To clarify the significance of mononuclear phagocytes in IgA nephropathy, renal biopsied materials from 45 patients with the disease were examined by the indirect immunoperoxidase method using anti-human monoclonal antibodies and by ultrastructural peroxidase (PO) cytochemistry. The monoclonal antibodies were FMC32, S-100 (alpha), My4, and LeuM5 for detection of mononuclear phagocytes and HLA-DR for Ia antigens. Mesangial hypercellularity in IgA nephropathy was divided into three grades. The number of monocyte/macrophages per glomerulus differed significantly among the grade of mesangial hypercellularity. In the capillary lumen, monocytes were more numerous in the group with slight mesangial hypercellularity. By contrast, macrophages were often found in the Bowman's space and mesangial area of the glomeruli in the advanced group. In the renal interstitium, the number of monocyte/macrophages per 100 interstitial cells differed significantly among the degree of interstitial damage, and they were observed mainly around sclerotic glomeruli. Ultrastructural PO cytochemistry revealed infiltration of monocytes, exudate macrophages, and/or PO-negative macrophages. Clinicopathological study showed a relationship between the number of monocyte/macrophages per glomerulus and the number of glomerular crescents and the degree of proteinuria. The constancy of the percentage of exudate macrophages and polymorphonuclear leukocytes were observed irrespective of the grade of mesangial hypercellularity. On the other hand, the increasing percentage of PO-negative macrophages and decreasing percentage of monocytes were observed over the grade. These results suggest that mononuclear phagocytes might play an important role in the pathogenesis of mesangial hypercellularity, and irreversible glomerular damage and interstitial tissue injury in IgA nephropathy.

Morphological and immunohistochemical studies using the anti-macrophage monoclonal antibody RbM2 were performed in cholesterol-fed rabbits. From the beginning of the experiment, the levels of lipoproteins showed the pattern of familial type III hyperlipoproteinemia patients, and glomerular endothelial and mesangial cells had lipid deposits. By the 3rd week, RbM2-positive cells appeared in the capillary lumina. These cells became larger and increased in number after the 8th week. Although they had become very large and had increased noticeably by the 20th week, few sclerotic glomeruli were observed. We could hardly detect any proliferation of or foamy changes in the mesangial cells, and monocyte/macrophages showed no proliferative capacity within the glomeruli. These findings suggest that hyperlipidemia alone did not cause proliferation or foam transformation of the mesangial cells. The glomerular macrophages, probably derived from circulating monocytes, did not induce a glomerular injury under the short-term hyperlipidemic conditions of these experiments.

Two monoclonal antibodies (MAbs) against human renal glomeruli, HEP1 and HBM1, were produced using isolated human glomeruli as an antigen. Immunohistochemical and immunoelectron microscopic analyses revealed that the recognition site of HEP1 is the cell surface of the visceral glomerular epithelial cells. HEP1 showed no reaction in the renal interstitium or in other tissues. HBM1 recognized an antigen present in the basal lamina of the renal glomeruli, Bowman's capsule, and partly in the basement membrane of renal tubules, but it was not reactive with the mesangial matrix or renal interstitium. The isotype of both MAbs was IgG1, k. The molecular weights of their corresponding antigens were 127-177 and 220 kD, respectively. Besides human tissues, HEP1 also showed cross-reactions with antigens in the visceral glomerular epithelial cells of various animals other than mice. HBM1 recognized human antigen only. Using both MAbs, eight cases of crescentic glomerulonephritis were examined immunohistochemically. As a result, it was demonstrated that the crescents may not be formed by visceral glomerular epithelial cells. From this study, these two MAbs appear to be useful markers for the evaluation of renal glomerular disorders.

Miyakawa H, Iyonaga K, Arima S, Yonekawa Y, Suga M, Ando M (First and Third Departments of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan). A superfemale with primary Sjögren's syndrome which involved systemic organs (Case report). J Intern Med 1997; 242: 261–5. A 52‐year‐old Japanese woman complicated by a sex chromosomal anomaly as a superfemale, a mosaic of XXXXX/XXXX/XXX/XX/XO, with mild mental retardation, was hospitalized for dry mouth, dry eyes, and proteinuria. The sialography of the right parotid gland showed a globular‐type gland enlargement. A definite diagnosis of primary Sjögren's syndrome (SS) was made, and further examinations revealed not only typical sicca syndrome but also systemic extraglandular lymphocytic infiltration; interstitial pneumonitis, glomerular‐ and interstitial nephritis, superficial gastritis, thyroiditis, and a severe excitation conductive impairment of heart. We report a very rare case of superfemale with primary SS which involved systemic organs.

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