Identification of monosomy 3 in choroidal melanoma by chromosome in situ hybridisation

BACKGROUND/AIMS

In uveal melanoma monosomy 3 is emerging as a significant indicator of a poor prognosis. To date most cytogenetic studies of uveal melanoma have utilised fresh tissue or DNA extracted from tissue sections. In this study chromosome in situ hybridisation (CISH) was used to study monosomy 3 in tissue sections. The copy number of chromosome 3 was determined and related to patient survival.

METHODS

Archival glutaraldehyde or formalin fixed, paraffin embedded material was obtained from 30 metastasising and 26 non-metastasising choroidal melanomas. Hybridisations were performed using centromere specific probes to chromosomes 3 and 18. Chromosome 18 was included as a control as previous abnormalities in uveal melanoma have not been described. Chromosomal imbalance was defined on the basis of changes in both chromosome index and signal distribution.

RESULTS

CISH was successfully performed on both glutaraldehyde and formalin fixed tissue. Four cases were unsuccessful because of extensive tumour necrosis. All cases were balanced for chromosome 18. Monosomy 3 was detected in 15 of the 26 cases of metastasising melanoma; the 26 non-metastasising tumours were all balanced for chromosome 3. Monosomy 3 was significantly associated with metastases related death.

CONCLUSION

CISH can successfully identify monosomy 3 in archival glutaraldehyde or formalin fixed, paraffin embedded tissue sections. Similar to previous studies monosomy 3 is a significant predictor of metastases related death.

Endometrial apoptosis in patients with dysfunctional uterine bleeding

AIMS

To assess glandular apoptosis in the zona functionalis of proliferative phase endometrium in normal individuals and in patients with dysfunctional uterine bleeding (DUB).

METHODS AND RESULTS

Routinely processed, haematoxylin and eosin-stained endometrial biopsies were assessed in 26 patients with symptomatic menstrual abnormality, mainly menorrhagia, and in 24 controls. All biopsies were in the proliferative phase and had been reported as within normal limits and consistent with the menstrual cycle dates provided. Apoptotic and mitotic figures were counted in a minimum of 100 transversely sectioned endometrial glands in all cases. In 16 biopsies (12 DUB and four controls) apoptosis was further assessed using the in situ terminal deoxynucleotidyl-transferase-mediated 2'-deoxyuridine-5'-triphosphate (dUTP) nick-end labelling (TUNEL) method. Apoptotic figures were identified in most control biopsies averaging 5.6/100 glands, and were significantly increased in biopsies from patients with DUB averaging 13.9/100 glands. There was no difference in mitotic figure counts. Apoptoses tended to be clustered within adjacent glands in both groups and individual glands exhibited both mitotic and apoptotic activity. Application of the TUNEL method gave broad agreement with morphological assessment although approximately 20-25% of typical apoptotic figures were not labelled.

CONCLUSIONS

Endometrial glandular apoptosis is present in most normal proliferative phase biopsies and appears increased in some cases of DUB. The significance of this finding is not known but increased apoptosis may serve as a morphological marker of abnormal endometrial development in otherwise normal biopsy specimens.

Detection of cytomegalovirus in upper gastrointestinal biopsies from heart transplant recipients: comparison of light microscopy, immunocytochemistry, in situ hybridisation, and nested PCR

AIM

To establish the diagnostic value of in situ hybridisation and the nested polymerase chain reaction (PCR) in detecting clinically relevant cytomegalovirus (CMV) infection in upper gastrointestinal biopsies from heart transplant patients.

METHODS

Test sensitivity and specificity for detection of CMV early gene RNA by in situ hybridisation and CMV intermediate early gene by PCR were established and then compared with haematoxylin and eosin (H&E) and immunocytochemical detection of CMV in order to establish the best pathological diagnostic approach. All investigations were carried out on formalin fixed, paraffin embedded tissue.

RESULTS

Nested PCR had the highest test sensitivity, followed by in situ hybridisation and immunocytochemistry with the same sensitivity; H&E had the lowest. H&E and immunocytochemistry were the most specific but both had a significant false negative rate which was less of a problem with PCR. However, PCR gave no other diagnostic information, and in situ hybridisation was no better than immunocytochemistry. Both in situ hybridisation and PCR were technically complex and more expensive.

CONCLUSIONS

H&E and immunocytochemistry represent the best initial screen for CMV and other diseases in upper gastrointestinal biopsies from heart transplant patients. If H&E and immunocytochemistry were negative, nested PCR could significantly increase the diagnostic yield of clinically relevant CMV infection. In situ hybridisation appeared to have no advantages and some drawbacks compared with immunocytochemistry and PCR.

