Lepromatous leprosy treated with recombinant interferon gamma: cutaneous histologic changes.

We report on the histologic changes occurring in single cutaneous lesions, from six active lepromatous patients, 1 week following the administration of three daily intradermal injections, 35 micrograms each, of recombinant interferon gamma (rIFN-gamma). Except for a strong induration at the injection site, rIFN-gamma produced no adverse systemic reactions and was able to promote a remarkable influx of T-lymphocytes, mononuclear phagocytes with large nuclei, nonvacuolated cytoplasm, and reduced lysozyme reactivity. Furthermore, despite no clear-cut reduction of mycobacterial dermal burden, bacilli showed a clear increase in the granular appearance. Present findings provide a basis for further elucidation of rIFN-gamma as an additional tool for leprosy treatment.

Biological false positive test for syphilis in lepromatous leprosy patients with concomitant hepatitis B virus infection.

Within the wide range of immunological abnormalities occurring in lepromatous leprosy (LL), antiphospholipid antibodies unrelated to treponemal infection, the so-called biological false positive test for syphilis (BFP), have long been recognized. Considering that BFP may also be encountered in different clinical situations, the fact that whether BFP in LL occurs solely or is associated with other concomitant infections or serological abnormalities was investigated. For this purpose, two groups of LL patients with similar clinical features and no evidence of treponemal infection were studied, one group with BFP (n = 21) and the other without BFP (n = 13). At the time of study, patients underwent the following tests: hepatitis B surface antigen (HBsAg), anti-Trypanosoma cruzi specific antibodies, infectious mononucleosis-associated heterophil antibodies, rheumatoid factors, antinuclear antibodies, anti-dsDNA antibodies and gamma-globulin serum levels. Except for HBsAg, which was more frequently detected in patients with BFP (p < 0.02), the other variables showed no significant differences between groups. This finding suggests the possibility that simultaneous infection with hepatitis B virus could contribute, to some extent as an additional factor, to the generation of an altered humoral immune response. The possible physiopathologic significance of anti-phospholipid antibodies, in the light of current knowledge, is also discussed.

T lymphocyte subpopulations in leprosy patients and their relation with circulating immune complexes.

The possible relationship between circulating immune complexes (CIC) and peripheral T lymphocyte populations was studied in thirteen active multibacillary leprosy (10 lepromatous--LL--and 3 borderline lepromatous--BL--) and 19 matched controls. Theophylline-resistant T cells (The-R, a lymphocyte subpopulation displaying helper activity on B cells) and total T cells were assessed by means of the E rosette technique, with and without previous theophylline incubation, 1h 37 degrees C, respectively. CIC were quantified by 125I-C1q binding test. Although leprosy patients showed a statistical non significant light depression in total T cells the remarkable variability in circulating levels of The-R T cells enabled us to separate them into two well delineated groups (in relation to this variable p less than 0.001) with no difference in age, sex and bacteriologic state: a) leprosy patients with The-R T cells proportionally conserved (6LL and 2BL); b) leprosy patients with The-R T cells proportionally depressed (4LL and 1BL). Patients belonging to the latter group showed the highest statistically significant levels of CIC. Even though we do not discard an unknown factor being responsible for our findings, we believe that this inverse relationship between elevated CIC and depressed The-R circulating T cells might be representing a lower helper activity on antibody synthesis intending to reduce its excessive production.

Inmunopatologia de la lepra / Immunopathology of leprosy

Se comentan los estudios en convivientes íntimos de enfermos de Lepra, donde se observó una relación inversa entre grado y tiempo de exposición al Mycobacterium leprae (MI) y la magnitud de la respuesta inmune in vivo hacia el bacilo (reacción de Mitsuda); esta variable por otro lado, se halla influenciada por un importante grado de determinación genética. En un modelo murino experimental, la artritis por adyuvante, también se comprobó que el tratamiento con MI inducia una población de células esplénicas supresoras, con actividad regulatoria sobre la respuesta inmune celular. Se plantean además, las posible alteraciones inmunorregulatorias involucradas con la excesiva respuesta humoral que sirve de sustrato para la generación del episodio de eritema nudoso leproso (ENL)

Inmunopatologia de la lepra / Immunopathology of leprosy

Se comentan los estudios en convivientes íntimos de enfermos de Lepra, donde se observó una relación inversa entre grado y tiempo de exposición al Mycobacterium leprae (MI) y la magnitud de la respuesta inmune in vivo hacia el bacilo (reacción de Mitsuda); esta variable por otro lado, se halla influenciada por un importante grado de determinación genética. En un modelo murino experimental, la artritis por adyuvante, también se comprobó que el tratamiento con MI inducia una población de células esplénicas supresoras, con actividad regulatoria sobre la respuesta inmune celular. Se plantean además, las posible alteraciones inmunorregulatorias involucradas con la excesiva respuesta humoral que sirve de sustrato para la generación del episodio de eritema nudoso leproso (ENL) (AU)

[Immunopathology of leprosy]. / Immunopatología de la lepra.

