Leukaemic mantle cell lymphoma with t(11;14) and trisomy 12 showing clinical features of state A0 B cell chronic lymphocytic leukaemia

The precise diagnosis of lymphoma usually requires the histological examination of lymph nodes or involved tissues. Mantle cell lymphoma is a form of intermediate grade non-Hodgkin's lymphoma in which typical morphological immunophenotypic and cytogenetic features have been recognised. A case of leukaemic mantle cell lymphoma with the characteristic reciprocal translocation t(11;14) together with trisomy 12, a chromosomal abnormality usually associated with B cell chronic lymphocytic leukaemia (CLL), is presented. This combination of cytogenetic abnormalities has not been reported previously. The lack of lymphadenopathy and hepatosplenomegaly in this patient is more in keeping with stage A0 CLL. This case demonstrates the close clinical and biological relationship between mantle cell lymphoma and CLL.     

Variability in apoptotic response to poliovirus infection

In several cell types, poliovirus activates the apoptotic program, implementation of which is suppressed by viral antiapoptotic functions. In such cells, productive infection leads to a necrotic cytopathic effect (CPE), while abortive reproduction, associated with inadequate viral antiapoptotic functions, results in apoptosis. Here, we describe two other types of cell response to poliovirus infection. Murine L20B cells expressing human poliovirus receptor responded to the infection by both CPE and apoptosis concurrently. Interruption of productive infection decreased rather than increased the proportion of apoptotic cells. Productive infection was accompanied by the early efflux of cytochrome c from the mitochondria in a proportion of cells and by activation of DEVD-specific caspases. Inactivation of caspase-9 resulted in a marked, but incomplete, prevention of the apoptotic response of these cells to viral infection. Thus, the poliovirus-triggered apoptotic program in L20B cells was not completely suppressed by the viral antiapoptotic functions. In contrast, human rhabdomyosarcoma RD cells did not develop appreciable apoptosis during productive or abortive infection, exhibiting inefficient efflux of cytochrome c from mitochondria and no marked activation of DEVD-specific caspases. The cells were also refractory to several nonviral apoptosis inducers. Nevertheless, typical caspase-dependent signs of apoptosis in a proportion of RD cells were observed after cessation of viral reproduction. Such "late" apoptosis was also observed in productively infected HeLa cells. In addition, a tiny proportion of all studied cells were TUNEL positive even in the presence of a caspase inhibitor. Degradation of DNA in such cells appeared to be a postmortem phenomenon. Biological relevance of variable host responses to viral infection is discussed.