Comparison of in situ hybridisation and polymerase chain reaction in the diagnosis of B cell lymphoma

AIM

To compare the sensitivity of the detection of immunoglobulin light chain messenger RNA (mRNA) restriction by in situ hybridisation (ISH) and clonal immunoglobulin heavy chain gene rearrangements by polymerase chain reaction (PCR) in the diagnosis of B cell lymphoma.

METHODS

Analyses were applied to formalin fixed, paraffin wax embedded, routine diagnostic specimens from cases with a provisional diagnosis of reactive lymph node (n = 23), B cell lymphoma (n = 21), and T cell lymphoma (n = 4). Nonisotopic ISH for kappa and lambda immunoglobulin light chain mRNA was performed using both fluorescein and digoxigenin labelled oligodeoxynucleotide probe cocktails. PCR was carried out on DNA extracted from sections using primers to framework 3 (Fr3) of the V segments and to conserved sequences from the J regions of the immunoglobulin heavy chain genes.

RESULTS

All reactive lymph nodes showed a polyclonal pattern of light chain mRNA by ISH, although one showed an excess of kappa positive cells. Nineteen of 21 (90%) cases of B cell lymphoma showed light chain restriction, and a further case showed a vast excess of kappa positive cells. By PCR, 20 of 23 reactive nodes (87%) showed a polyclonal pattern. In 13 of 21 B cell lymphomas (62%) a clonal band was detected.

CONCLUSION

In the diagnosis of B cell lymphoma in routinely processed diagnostic material ISH for light chain mRNA was more sensitive (90%) than PCR for heavy chain gene rearrangement using Fr3 and J region primers (62%).

Sequential malt lymphomas of the stomach, small intestine, and gall bladder

Low grade lymphomas of mucosa associated lymphoid tissue (MALT) are indolent neoplasms that, although tending to remain localised for many years, may spread to other mucosal sites. A 53 year old woman treated by total gastrectomy for low grade MALT lymphoma of the stomach developed a recurrence in the small bowel 18 years later, and a further recurrence involving the gall bladder after three years in complete clinical remission after chemotherapy. In situ hybridisation showed that the small intestine and gall bladder recurrences had the same pattern of light chain restriction. Tumour from all three sites was shown to be derived from a single clone by the demonstration of an identical immunoglobulin heavy chain gene rearrangement by the polymerase chain reaction. The case illustrates the propensity of MALT lymphomas to "home" to mucosal sites and gives an insight into their behavior over an extended follow up.

In situ hybridization and its diagnostic applications in pathology

In situ hybridization (ISH) is a technique by which specific nucleotide sequences are identified in cells or tissue sections. These may be endogenous, bacterial or viral, DNA or RNA. On the basis of research applications, the technique is now being translated into diagnostic practice, mainly in the areas of gene expression, infection and interphase cytogenetics. Diagnostic applications are most often based on short nucleotide sequences (oligomers) labelled with non-isotopic reporter molecules, and sites of binding may be localized by histochemical or immunohistochemical methods. The technique can be applied to routinely fixed and processed tissues; with some targets, it is even possible to obtain hybridization in autopsy material. ISH has been used to detect messenger RNA (mRNA) as a marker of gene expression, where levels of protein storage are low; for example, to confirm an endocrine tumour as the source of excess hormone production. Its application in infectious diseases has to date been mainly in viral infections, such as the typing of human papillomavirus (HPV) or the detection of Epstein-Barr virus by the presence of small nuclear RNAs (EBERs). The expression of mRNAs for histone proteins has been used to detect cells in S phase, and related methods may be applied to detect apoptotic cells. Using probes to chromosome-specific sequences, it is possible to detect aneuploidy, and to document changes in specific chromosomes, which may have prognostic significance in some tumours, such as B-cell chronic lymphatic leukaemia. Using sequence-specific probes, translocations can be identified, such as the t(11;12) of Ewing's sarcoma. This review presents an outline of the technique of in situ hybridization and discusses areas of current and potential diagnostic application.

Analysis of clonality in cytologic material using the polymerase chain reaction (PCR)

Immunoglobulin heavy chain (IgH) gene rearrangement analysis was performed on 27 fine needle aspiration (FNA) specimens (13 reactive hyperplasia, 11 B cell non-Hodgkin's lymphoma (B-NHL), one Hodgkin's disease and two suspicious of non-Hodgkin's lymphoma). Satisfactory amplification was achieved in 23/27 cases. A polyclonal pattern was seen in 14 cases (11 reactive hyperplasia, one B-NHL, one suspicious of lymphoma, one Hodgkin's disease). A monoclonal band was seen in nine cases (eight B-NHL, one reactive hyperplasia). Amplification was unsuccessful in four cases. Clonal analysis by PCR-based IgH gene rearrangement analysis can be successfully applied to FNA material and can be useful in diagnosis, but the results must be interpreted in conjunction with morphology and other ancillary information.