Studies including close contacts of leprosy patients were performed; an inverse relationship between degree and length of exposure to Mycobacterium leprae (MI) and the magnitude of the in vivo specific immune response (Mitsuda reaction) was observed. On the other hand, this variable is greatly influenced by genetic determination. In the experimental adjuvant arthritis model, MI treatment was able to trigger a splenic suppressor cell population with regulatory activity on the immune response. These results suggest that the erythema nodosum leprosum episode (ENL) is related to an excessive humoral response and immunoregulatory alterations.

Imunopatologia de la lepra / Immunopathology of leprosy

Se comentan los estudios en convivientes íntimos de enfermos de Lepra, donde se observó una relación inversa entre grado y tiempo de exposición al Mycobacterium leprae (MI) y la magnitud de la respuesta inmune in vivo hacia el bacilo (reacción de Mitsuda); esta variable por otro lado, se halla influenciada por un importante grado de determinación genética. En un modelo murino experimental, la artritis por adyuvante, también se comprobó que el tratamiento con MI inducia una población de células esplénicas supresoras, con actividad regulatoria sobre la respuesta inmune celular. Se plantean además, las posible alteraciones inmunorregulatorias involucradas con la excesiva respuesta humoral que sirve de sustrato para la generación del episodio de eritema nudoso leproso (ENL)

Immunopatología de la lepra. / [Immunopathology of leprosy]

Studies including close contacts of leprosy patients were performed; an inverse relationship between degree and length of exposure to Mycobacterium leprae (MI) and the magnitude of the in vivo specific immune response (Mitsuda reaction) was observed. On the other hand, this variable is greatly influenced by genetic determination. In the experimental adjuvant arthritis model, MI treatment was able to trigger a splenic suppressor cell population with regulatory activity on the immune response. These results suggest that the erythema nodosum leprosum episode (ENL) is related to an excessive humoral response and immunoregulatory alterations.

Evaluation of circulating immune complexes in leprosy.

Circulating immune complexes (CIC) were evaluated in leprosy by 4 methods: the 125I-C1q binding assay (C1q), the platelet aggregation test (PAT), the 3.5% polyethylene glycol (PEG) precipitation test and the 2.5% PEG precipitation assay. Serum samples belonged to lepromatous leprosy bacilloscopy positive (LL+), lepromatous leprosy bacilloscopy negative (LL-), tuberculoid (TT) and first grade contact group (Co). Studies performed by the 3 first methods showed higher CIC levels in LL+ group (p less than 0.01) and lower values in the 3 others, all of them when compared to normals. On the contrary, the 2.5% PEG precipitation test gave less discriminative results giving only p less than 0.01 in LL+. CIC values obtained in the contact group showed significant results compared to normals but similar to LL- and TT groups. The C1q binding assay and the PAT were the most discriminative methods giving r = 0.90; C1q versus 3.5% PEG, r = 0.36; C1q vs 2.5% PEG, r = 0.14. The PAT compared to 3.5% PEG, r = 0.48 and PAT vs. 2.5% PEG, r = 0.24. Therefore it may be concluded as follows: a) The radioiodinated C1q binding assay and the PAT are recommended for the study of CIC in leprosy; b) The 2.5% PEG precipitation assay offers less sensitivity since it gave similar value in LL-, TT, Co and controls; c) CIC levels observed in LL+ patients may be induced by the antigenic overload demonstrated by the positive bacilloscopy; d) The contacts have CIC levels significantly different from the normal population possibly caused by a subclinical infection.

[Study of T lymphocyte subpopulations in patients with leprosy, using incubation with theophylline]. / Estudio de subpoblaciones de linfocitos T en pacientes con lepra, mediante la incubación con teofilina.

T cells and the theophylline resistant cells (the-r, helper cells) in peripheral blood of patients with different forms of leprosy were studied. Active lepromatous patients (LL+) showed a significant decrease in T lymphocytes and the-r cells. Nevertheless, in LL+ developing a reactional episode of erythema nodosum (LL-ENL) a restoration in the level of the-r cells was observed. It is concluded that in LL+ patients the depression of T cells and the-r cells represents an imbalance in the T-T cellular cooperation with a defective cellular immune response. On the other hand, the recovery of the-r cells in LL-ENL support the hypothesis of a cell mediated immune mechanism in the immunopathology of this reactional episode.

