An Immunohistochemical Study on Isotypes of the Immune Complexes Trapped by Follicular Dendritic Cells (FDC) in Various Human Lymphoid Tissues

Follicular dendritic cells (FDC) are well known to trap and retain immune complexes (IC) containing various isotypes of immunoglobulins1,2,3. In addition, it has been reported that FDC retained IC with peculiar isotypes of immunoglobulins in certain diseases (IgAl in IgA nephropathy4,5, IgE in Kimura’s disease6 etc). These observations imply the particular relationships between isotype of the immunoglobulin constituting IC retained by FDC and immune responses or pathogenesis of certain immunopathological conditions. In the present study, distribution of each isotype of immunoglobulins was systemically examined in human various lymphoid tissues using immunohistochemical techniques with special reference to the reactivity within germinal centers (GC).