The immunopathogenesis of vitiligo.
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Antigens, CD↗
Biomedical subjects
L Baranda
Publications and source records attributed to L Baranda.
Lack of expression of intercellular adhesion molecule ICAM-1 in lepromatous leprosy patients.
It is conceivable that an abnormal expression of cell-adhesion molecules can contribute to the poor inflammatory response seen in some inflammatory skin diseases. Adhesins are cell-surface molecules that are expressed by many cell types. The main function of adhesins appears to be the promotion of cellular interactions, such as those occurring between immune cells. The epidermis of patients with inflammatory skin diseases exhibits an increased expression of ICAM-1, and it has been postulated that such increased expression can be important in the genesis of cutaneous inflammation. The expression of cell-adhesion molecules (LFA-1, LFA-2, LFA-3 and ICAM-1) in skin lesions of leprosy patients was studied, as well as the in vitro expression of these molecules induced with gamma interferon (IFN-gamma). A lack of expression of ICAM-1 in the epidermis of lepromatous patients was noted; in addition, no expression of ICAM-1 was seen in the nearly normal skin from these patients incubated with IFN-gamma. A similar expression of the four molecules studies was noted in the dermis of both the lepromatous and tuberculoid types of leprosy. The epidermis of the lepromatous leprosy patients appears to have a defective expression of ICAM-1.
Antigens, CD↗
Immune sensitization against epidermal antigens in polymorphous light eruption.
To get further insight into the pathogenesis of polymorphous light eruption, we studied nine patients with polymorphous light eruption and six healthy persons. Two skin biopsy specimens were obtained from each person, one from previously ultraviolet light-irradiated skin and another one from unirradiated skin. An epidermal cell suspension, skin homogenate, or both were prepared from each specimen. Autologous cultures were made with peripheral blood mononuclear cells combined with irradiated or unirradiated skin homogenate and peripheral blood mononuclear cells combined with irradiated or unirradiated epidermal cell suspension. Cell proliferation was assessed by 3H-thymidine incorporation assay. The response of peripheral blood mononuclear cells to unirradiated epidermal cells or unirradiated skin homogenate was similar in both patients and controls. However, peripheral blood mononuclear cells from patients with polymorphous light eruption showed a significantly increased proliferative response to both irradiated epidermal cells and irradiated skin homogenate. Our results indicate that ultraviolet light increases the stimulatory capability of polymorphous light eruption epidermal cells in a unidirectional mixed culture with autologous peripheral blood mononuclear cells. This suggests that an immune sensitization against autologous ultraviolet light-modified skin antigens occurs in polymorphous light eruption.
Adolescent↗
Evidence of cell-mediated immune contrasuppression in lepromatous leprosy: modulation of a putative T contrasuppressor cell-subset.
Some lepromatous leprosy (LL) patients are characterized by the presence of activated suppressor T cells that specifically inhibit the immune response to Mycobacterium leprae antigens. Immune contrasuppressor (CS) cell activity antagonize suppressor function. Whereas the former function has been extensively studied in leprosy, the latter has not been explored. We studied the peripheral blood mononuclear cells (PBMNC) of 20 patients with leprosy (10 lepromatous and 10 tuberculoid) and six healthy contacts. We found CS-like activity in the PBMNC from some LL patients when assayed in vitro using lepromin as antigen. This CS-like function was found in CD8+, vicia villosa adherent (VV+) T cells. CS-like activity was not detected in PBMNC from either tuberculoid patients or healthy contacts. Pre-treatment of CD8+, VV+ cells with either recombinant IL-2 (5 u/ml) or recombinant interferon-gamma (1,000 u/ml) did not modify significantly their putative CS function. However, in 50% of lepromatous patients the pre-incubation of CD8+, VV+ cells with both lymphokines together increased significantly the CS-like activity. These data suggest that the in vitro immune response to M. leprae in some LL patients can be augmented by either modifying numerically the contrasuppressor T cells or activating them with lymphokines.
Antigens, Bacterial↗
Quantitative analysis of contrasuppressor T lymphocytes in leprosy; induction of Ia antigens with gamma interferon.