[Characterization of experimental infection with Mycobacterium lepraemurium in 2 strains of mice]. / Caracterización de la infección experimental con Mycobacterium lepraemurium en dos cepas de ratones.

A model of experimental leprosy in two strains of mice, namely CBA/J and CBi, has been developed based on: 1) the histological examination of a granuloma in the hind foot pad 200 days after inoculation of 0.30 microliter of Mycobacterium lepraemurium (6 x 10(8) MLm/ml); 2) the assessment of T lymphocytes in the granuloma identified by the alpha-naphthyl acetate method for esterase, and c) dissemination of the infection. The histological findings in the low resistance CBA/J strain included positive acid fast bacilli vacuolated cells, without lymphocytic infiltration, scarce number of T lymphocytes and a generalized and important dissemination, similarly to the one observed in human lepromatous leprosy. The histological findings in the hind foot pad granuloma of 30-40 per cent of the medium to high resistance CBi strain, consisted of vacuolated cells and lymphocytic infiltration, a large number of T cells and a scarce dissemination, similar to the human borderline leprosy. Both strains present a different susceptibility to a unique challenge with the mycobacterium which could be useful to disentangle the immunogenetic components involved, by means of appropriate selection and crosses. Furthermore, it could be of interest to perform immunoprotection assays in CBi mice, which might have some bearing on the development of a vaccine in human leprosy.

Caracterización de la infección experimental con Mycobacterium lepraemurium en dos cepas de ratones. / [Characterization of experimental infection with Mycobacterium lepraemurium in 2 strains of mice]

A model of experimental leprosy in two strains of mice, namely CBA/J and CBi, has been developed based on: 1) the histological examination of a granuloma in the hind foot pad 200 days after inoculation of 0.30 microliter of Mycobacterium lepraemurium (6 x 10(8) MLm/ml); 2) the assessment of T lymphocytes in the granuloma identified by the alpha-naphthyl acetate method for esterase, and c) dissemination of the infection. The histological findings in the low resistance CBA/J strain included positive acid fast bacilli vacuolated cells, without lymphocytic infiltration, scarce number of T lymphocytes and a generalized and important dissemination, similarly to the one observed in human lepromatous leprosy. The histological findings in the hind foot pad granuloma of 30-40 per cent of the medium to high resistance CBi strain, consisted of vacuolated cells and lymphocytic infiltration, a large number of T cells and a scarce dissemination, similar to the human borderline leprosy. Both strains present a different susceptibility to a unique challenge with the mycobacterium which could be useful to disentangle the immunogenetic components involved, by means of appropriate selection and crosses. Furthermore, it could be of interest to perform immunoprotection assays in CBi mice, which might have some bearing on the development of a vaccine in human leprosy.

Evaluation of circulating immune complexes in leprosy.

Circulating immune complexes (CIC) were evaluated in leprosy by 4 methods: the 125I-C1q binding assay (C1q), the platelet aggregation test (PAT), the 3.5

polyethylene glycol (PEG) precipitation test and the 2.5

PEG precipitation assay. Serum samples belonged to lepromatous leprosy bacilloscopy positive (LL+), lepromatous leprosy bacilloscopy negative (LL-), tuberculoid (TT) and first grade contact group (Co). Studies performed by the 3 first methods showed higher CIC levels in LL+ group (p less than 0.01) and lower values in the 3 others, all of them when compared to normals. On the contrary, the 2.5

PEG precipitation test gave less discriminative results giving only p less than 0.01 in LL+. CIC values obtained in the contact group showed significant results compared to normals but similar to LL- and TT groups. The C1q binding assay and the PAT were the most discriminative methods giving r = 0.90; C1q versus 3.5

PEG, r = 0.36; C1q vs 2.5

PEG, r = 0.14. The PAT compared to 3.5

PEG, r = 0.48 and PAT vs. 2.5

PEG, r = 0.24. Therefore it may be concluded as follows: a) The radioiodinated C1q binding assay and the PAT are recommended for the study of CIC in leprosy; b) The 2.5

PEG precipitation assay offers less sensitivity since it gave similar value in LL-, TT, Co and controls; c) CIC levels observed in LL+ patients may be induced by the antigenic overload demonstrated by the positive bacilloscopy; d) The contacts have CIC levels significantly different from the normal population possibly caused by a subclinical infection.

