Endothelial cell chimerism after renal transplantation and vascular rejection.

BACKGROUND: The blood vessels of a transplanted organ are the interface between donor and recipient. The endothelium in the blood vessels is thought to be the major target for graft rejection. Endothelial cells of a transplanted organ are believed to remain of donor origin after transplantation. We aimed to verify this concept. METHODS: We studied biopsy samples from 12 renal transplants for the presence of endothelial cells of recipient origin. We used three different techniques: immunohistochemistry for MHC class-I antigens, immunohistochemistry for ABO-blood-group antigens, and in-situ hybridisation for X and Y chromosomes. After we had confirmed that these techniques did identify endothelial cells of recipient origin, tests were done in a second group of 26 patients to find out whether endothelial chimerism correlated with graft rejection. FINDINGS: We found a strong correlation between the percentage of recipient endothelial cells in the peritubular capillaries and the type of graft rejection (r = 0.71, p < 0.0001). These cells were found mainly in grafts of patients who had had rejection, especially among patients with vascular rejection. In grafts of patients without rejection only sporadically recipient endothelial cells were detectable. INTERPRETATION: Our data show that endothelial cells of the recipient can replace those of the donor. This replacement is associated with graft rejection. We postulate that endothelium that is damaged by vascular rejection is repaired by endothelial cells of the recipient.

Rapid verification of the identity of questionable specimens using immunohistochemistry with monoclonal antibodies directed against HLA-class I antigens.

AIMS: A case report is presented in which an unexpected pathological diagnosis raised the possibility that biopsies of two patients were mixed-up. Since these biopsies were obtained from kidney transplant patients, the HLA-typings of both patients were known. METHODS AND RESULTS: We developed an immunohistochemical method using HLA-class I specific monoclonal antibodies to recognize the donor and recipient antigens in these biopsies. Using this method we could confirm the identity of the patients of whom the biopsies had been taken. CONCLUSIONS: This method, which uses the highly polymorphic HLA-system, is potentially useful for rapid and easy verification of the identity of specimens if a mix-up is suspected.

Using Kryofix as alternative for formalin results in more optimal and standardized immunostaining of paraffin sections.

Although used for over one century formalin has several disadvantages which Kryofix, an alternative fixative for paraffin blocks used in Leiden for 6 years, does not have. In this study the effects of Kryofix on tissue regarding immunohistochemistry are compared with those of buffered formalin. All markers studied showed enhanced staining in the Kryofix blocks after 4 hours of fixation, whilst in some cases the immunostaining of the formalin blocks was even negative. For all markers, the sera could be further diluted for the Kryofix sections, for some with as much as a factor 20, enhancing the cost-effectiveness of the method. We established that for formalin, the fixation time strongly influenced the results. For Kryofix there was no time factor: the immunostaining results of 1 hour fixation were identical to those after 3 months of fixation. This study shows that by this method of fixation, in which there is no cross-linking of proteins, immunostaining of paraffin sections is optimized and standardized.

Amine and peptide hormone production by lung carcinoid: a clinicopathological and immunocytochemical study.

A consecutive series of 38 lung carcinoid tumours (36 surgical and two necropsy specimens) was studied. Histopathological features and amine and peptide hormone immunoreactivity were correlated with gross characteristics (size, location) and clinical data. Peripheral carcinoids were detected a decade later than central carcinoids and tended to be bigger. In general, the histological characteristics of peripheral and central carcinoids were similar; atypical features, however, were more common in peripheral carcinoids. Most carcinoids contained many argyrophilic cells (58%). Although argentaffinic cells were not found, serotonin immunoreactive cells were present in 32% of the tumours. Peptide hormone immunoreactivity (adrenocorticotrophic hormone (ACTH), calcitonin, somatostatin, gastrin) was rare. In one case massive ACTH production had caused clinically manifest Cushing's syndrome. In two other cases few ACTH immunoreactive cells were found and in one case calcitonin immunoreactive cells were present. The relative rarity of hormone production in lung carcinoids and the predominantly benign course of the tumour preclude the use of peptide hormone production as a prognostic indicator.

Efficiency and sensitivity of indirect immunoperoxidase methods.

