RESUMEN
We have previously shown that TAP1-/- mice reject heart and skin grafts lacking an H-2 disparity. TAP1-/- mice, which are deficient for MHC-I molecules, probably have a T-cell repertoire with distinct reactivity to these molecules. We speculated that this rejection could be mediated by CD4+ T cells reactive to H-2(b) class I molecules, or to class I-derived peptides presented by self-APC. This hypothesis was tested in the present work. Presensitization of TAP1-/- mice with H-2K(b) peptides accelerated the rejection of C57BL/6 (H-2(b)) skin grafts (MST 13 days, P <.0057), indicating that these peptides were able to mobilize effector T cells that participate in rejection. In addition, CD4 T-cell depletion before transplantation induced a significant delay in rejection (P <.0011), showing that CD4 T cells have a major role in the rejection process, though other cells may also contribute. In conclusion, these results support our hypothesis that H-2(b) molecules may be targeted in graft rejection without an H-2 disparity. The low expression of MHC-I molecules on TAP1-/- mice may determine the selection of a T-cell repertoire that is reactive to self-MHC-I molecules, a phenomenon that is probably beyond the control of peripheral regulatory mechanisms.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/fisiología , Linfocitos T CD4-Positivos/inmunología , Rechazo de Injerto/inmunología , Depleción Linfocítica/métodos , Trasplante de Piel/inmunología , Transportador de Casetes de Unión a ATP, Subfamilia B, Miembro 2 , Transportadoras de Casetes de Unión a ATP/genética , Animales , Modelos Animales de Enfermedad , Supervivencia de Injerto/inmunología , Antígenos H-2/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de TiempoRESUMEN
PURPOSE: To determine the value of pericardial biopsy as a complementary exam in the etiology of pericardial effusion. METHODS: We analyzed retrospectively (from 1990 to 1997) 38 patients with pericardial effusion. The age ranged between 3 months and 79 years (mean 41.15 +/- 21.78 years). Pericardial biopsy was performed in all cases through a subxiphoid incision. RESULTS: In 4 patients (10.5%) the biopsy was able to define etiology, 2 had tuberculosis and 2 neoplasias (1 undetermined adenocarcinoma, 1 mesotelioma). In 34 patients the biopsy showed non-specific chronic pericarditis. CONCLUSION: Pericardial biopsy was not an effective method to determine the etiological diagnosis in pericardial effusion patients. We believe that we have to individualize the indication of pericardial biopsy especially if tuberculosis or neoplasia are suspected.