Follicular dendritic cells in follicular lymphoma and types of non-Hodgkin lymphoma show reduced expression of CD23, CD35 and CD54 but no association with clinical outcome.

AIMS: Follicular dendritic cells (FDC) are specialized antigen-presenting cells found exclusively in the germinal centre (GC), which can be detected in B cell non-Hodgkin lymphomas (NHL) as reactive bystander cells. Recently, gene expression profiling has revealed that FDC networks might be associated with clinical outcome in follicular lymphoma. The aim was to characterize FDC in NHL and to evaluate a possible association with outcome in follicular lymphoma. METHODS AND
RESULTS: The extent and immunophenotype of FDC was determined semi-quantitatively in reactive GC and NHL (follicular lymphoma, angioimmunoblastic T cell lymphoma, mantle cell lymphoma) using fluorescence double staining and digital image analysis. In all NHL tested CD23 and CD35 and CD54 were expressed at relatively low levels on FDC, comparable to FDC found in the dark zone of the GC. However, the extent of FDC networks did not correlate with the clinical outcome of 102 patients with follicular lymphomas treated within a prospectively randomized trial.
CONCLUSIONS: FDC found in different types of NHL show quantitatively reduced expression of several proteins, suggesting that there are functional differences between FDC in normal GC and NHL. The extent of the FDC networks in follicular lymphoma is not useful as a prognostic marker.