Influence of delayed immune reactions on human epidermal keratinocytes.

The epidermal changes that occur in human cutaneous immune responses have been investigated in the tuberculin reaction and in the lesions of tuberculoid and lepromatous leprosy and cutaneous leishmaniasis. In each situation, there was a dermal accumulation of monocytes and T cells, and the epidermis exhibited thickening. In the tuberculin response, the thickness of the epidermis sometimes doubled in 48-72 hr, and this was attributed to increases in both size and number of keratinocytes. In addition, the phenotype of the keratinocytes changed from Ia- to Ia+. Similar changes in keratinocyte Ia-antigen expression occurred in the epidermis overlying untreated tuberculoid leprosy and cutaneous leishmaniasis lesions, but not in lepromatous leprosy. We suggest that one or more epidermal growth factors may be generated in the course of a delayed immune reaction in the dermis.     

In vivo responses to Mycobacterium leprae: antigen presentation, interleukin-2 production, and immune cell phenotypes in naturally occurring leprosy lesions

To investigate the immune defect in lepromatous leprosy we studied immune cell phenotypes, lymphocyte activation states, and interleukin-2 (IL-2) production in naturally occurring leprosy skin lesions. Mouse hybridoma monoclonal antibodies reacting with the IL-2 receptor (anti-Tac), unbound IL-2 (DMS-1), antigen-presenting Langerhans' cells (OKT6) and the OKT4-Leu3 and OKT8 T-lymphocyte subpopulations were used with indirect horseradish peroxidase and alkaline phosphatase techniques on frozen biopsy sections. The percentage of Tac+ lymphocytes and the number of OKT6+ cells in the epidermis and dermal granuloma were significantly correlated in naturally occurring lesions (correlation coefficient 0.79) and were higher in tuberculoid than in lepromatous lesions. Leu3 antigen was expressed by 70-90% of Tac+ cells in tuberculoid lesions. Although the percentage of cells producing IL-2 was low in lesions of both lepromatous and tuberculoid patients, it was about 15 times greater in tuberculoid than in lepromatous lesions (0.032 +/- 0.037 tuberculoid vs 0.0019 +/- 0.023 lepromatous). There was an association between the number of OKT6+ cells and the percentage of IL-2-producing cells, but the association was weaker than that of OKT6+ cells and the percentage of IL-2 receptor-bearing cells (r = 0.2), implying that IL-2 production is not an intervening variable in the latter association. The absolute number of OKT4-Leu3+ lymphocytes was significantly different in different clinical leprosy groups and was positively correlated with host resistance (mean OKT4-Leu3+ cells/mm2 in 6 micron sections; 1412 +/- 288 tuberculoid, 400 +/- 93 borderline lepromatous, 200 +/- 100 polar lepromatous; r = 0.95). Absolute numbers of OKT8+ cells/mm2 in lesions were not significantly different. We conclude that there is a relative paucity of OKT4-Leu3+ cells as well as IL-2-producing cells at the local level in lepromatous leprosy lesions. Possible functional relationships between these findings and the failure of macrophage activation and destruction of Mycobacterium leprae in lepromatous leprosy are discussed.     

In vitro studies on dermal leprosy granulomas: assessment of division and protein synthesis of cells

Single cell suspension from dermal leprosy granulomas (10 tuberculoid and 10 lepromatous) was prepared and an assessment of the division and protein synthesis by the cells was made. The cells of tuberculoid granulomas showed a high incorporation of 3H-thymidine and 14C-leucine. On the contrary, the cells of the lepromatous granulomas exhibited poor division but their protein synthesis remained unimpaired. These observations suggest that the epithelioid cell granuloma of tuberculoid leprosy appears to be more active and secretory than the macrophage granuloma of lepromatous leprosy.     