Demonstration of insulin production and storage in insulinomas by in situ hybridization and immunocytochemistry

Twelve cases of insulinoma were studied to assess the amount of hormone synthesis and hormone storage by the tumour and to see what effect a hormone-producing tumour has on the adjacent normal islets. This was investigated by performing in situ hybridization, which detects hormone messenger RNA, thus giving an indication of the degree of hormone synthesis by the tumour, and immunocytochemistry, which detects the hormone itself, thus giving an indication of the amount of hormone stored in the tumour cells. It was found that in most cases there was less hormone stored within the tumour cells than in adjacent islet cells. In a minority of cases, this decrease in stored hormone was associated with reduced hormone synthesis, but the majority of cases showed either equivalent or increased levels of hormone mRNA in the tumour cells compared with adjacent islets. In addition, it was noted that, unlike some other endocrine organs, the presence of a hormone-producing tumour within the pancreas did not appear to inhibit hormone synthesis in the adjacent normal tissue.

Expression of p53 in adrenocortical tumours: clinicopathological correlations

There are limited data to suggest that abnormalities of p53 expression may be a late event in the development of adrenocortical tumours. This has been investigated further by examining a series of adrenocortical adenomas and carcinomas by immunohistochemistry for p53 expression and a subset for evidence of mutation in exons 5-8 of the p53 gene using polymerase chain reaction/single strand conformational polymorphism (PCR/SSCP). In carcinomas, the findings have been correlated with survival data and with tumour ploidy. Immunopositivity for p53 was seen in 4 of 34 adenomas and 22 of 42 carcinomas. Mobility shifts were identified in 1 of 4 adenomas and 10 of 21 carcinomas. There was no correlation between immunostaining pattern or PCR/SSCP evidence of mutation and either survival or disease-free survival in carcinoma. There was also no correlation between p53 status and tumour ploidy. While these findings support a role for p53 in tumour progression, abnormal p53 expression does not appear to have any significant prognostic effect in carcinoma.

A search for evidence of viral infection in pancreases of newly diagnosed patients with IDDM

Techniques were developed to look for evidence of viral infection in formalin-fixed paraffin-embedded autopsy pancreatic tissues from patients who had died of recent-onset insulin-dependent diabetes mellitus. DNA extracted from 47 pancreases in which good DNA preservation was confirmed was analysed by a polymerase chain reaction for Epstein-Barr virus and by a nested polymerase chain reaction for cytomegalovirus. Histological sections from 29 pancreases in which there was good RNA preservation were tested for the presence of enterovirus and Epstein-Barr virus using in situ hybridization techniques. Seventy-five pancreases were analysed immunohistochemically for the presence of mumps virus. None of these viruses could be detected in any of the diabetic pancreases studied. Control studies suggested that the techniques employed were as sensitive as culture done at the time of autopsy. Pancreas was available for study in 9 infants who had died of myocarditis; enterovirus was demonstrable in islets in 5 of these cases. An acute or persisting infection in the pancreas at the time of clinical onset of insulin-dependent diabetes by any of the 4 virus included in this study seems unlikely.

Immunoglobulin light chain mRNA detected by in situ hybridisation in diagnostic fine needle aspiration cytology specimens

AIMS

To demonstrate expression of immunoglobulin light chain mRNA in diagnostic fine needle aspiration (FNA) cytology specimens using an in situ hybridisation (ISH) technique; and to evaluate ISH in a series of reactive lymphoid proliferations and malignant lymphomas.

METHODS

Forty diagnostic FNA specimens showing a lymphoid cell population were examined for immunoglobulin light chain mRNA expression using ISH. Aspirates were obtained from lymph node (n = 34), salivary gland (n = 3), subcutaneous tissue, thyroid and breast (n = 1 each). The cases included 20 B cell lymphomas, five cases of Hodgkin's disease and 15 reactive lymphoid proliferations. Comparison with light chain immunoreactivity was made in 36 cases and histological correlation from biopsy material was available in 24.

RESULTS

Immunoglobulin light chain restriction was demonstrated in 14 of 20 B cell lymphomas using ISH and in six of 17 B cell lymphomas using immunocytochemistry. A polytypic pattern of light chain expression was observed in four of five cases of Hodgkin's disease with both techniques, and in 12 of 15 and 11 of 14 reactive lymphoid proliferations using ISH and immunocytochemistry, respectively.

