R. C. Nairn

Mucinous colorectal carcinoma: Immunopathology and prognosis

&NA; A total of 519 colorectal carcinomas were examined for the presence or absence of mucinous differentiation by means of microscopical morphometry. Of these, 28% had objectively measurable amounts of mucinous tumour epithelium. Tumours with >50% mucinous areas (14%) had significantly poorer prognosis than non‐mucinous in stages A and C, while mucinous differentiation did not correlate with prognosis in stages B and D. Lymph nodes regional to mucinous tumours had significantly less paracortical response, and those with >50% mucinous differentiation, significantly less perivascular lymphocyte cuffing at the tumour margins. These lymph node and stromal compartments are putative T‐lymphocyte areas, and hence our findings suggest that mucinous tumours are either less stimulatory or perhaps inhibitory of cell‐mediated immunity.

Immunological Reactivity in Patients with Carcinoma of Colon

Sixty cases of colonic carcinoma have been investigated for antitumour immunoreactivity. The tests employed were blood lymphocyte reactivity and complement-dependent serum cytotoxicity against cultured tumour cells, and immunofluorescence for membrane staining of viable tumour cells and cytoplasmic staining of dried tumour cells in films. Nineteen cases were positive by one or more tests and the most frequent positive response, lymphocytotoxicity, was detected in 8 of the 24 cases tested in this way. The lymphocytotoxicity persisted in a case tested three times over a year. Immunoreactivity against tumour cell surface, as by lymphocyte or serum cytotoxicity or membrane immunofluorescence, was restricted to colonic carcinomas but there was an additional element of individual specificity; cross-reactivity with other tissues and tumours was not observed. Lymphocytes from regional lymph nodes were non-reactive even in a case with positive blood lymphocyte cytotoxicity against the carcinoma cells.

Fluorescence polarization assay by flow cytometry.

Fluorescence polarization measurement on cell suspensions provides a highly sensitive means for detecting subtle changes in the cells, such as occur early after lymphocyte activation or on malignant transformation. We review here the principles of fluorescence polarization, its measurement by a commercially available flow cytometer and application of such assays especially in cellular immunology.

Immunohistological patterns of carcinoembryonic antigen in colorectal carcinoma. Correlation with staging and blood levels

&NA; Forty‐four primary adenocarcinomas of the large bowel and 2 liver metastases were stained for carcinoembryonic antigen (CEA) in tissue sections by indirect immunofluorescence. All tumours were positive and showed either one or more of 3 different patterns‐luminal; linear at surface of the tumour cells; cytoplasmic. In most cases (83%), two or all 3 patterns were seen in the same or in different parts of a tumour. The immunohistological staining was concordant with preoperative blood levels of CEA in 31 cases (67%) in that 26 tumours showed strong immunofluorescence associated with blood CEA above 2.5 μg/l, and 5 showed weak staining and blood CEA values less than 2.5/μg/l. However, in 7 strong staining was associated with low blood CEA, and in 8 weak staining was associated with high blood levels. The dissociation between histological and blood CEA findings in 1/3 of the cases, together with the marked variation within the same tumour and differences between one of the primaries and its liver recurrence, suggest that CEA immunohistology is of no better prognostic value than blood CEA levels. There was no association between CEA immunohistology and tumour staging or differentiation. However, blood CEA levels were significantly higher in tumours with extensive local or distant spread (stage D) and in poorly differentiated tumours.

Specific Immune Response in Human Skin Carcinoma

Eight out of nine patients with squamous cell carcinoma of skin have shown immunological reactivity against their own tumour cells by one or more tests with their sera or peripheral blood lymphocytes. The tests included membrane and cytoplasmic immunofluorescence, and, with cultured tumour, complement-dependent serum cytotoxicity and lymphocyte attack. One case examined in depth had an unusually conspicuous lymphocyte and plasma cell reaction on histological examination, and was positive by all four tests; a time-lapse cinephoto-micrographic record over seven days was obtained of the attack on the carcinoma cells in culture by the patients lymphocytes.

Criteria of cell killing in vitro

The attachment of cells to plastic tissue culture plates is a widely used criterion of cell viability in microcytotoxicity assays. When cell suspensions of primary human colon carcinoma and melanoma cells which were of low initial viability (assessed by trypan blue exclusion) were allowed to adhere to tissue culture plates, many of the adhering cells did not satisfy other criteria of cell viability. They did not stain with fluorescein diacetate but did stain with propidium iodide and fluorescein-labelled antinuclear antibodies. Using complement-mediated cytotoxicity, relatively weak activity was inconsistently demonstrated against these cells. On the other hand, strong activity was always demonstrated against highly viable cells from one colon carcinoma and two melanoma cell lines. Immunologically mediated damage to these cells was demonstrated readily by loss of the ability to stain with fluorescein diacetate, but not by cell detachment.

Gastric antigens in health and disease. Behaviour in early development, senescence, metaplasia, and cancer.

Immunofluorescence studies of the behaviour of gastric antigens in health and disease have shown that during foetal development both gastric and intestinal antigens are present in the gastric superficial mucous epithelium. The intestinal component disappears soon after birth; it re-emerges in senescence and in metaplasia and neoplasia, while the gastric antigen, which normally persists in adult life, is depleted in these circumstances. The loss of adult and the re-emergence of foetal antigen in both metaplasia and neoplasia suggest a possible fundamental relationship between these conditions; the phenotypic variation may reflect cytogenetic liability, which has malignant transformation as a final irreversible step.

Another oncofoetal antigen in colonic carcinoma.

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PERNICIOUS ANAEMIA AUTOANTIBODY TO GASTRIC PARIETAL CELLS: IMMUNOFLUORESCENCE TEST WITH RAT STOMACH.

Rat stomach provided an excellent substrate for immunofluorescence testing of gastric parietal cell autoantibodies in 65 human sera. The results of similar tests using human stomach corresponded closely in the 42 cases examined. The rat stomach had some advantage over human stomach in its ready availability in the fresh state, its occasional brighter staining reactions, and its avoidance of non-specific staining by the sandwich immunofluorescence technique.

TAMM-HORSFALL PROTEIN IN KIDNEYS OF HUMAN EMBYROS AND FOREIGN SPECIES

Summary Antiserum to Tamm‐Horsfall (TH) urinary protein was prepared in rabbits by immunizing them with the protein purified from normal human urine. By immunofluorescent staining of adult human kidney sections, the TH protein was located in the distal convoluted tubules and the loops of Henle. Human embryos from 8 weeks of age to full term were then examined for the protein, and it was present in embryos of all ages, occurring in the same location as in adult kidney. Kidneys from foreign species of vertebrates were also studied for tubular material crossreacting with the antibody to the human protein. Tamm‐Horsfall protein was identified by this means in the kidneys of all the placental mammals tested, but in no other class of vertebrates.