A. Heryet

The immunohistological detection of platelets, megakaryocytes and thrombi in routinely processed specimens

The production and characterization of a new monoclonal antibody, Y2/51, against platelet glycoprotein IIIa is described. A useful feature of this antibody is its ability to recognize platelets and megakaryocytes in formalin‐fixed routinely processed material. It could also be used to reveal platelets both in thrombi in large vessels and in microthrombi too small to be readily apparent on conventional microscopic examination. For this purpose it was helpful to use the antibody in conjunction with a new monoclonal reagent (Ret40f) against red cell sialoglycoprotein β‐which detects red cells and their precursors in routinely processed tissue. The use of these antibodies should be valuable for the detection of thrombi in a variety of situations such as renal transplant rejection, coronary artery disease and vasculitis.

Granular cell tumours revisited. An immunohistological and ultrastructural study.

Twenty‐five granular cell tumours were stained with a panel of antibodies to histiocytic, muscle, neural, neural crest, epithelial and endothelial markers. Electron microscopy was also performed in six cases. Twenty‐four of the cases were similar morphologically and immunocytochemically. One case with features of an endothelial origin is described. The present study strongly supports the viewpoint that granular cell tumours are a distinct entity rather than being the common appearance of a group of lesions of differing histogenesis. Origin from a neural crest‐derived peripheral nerve‐related cell is favoured.

Expression of HLA-DR antigens on bile duct epithelium in primary sclerosing cholangitis.

The expression of HLA class I (HLA-A, B, C) and class II (HLA-DR) antigens on the biliary epithelium of 10 patients (nine men) with primary sclerosing cholangitis (PSC) was investigated using an immunoperoxidase technique on cryostat sections. Five patients were staged as grade II and five grade III on hepatic histology. None were cirrhotic. as grade II and five grade III on hepatic histology. None were cirrhotic. Controls were nine patients with primary biliary cirrhosis (PBC), five with extra hepatic biliary obstruction, 15 with other forms of chronic liver disease and six with normal livers. Bile ducts from the normal subjects and patients with chronic liver disease did not express HLA-DR antigens. In contrast, all 10 of the PSC biopsies showed varying degrees of HLA-DR staining of the biliary epithelium. Expression of DR antigens was also found on the bile ducts of all five patients with extra hepatic biliary obstruction and in six of nine patients with PBC. Expression of HLA class I antigens was seen on the biliary epithelium of all the biopsies examined. Increased numbers of helper and suppressor T-cells were seen in the portal tracts of all the PSC patients. This study has confirmed that aberrant expression of HLA-DR may occur on the biliary epithelium of some, but not all, patients with PBC. In addition, the study has shown that aberrant expression of HLA-DR always occurs in PCS at an early stage of histological liver damage. While this may be important in the pathogenesis of PSC, the aberrant expression in extra hepatic biliary obstruction suggests that it may be a secondary phenomenon.

Peripheral blood and portal tract lymphocyte populations in primary sclerosing cholangitis

The relative distribution of lymphocyte subpopulations in the blood and liver of patients with primary sclerosing cholangitis (PSC) and related diseases has been studied using immunoenzyme techniques. The peripheral blood CD4/CD8 T lymphocyte ratio was significantly higher in active ulcerative colitis (UC) and in PSC with inactive UC than in inactive UC alone. In contrast, no relationship with disease activity was seen in Crohns disease. The portal tract t lymphocyte count per high power field (mean +/- S.D.) was higher in pre-cirrhotic PSC (173 +/- 105) and primary biliary cirrhosis (PBC: 210 +/- 110) than in histologically normal liver (42 +/- 27). However, the overall portal tract CD4/CD8 ratio was similar in PSC (1.49), PBC (1.89) and normal controls (1.63). The results are consistent with immunological involvement in the pathogenesis of PSC, but argue against the hypothesis that changes in the peripheral blood T cell subsets are due to sequestration at the site of tissue inflammation.

Is it necessary to embed bone marrow biopsies in plastic for haematological diagnosis

With the increase in the use of bone marrow trephines for diagnosis have come numerous reports that traditional methods of preparation (by decalcification and embedding in paraffin wax) should be replaced by plastic embedding to avoid decalcification. It has been argued that only by this means can the high quality preparations needed for accurate haematopathological diagnosis be achieved. The present study challenges this viewpoint and argues that with a little extra care and attention conventional paraffin embedding techniques can give equally high quality preparations. Sections prepared in this way meet the diagnostic needs of the haematologist, without requiring a separate technique to be established in the pathology laboratory solely for bone marrow trephines.