CONCLUSIONS

The assessment of immunoglobulin light chain expression is a useful adjunct to morphology in the diagnosis of reactive and malignant lymphoid proliferations in FNA specimens. Light chain restriction can be shown using either immunocytochemistry or ISH, but the latter is more sensitive in the diagnosis of B cell lymphoma.

p53 immunoreactivity and mutation of the p53 gene in smooth muscle tumours of the uterine corpus

Mutation and overexpression of p53 have been described in uterine malignant mixed Müllerian tumours and in endometrial adenocarcinoma, where it has been associated with a poor prognosis. This study examines p53 expression and mutation of the p53 gene in benign and malignant smooth muscle tumours of the uterine corpus. p53 expression was evaluated by immunohistochemistry in formalin-fixed, paraffin-embedded tissue from 23 leiomyosarcomas, 10 tumours of uncertain malignant potential (TUMPs), and 18 leiomyomas. Single-stranded conformational polymorphism, (SSCP) analysis of exons 5-8 of the p53 gene was performed on 13 leiomyosarcomas, nine TUMPs, and eight leiomyomas. With microwave antigen retrieval, p53 immunoreactivity was seen in 13/23 microwave treatment, staining was abolished in three leiomyosarcomas, all immunoreactive TUMPs, and the single positive leiomyoma. SSCP analysis revealed mutation in three leiomyosarcomas. There was one mutation in exon 5 in a case with positive immunohistochemistry. Two cases with negative staining showed mutation, one in exon 7 and one in exon 8. Mutation was present in exon 7 in 4/9 and in exon 6 in 1/9 TUMPs. All of these cases showed positive immunohistochemistry. There was no significant difference in outcome between cases with and without positive immunohistochemistry. p53 expression is seen in a significant proportion of uterine leiomyosarcomas. Microwave antigen retrieval increases the proportion of positive cases and also results in positive staining in TUMPs. Mutation of the p53 gene occurs in only a minority of leiomyosarcomas and in a significant proportion of TUMPs. Positive immunohistochemistry does not, however, correlate with the presence of mutation and other factors may be responsible for p53 detection in many cases.

Coincidental occurrence of primary hyperparathyroidism and cancer-associated hypercalcaemia in a middle-aged man

Primary hyperparathyroidism (PHPT) is found not uncommonly in patients with cancer. In this report, however, we describe a patient where both humoral hypercalcaemia of malignancy and PHPT were present coincidentally. A 47-year-old man was found to have PHPT due to parathyroid hyperplasia. Serum parathyroid hormone (PTH) levels, which were elevated before parathyroidectomy, were undetectable post-operatively; however, hypercalcaemia persisted. Nephrogenous cyclic adenosine monophosphate was elevated along with this undetectable PTH, indicative of the presence of a PTH-like factor in the serum. This was confirmed by the finding of an elevated level of PTH-related protein (PTHrP) in plasma (9.1 pmol/l, normal < 2.6 pmol/l). Secondary carcinoma was identified in a lesion in the region of the manubrium sternii. This stained positively for PTHrP by immunocytochemistry and PTHrP messenger RNA was detected by in-situ hybridization. This case illustrates the value of sensitive PTH assays in distinguishing PHPT from other causes of hypercalcaemia and also shows the importance of considering primary hyperparathyroidism in the differential diagnosis of the patient with cancer and hypercalcaemia.

Demonstration of pro-opiomelanocortin mRNA in pituitary adenomas and para-adenomatous gland in Cushing's disease and Nelson's syndrome

Pro-opiomelanocortin (POMC) mRNA was demonstrated in pituitary adenomas from 16 patients with Cushing's disease and 10 with Nelson's syndrome. The intensity of signal was significantly greater in Nelson's syndrome than in Cushing's disease and there was a trend towards a greater proportion of positive cells. This probably reflects inhibition of POMC gene expression by the high circulating levels of cortisol in Cushing's disease. In the para-adenomatous gland, the intensity of signal was variable in cells showing Crooke's hyaline change, ranging from negative to strongly positive, in keeping with the functional heterogeneity of corticotrophs. In one case, junctional corticotrophs were present and these were more intensely stained than anterior lobe corticotrophs in the same gland. This supports the concept that these cells are subject to different regulatory influences from corticotrophs in the anterior lobe. Whether this is related to differences in embryological origins or to local factors is at present unclear.

Expression of the pro-opiomelanocortin gene in lung neuroendocrine tumours: in situ hybridization and immunohistochemical studies

Neuroendocrine tumours of the lung may be associated with the ectopic adrenocorticotrophin (ACTH) syndrome and may synthesize and secrete ACTH-related peptides in the absence of the syndrome. However, immunocytochemical analysis may not confirm these biochemical findings, particularly in small cell carcinoma, which is poorly granulated. To investigate further the morphological evidence for expression of the pro-opiomelanocortin (POMC) gene in neuroendocrine lung tumours, we have examined a series of 46 small cell carcinomas and 13 carcinoid tumours of the lung by in situ hybridization for POMC mRNA using a digoxigenin-labelled oligoprobe. We have compared the findings with the immunocytochemical detection of ACTH and beta-endorphin. In situ hybridization was positive in 15 of 46 small cell carcinomas (33 per cent) and in 8 of 13 carcinoid tumours (62 per cent). Immunocytochemical staining was positive in only one carcinoid tumour. These in situ hybridization studies have corroborated biochemical data indicating POMC gene expression in a high proportion of lung neuroendocrine tumours. This suggests that the low levels of expression detected by immunocytochemistry may be due to low levels of hormone storage. Multivariate analysis showed a weak negative association between POMC expression and survival in small cell carcinomas, although this did not reach statistical significance.