Comparison of the characteristics of infiltrates in skin and nerve granulomas of leprosy

The characteristics of infiltrates in the dermal and neural granulomas from the same leprosy patients were compared by preparing a single cell suspension. Skin and nerve biopsies from 10 patients, 5 with tuberculoid and 5 with lepromatous leprosy were analysed. The granulomas contained lymphocytes and macrophages. Lymphocytes were the predominant infiltrating cells in the tuberculoid dermal and neural granulomas. A high proportion of lymphocytes in both the skin and nerve granulomas in these cases were activated T cells as they formed rosettes with sheep erythrocytes and expressed HLA-DR antigens. In contrast, lepromatous dermal and neural granulomas contained very few of these lymphocytes. Dermal and neural granulomas from both the types of leprosy contained mature macrophages as they were esterase positive, did not exhibit peroxidase activity and expressed HLA-DR antigens. These macrophages did not possess C3 surface receptors either. These findings suggest that the infiltrates in the skin and nerve granulomas of a given type of leprosy have similar characteristics.     

Effect of supernatants of dermal leprosy granulomas on lymphocyte morphology and function

A comparison has been made of the characteristics of dermal granulomas of tuberculoid and lepromatous leprosy by culturing them in vitro. The granulomas were derived from lesions of untreated patients and their effect was assessed on the morphology and function of lymphocytes derived from peripheral blood of normal individuals. The concentration of proteins released in the supernatants was similar in both the type of granulomas. However, the supernatants from the lepromatous granulomas markedly diminished the viability of lymphocytes when compared with supernatants derived from the tuberculoid granulomas. The supernatants from both the tuberculoid and lepromatous granulomas, contained soluble factors which depressed the 14C-leucine and 3H-thymidine incorporation by lymphocytes. The depression in 3H-thymidine uptake was more pronounced with the supernatants from the lepromatous granulomas while the diminution of 14C-leucine incorporation was more marked with supernatants from the tuberculoid granulomas. The supernatants did not show any migratory inhibitory activity in vitro. When the cells from the granulomas were dispersed and cultured in vitro, only very low concentration of proteins was detectable.     

The cellular content of dermal leprous granulomas: an immuno-histological approach

An indirect immunofluorescence technique with monoclonal antibodies has been used to identify T cells, T helper cells, T suppressor cells, and granulocytes in the dermal granulomas of 22 patients with leprosy. In tuberculoid leprosy, T helper cells predominated and T suppressor cells were located at the periphery of well-circumscribed granulomas. In lepromatous leprosy, the two subsets of T cells were numerous in treated patients. In ENL lesions, T cells were more numerous and T helper cells predominated. Enumerations of the T cell subsets in the dermis and in the blood showed similar changes, but these changes were quantitatively more marked in the dermal granulomas.     

Learning from lesions: patterns of tissue inflammation in leprosy.

The clinical forms of leprosy constitute a spectrum that correlates closely with the degree of cell-mediated immunity. Patients with tuberculoid leprosy develop strong cell-mediated responses and have only a few, localized lesions, whereas patients with multibacillary lepromatous leprosy are specifically unresponsive to antigens of Myobacterium leprae. T cells of the CD4+ subset predominate in tuberculoid lesions, whereas CD8+ cells predominate in lepromatous lesions. Monoclonal antibodies that distinguish subpopulations of CD4+ and CD8+ cells were used to analyze the distribution of T cells infiltrating lesions across the disease spectrum. In lepromatous lesions, T cells of T-suppressor phenotype (9.3-) were the predominant CD8+ cells and suppressor/inducer cells (2H4+, Leu-8+) represented half of the CD4+ subset. In tuberculoid lesions, helper T cells (CD4+4B4+) outnumbered suppressor/inducer T cells by 14:1, compared with a ratio of 1.2:1 in peripheral blood. Analysis of the precursor frequency of antigen-reactive T cells permitted us to estimate that there was a 100-fold enrichment of T cells able to proliferate in response to M. leprae antigens in tuberculoid lesions (2/100), when compared with blood from the same patients. The methods used here to characterize the T-lymphocyte subsets and frequency of antigen-reactive T cells in leprosy may be useful in analyzing immunological reactions occurring in lesions of other inflammatory and autoimmune diseases.     