Lepromatous leprosy is characterized by immune anergy and abnormal suppressor T-cell function. Contrasuppressor cells are a subset of CD8+, vicia villosa-adherent T lymphocytes. T-contrasuppressor (Tcs) cells act on T-helper cells to cause them to become unresponsive to the action of T-suppressor cells. In 8 lepromatous (LL) and 7 tuberculoid (TT) patients, and 6 healthy contacts we studied the percent of the following lymphocyte subsets: CD3+, CD4+, CD8+, Ia+, vicia villosa+ (VV+), CD8, VV+, VV, Ia+, and Ia, Tac+. This was done in baseline status as well as post-stimulation with recombinant gamma interferon (rIFN-gamma). We found that peripheral blood mononuclear cells from LL and TT patients and controls exhibit a similar number of putative contrasuppressor lymphocytes (CD8, VV+ cells). However, in the contrasuppressor subset from LL patients we found a low percent of Ia+ (p less than 0.05 compared to controls or TT). In the three groups studied, the rIFN-gamma enhanced the percent of Ia+ lymphocytes in the CD8, VV+ cell subpopulation. However, the CD8, VV+ lymphocytes from LL patients, despite the effect of rIFN-gamma, continue to have a low percent of Ia+ cells (p less than 0.05 compared to controls or TT). These findings suggest that LL patients might have abnormalities in the contrasuppressor immune circuit. Future functional studies on the role of Tcs cells in the anergy seen in LL will be required in order to define the apparent dysfunction occurring in this disease.
Antigens, Surface↗
Facial erythema and edema in a diabetic man. Mucormycosis.
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Adult↗
Decrease of helper T cells in children with recurrent respiratory tract infections.
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Child↗
Ketoconazole and gynecomastia.
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Gynecomastia↗
Natural killer cell-mediated cytotoxicity in cryptococcal meningitis.
There are evidences regarding the role of NK cytotoxic activity in the resistance against experimental C. neoformans infection. To assess the status of NK cell activity in human C. neoformans infection, we studied the peripheral blood of twelve patients with cryptococcal meningitis, six patients with CNS disease different to cryptococcal meningitis, and twelve healthy subjects. The number of CD16+cells and the NK cytotoxic activity of peripheral blood mononuclear cells was studied. The in vitro effect of exogenous IL-2 and interferon gamma on such cytotoxic activity was also studied. The number of CD16+ cells was not significantly different in patients compared to controls. However, cryptococcal patients exhibited a significant lower NK activity compared to both control groups (p less than 0.05 in both cases). The low NK activity of cryptococcal patients was fully reconstituted in vitro with the addition of rIL-2 but not with rIFN gamma. In vitro experiments suggest that the low NK activity of cryptococcal meningitis patients is not due to amphotericin B therapy or blockade of NK cells by C. neoformans-derived molecules. The results of this study suggests that patients with cryptococcal meningitis have a defective NK cytotoxic function and may aid to understand the pathogenesis of this disease.
Adult↗
Plasma levels and in vitro production of tumor necrosis factor-alpha and interleukin-6 in patients with amebic liver abscess.
We studied the plasma levels of tumor necrosis factor-alpha (TNF-alpha) interleukin-6 (IL-6) as well as the in vitro production of these cytokines by peripheral blood mononuclear cells, in 10 patients with amebic liver abscess (ALA) and seven healthy controls. TNF-alpha was measured using a bioassay with L929 fibroblasts; IL-6 was quantitated by the B9 cell line assay. In both assays, the number of viable cells was estimated by the conversion of MTT to formazan. TNF-alpha plasma levels were nondetectable (< 20 pg/mL) in ALA patients, as well as in the majority of healthy controls. The in vitro production of TNF induced by lipopolysaccharide was significantly decreased in ALA patients. Most ALA patients (8/10) had increased plasma levels of IL-6. Furthermore, the spontaneous production of IL-6 in vitro was significantly increased in ALA patients compared to controls. In the acute stage of the ALA, a negative relationship was found between the raised plasma levels of IL-6 and the in vitro diminished production of TNF-alpha. After recovery, ALA patients showed both normal plasma levels and in vitro production of TNF and IL-6. Our data corroborate previous reports regarding plasma levels of TNF in ALA, and suggest that E. histolytica induces the in vivo production of IL-6 through a TNF-independent pathway. The raised levels of IL-6 might in turn down-regulate the production of TNF in ALA patients.
Acute Disease↗