Detection of mRNA by in situ hybridisation and in northern blot analysis using oligodeoxynucleotide probes labelled with alkaline phosphatase

AIMS

To assess whether a reduction in intensity of signal observed using an alkaline phosphatase labelled oligodeoxynucleotide probe could be explained on the basis of procedural steps rather than reduced sensitivity.

METHOD

Signal intensity was assessed on in situ hybridisation for pro-opiomelanocortin (POMC) mRNA in rat pituitary and for somatostatin mRNA in human pancreas and in northern blot analysis for POMC mRNA in the presence and absence of formamide. The direct effects of formamide on the alkaline phosphatase detection step were assessed using histochemical enzyme detection in rat kidney.

RESULTS

All signals were reduced in systems containing formamide.

CONCLUSIONS

In the absence of formamide clear, strong signals for specific mRNAs can be obtained by in situ hybridisation and northern blot analysis using oligodeoxynucleotide probes directly labelled with alkaline phosphatase. Formamide seems to inhibit the activity of alkaline phosphatase.

The distribution of immunoreactive interferon-gamma-containing cells in normal human tissues

An immunohistochemical technique has been used to study the distribution of lymphocytes expressing interferon-gamma in normal adult tissues. The greatest concentrations of these cells were seen in mucosal sites exposed to a resident microflora. It is proposed that such organisms, by eliciting immune responses, provide the stimulus for the production of 'physiological' interferon-gamma. This in turn may act to preserve the 'tone' or readiness of the immune system.

The distribution and possible function of gamma interferon-immunoreactive cells in normal endometrium and myometrium

T-lymphocytes are present in normal endometrium, where they may have a role in the control of glandular maturation. T-cell activity could be related to the local secretion of cytokines such as gamma interferon, which has an anti-proliferative effect on endometrial epithelial cells in vitro. We have examined gamma interferon immunoreactivity and T-cell distribution in 24 normal pre-menopausal uteri. Endometrial appearances were representative of all stages of the menstrual cycle. Most cells in the lymphoid aggregates in the stratum basalis were stained by T-cell and gamma interferon antisera. T-lymphocytes were also scattered in glandular epithelium and throughout the stroma of basal and functional layers; immunoreactivity for gamma interferon was less consistent in these cells. There was no alteration in the intensity or distribution of gamma interferon staining in different phases of the menstrual cycle. Endometrial granulocytes (K-cells) present mainly in the late secretory endometria were not reactive with the gamma interferon antiserum. In addition to endometrial staining, T-cells were distributed in all areas of the myometrium in most uteri, and many myometrial lymphocytes were gamma interferon positive. These results support a role for gamma interferon in endometrial physiology, possibly as an inhibitor of epithelial proliferation.

Characterization of the inflammatory infiltrate in ovarian dysgerminoma: an immunocytochemical study

The inflammatory infiltrate has been characterized in 10 cases of ovarian dysgerminoma using a panel of antisera to T-cells, B-cells and macrophages. The expression of Class II major histocompatibility complex (MHC) antigens and the distribution of interferons alpha and gamma were also examined. T-lymphocytes were present in all tumours, often closely admixed with neoplastic elements. T-cells in most areas were immunoreactive with gamma interferon. B-cells were generally scanty although germinal centres were present in three tumours. Immunocytochemistry revealed greater numbers of macrophages than had been appreciated on routinely stained sections. Macrophages were closely related to both lymphoid and tumour cells, and many macrophages were immunoreactive for alpha interferon. Class II MHC expression was mainly restricted to macrophages and B-cell areas although occasional T-cells were also stained. Dysgerminoma cells did not express Class II MHC antigens.

Insulitis in type 1 (insulin-dependent) diabetes mellitus in man--macrophages, lymphocytes, and interferon-gamma containing cells

This study sought to determine, firstly, the relative frequency of lymphocytes and macrophages and, secondly, the percentage of lymphocytes containing interferon-gamma in inflamed islets (insulitis) of patients with type 1 (insulin-dependent) diabetes. Autopsy pancreases of 12 patients who had died of recent-onset type 1 diabetes and one pre-diabetic patient who had died of cardiomyopathy were examined immunohistochemically. In the 87 islets that were studied, the lymphocyte macrophage ratio was 9.7:1 and approximately 40 per cent of the lymphocytes contained interferon-gamma. Interferon-gamma release in the insulitis process may be involved in the pathogenesis of type 1 diabetes.

