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Three mitoses of endothelial glomerular cells have been observed by electron microscopy in 3 different nephropathies (a mixed membranous and proliferative glomerulonephritis, an intracapillary glomerulonephritis, and a mixed IgG-IgM cryoglobulinemia). Further light- and electron-microscopical and autoradiographic investigations on the occurrence and nature of the dividing cells responsible for glomerular hypercellularity in glomerulonephritis have been carried out in rats with an immunocomplex-induced glomerulonephritis. A statistically significant difference between treated and control animals have been found in the number of mitoses and DNA-synthesizing nuclei. All dividing glomerular cells observed by electron microscopy were endothelial. It is therefore proved that in glomerulonephritis an actual glomerular cell proliferation does occur; proliferating cells are suggested to be endothelial in nature.

A case of true hermaphroditism with 46, XX/46, XY karyotype is reported. The propositus, reared as a male, showed ambiguous external genitalia with perineoscrotal hypospadias, and internal genitalia represented by bilateral ovotestes, normal uterus and tubes. Periodic menstrual bleedings appeared at puberty. The endocrinologic data demonstrated the secretory activity of both the ovarian and the testicular tissue. The analysis of red cell, lymphocyte and serum markers, done on the propositus and on his parents, failed to show any evidence of double fertilization. On this basis, the origin of the XX/XY condition (mosaicism versus chimerism) and its developmental consequences are discussed.

A case of rapidly progressing glomerulonephritis accompanied by sarcoidosis is presented. The immunological pathogenesis of the underlying disease was shown by the positivity of the reactions for anti-IgA and anti-betal C/beta 1 A globulins and the presence of thick deposits in the mesexential matrix and some parts of the thickened basal membrane. Since generalised sarcoidosis is regarded as the expression of an immunological reaction to an unknown, diffuse antigen, this type of glomerulonephritis may be associated with the particular immunopathological condition observed in sarcoidosis.

The immunologic phenotype of the lymphocytes of 100 patients with chronic lymphocytic leukaemia (CLL) was investigated. Peripheral blood lymphocytes (PBL) were examined in all cases; in 46 patients with lymphadenopathy, a lymph node was biopsied and the histologic and immunologic patterns were assessed: 24 had a lymphocytic-lymphoplasmocytoid histology and 22 the follicular variant of lymphocytic lymphoma (mantle zone lymphoma, MZL). For comparison, lymph node suspensions from 19 patients with non-leukemic centrocytic lymphoma (CCL) were also studied. Significant differences in the PBL immunologic features were found between stage O and stage I patients. The phenotype of the lymphocytes of patients with lymphocytic histology was similar to that of stage 0 CLL patients, whereas major differences were found between these patients and those with mantle zone histology. This enables these patients to be recognized easily on immunologic grounds.

Cellular immunity in two brothers with thyroid carcinoma in a family presenting pathological thyroid changes is investigated. In these brothers a low PHA lymphocyte blast-transformation and an elevated number of surface membrane Ig bearing lymphocytes were observed. These data are discussed in relation to the question of immunological defects which frequently are present in carcinoma patients.

The primary role of the T-cell system in immune-complex glomerulonephritis induced by intravenous weekly injections of human serum albumin (HSA) in rats has been demonstrated. The development of histological, ultrastructural and immunological glomerular alterations which are clearly recognizable in intact animals was prevented by neonatal thymectomy. In vitro tests of cellular immunity (LIF and PHA responsiveness) revealed a close relationship between the involvement of functioning T-cell subpopulations (at least T-helper) and the development of the classic glomerulonephritic pattern. In other words HSA antigen recognition by T lymphocytes, their cooperation with B lymphocytes, and the activation of the latter with related antibody response represent the immunological sequence which leads to the formation of the soluble circulating immune-complexes responsible for the glomerular injury. Our findings suggest that the same immunological sequence can represent the pathogenetic basis for many forms of glomerulonephritis in which T-dependent antigen stimulation is demonstrable. Our data are also discussed in the light of results obtained by others in immuneglomerulonephritis induced in nude athymic mice.