In vitro studies on dermal granulomas of human leprosy: characterization of cells using monoclonal antibodies

Single cell suspensions from granulomas of leprosy cases were prepared to enable an in vitro study on the characteristics of infiltrating cells. In all, biopsies from 21 untreated cases of tuberculoid leprosy and lepromatous leprosy were analyzed. The granulomas were found to contain lymphocytes and macrophages. The numbers of lymphocytes were higher in the suspensions of tuberculoid granulomas in comparison to lepromatous granulomas. A high percentage of lymphocytes from tuberculoid granulomas expressed OKT11 and Ia-like antigens, thereby indicating the presence of activated T cells. The proportion of Leu3a+ cells was greater in comparison to OKT8+ cells in these granulomas. In lepromatous granulomas, only a few positive lymphocytes expressing OKT11 or OKT8 antigens were observed. The ratio of Leu3a+:OKT8+ cells (2.79 +/- 0.61) was higher in the tuberculoid granulomas than in the lepromatous granulomas. Most macrophages from both types of granulomas expressed Ia-like antigens.     

Distinct patterns of microvasculature in the cutaneous lesions of leprosy

This work is an investigation on the microvasculature of the cutaneous infiltrates of leprosy with the immunohistochemical staining of endothelial cells in cutaneous biopsies. Anti-Factor VIII-related antigen antibody (anti-FVIII-ra) and Ulex Europaeus-1 lectin (UEA-1) binding were utilized as endothelial cell markers. Thirty-nine patients grouped according to the Ridley-Jopling classification (14 borderline tuberculoid, 18 borderline lepromatous, 6 lepromatous, and 1 indeterminate leprosy) were selected for this study. Two microvascular architectural patterns could be clearly distinguished: lepromatous lesions presented a dense and tortuous mesh of microvessels among the Mycobacterium leprae-glutted macrophages; whereas the microvessels in the tuberculoid lesions were restricted to the periphery of the granulomas and were not seen among the central epithelioid cells. We were able to distinguish three basic morphological kinds of infiltrate distribution related to the microvessels: micronodules, cords and macronodules. Intensifications of the FVIII-ra immunoreactivity and UEA-1 binding capacity were observed in the endothelial cells of microvessels involved by the inflammatory infiltrate. A distinct cytokine expression profile at the leprosy poles and the role of mast cells in angiogenesis were speculated as factors contributing to these distinct patterns. Growth of the lesion and systemic dissemination of M. leprae in the bipolar spectrum of leprosy may hypothetically be influenced by the vascular-infiltrate relationship. The detection of angiogenesis in the cutaneous lesions of leprosy may bring about alternate and/or additional strategies for leprosy treatment.     

Hepatic morphology in reactional states of leprosy

Liver function tests and liver biopsies were studied in 23 leprosy patients in reaction and 10 without reaction. The liver biopsies in leprosy patients with reaction showed exudative lesions, epithelioid and tuberculoid granulomas, and foam-cell granulomas. Portal vasculitis was encountered in a few cases. Neutrophilic infiltration into the foam-cell granulomas was seen in a few cases of lepromatous (LL) leprosy with reaction. In six cases of borderline (BL, BB and BT) leprosy with reaction, a spectrum of lesions bearing footprints of exudative lesions were seen evolving into epithelioid-cell granulomas. Foam-cell granulomas and tuberculoid and epithelioid granulomas along with exudative lesions were encountered in two cases on individual biopsy strips. An altered albumin-to-globulin ratio was the chief functional derangement observed in these cases. The spectrum of changes observed in borderline leprosy with reaction could be discrete steps in the evolution of upgrading reaction.     