Pituitary macroadenomas associated with hyperprolactinaemia: immunocytochemical and in-situ hybridization studies

OBJECTIVE

We have assessed whether in-situ hybridization for prolactin messenger RNA (mRNA) provides additional information for the classification of pituitary macroadenomas associated with hyperprolactinaemia.

DESIGN

In-situ hybridization for PRL mRNA was performed on surgical biopsies of pituitary adenomas and the results correlated with serum PRL levels and PRL immunoreactivity.

PATIENTS

Twenty-one patients (11 men, 10 women) were included; five had normal serum PRL levels, 11 mild hyperprolactinaemia (less than 3000 mU/l) and five marked hyperprolactinaemia (greater than 3000 mU/l).

MEASUREMENTS

Immunocytochemistry for PRL and in-situ hybridization for PRL mRNA were performed on surgical biopsies.

RESULTS

Immunoreactivity for PRL was detected in tumours from all patients with serum PRL greater than 3000 mU/l and in one of 11 patients with mild hyperprolactinaemia. Positive signal for PRL mRNA was detected in four of five immunopositive cases studied, in a further two cases with mild hyperprolactinaemia, and in one tumour associated with normal serum PRL level.

CONCLUSIONS

In-situ hybridization provides evidence of PRL gene activation in the absence of immunoreactivity for prolactin. This may reflect low levels of hormone storage or defective translation of the mRNA.

Non-isotopic in situ hybridization with digoxigenin and alkaline phosphatase labelled oligodeoxynucleotide probes. Applications in pituitary gland

We report the application of digoxigenin labelled oligonucleotide probes for the detection of hormonal messenger RNAs (mRNAs) in human pituitary adenomas. Positive signal for the appropriate mRNA was detected in tumours associated with Cushing's disease, acromegaly and hyperprolactinaemia, where immunoreactivity for adrenocorticotrophin (ACTH) growth hormone and prolactin had also been confirmed. In addition, we report the detection of proopiomelanocortin (POMC) mRNA in the rat pituitary gland using an oligodeoxynucleotide probe directly linked to alkaline phosphatase.

Spatial correlation between thyroid epithelial cells expressing class II MHC molecules and interferon-gamma-containing lymphocytes in human thyroid autoimmune disease

In this immunohistochemical study we addressed the question whether aberrant class II MHC expression by thyroid epithelial cells (thyrocytes) in established thyroid autoimmune disease is the result of release of interferon-gamma (IFN-gamma) by adjacent lymphocytes. Thyroids from eight cases of Hashimoto's thyroiditis, 13 cases of Graves' disease and 10 cases of focal thyroiditis were studied. Both thyrocytes expressing class II MHC and lymphocytes containing immunoreactive IFN-gamma were found in all 31 autoimmune thyroids. In a serial section study of these thyroids, IFN-gamma-expressing lymphocytes were found within 50 microns of class II MHC-positive thyrocytes in 89% of 282 randomly selected fields. Conversely, class II MHC-positive thyrocytes were found within 50 micron of aggregates of IFN-gamma-positive lymphocytes in 82% of 272 randomly selected fields. These findings support the view that in established thyroid autoimmune disease expression of class II MHC by thyrocytes is the result of local release of IFN-gamma.

A search for the presence of the enteroviral capsid protein VP1 in pancreases of patients with type 1 (insulin-dependent) diabetes and pancreases and hearts of infants who died of coxsackieviral myocarditis

Using an antiserum raised to a recombinant coxsackie virus B 3 capsid protein, VP1, an immunocytochemical technique was developed which was capable of detecting the presence of all coxsackie B viruses in formalin fixed paraffin embedded infected tissue culture cells. This technique was tested on autopsy heart and pancreas from 21 patients who were thought to have died of acute coxsackievirus B myocarditis. Cardiac myocytes were positive for the VP1 protein in 12 of 20 cases where the heart was available for study. Insulitis was present in the pancreas in seven of these cases and in all seven islet endocrine cells containing VP1 were found. VP1 was only rarely found in exocrine pancreas. In heart and pancreas, cells shown to contain VP1 usually showed signs of necrosis. Autopsy pancreases from 88 patients who had died at clinical presentation of Type 1 (insulin-dependent) diabetes mellitus showed no evidence of the presence of VP1. The continuing destruction of insulin-secreting B cells seen at the time of death in the diabetic pancreas is unlikely to be due to a direct cytopathic effect of a coxsackie B virus. However, this study does not exclude the possibility that a persistent infection of B cells by a defective enterovirus may result in their destruction by an autoimmune mechanism.