Kupffer cell number is normal, but their lysozyme content is reduced in alcoholic liver disease.

A quantitative immunohistochemical study of Kupffer cells in liver biopsies from alcoholics was carried out. Two markers were compared, lysozyme and an antimacrophage monoclonal antibody EMB/11. The results showed that there is no significant reduction in Kupffer cell numbers in acute and chronic alcoholic liver disease but that there is a reduction in the number of Kupffer cells staining positively for lysozyme. Thus, those clinical phenomena such as endotoxaemia in alcoholic liver disease are not due to reduction in Kupffer cell number but perhaps to a functional deficit in these cells.

The L1 antigen and squamous metaplasia in the bladder

The L1 antigen was investigated as a marker of squamous differentiation in urothelium using a monoclonal antibody Mac387, and the results were compared with the expression of high molecular weight cytokeratins. L1 antigen was consistently demonstrated in all instances of partial and complete squamous metaplasia and in squamous carcinomas. In contrast, pure transitional cell carcinomas (except one with minor focal staining), adenocarcinomas and normal and hyperplastic urothelium did not label. In a few squamous carcinomas in situ, the pattern of labelling obtained with Mac387 was different from that seen in invasive squamous carcinomas and metaplasias. Compared with high molecular weight cytokeratins, the expression of L1 was more intense in areas of squamous differentiation. L1 expression, as identified by antibody Mac387, may therefore serve as a useful marker of squamous differentiation in urothelial lesions.

The Value of Immunocytochemistry in Differentiating High-Grade: Lymphoma from Other Anaplastic Tumours: A study of anaplastic tumours from 1940 to 1960

Immunocytochemistry is now established in many histology laboratories for diagnostic purposes and is routinely used in ascribing an origin to poorly differentiated tumours. This raises the question of whether traditional morphological skills are being abandoned in favour of new technology and, if so, whether that is justified. Twenty-three lymph node biopsies diagnosed as anaplastic carcinoma, reticulosarcoma or unclassifiable tumour between 1940 and 1960 (when immunocytochemistry was not available) were retrieved from the archives of the Radcliffe Infirmary. Paraffin sections were stained with a panel of monoclonal antibodies previously shown to be useful in the identification of tumours of uncertain origin. Of the 15 cases given a definite morphological diagnosis six (40%) were shown to be incorrect on the basis of immunostaining. In the eight remaining cases in which no diagnosis was recorded immunostaining provided a clear diagnosis in seven instances. These results are similar to those recorded on contemporary cases and demonstrate the value of immunocytochemical staining, as an adjunct to traditional morphological examination. In addition, it is clear that currently available monoclonal antibodies are suitable for use on routinely processed material more than 30 years old.

The prognostic significance of immunophenotype in high-grade non-Hodgkin's lymphoma

The prognostic value of immunophenotyping lymphomas was assessed by studying 51 cases of high‐grade non‐Hodgkins lymphoma for which long term clinical follow‐up (14–28 years) was available. Using antibodies which identify T‐ and B‐cell‐related antigens in formalin‐fixed, paraffin‐embedded material, 43 were shown to be of B‐cell and eight of T‐cell phenotype. In terms of survival, cases of high‐grade T‐cell lymphoma fared significantly worse (P < 0.05) than cases of high‐grade B‐cell subtype. These findings support the belief that T‐cell lymphomas have a more aggressive clinical course than their B‐cell counterparts.

Inappropriate expression of blood group antigens on biliary and colonic epithelia in primary sclerosing cholangitis.

The distribution of carbohydrate antigens of the ABO, Lewis, and Kell systems was examined in biliary and colonic epithelial of 11 patients with primary sclerosing cholangitis (PSC) using a panel of 11 monoclonal antibodies. Controls consisted of 27 liver biopsy specimens (11 normal, six alcoholic liver disease, five extrahepatic obstruction, and five primary biliary cirrhosis) and 24 colonic biopsy specimens (six normal, four Crohns disease, and 14 ulcerative colitis). There was inappropriate staining with anti-A (four of six, 66%) and anti-B (nine of 11, 81%) in biliary epithelium of PSC patients compared with normal and disease controls. Expression of Lewis antigens was increased in patients with cholestatic liver disease. Ninety one per cent of PSC patients showed a similar pattern of inappropriate staining by anti-A and anti-B antibodies in colonic epithelium compared with 33% of normal and 42% of inflammatory bowel disease controls. There is inappropriate expression of A and B carbohydrate antigens in biliary and colonic epithelium in PSC. Whether these oncofetal antigens are implicated in the pathogenesis of this condition is discussed.