The clinico-pathologic data of 37 primary lymphomas of the brain were retrospectively reviewed. The tumors were classified according to the Kiel classification and the Working Formulation System. They represented 1.02% of all primary intracranial tumors of our series. The radiologic prediction appeared to be difficult: the suspicion was maximal when the absence of pathologic vessels at angiography occurred in a meningioma-like lesion at CT. Median survival was 4.53 months in the 16 cases who underwent surgery only versus 25.7 months in the 8 cases operated and irradiated with 40-60 Gy (p less than 0.01). The prognosis of lymphomas of the CNS, even if radioresponsive tumors, remains poor. Most patients relapse after treatment, most often locally in the brain, with a variable frequency of spinal or systemic localization.

We report and discuss a case consisting of 2 lesions that developed at different times in the same parotid gland. Although the first lesion showed morphologic features similar to those of the benign lymphoepithelial lesion, a monotypic IgM/K pattern was also revealed by the immunoperoxidase method in its lymphoid infiltrates. Thus, on cytologic grounds, the first lesion was classified as lymphoplasmacytic immunocytoma (according to Kiel criteria). In the second lesion, which recurred 3 years later, the prominent feature was a marked predominance of plasma cells with the same monoclonal IgM/K as the preceding lymphoma. These findings suggests that a B-lymphomatous cell monoclone may undergo morphologic maturation along the lineage of its competence. Secondly, they indicate that every case of benign lymphoepithelial lesion of the salivary glands should undergo thorough immunologic evaluation to exclude the possibility of signs of precocious lymphomatous transformation.

The extent and distribution of alfa-naphthyl acetate esterase (ANAE) activity in both normal thymuses and thymuses or thymomas from patients with myasthenia gravis were investigated by enzyme histochemistry. In all a closely similar distribution of ANAE activity was recognizable. ANAE positive thymic lymphocytes were distributed preferentially at the cortico-medullary junction and in the medulla. Their numbers at these sites were higher in myasthenic patients than in normal adults (P less than 0.001) and lowest in fetuses. The relative numbers of cells showing both ANAE activity and EN-rosette-forming capacity was lower in thymocytes than peripheral lymphocytes but was increasing higher in thymuses from fetal, adult and myasthenic patients and in thymomas. These findings are discussed in relation to the stage of maturity of thymocytes and the importance of intrathymic immunological challenge in the attainment of these cells of functional properties usually acquired in the periphery.

The lymphoid tissue provides the most productive conditions to the application of immunohistochemical techniques. This tissue is composed of many B and T phenotypically different cell populations ranging from stem cells to completely differentiated lymphocytes which can be identified by using monoclonal antibodies. These techniques also are of great help in classifying the malignant lymphocyte counterparts and, thus, in defining diagnostic and prognostic characters of different lymphomas/leukaemias.

Here we present the characterization of a new antigen called CB02 which is present on B cells and on a subset of CD16+ large granular lymphocytes. The pattern of reactivity of this molecule on normal cells, B cell lines, leukemic cells and tissue sections suggests that the CB02 molecule is expressed by B cells before isotype switch and is lost during terminal differentiation. Furthermore, the CB02+ population encompassed natural killer (NK) cells exerting significant cytotoxic activity: in fact, peripheral blood lymphocytes depleted of the CB02+ subset display a marked reduction in NK activity.

The non-Hodgkin's lymphomas (NHL) occurring in children are described on the basis of the Kiel classification. As a rule, the NHL in children are of high-grade malignancy. The morphologic and immunologic features of all types of high-grade malignant B-cell lymphoma are described. The most frequent type of B-NHL in children is B-lymphoblastic lymphoma, including Burkitt and non-Burkitt types. Centroblastic lymphoma, immunoblastic lymphoma and unclassified high-grade malignant NHL are less common in children. The difference between the morphologic term "unclassified" and the immunologic definition "non-B/non-T" or "null" (or "unclassified") is explained. The equivalents of the various lymphoma types in the Lukes-Collins and Rappaport classifications are given.