Immunoreactive alpha interferon in cervical flat koilocytic lesions and intraepithelial neoplasia

Immunocytochemical staining for alpha-interferon was carried out on cervical biopsy specimens showing non-condylomatous koilocytic atypia (n = 12) and cervical intraepithelial neoplasia (n = 18), both of which are associated with human papilloma virus (HPV) infection. Normal cervical tissue obtained from hysterectomy specimens was also assessed. Koilocytes were not immunoreactive for alpha interferon and keratinocyte staining was observed in only four cases of intraepithelial neoplasia. HPV infection alone does not therefore seem to induce the production of alpha interferon in cervical squamous epithelium. There was variable but, in some cases, prominent staining of cells in the stromal inflammatory infiltrate as well as intraepithelial cells which had morphological and immunocytochemical characteristics of Langerhans' cells. Alpha interferon immunoreactivity in Langerhans' cells is in keeping with derivation from the mononuclear phagocyte system and may be important in the host response to HPV infection.

Immunolocalization of alpha interferon in liver disease

The expression of immunoreactive alpha interferon was examined in 78 liver biopsy specimens using an indirect immunoperoxidase technique. Biopsy specimens included cases of acute viral hepatitis, chronic active hepatitis, primary biliary cirrhosis, alcoholic hepatitis, large bile duct obstruction and normal liver. Kupffer cells were positive for alpha interferon in all cases. Hepatocytes were negative for alpha interferon in normal liver but in acute viral hepatitis were positive in perivenular and necrotic areas. Hepatocytes were positive in periportal areas, associated with piecemeal necrosis, in chronic active hepatitis and primary biliary cirrhosis, and were positive in perivenular areas in alcoholic hepatitis and large bile duct obstruction. The unexpected finding of alpha interferon in hepatocytes in non-viral liver disease indicates that the presence of this substance in liver cells cannot be taken as a specific marker of viral infection.

The pancreas in acute graft versus host disease in man

Twenty-six bone marrow transplant recipients, 14 of whom had evidence of acute graft versus host disease at autopsy, were studied. The pancreas in four of these patients exhibited changes thought to be due to acute graft versus host disease. Pathognomonic findings were in exocrine ducts which showed marked epithelial cellular atypia associated with a mild lymphocytic infiltrate. This was accompanied by ulceration and intraluminal haemorrhage in severe cases. In three of these four cases ductal epithelium showed marked hyperexpression of class I and class II major histocompatibility complex molecules. By contrast islets were not inflamed, showed no evidence of endocrine cell damage and no abnormalities of major histocompatibility complex expression were seen.

The distribution of immunoreactive interferon-alpha in normal human tissues

The cellular distribution of immunoreactive interferon-alpha (IFN-alpha) was studied in formalin-fixed paraffin-embedded normal human tissues from 36 different organs. These samples were drawn from over 300 individuals none of whom had evidence of viral infection. Tissue histiocytes from all organs in the body, with the exception of brain and renal cortex and medulla, stained positively for IFN-alpha. Kupffer cells, pulmonary alveolar macrophages and lymph node macrophages were also positive. Parenchymal cells in some other organs also appeared to contain immunoreactive IFN-alpha. These included cuboidal lining cells of the choroid plexus in the brain, thyroid follicular cells, pituitary endocrine cells, adrenocortical cells and parathyroid principal and oxyphil cells. These findings are compatible with previous suggestions that IFN-alpha may be synthesized and released in the absence of viral infection and may thus have a role in normal physiology. The presence of IFN-alpha in most cells of the mononuclear phagocyte system suggests that these cells may play a major part in defence against viral infection.

The pancreas in idiopathic Addison's disease--a search for a prediabetic pancreas

Autopsy pancreases were studied from 14 patients who had idiopathic Addison's disease. One patient had been diabetic for 12 years and three patients were found to be diabetic during their terminal admission. While there was no evidence of diabetes or destruction of insulin-secreting beta cells in the remaining 10 patients, islets in one pancreas exhibited many of the histological and immunohistochemical features seen in the patients with recent onset diabetes. These included the presence of alpha-interferon in endocrine cells, hyper-expression of class I major histocompatibility complex molecules by endocrine cells in islets where alpha-interferon was also present, aberrant expression of class II major histocompatibility complex molecules by endocrine cells and the presence of insulitis. Since the combination of these changes has only been described in type 1 diabetes it is thought that the appearances seen in this pancreas were those of prediabetes.

