Correction to: A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era: selecting cases, matching clinical benefit

The first and family names of the authors were interchanged and are now presented correctly. The original article has been corrected.

Prominent Plasmacytic Differentiation in the Recurrence of a Parotid Immunocytoma. A Morphologic and Immunohistochemical Study

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 monotoypic 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.

Primary Lymphomas of the Brain: A Clinico-Pathologic Review of 37 Cases

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 < 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.

Role of the Perivascular Epithelium in the Histogenesis of Hassall's Corpuscles

Thirteen human thymuses and one thymoma were morphologically and immunohistologically investigated to define the histogenesis of Hassall's corpuscles (HCs). The following monoclonal antibodies: antisquamous cytokeratin on paraffin sections and TE-4 and TE-8 on frozen sections, were used to show the distribution of the epithelial components; PAL-E on frozen and anti-CD31 and anti-CD34 on paraffin sections detected the endothelial cell distribution. In the thymoma, epithelial onion-like structures, looking like true HCs, were found to originate from the perivascular epithelium lining dilatated spaces and some of them partially obliterated the space where the blood capillary showed thickened wall and endothelial regressive changes. Antisquamous cytokeratin stained: (1) in the thymus: subcapsular, medullary, and HC epithelial cells; (2) in the thymoma: epithelial cells lining the perivascular spaces and forming HCs. TE-4 stained: (1) in the thymus: the subcapsular and medullary epithelium; (2) in the thymoma: the epithelium lining the perivascular spaces and epithelial cells forming HCs. TE-8 stained: (1) in the thymus: HCs only; (2) in the thymoma: HCs and perivascular epithelial cells. PAL-E, CD31, and CD34, which specifically react with endothelial cells, stained remnants of capillary structures in the core of some HCs. The results indicate that: (1) corpuscular structures in thymoma originate from perivascular epithelium; (2) thymus medullary epithelial cells stained by cytokeratin and TE-4 correspond to perivascular epithelial cells whose staining is well documented in thymoma; (3) the subcapsular-perivascular epithelium and HCs represent different steps of differentiation of a single ectodermal cell lineage; (4) the PAL-E-, CD31-, and CD34-positive reaction in the core of some HCs suggests that the perivascular epithelium would be stimulated to transform into HCs as a consequence of endothelial changes with fragmentation of the capillary included in the perivascular space.

Exhaled nitric oxide and nitric oxide synthase expression in Hodgkin's disease

Hodgkin's disease (HD) is a malignant lymphoma with frequent mediastinal involvement, characterized by a significant inflammatory infiltration. Exhaled nitric oxide (FENO), is present in healthy humans, and has been proven to be increased in eosinophilic diseases such as allergic asthma. We investigated whether FENO is increased in mediastinal HD and whether NO is produced by lymphoma tissue. To this aim FENO was measured in 56 HD patients, 17 with and 39 without bulky mediastinal involvement, in the period from January 2007 to December 2008. Thirty-seven patients were reassessed after remission. Lymph node biopsies of 10 patients were evaluated for inducible (iNOS) and constitutive (eNOS) nitric oxide synthase expression by immunohistochemistry. FENO resulted significantly related to the mediastinal mass maximum diameter (p=0.009) and was significantly higher in patients with as compared to those without bulky mediastinal disease (38.7 ppb, CI 95% 19.3-58.0, versus 20.7 ppb, CI 95% 16.6-24.7; p=0.009). iNOS and eNOS immunoreactivity was observed in tumour and inflammatory cells (eosinophils and histiocytes). Only in patients with bulky mediastinal HD there was a significant decrease in FENO (from 50.4 ppb CI 95% 18.0-82.8 to 11.1 ppb CI 95% 4.4-17.8, p=0.011). In conclusion, high FENO and NOS expression in lymph-nodes indicate that NO is a component of the inflammatory network of HD. FENO may be proposed for the assessment and follow up of bulky mediastinal HD patients.

Double step paraneoplastic brainstem encephalitis: a clinicopathological study

A case of brainstem encephalitis in a man positive for both anti-Hu and anti-Ri antibodies is reported. This case had an unusual double step evolution and progressive involvement of different CNS subdivisions at MRI. Brainstem encephalitis developed abruptly, mimicking a posterior vascular deficit with vertigo and dizziness. These symptoms transiently remitted completely after a few days to relapse acutely 1 month later with sudden loss of consciousness, followed by confusion, disorientation, dysarthria, dysphagia and reduced thermic sensation on the right side. Within another few days, the patient developed acute respiratory failure and died some weeks later. MRI was negative at the beginning but later showed a progressive ascending involvement of the brainstem and thalamus. At autopsy, this picture corresponded to lymphocytic infiltration, preferentially B cells into the perivascular spaces and T cells in the brainstem parenchyma, confirming that T cells could be the effector of cytotoxicity, probably in the presence of cooperation with B cells that were well represented in this setting.

Hepatocellular carcinoma complicating primary sclerosing cholangitis in Crohn's disease. A case report

The prevalence of primary sclerosing cholangitis (PSC) in Crohn's disease (CD) patients is up to 8.5%. Although cholangiocarcinoma may complicate long-standing PSC in one third of the cases if follow-up is extended long enough, hepatocellular carcinoma (HCC) is a rare complication of PSC. The concomitant presence of PSC, HCC and CD have been reported sporadically. We discuss here a case of association of these three conditions.