The acid phosphatase (AP), beta-glucuronidase (BG), and alpha-naphthyl-acetate esterase (ANAE) distribution and the morphology of stage 0 B-CLL lymphocytes were studied. The results were compared with the same hydrolase equipment and morphology of normal B-cell populations showing the B-CLL-like phenotype, and thus regardable as the possible counterpart of leukaemic cells. The functional and structural characters of the former were strikingly different from those of the latter. In fact the normal B-cell population with B-CLL-like phenotype showed an homogeneous enzyme pattern with predominant ANAE and a strictly lymphocytic cell morphology. In contrast, the leukaemic cells showed various and unrelated morphological and cytochemical features, thus forming apparent subgroups of B-CLL. The development of an irregular "switch on" mechanism in the blocked malignant cell clone, may account for these functional and structural maturation discrepancies. Moreover, the fact that in the leukaemic cells ANAE activity could be demonstrated only after the appearance of the other hydrolases, makes it a marker of functionally differentiated B lymphocytes.

The phenotypical characteristics of human epithelial and lymphoid cells have been studied with immunohistochemical methods on frozen sections of 12 thymomas. On the basis of the cytohistological characteristics of thymoma epithelial cells (EC) the thymomas were divided in cortical, medullary and mixed types, according to recently developed light microscopical criteria. When tested with a series of monoclonal antibodies, thymoma EC were all stained by the antibody Ki-M3 (as in the thymus), but reacted with anti-HLA-DR, anti-HLA-A,B,C and with a new monoclonal antibody to cortical EC, 21A6, to a lesser extent and with weaker, variable intensity in comparison with the normal thymus. Cortical type thymomas were most reactive and the medullary type almost negative. Thymomas, like normal thymus showed different immunoreactivity patterns with antibodies to prekeratins of different specificities. Cortical type thymomas and areas in mixed thymoma showed an EC staining with the antibody to non-squamous type keratin (35 beta H11) whereas medullary type thymomas and areas showed staining with antibodies to squamous-type keratin (34 beta E12-IV/82) in addition. Lymphoid cells with cortical (OKT6+, Leu 1 weakly+, Leu 2a+, Leu 3a+) or mature medullary (OKT6-, Leu 1 strongly+, Leu 2a or Leu 3a+) phenotype were found to colonize tumours with different EC types. These immunohistochemical findings largely confirm our earlier cytological distinction of thymoma EC. In addition important differences have been observed in neoplastic cortical EC concerning the HLA-DR and 21A6 immunoreactivity that may be intimately related to the neoplastic process and paraneoplastic immune phenomena.

Solitary myeloma is an uncommon lesion which may occur in many organs, mainly in the rhinopharynx. This lesion usually appears as non-secretory, and it is constituted by either typical plasma cells or large and atypical cells resembling epithelial anaplastic cells. Therefore, and immunofluorescent method on paraffin-embedded sections may be applied to reveal the presence and the monoclonality of the intracytoplasmic Ig in the pathological cells. In this paper we report a study on 22 patients suspected to bear a rhinopharyngeal tumor investigated by immunofluorescence. Moreover, in 4 cases peripheral blood lymphocytes were also studied. The results are discussed on the basis of the modern immunological trends.

An experimental study by the authors, on the effects of local-regional hyperthermia on bladder B.N.A. induced carcinoma of the dog has been going on since 1966. The authors have observed complete disappearance in the animals of the mucosa and sub-mucosa neoplasia, even after 6 years from the date of treatment. The sterilization of the neoplastic surface was checked by several histological sections observations on two excised bladders. As the results showed no negative secondary effects, the authors have started, since 1973, a clinical study of hyperthermia treatment of the bladder, vagina, female urethra and rectum stump carcinoma. Heat was obtained and introduced into the bladder by leans of an apparatus specifically designed for this purpose; the double-circuit terminal probe supplies a thermocouple controlled constant temperature. We are submitting the cases treated together with a discussion on results obtained and problems faced.

