Nonresident macrophages are absent from glomeruli in IgA nephropathy.

The presence of nonresident cells of monocyte-macrophage lineage was investigated in 50 renal biopsies, including 20 from patients suffering from IgA nephropathy. Histochemical and immunological techniques were used to identify, respectively, nonspecific esterase and peroxidase activities and HLA class II molecules. Although intraglomerular phagocytes were observed in all control biopsies, small numbers were seen in only two samples from patients with IgA nephropathy.

Expression of CD 25 (Tac antigen) in lymphoid leukemias and non-Hodgkin lymphomas.

A monoclonal antibody to IL2 receptor Tac/CD 25 antigen was included in the phenotyping panel of 92 leukemic proliferations. Spontaneous expression of this molecule was observed in one disorder of T-phenotype only, but in 75% of B-chronic lymphocytic leukemia (CLL) and on cells from B-cell leukemic lymphomas. These findings provide further evidence for a non-T-cell restriction of IL2 receptor and raise the question of multiple gene derepression in hematologic disorders of B-lineage.