Tamm-Horsfall protein in lymph nodes

Autoimmune Responses to Tamm-Horsfall Protein in the Pathogenesis of Chronic Pyelonephritis

Although the role of bacterial infection as the major determinant in the development of acute pyelonephritis has been well documented for years, the nature of the renal scarring typical of chronic "atrophic" pyelonephritis has been a matter of controversy for at least three decades. In the past, recurrent bacterial infection of the kidney was thought to be responsible for the pathologic entity of "chronic pyelonephritis." However, more recent studies suggest that recurrent bacteriuria, in the absence of some form of obstructive uropathy, rarely produces chronic pyelonephritis. The close association between vesicoureteral reflex and chronic pyelonephritis has also been firmly established and has been observed to occur frequently in the absence of urinary tract infection. However, the mechanism by which vesicoureteral reflux injures the kidney has not been firmly established. A number of observations have suggested that some normal component of urine, particularly Tamm-Horsfall protein, might serve as an antigenic determinant involved in the immunopathogenesis of renal scarring in vesicoureteral reflux. The present studies were designed to investigate the immunopathogenic role of Tamm-Horsfall protein in a rabbit model of tubulointerstitial nephritis, and in a swine model of reflux nephropathy. The immune responses to Tamm-Horsfall protein in patients with recurrent nephrolithiasis were also examined, as were the antigenic similarities between Tamm-Horsfall protein and protein-containing components of uropathic bacteria. The results of these studies indicate that autoimmune responses to Tamm-Horsfall protein may occur after exposure to Tamm-Horsfall protein by intravenous challenge in rabbits, and by urinary reflux in pigs, as well as in recurrent nephrolithiasis in man.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous Tamm-Horsfall protein polyps: report of a case in association with a hematoma that mimicked a renal neoplasm

Tamm-Horsfall protein (THP) is a glycoprotein produced only in the thick ascending limb of the loop of Henle. Its primary physiological function is unknown, but it may have a role in host defense against infectious organisms. THP is the primary scaffolding protein in all varieties of tubular casts. Under certain conditions, THP may be extruded from tubular lumens into the interstitium and lymphatic channels. It even may be found within lymph nodes sampled for staging of neoplastic conditions. THP deposits were described in lumens of large veins. The pathogenetic basis of this finding is not known, but obstruction of renal outflow was suggested, and several cases were associated with macroscopic hematuria. We report a case of intravenous THP polyposis in which, in addition to abundant hemorrhage, there was formation of a hematoma. This measured 12 cm in diameter and caused clinical concern for the possibility of renal cell carcinoma. Although the cause of the hematoma was not apparent, the association with striking intravenous polyps of THP is noteworthy because this represents the first association of intravenous THP polyps with a large intraparenchymal hematoma.

Cellules épithéliales bénignes et protéine de Tamm-Horsfall dans les ganglions lymphatiques des pièces de néphrectomie pour néphroblastome : Un piège diagnostique

When a lymph node metastasis is discovered during the pathology examination of surgical specimens with nephroblastoma, the tumour is classified as stage III, according to the classification of the International Society of Paediatric Oncology (SIOP 2001), and post-operative intensive treatment of the patient includes irradiation and chemotherapy. Benign epithelial cells in perinephric lymph nodes in cases of renal tumours in childhood may be confused with metastases. They are often associated with an accumulation of Tamm-Horsfall protein in lymph node sinuses. This case illustrates latero-aortic lymph node complexes of benign epithelial cells and Tamm-Horsfall protein in a 16-month-old girl with surgical resection of a nephroblastoma after pre-operative chemotherapy. The nephroblastoma was predominantly epithelial and was classified as SIOP stage I. There were accumulations of Tamm-Horsfall protein in lymph node sinuses, in lymphatic vessels, in the kidney outside the tumour, and in the renal sinus. This association of epithelial cells with deposits of Tamm-Horsfall protein and their resemblance to cells of the distal convoluted tubules favour a diagnosis of benignity. A definitive diagnosis is supported by the small size of the cells, their bland nuclei, and morphological features differing from those of tumour cells, but deposits of Tamm-Horsfall protein may be associated with true lymph node metastases.