The difficulty to recognize morphologically the biological nature of the exuberant plasma cell proliferations is known by every pathologist. Therefore, an immunohistochemical method has been applied to routine paraffin-embedded sections of biopsies from 26 patients suspected to bear a solitary plasmacytoma. The method has allowed to distinguish between monoclonal (likely to be neoplastic) and polyclonal cases (likely to be reactive).

Spontaneous rosettes and membrane immunofluorescence for the various classes of heavy and light immune globulin have been determined on lymphocyte subfractions obtained from the blood of 6 normal subjects and 16 patients with CLL by separation on gradients of various density. Whereas in the normal subject lymphocyte immunological features proved similar in all fractions, in CLL they presented significant differences from fraction to fraction, with the presence only in certain fractions of the lymphocyte peak with monoclonal membrane immune globulin and without peak coincidence for IgD and IgM, probably as a result of changes in the physico-chemical features of the lymphocytes occurring during maturation. All fractions presented a sizeable complement of lymphocytes not forming rosettes and without demonstrable membrane immune globulins. The correlation between the behaviour of membrane labels and lymphocyte morphology, stage, duration and course of the disease has been analysed. The variability in lymphocyte subfraction characteristics separable at different densities may explain discrepancies of findings in researches carried out in lymphocytes that separate only at gradient of density 1077.

Plain paraffin was pellets and pellets containing 1% and 5% 20-MCA were implanted in the bladder of 219 C57 X IF and Swiss mice of both sexes. One hundred and fifty four survived and were killed after 40-42 weeks; 56 had been implanted with plain pellet and 98 with pellet containing the carcinogen. Only one bladder tumour (1,8%) developed in the former, whereas 35 tumours (35.7%) were found in the latter group. When a pellet containing 20-MCA was used, the tumour incidence was related to the strain and sex of the animals, rather than to the amount of carcinogen in the pellet. As a matter of fact, irrespective of the concentration of 20-MCA, females C57 X IF gave a significantly higher tumour yiels (87.5%) than males and Swiss mice of both sexes. It is concluded that when bladder implantation is used to induce tumours in mice, the results must be strictly referred to strain and sex. Besides tumours, areas of marked epithelial hyperplasia were seen in bladders implanted with either plain pellet or pellet containing 20-MCA. The possible meaning of this hyperplasia is briefly discussed and the need for further investigation stressed.

Aspecific immunosuppression in neoplasia has long been known, even though all its biological aspects are not yet fully understood. Inhibition of leukocyte migration (LIF) was studied before and after the use of levamisole in vitro to determine whether changes occurred in cell reactivity. The results of the investigation are discussed in the light of modern immunopathological theories.

Twenty-six human thymomas were studied in an attempt to correlate their morphological appearance with the type and degree of T-lymphocyte maturation, as determined by acid alpha-naphthyl-acetate esterase (ANAE) activity and immunological analysis. Four normal human thymuses were used for purposes of comparison. Two morphological patterns were identified in the thymomas. The distinction was based largely on similarities between the neoplastic epithelial cells and normal cortical and medullary epithelial cells, and on the relative proportions of epithelial cells and lymphocytes. By these criteria "medullary" and "cortical" patterns were identified. In several thymomas both patterns were present in the same tumor ("mixed-type pattern"), producing alternating dark cortical-like areas and lighter foci of medullary differentiation. A good correlation was found between the two patterns and the phenotype of the T-associated lymphoid component. ANAE activity, which was completely lacking in normal cortical thymocytes, was almost absent in the phenotypically immature T-cells of cortical-type thymomas. By contrast, in the medullary-type thymomas, T-cells showed immunological features in common with medullary thymocytes. This was characterized by strong ANAE activity in the majority of cells with a staining pattern corresponding to that of peripheral T-lymphocytes. In addition, most of the proliferating epithelial cells in medullary-type thymomas stained strongly with anti-cytokeratin and anti-epidermal-type keratin antisera. In the mixed-type thymomas the epithelial cell morphology and the immunohistochemical and enzymic features of the T-cells were found to be closely related to the respective cortical--or medullary-like areas. It was concluded that the various characteristics of normal thymic cortex and medulla studied are also present in thymomas. In particular, in medullar-type thymomas the presence of many of the features of normal thymic medulla, such as a squamous cell component, macrophages and interdigitating reticulum cells, may constitute a microenvironment which operates actively in T-cell education. This may account for the functional activities, characteristic of peripheral T-lymphocytes, which T-lymphocytes attain in these thymomas.