Massive synchronous B-cell necrosis causing type 1 (insulin-dependent) diabetes--a unique histopathological case report

A 22-year-old Chinese male died in hyperglycaemic coma following a 36-h illness. The only significant pathological findings were in the pancreas where there was a heavy diffuse infiltrate of lymphocytes admixed with numerous eosinophils, macrophages and polymorphs. There appeared to have been massive, recent, synchronous necrosis of insulin-secreting B cells with no destruction of any other pancreatic parenchymal cells. The biochemical findings of severe hyperglycaemia, insulinopoenia, but a normal glycosylated HbA1 were compatible with an acute onset to the patient's diabetes. These features contrast with the very much slower destruction of B cells associated with insulitis seen in "classical" Type 1 (insulin-dependent) diabetes.

Immunoreactive alpha-interferon in insulin-secreting beta cells in type 1 diabetes mellitus

Of 37 pancreases removed at necropsy from patients with type 1 diabetes 34 had residual beta cells. In 33 of the 34 the beta cells were positive for immunoreactive alpha-interferon, and this finding in islets was related to hyperexpression of class I major histocompatibility complex (MHC) antigens. Of islets showing class I hyperexpression 93% contained alpha-interferon compared with 0.4% of those showing no hyperexpression. Among 80 control pancreases significant numbers of beta cells containing alpha-interferon were present only in 4 cases of acute infantile viral pancreatitis, known to be caused by Coxsackie-B viral infection in 3 cases. Chronic viral infection of beta cells may underlie the pathogenesis of some cases of type 1 diabetes.

Aberrant expression of class II major histocompatibility complex molecules by B cells and hyperexpression of class I major histocompatibility complex molecules by insulin containing islets in type 1 (insulin-dependent) diabetes mellitus

Twenty-three patients with recent onset Type 1 (insulin-dependent) diabetes in whom residual insulin secreting B cells were present and 12 patients with disease of more prolonged duration (maximum 9 years), 8 of whom had residual B cells, were studied. Aberrant expression of Class II major histocompatibility complex molecules was demonstrated immunohistochemically on insulin secreting B cells in 21 out of 23 patients with recent onset disease and 6 of the patients with more prolonged disease. No such expression was seen on glucagon secreting A cells or somatostatin secreting D cells. Islets where there was marked hyperexpression of Class I major histocompatibility complex molecules on islet endocrine cells were seen in all cases in which residual B cells were present. Ninety-two per cent of insulin containing islets but only 1% of insulin deficient islets exhibited this phenomenon (p less than 0.001, Chi-squared test). There was evidence to suggest that both these abnormalities of major histocompatibility complex expression preceded insulitis within a given islet. They also appeared to be unique to Type 1 diabetes, being absent in pancreases of patients with Type 2 (non-insulin-dependent) diabetes, chronic pancreatitis, cystic fibrosis, graft-versus-host disease and Coxsackie B viral pancreatitis. The development of autoimmunity to B cells in Type 1 diabetes may be a "multistep" process in which abnormalities of major histocompatibility complex expression on islet endocrine cells are crucial events.

Aberrant expression of HLA-DR antigens by insulin-containing beta-cells in recent-onset type I diabetes mellitus

The pancreases of 14 children who died of type I diabetes were studied immunohistochemically for aberrant expression of HLA-DR antigens on islet endocrine cells. Two cases in which no residual insulin-secreting beta-cells were present had no evidence of HLA-DR expression on endocrine cells. Insulin-containing islets were present in the remainder, and HLA-DR-positive endocrine cells were demonstrable in all of them. Endocrine cells expressing HLA-DR were present in 171 of 630 insulin-containing islets from all the cases. However, HLA-DR-positive endocrine cells were not seen in 2060 insulin-deficient islets, providing evidence that of the four hormone-producing cells in the pancreas only the beta-cells expressed HLA-DR. Sections double stained for HLA-DR and the pancreatic hormones confirmed this view. Most islets in which HLA-DR-positive endocrine cells were seen had no evidence of insulitis, suggesting that within an individual islet, aberrant expression of HLA-DR on beta-cells may precede the inflammatory infiltrate.

The histopathology of the pancreas in type 1 (insulin-dependent) diabetes mellitus: a 25-year review of deaths in patients under 20 years of age in the United Kingdom

A 25-year computerised survey of deaths in the United Kingdom among diabetic patients of 19 years of age and under was performed. Suitable pancreatic material was available in 119 out of the 498 identified patients. The duration of diabetes was known in 95 of the 119 patients. In 60 patients it had been present for less than 1 year. Insulitis was present in 47 of the 60 patients (78%) with recent onset disease, and was also found in 3 patients who had been treated for diabetes for between 1 and 6 years. In cases in which it was identified, insulitis affected 23% of islets containing insulin, but affected only 1% of islets which were insulin deficient, thus supporting the concept that insulitis represents an immunologically mediated destruction of insulin secreting B cells. Four patients appeared to have a different disease from classical Type 1 (insulin-dependent) diabetes in that there was no evidence of insulitis and all islets contained insulin. The age of onset of diabetes was eighteen months or less in these patients.