A comparative immunohistochemical study of malignant mesothelioma and renal cell carcinoma: the diagnostic utility of Leu-M1, Ber EP4, Tamm-Horsfall protein and thrombomodulin

Metastatic renal cell carcinoma has occasionally been reported to mimic malignant pleural mesothelioma. Morphologically, histochemically and immunohistochemically, similarities in the two tumours exist making their differentiation difficult, particularly in biopsy specimens. The aim of this study was to make a comparative immunohistochemical analysis of the two tumours by use of a panel of four antibodies (Leu M1; Ber EP4; thrombomodulin and Tamm-Horsfall protein). Their suitability in differentiating between the two tumours was assessed. We examined 20 cases of renal cell carcinoma and 20 cases of malignant pleural mesothelioma. On immunostaining with Leu M1, 14 of 20 renal cell carcinomas were positive, yielding 70% sensitivity and 95% specificity and one of 20 mesothelioma. In comparison, Ber EP4 antibody stained only seven of 20 of the renal cell carcinomas. In addition, it was noted that four tubulo-papillary pattern renal cell carcinomas stained positively with both anti-Leu M1 antibody and Ber EP4 antibody. Thrombomodulin immunostaining was present in 11 of 20 mesotheliomas (55% sensitivity and demonstrated 95% specificity) and one of 20 renal cell carcinomas. For epithelial mesotheliomas only, thrombomodulin staining was identified in 10 of 14 cases. In the differentiation of renal cell carcinoma from epithelial mesothelioma we recommend the use of Leu M1 and thrombomodulin as diagnostically useful markers. None of the antibodies used in this study was effective in distinguishing sarcomatoid renal cell carcinoma from sarcomatous mesothelioma. Tamm-Horsfall protein showed little diagnostic utility in differentiating the two tumours.

Benign nodal lesions mimicking metastases from pediatric renal neoplasms: a report of the National Wilms' Tumor Study Pathology Center

Regional lymph node status is a key factor in the staging of pediatric renal tumors on the National Wilms' Tumor Study (NWTS). A review of cases entered on the NWTS has uncovered a number of cases where benign lymph node findings were mistaken for metastases. Most frequently, this was due to the presence of complexes of epithelial cells and Tamm-Horsfall protein within nodal sinuses. The epithelial cells were derived from damaged nephrons, usually resulting from obstruction by tumor. Another epithelial pseudometastic lesion, intranodal squamous epithelial cells, was found to originate from metaplastic calyceal urothelium. Benign mesothelial or coelomic inclusions similar to those previously described in pelvic and periaortic lymph nodes of adult females were found in nodes of four patients, including two boys, who are, to our knowledge, the first to be described with this finding. Other sources of confusion included protrusion of lymphoid follicles or germinal centers into nodal sinuses, thick endothelial cells of postcapillary venules mimicking epithelial tubules, nodal megakaryocytes resembling anaplastic nuclear changes, and histiocytic granulomas. Immunocytochemical methods were useful in evaluating some of these phenomena. Recognition of these pseudometastatic lesions is essential in order to avoid unnecessary and potentially hazardous therapeutic intensification.

Tamm-Horsfall protein outside the kidney

Tamm-Horsfall protein is the main protein in normal urine and readily precipitates. Previously there has been little study of the protein outside the kidney. An antiserum to the protein was used in an immunohistological investigation of human tissues. No Tamm-Horsfall protein was detected in normal organs other than the kidney. The protein was detected outside the kidney in abnormal organs in three general sites: (i) in ulcers of epithelial surfaces exposed to urine, (ii) deep in the wall of a bladder that had had previous surgery and (iii) in lymph nodes at the hilum of kidneys that had been obstructed or contained extra-tubular deposits of the protein. There was little evidence of a cellular response to the deposits of Tamm-Horsfall protein. The antiserum to Tamm-Horsfall protein is a good immunohistological marker of extravasated urine and is useful in the study of such conditions as fistulas of the urinary tract, operations on the urinary tract and reflux of urine into lymphatics and lymph nodes.