Data regarding the commonest biohumoral tests of liver function obtained in 53 highly obese women of more or less young age, non-diabetic, non alcolist and without cardiovascular complications are reported. Liver biopsy was carried out in 23 of these patients for the purpose of studying the liver histologically. On the whole, liver function tests gave normal results: specifically, B.S.F. clearance was normal in 91% of the cases and retention at 45' was normal in 77%. Histologically, only 9% showed normal liver parenchyma. The vast majority showed a varying extent of fat infiltration and in 30% this was also fibrosis. No relationship was found to exist between the extent of histological changes and B.S.F clearance and retention values.

An immunohistological analysis with a panel of monoclonal and polyclonal antibodies was performed in 20 cases of squamous cell carcinoma originating in the oral cavity, oropharynx and larynx. The epithelial antigens were detected in all cases with variable patterns of positivity: cytokeratins and epithelial membrane antigen were positive in a high number of neoplastic cells in the carcinomas with a high grade of differentiation, whereas a lesser number of positive cells was observed in the poorly differentiated carcinomas. On the contrary the tissue polypeptide antigen was detected in a considerable number of neoplastic cells in the poorly differentiated carcinomas as well as in the fields with basal and cylindric cells. Mesenchymal antigens were negative in all tumors, except one case with pseudosarcomatous patterns, which was vimentin-positive. The detection of an immunohistochemical spectrum of squamous cell carcinomas may give further information on the biological characteristics, and consent to identify subtypes with a different histogenesis.

In view of some data of the literature suggesting that immunological changes could play a role in the pathogensis of diabetes mellitus and of its complications, we carried out a study of the lymphocyte populations of 44 diabetic subjects by means of E, EA, EAC rosettes and membrane immunofluorescence. A quarter of the patients had decreased E rosettes: all of these had long-lasting, insulin-dependent, poorly controlled diabetes. Some of these patients had also increased membrane IgG globulins. In 5 patients with recent onset, insulin-independent diabetes, E rosettes were increased. No significant changes of EA and EAC rosettes were observed. These findings suggest that changes of lymphocyte populations do not play any role in the pathogenesis of diabetes, while these may be the consequence of the metabolic disorder and these may favour the onset of complications of the disease.

In Hodgkin's disease, blood cultures showed a close relationship between the rate of blastic transformation of PHA-stimulated lymphocytes and the number of macrophages appearing in unstimulated cultures. Despite individual variations, in single cases the yield of macrophages agreed closely with the lymphocyte transformation rate. Results are discussed in connection with hypothesis on the origin of macrophages in culture.

Eight cases of human thymoma have been analyzed on cryostat sections with the monoclonal antibody Ki67, which reacts with cells in the proliferative phases of the cell cycle. The aim was to assess the proportion of proliferating thymocytes among lymphoid cells in the thymoma samples. In all cases a large number of cells (mean, 58.75%; range, 35-80%), recognized as thymocytes by morphology and lack of cytokeratin expression in a combined immunohistochemical assay, exhibited nuclear Ki67 staining. These findings differ from the reactivity pattern observed in age-matched nonneoplastic thymuses where lower growth activity of cortical thymocytes was observed (15-20% Ki67+ cells). Intensive thymocyte proliferation in thymomas may represent one of the factors which lead to autoimmunity in myasthenia gravis and thymomas.