A histopathological study of lymphnodes in 43 cases of leprosy

Eighty cases of leprosy including 60 cases of lepromatous type and 20 cases of tuberculoid type, during the period of 1974-75, have been examined for evidence of lymphnode enlargement. Of the 52 cases of enlarged lymphnodes, lymphnode biopsy was done in 43 cases including 38 cases of lepromatous type and 5 cases of tuberculoid type. The lymphnodes have been studied for evidence of any pathological changes and presence of acid-fast bacilli. In cases of lepromatous leprosy, lepromas and acid-fast facilli were seen in 92.2 per cent of the cases and patchy fibrosis was noted in 23.6 per cent of the cases. No amyloid could be demonstrated. In cases of tuberculoid leprosy, only non-specific reticular hyperplasia was noted. No specific granuloma or acid-fast bacilli could be demonstrated. The findings have been described in detail and discussed in the light of previous published data.     

Biochemical, immunological and genetic studies in leprosy. II. Profile of immunoglobulins, complement components and C-reactive protein in sera of leprosy patients and healthy controls.

Various classes of immunoglobulins (IgA, IgM, IgG, IgD and IgE), complement components (C3 and C4) and C-reactive protein (CRP) were estimated in sera from normal healthy controls and leprosy (lepromatous and tuberculoid) patients from Ethiopia. Higher levels of IgA, IgM, IgG and IgD were found in lepromatous leprosy compared with normal healthy people while in tuberculoid leprosy only IgM, IgG and IgD levels were increased. Borderline leprosy patients showed increase in IgG level only. Although an increase in IgE was noted in lepromatous leprosy, it was not significant; the variations in IgE levels could be due to different socioeconomic background and exposure to intestinal parasites. C3 component was significantly reduced in leprosy patients compared with healthy controls while no difference in C4 component was observed. The results point towards an involvement of the "alternate pathway". A positive test against C-reactive protein antiserum was given by about 20% of the normal healthy controls while more than 60% lepromatous and tuberculoid leprosy patients were CRP positive. The results are discussed in relation to the status of immunoglobulins and complement components in leprosy and possible factors (environmental and genetic) which might affect them.     

A preliminary study of correlation of immuno-histological and ultrastructural characteristics of neural granuloma in leprosy patients.

With an aim to better understand the pathogenesis of nerve damage in leprosy, peripheral nerve biopsies from six untreated leprosy cases (3 BT/TT and 3 BL/LL) were studied by electronmicroscopy and immuno-histology. In addition to routine histopathology for diagnosis, infiltrating cells of granuloma were characterized after preparation of single cell suspension. The lymphocytes in the lesion were characterized by E and EAC rosetting and macrophage phagocytic system (MPS) cells were studied using histochemical markers like esterase and peroxidase. The results indicate that the lymphocyte content was significantly greater in tuberculoid neural granuloma compared to lepromatous nerves and these formed rosettes with sheep erythrocytes (E) and expressed HLA-DR antigen suggesting that they are activated T cells. Infiltrating macrophages in both the tuberculoid and lepromatous neural granuloma were esterase positive, peroxidase negative and did not form rosettes with sheep erythrocytes or EAC. Ultrathin sections of tuberculoid granuloma showed lymphocytes clearly associated to epithelioid macrophages having well developed Golgi apparatus and rough endoplasmic reticulum. Correlation of these immunological and ultrastructural characters suggests that hypersensitivity mechanisms are possibly responsible for nerve damage in tuberculoid leprosy. Ultrastructural examination of lepromatous nerves, on the other hand, showed the predominance of macrophages with large nucleus, heavily bacillated Schwann cells, and a few lymphocytes. The correlation of immuno-histological and ultrastructural characters indicates that the mechanism(s) of nerve damage in lepromatous leprosy are basically different wherein hypersensitivity appears to play a very limited role.     

Simultaneous upgrading reaction and erythema nodosum leprosum in a patient with lepromatous leprosy

A case of lepromatous leprosy with erythema nodosum leprosum (ENL) undergoing treatment with dapsone, rifampin, and thalidomide developed focal tuberculoid granulomas in the ENL lesions. This is the first report known to the authors of a lepromatous leprosy patient in whom ENL and an upgrading reaction occurred simultaneously.     

