T-cell/histiocyte-rich large B-cell lymphoma shows transcriptional features suggestive of a tolerogenic host immune response.
Background: Gene expression profiling has successfully identified the prognostic significance of the host response in lymphomas. The aggressive T-cell/histiocyte-rich large B-cell lymphoma and the indolent nodular lymphocyte-predominant Hodgkin's lymphoma are both characterized by a paucity of tumor cells embedded in an overwhelming background. The tumor cells of both lymphomas share several characteristics, while the cellular composition of their microenvironment is clearly different.
Methods: We collected 33 cases of T-cell/histiocyte-rich large B-cell lymphoma and 56 cases of nodular lymphocyte-predominant Hodgkin's lymphoma and performed microarray gene expression profiling on ten cases of each lymphoma, to obtain a better understanding of the lymphoma host response. By quantitative reverse transcriptase polymerase chain reaction we verified that these 20 selected cases were representative of the entire population of T-cell/histiocyte-rich large B-cell and nodular lymphocyte-predominant Hodgkin's lymphomas.
Results: We observed that the microenvironment in nodular lymphocyte-predominant Hodgkin's lymphoma is molecularly very similar to a lymph node characterized by follicular hyperplasia, while the microenvironment in T-cell/histiocyte-rich large B-cell lymphoma is clearly different. The T-cell/histiocyte-rich large B-cell lymphoma signature is hallmarked by up-regulation of CCL8, interferon-gamma, indoleamine 2,3 dioxygenase, VSIG4 and Toll-like receptors. These features may be responsible for the recruitment and activation of T cells, macrophages and dendritic cells, characterizing the stromal component of this lymphoma, and may point towards innate immunity and a tumor tolerogenic immune response in T-cell/histiocyte-rich large B-cell lymphoma.
Conclusions: The gene expression profile of T-cell/histiocyte-rich large B-cell lymphoma, in comparison with that of nodular lymphocyte-predominant Hodgkin's lymphoma, shows features suggestive of a distinct tolerogenic host immune response that may play a key role in the aggressive behavior of this lymphoma, and that may serve as a potential target for future therapy.