[Delayed cutaneous response to different antigens in household contacts of leprosy patients and controls]. / La respuesta cutánea tardía a diferentes antígenos en convivientes de pacientes lepromatosos y testigos.

The delayed type hypersensitivity (DTH) response to PPD, candidin and histoplasmin, and Mitsuda reaction (MR) in household contacts (HC) of multibacillary (HCM) and paucibacillary (HCP) leprosy patients, and non exposed controls was studied. Intradermal tests with 0.1 ml. of each antigen were performed and read after 48 hours. Late nodular reaction to ML (MR) was evaluated at the 21st day post-challenge. As we had formerly demonstrated, MR was depressed in HCM. Interestingly, this reaction was also depressed in HCP to a lesser magnitude. HCM had a lower DTH response to histoplasmin in relation to PPD and candidin when persons were simultaneously challenged with the three antigens. According to these results we conclude that: a), HCM have a depression in late lepromin reaction; b), in HCP the depression in MR is of a lower magnitude. We hypothesize that in healthy contacts of bacilliferous patients an active mechanism of immunosuppression to mycobacterial antigens may be produced. Alterations in the skin response to histoplasmin is discussed.

El componente genético de la respuesta inmune al Mycobacterium leprae en individuos sanos / Genetic component of the immune response to Mycobacterium leprae in healthy individuals

Se estudió la heredabilidad (h2) para la reacción de Mitsuda (RM) en 116 personas sanas, inoculadas por primera vez con 0,1 ml de 4x107 Mycobacterium leprae/ml. Cualitativamente, la RM fue analizada como "carácter umbral", en base a la incidencia de individuos negativos a esta prueba en la población general (13 de 116, qg = 0,112) y en todos los hermanos de cada no reactor (caso índice o propósito) (6 de 17, qr = 0,353); se efectuó el cálculo de h2 por los métodos de Falconer y Edwards, con valores de 0,98 ñ 0,3 y 1,19 ñ 0,3, respectivamente. Dado que las respuestas negativas se apartaban de la distribución normal, el análisis del componente genético en la respuesta cuantitativa de la RM se efectuó sólo en las hermandades donde no existían individuos no reactores, hallándose un coeficiente de correlación intraclase (r1) de 0,47. Para una mejor estimación del efecto genético aditivo, 19 hermandades con ambos progenitores RM positivos fueron analizados mediante la regresión entre la RM de los hijos y el promedio de la de sus padres, con una h2 = 0,35 ñ 0,13. Se concluye que la h2 para la RM presenta dos componentes. Como "carácter umbral" se puede postular que se hallaría controlada y/o regulada por muy pocos pares de genes con alta penetrancia. Al favorecerse una reacción positiva (en individuos reactores), estos genes pondrían en funcionamiento un sistema poligénico, cuya aditividad sumada a factores ambientales, justificaría la variación en la magnitud de la respuesta

El componente genético de la respuesta inmune al Mycobacterium leprae en individuos sanos / Genetic component of the immune response to Mycobacterium leprae in healthy individuals

Se estudió la heredabilidad (h2) para la reacción de Mitsuda (RM) en 116 personas sanas, inoculadas por primera vez con 0,1 ml de 4x107 Mycobacterium leprae/ml. Cualitativamente, la RM fue analizada como "carácter umbral", en base a la incidencia de individuos negativos a esta prueba en la población general (13 de 116, qg = 0,112) y en todos los hermanos de cada no reactor (caso índice o propósito) (6 de 17, qr = 0,353); se efectuó el cálculo de h2 por los métodos de Falconer y Edwards, con valores de 0,98 ñ 0,3 y 1,19 ñ 0,3, respectivamente. Dado que las respuestas negativas se apartaban de la distribución normal, el análisis del componente genético en la respuesta cuantitativa de la RM se efectuó sólo en las hermandades donde no existían individuos no reactores, hallándose un coeficiente de correlación intraclase (r1) de 0,47. Para una mejor estimación del efecto genético aditivo, 19 hermandades con ambos progenitores RM positivos fueron analizados mediante la regresión entre la RM de los hijos y el promedio de la de sus padres, con una h2 = 0,35 ñ 0,13. Se concluye que la h2 para la RM presenta dos componentes. Como "carácter umbral" se puede postular que se hallaría controlada y/o regulada por muy pocos pares de genes con alta penetrancia. Al favorecerse una reacción positiva (en individuos reactores), estos genes pondrían en funcionamiento un sistema poligénico, cuya aditividad sumada a factores ambientales, justificaría la variación en la magnitud de la respuesta (AU)