Epidermal changes in reactional leprosy: keratinocyte Ia expression as an indicator of cell-mediated immune responses

Significant epidermal changes were observed in lesions of leprosy patients undergoing type 1 (reversal) and type 2 (erythema nodosum leprosum, ENL) reactions. Using indirect immunofluorescence and frozen sections stained with the appropriate monoclonal antibodies, an increase in epidermal cell layers, the presence of Ia on keratinocytes, an increase in Langerhans' cell numbers, and scattered T cells within the epidermis were seen in both types of reactions. Although borderline tuberculoid patients with type 1 reactions showed the consistent presence of Ia on all keratinocytes, lepromatous patients undergoing ENL reactions showed only a patchy distribution. Taken together, these studies indicate that local T-cell activation leading to the production of terminal lymphokine, such as interferon-gamma, with subsequent induction of Ia on epidermal cells may be an important event in reactional leprosy states. It is of interest that the hitherto considered "anergic" lepromatous patients should recover temporary T-cell reactivity during the natural course of the disease.     

Studies of cell death (apoptosis) and cell division in leprosy granulomas

We have studied the histological changes across leprosy lesions by taking biopsies from the center and edge of the lesions and from the clinically uninvolved skin outside the lesions. A comparison of the granuloma fraction (GF) between biopsies from the center and edge of lesions and the adjacent unremarkable skin shows that the greatest GF is found at the edge of lesions, except in early tuberculoid (BT) cases when biopsies from the center have the greatest GF. Central healing of leprosy lesions occurs without tissue necrosis or appreciable fibrosis. Apoptosis, a form of individual cell death in living tissues, is known to be the mechanism of cell loss in a variety of situations, and we have found it to occur in leprosy lesions. Apoptotic activity is greatest at the edge of established tuberculoid lesions, but can be found in the center of the lesion in early cases. We, therefore, suggest that apoptosis is the mechanism by which epithelioid cells are lost during central healing in tuberculoid leprosy lesions. In the small number of multibacillary cases studied, apoptosis were found in biopsies from both the center and edge of the lesions. Mitoses can be found in biopsies from both lepromatous and tuberculoid lesions. However, the degree of mitotic activity does not appear to be related to the position of the biopsy within the lesion, and immigration of monocytes into the granulomas may be of greater importance than cell division in maintaining the numbers of epithelioid cells or macrophages present.     

Histological assessment of dermal nerve damage occurring during multidrug therapy for leprosy

This is a prospective histomorphological assessment of dermal innervation in biopsies taken before and after multidrug therapy (MDT) from 41 leprosy patients: 35 borderline tuberculoid (BT), 3 borderline lepromatous (BL), 3 lepromatous (LL). Biopsies of the same lesions taken before commencement (diagnostic therapy) and at the end of therapy (check biopsy) were compared. Hematoxylin and eosin, immunoperoxidase stain for S-100 protein, and the Holmes' silver impregnation method for nerve cells and fibers were used. Skin biopsies were classified as having detectable or undetectable nerves. Of 35 patients with BT leprosy, 17 had no detectable nerves in their diagnostic biopsies; in the check biopsies of 13 of these 17, dermal nerves remained undetectable, in 2 they were S-100 positive but were Holmes negative. Identifiable dermal nerves were present in diagnostic biopsies from 18 patients; in the check biopsies 5 of these 18 had no detectable nerves while in the remaining 13 nerve branches could be detected. The study provides histological documentation of complete damage to dermal innervation in 62.85% (22/35) of patients with BT leprosy, of which 14.28% (5/35) occurred during MDT. Of the patients with detectable dermal innervation at the onset of MDT, 27.7% (5/18) suffered continuing damage during MDT.     

