El descenso del número de linfocitos B de memoria en pacientes con inmunodeficiencia variable común está asociado a una apoptosis aumentada de esta población celular. Desarrollo de un método nuevo para la detección de la apoptosis en muestras de sangre completa

Abstract

Common Variable Immunodeficiency (CVID) is a heterogeneous disease characterised by low memory B cell counts in peripheral blood (PB). Although previous reports have attributed memory CD27+ B cell decrease to a possible defective germinal centre development, the cause of this defect remains basically unknown. On the other hand, increased apoptosis has been implicated in the pathogenesis of several diseases, and could be another factor that contributes to explain memory B cell reduction. However, a negative balance between apoptosis/survival of memory B cells in CVID patients has still not been documented. Therefore, we asked whether increased apoptosis was relevant in CVID. To test this concept, total and memory B cells from CVID patients and healthy controls were studied by flow cytometry to determine spontaneous and induced apoptosis. Apoptosis was measured by Annexin-V expression after a 24 hour culture with and without anti-CD95 proapoptotic monoclonal antibody. We also developed a new and sensitive method that uses 7-amino-actinomycin D (7-AAD) to measure very low numbers of apoptotic cells in whole PB. Our results clearly indicate diminished absolute counts and higher apoptosis in memory B cells from CVID patients than in healthy controls (P < .01). Moreover, we also demonstrate that CD95 is not implicated in regulating memory B cell apoptosis.