The peroxidase-antiperoxidase (PAP) complex method has repeatedly been claimed to be more sensitive and antibody efficient than the indirect peroxidase labeled antibody method. However, most studies comparing these methods used tissue sections as the test material. However, test systems with known amounts of antigen will allow more reliable comparison of these methods and quantitative evaluation of method sensitivity. We therefore compared the antibody efficiency and sensitivity of these methods for the detection of human chorionic gonadotropin in an enzyme linked immunosorbent assay (ELISA), an antigen spot test (AST) and tissue sections of choriocarcinoma. In the PAP technique rabbit PAP and goat anti-rabbit antibody were applied. The same antibody was peroxidase-labeled with the periodate technique and used in the labeled antibody method. In the ELISA the PAP method resulted in slightly higher antibody efficiency than the labeled antibody method. At low primary antibody dilutions the intensity of the reaction decreased with the PAP method but remained high with the labeled antibody method, in the ELISA as well as on tissue sections. In the AST the labeled antibody method and the PAP method appeared to be equally sensitive.

Medullary differentiation of anaplastic thyroid carcinoma.

Fourteen cases of anaplastic carcinoma of the thyroid (ACT) were studied with silver staining and immunohistochemical technics for signs of medullary differentiation. For comparison a series of 11 cases of medullary carcinoma of the thyroid (MCT) was studied. In nine out of 14 cases of ACT both argyrophilia and immunoreactive calcitonin could be detected as evidence of an apparent C-cel origin of these tumors. Most of the patients with these anaplastic medullary carcinomas died within 6 months after the histological diagnosis was made. It is concluded that the histological diagnosis of anaplastic variants of MCT can only be made on the basis of argyrophilic cytoplasmic granules and calcitonin immunoreactivity. In contrast to well differentiated MCT the anaplastic medullary carcinoma is characterized by a poor prognosis.

Human chorionic gonadotrophin and alpha-fetoprotein in testicular germ cell tumours: a retrospective immunohistochemical study.

A series of testicular germ cell tumours (46 seminomas and 27 non-seminomas) was studied immunohistochemically with regard to the presence of alpha FP and HCG. In three seminomas, HCG reactive syncitiotrophoblast-like giant cells (STLG) were found. Immunoreactive alpha FP did not occur in seminomas. In differentiated mature teratomas HCG or alpha FP could not be demonstrated. In embryonal carcinomas with or without teratoma (MTI/MTU/MTT) HCG immunoreactivity was found in 83%, usually localized in STLG. In 75% of these tumours alpha FP could be demonstrated. This protein was localized in foci of endodermal sinus or yolk sac differentiation, but also in single cells and cell clusters in areas of embryonal carcinoma. In some cases syncitial cells were present which contained both HCG and alpha FP. Immunostaining of tumour markers appeared not to provide important additional criteria for classification of these tumours in the currently available classifications. The significance of HCG containing STLG in seminomas deserves further investigation. Prospective studies of embryonal carcinoma with or without teratoma (MTI/MTU/MTT) will be necessary to evaluate the possible prognostic importance of the presence of alpha FP or HCG or both.

A simplified method for the rapid preparation of peroxidase-anti peroxidase (PAP) complexes.

A modified method is described for the rapid production of peroxidase-antiperoxidase complexes to be used in immunocytochemistry. In this method anti-peroxidase antibodies are precipitated from crude serum with peroxidase at equivalence and subsequently resolubilized at low pH with excess peroxidase. The complexes are isolated from unbound immunoglobulin and peroxidase by gelfiltration. The method combines the advantages of both previously described preparation procedures. The resulting PAP-complex, when tested in indirect immunocytochemistry, is comparable to that obtained in established preparation procedures.

Morphology and immunohistochemically-defined endocrine function of pancreatic islet cell tumours.

Thirty pancreatic islet cell tumours were histologically classified and analysed for their possible peptide hormone content using the immunohistoperoxidase method. Seven tumours contained insulin, six tumours contained gastrin and eight tumours contained glucagon. One tumour contained all three hormones. In the insulin and gastrin-containing tumours, the cells were usually arranged in solid nests of cells, with tubular and acinar formations in about half the cases. In the glucagon-containing tumours the cells were mainly arranged in anastomosing ribbons consisting of one of two layers of small cells. Most of the hormone-containing tumours were argyrophilic using Grimelius' silver reaction. All but one of the glucagon-containing tumours were incidental findings at autopsy. About half of the other tumours had metastasized. It is concluded that a relation exists between the histological pattern of growth and immunohistochemically defined endocrine function of pancreatic islet cell tumours.