OKT6+ epidermal Langerhans' cell numbers in DNCB reactions among leprosy patients

A study was made on the Langerhans' cells at the sites of contact sensitivity skin reactions in 45 untreated leprosy patients. The skin reaction was induced by 2,4-dinitrochlorobenzene (DNCB). Langerhans' cells were quantitated using OKT6 monoclonal antibody and indirect immunofluorescence. Clinically, the skin reaction in the tuberculoid patients was positive at 4, 24, and 48 hr, while the lepromatous patients failed to respond at any of the time intervals. Sequential histological analysis of the skin reaction showed predominantly mononuclear cell infiltrates around the blood vessels and neurovascular bundles in both the tuberculoid and lepromatous patients. Time kinetic assessment showed no difference in the numbers and distribution of OKT6+ epidermal Langerhans' cells at the site of the DNCB skin reactions among the tuberculoid and lepromatous patients. This, therefore, suggests that either there is a functional defect in Langerhans' cells or some other mechanism(s) such as a T-cell abnormality is responsible for the lack of clinical reaction in lepromatous patients.     

Nodular leprosy of childhood and tuberculoid leprosy: a comparative, morphologic, immunopathologic and quantitative study of skin tissue reaction

Nodular leprosy of childhood (NL) is a benign clinical variant of tuberculoid leprosy that affects breast-feeding infants and children that remained in a highly infected environment. The lesions resolve with complete healing and NL has been considered a manifestation of allergy and congenital immunity to Mycobacteria leprae. We studied the tissue reaction, Mycobacterial antigen frequency, and the lymphocyte subsets (CD45RO+, CD4+, CD8+, B, NK), dendritic cells (epidermal CD1a+ cells and S100+ dermal dendrocytes), and macrophages in skin lesions of a clinically well characterized NL group (N = 11). Results were compared to children (N = 23) and adults (N = 24) with classical tuberculoid leprosy. NL lesion histopathology was characterized by dense granulomatous inflammatory reaction, with a greater number of confluent tubercles when compared to the other groups. Neural compromise was seen in all biopsies. The frequency of Mycobacterium antigen was similar in all groups. The population of CD45RO+, CD4+ and CD8+ T lymphocytes, natural killer cells, B lymphocytes, CD1a+ epidermal cells, and macrophages of NL lesions did not differ from the other groups. The number of S100+ dermal dendritic cells of the NL group was smaller than that of the adult group, although it did not differ from the other group of children. Except for the confluent tubercules, our data could not disclose any other difference in the tissue reaction of NL, in spite of its peculiar clinical features and evolution when compared with the classical tuberculoid leprosy. The localization of NL lesions may be the result of the intimate skin contact with lepromatous parents or relatives, in areas such as cheeks, arms, buttocks, and limbs, and the innoculation of M. leprae into skin may strongly stimulate cell mediated immunity (CMI) against the bacilli. These circumstances might explain the good CMI response leading to high resistance, stability, and auto-resolution of nodular leprosy of childhood.     

HLA-linked control of predisposition to lepromatous leprosy

In a study of the relation between HLA and lepromatous leprosy, HLA haplotype segregation was analyzed in 28 families with multiple cases of different types of leprosy. The inheritance of HLA-DR2, HLA-DR3, and HLA-MT1, which had previously been shown to be associated with susceptibility to leprosy or with a leprosy type, was analyzed separately. Segregation occurred in a significantly nonrandom fashion in both polar tuberculoid leprosy and lepromatous leprosy. This finding indicated HLA-encoded control of a predisposition to both of these forms of the disease. In both cases the segregation observed among healthy siblings was random. Thus, susceptibility to leprosy per se is probably not controlled by HLA-linked genes. HLA-DR3 was inherited preferentially by children with polar tuberculoid leprosy rather than lepromatous disease (P = .02), and HLA-MT1 was inherited preferentially by children with lepromatous leprosy (P = .04). The results confirmed the association of these genetic markers with leprosy type.