PARTICIPATION OF MACROPHAGES IN SEGMENTAL ENDOCAPILLARY PROLIFERATIONPRECEDING FOCAL GLOMERULAR SCLEROSIS

We studied infiltrating cells in the glomeruli of eight cases with foc al segmental endocapillary proliferation (FSEP) using monoclonal antib odies to leukocyte common antigen, T cells, B cells, and monocytes/mac rophages (Mo/Mphi). It was demonstrated by sequential biopsies perform ed in five cases that FSEP preceded focal glomerular sclerosis (FGS). Cell types in FSEP were compared with those in FGS from 17 patients wi th persistent nephrotic syndrome, ten non-nephrotic patients, and eigh t patients with nephrotic syndrome which was initially responsive to s teroid therapy but relapsed, as well as minimal change specimens from nine nephrotic patients. In the glomeruli, the mean total leukocyte co unts increased significantly in the FSEP group (P < 0.01). The serial sections in FSEP revealed that Mo/Mphi were the predominant cells and were localized in areas of endocapillary proliferation. T-cell or B-ce ll infiltration was less marked. The extensive intracapillary distribu tion of p150,95 antigen belonging to the integrin family and acting as a C3bi receptor suggested that FSEP may be mediated by adhesion molec ules expressed on Mo/Mphi. These findings indicate that Mo/Mphi may pl ay a key role in FGS which shows endocapillary proliferation in the in itial stage.