Serum antibody against Tamm-Horsfall protein in patients with renal cell carcinoma

We assayed sera from 24 patients with metastatic renal cell carcinoma for class specific antibody against urinary Tamm-Horsfall protein (THP) using indirect solid-phase radioimmunoassay techniques. Overall, 16 patients had elevated antibody levels (greater than 2 SD above the mean levels of control subjects). IgG against THP was elevated in eight of the patients, IgA in 12, and IgM in five. However, THP was not identifiable by immunohistochemical techniques in the sections of 15 of 24 tumors available for study. Nine of the 15 tumors were from patients with elevated antibody levels. Serum antibody against THP in patients with renal cell carcinoma appears to result from antigenic stimulation by THP derived from the urine rather than from the neoplasm.

Cystic Nephroma in Children. Report of a Case

A case of cystic nephroma is described in a 20-month-old female. The diagnosis of this rare renal pathologic lesion is essentially based on its pathologic features. The treatment consisted of nephrectomy followed by a brief course of chemotherapy. The literature is reviewed with regard to the pathologic features and treatment of this lesion, which has a favorable prognosis.

Epithelial inclusions and Tamm-Horsfall protein in paranephric lymph nodes. A light microscopy and immunocytochemical study

An unusual histological pattern made up of tubular structures and clusters of apparently epithelial cells floating within sinusoidal deposits of Tamm-Horsfall (TH) protein was observed in several lymph nodes removed with renal tumours (3 Wilms' tumours, 1 cystic nephroma) and pathological but non neoplastic kidneys (2 cases of reflux nephropathy). Masses of TH protein, often containing desquamated tubular epithelial cells, were also found in tubules, interstitium and perivascular lymphatic vessels of the resected kidneys, but never in the tumour tissue. Lymph nodes draining renal tumours, although moderately enlarged because of reactive hyperplasia and TH protein deposits, did not contain metastases. Our findings suggest that these inclusions originate from renal tubular epithelium and are transported to paranephric lymph nodes along with TH protein.

Tamm-Horsfall protein: unusual, large perinephric deposits

A case in which unusually large deposits of Tamm-Horsfall protein were identified in perinephric adipose tissue is presented. The deposition around the kidney in this case was most likely due to calyceal rupture, secondary to distal ureteric obstruction. The peculiar gross and microscopic appearance of these deposits, their intense staining with the periodic acid--Schiff technique, and their association microscopically with epithelial fragments raised the possibility of infiltration by mucin-producing adenocarcinoma. The localization of Tamm-Horsfall protein in the deposits by the immunoperoxidase technique helped to confirm their true nature.

Extratubular efflux and nephropathy

The extratubular efflux of periodic acid-Schiff (PAS) positive material is used as a histological indicator of intrarenal reflux, and correlation of the PAS positive material and interstitial as well as glomerular changes were analyzed in 114 surgical specimens consisting of renal calculi, hydronephrosis, vesicoureteral reflux, and others. (1) The incidence of extratubular efflux was apparently higher in the kidneys of hydronephrosis. (2) PAS positive material was seen not only in the interstitium but also flowed into the venous and lymphatic spaces. (3) Potent interstitial mononuclear cell infiltration and larger amounts of PAS positive material were seen in the kidneys showing a moderate grade of hydronephrosis rather than renal calculi. (4) Global glomerular sclerosis was the most frequent glomerular lesion, and segmental sclerosis and crescentic epithelial reaction in a small number of glomeruli were also noted. These results imply that intrarenal reflux could play an important role in the development of various renal tissue injuries.

Immunoblastic lymphoma with extracellular and intravascular immunoglobulin deposits: immunocytochemical and electron microscopic studies

Immunoblastic lymphoma (IBL) showing features of angioimmunoblastic lymphadenopathy (AIBL) is described. Abundant eosinophilic extracellular deposits were present in lymph nodes. Electron microscopic and immunoperoxidase studies showed this material was composed of degenerating tumor cells and polyclonal immunoglobulins (Mu and Alpha heavy chains and Kappa and Lambda light chains). Numerous arborizing vessels were thickened with monoclonal IgM(K) immunoglobulins. The tumor cell lysis and degeneration are though to be due to the high cell turnover and immune reaction to unrecognized substances.