency and inferiority which can only be heightened by the social stigma associated with leprosy. Nevertheless, they bear an enormous responsibility for the health of their families, often as head of the household, and they often possess a unique capacity to influence community opinion. With the introduction of multidrug therapy, leprosy control throughout the world is no longer an unrealistic goal. Active vaccination may constitute the other factor necessary for eventual eradication of the disease. The incorporation of women at all levels into active roles in health care programs may constitute one of the decisive factors in the success or failure of leprosy control.

Preliminary study of cellular immunity to Mycobacterium leprae protein in contacts and leprosy patients.

Because of the good results obtained in the mononuclear cell (T lymphocyte) proliferative response in tuberculoid leprosy patients and family contacts and healthy Mitsuda-positive volunteers using Mycobacterium leprae soluble extract, we prepared different protein fractions from the soluble extract. We used the T-cell Western blot technique with separation by electrophoresis in SDS-polyacrylamide gels and transfer onto nitrocellulose membranes. Each unstained blot was converted into 18 fractions of antigen-bearing particles and tested with peripheral blood mononuclear cells from 21 individuals including Mitsuda-positive contacts, vaccinated lepromatous leprosy (LL) patients, borderline tuberculoid (BT) patients, and unvaccinated lepromatous patients. The stimulation index (SI) of the contacts was higher to the different fractions in comparison with the leprosy patients. They showed four peaks of stimulation to fractions 66-55, 45-29, 22-18, and 14 kDa. The second highest responders were BT patients, followed by vaccinated LL patients. The unvaccinated patients did not respond significantly to any of the fractions (SI less than 1).

Immunosuppression and cellular immunity reactions in leprosy patients treated with a mixture of Mycobacterium leprae and BCG.

Suppressor reactivity was studied in a group of leprosy patients before and after immunotherapy with a mixture of Mycobacterium leprae and BCG. The treatment increases the responses in lymphocyte transformation tests to levels which are comparable to those observed in BT-TT patients and reduces suppressor activity. The soluble extract of M. leprae appears to be more sensitive than purified intact bacilli in the lymphocyte transformation tests, but this preparation did not induce suppressor reactivity with the regularity observed when using a Dharmendra preparation.

Gamma interferon production induced by antigens in patients with leprosy and American cutaneous leishmaniasis.

In this study, we measured gamma interferon production in mononuclear cell cultures from patients with diverse forms of leprosy and American cutaneous leishmaniasis. We studied patients with lepromatous, borderline lepromatous, borderline, and borderline tuberculoid forms of leprosy, as well as a Mitsuda-negative contact. In leishmaniasis we studied patients with localized cutaneous, mucocutaneous, and diffuse cutaneous forms of the disease. High correlation was observed between gamma interferon production and lymphocyte proliferation assays in both diseases. Resistant forms of both diseases showed significant reactivity, while the severe progressive forms were characterized by insignificant responses in both assays. Localized cutaneous leishmaniasis is characterized by variability in gamma interferon production, which may be of prognostic value in longitudinal studies.

Lymphocyte suppression in leprosy induced by unique M. leprae glycolipid.

Leprosy remains a significant medical and social problem in many developing countries. The varied forms of the disease form a spectrum. At one pole, tuberculoid leprosy, patients develop high levels of cell-mediated immunity which results in the killing and clearing of bacilli in the tissues. At the lepromatous pole, patients exhibit a selective immunological unresponsiveness to antigens of Mycobacterium leprae so that the organisms inexorably multiply in the skin. We have suggested that in lepromatous leprosy one or a small number of unique antigenic determinants present on M. leprae might induce specific suppressor cells that inhibit the reactivity of helper T-cell clones capable of recognizing other specific or cross reactive determinants. Although unique epitopes have been identified by monoclonal antibodies on a small number of M. leprae proteins, the only unique species of antigen present in M. leprae, and not on any other species of mycobacteria so far examined, is a phenolic glycolipid (gly-I). We show here that this unique antigen of M. leprae is capable of inducing suppression of mitogenic responses of lepromatous patients' lymphocytes in vitro and provide evidence that the suppressor T cells recognize the specific terminal trisaccharide moiety.