Prolonged survival in poor-risk diffuse large B-cell lymphoma following front-line treatment with rituximab-supplemented, early-intensified chemotherapy with multiple autologous hematopoietic stem cell support: a multicenter study by GITIL (Gruppo Italiano Terapie Innovative nei Linfomi)

A prospective multicenter program was performed to evaluate the combination of rituximab and high-dose (hd) sequential chemotherapy delivered with multiple autologous peripheral blood progenitor cell (PBPC) support (R-HDS-maps regimen) in previously untreated patients with diffuse large B-cell lymphoma (DLB-CL) and age-adjusted International Prognostic Score (aaIPI) score 2-3. R-HDS-maps includes: (i) three APO courses; (ii) sequential administration of hd-cyclophosphamide (CY), hd-Ara-C, both supplemented with rituximab, hd-etoposide/cisplatin, PBPC harvests, following hd-CY and hd-Ara-C; (iii) hd-mitoxantrone (hd-Mito)/L-Pam + 2 further rituximab doses; (iv) involved-field radiotherapy. PBPC rescue was scheduled following Ara-C, etoposide/cisplatin and Mito/L-Pam. Between 1999 and 2004, 112 consecutive patients aged <65 years (74 score 2, 38 score 3) entered the study protocol. There were five early and two late toxic deaths. Overall 90 patients (80%) reached clinical remission (CR); at a median 48 months follow-up, 87 (78%) patients are alive, 82 (73%) in continuous CR, with 4 year overall survival (OS) and event-free survival (EFS) projections of 76% (CI 68-85%) and 73% (CI 64-81%), respectively. There were no significant differences in OS and EFS between subgroups with Germinal-Center and Activated B-cell phenotype. Thus, life expectancy of younger patients with aaIPI 2-3 DLB-CL is improved with the early administration of rituximab-supplemented intensive chemotherapy compared with the poor outcome following conventional chemotherapy.

Myeloid sarcoma: clinico-pathologic, phenotypic and cytogenetic analysis of 92 adult patients

Myeloid sarcoma (MS) is a rare neoplasm whose knowledge is largely based on case reports and/or technically dated contributions. Ninety-two MSs in adulthood with clinical data available were evaluated both morphologically and immunohistochemically. Seventy-four cases were also studied by fluorescent in situ hybridization on tissue sections and/or conventional karyotyping on bone marrow or peripheral blood. Histologically, 50% of the tumors were of the blastic type, 43.5% either monoblastic or myelomonocytic and 6.5% corresponded to different histotypes. CD68/KP1 was the most commonly expressed marker (100%), followed by myeloperoxidase (83.6%), CD117 (80.4%), CD99 (54.3%), CD68/PG-M1 (51%), CD34 (43.4%), terminal-deoxy-nucleotidyl-transferase (31.5%), CD56 (13%), CD61/linker for activation of T cells (2.2%), CD30 (2.2%) and CD4 (1.1%). Foci of plasmacytoid monocyte differentiation were observed in intestinal cases carrying inv16. Chromosomal aberrations were detected in about 54% of cases: monosomy 7(10.8%), trisomy 8(10.4%) and mixed lineage leukemia-splitting (8.5%) were the commonest abnormalities, whereas t(8;21) was rare (2.2%). The behavior was dramatic irrespective of presentation, age, sex, phenotype and cytogenetics. Most if not all, long survivors received bone-marrow transplantation. The present report expands the spectrum of our knowledge showing that MS has frequent monoblastic/myelomonocytic differentiation, displays distinctive phenotypic profile, carries chromosomal aberrations other than t(8;21), and requires supra-maximal therapy.

[The Haemolymphopathology Italian Group (H.I.G.): an essential resource for the new technical and organization problems troubling modern haemolymphopathology diagnostics]

Recently, many progresses have been recorded in the molecular and histogenetic characterization of the haematopoietic and lymphoid tumours, resulting in important classifying changes. As a consequence, the exact definition of lymphoma subtype requires an integration between traditional morphologic "expertise" and several bio-functional data obtained from advanced and complex ancillary techniques (immunohistochemistry, molecular biology and cytogenetics). At the same time, the data provided by gene expression profiling studies are going to deeply modify the therapies in haematological cancers. These studies are expected to allow the achievement of single-patient-tailored genic therapy; for this reason it is necessary to get biological samples of good quality. Indeed, while these progresses contribute to highlight the pathologist's diagnostic role, they should make us reflect on the state of the art of the Italian haemolymphopathology diagnostics and on its ability to cope up with the new challanges. The aim of this article is to outline a realistic picture of the present condition, and to explain the reasons for setting up, inside SIAPEC-IAP, the Haemolymphopathology Italian Group (H.I.G.). The purpose of H.I.G. will be twofold: first of all, scheduling of a series of projects so as to the haemolymphopathological diagnostic standardization; secondly, building a national network among all the pathologists involved in this exciting and complex field of the anatomic pathology.

Disseminated Kaposi's sarcoma associated with idiopathic CD4+ lymphocytopenia and low dose steroid therapy

A case of disseminated Kaposi sarcoma in a 76-year-old woman treated with low-dose steroids for a seronegative polyarthritis is described. HIV serology was negative, whereas PCR for HHV-8 was positive. The patient presented with a profound reduction in the peripheral blood CD4+ cell count and a decrease in serum immunoglobulins and was diagnosed as having idiopathic CD4+ lymphocytopenia. The clinical picture was characterized by limited cutaneous lesions with typical features of KS associated with widespread visceral involvement and unusually aggressive behaviour.

Association between Crohn's disease and Conn's syndrome. A report of two cases

The natural history of Crohn's disease (CD) is characterised by periods of remission followed by phases of flares. Persistent or intractable diarrhoea may be associated with ileal disease or arise following ileal resection, resulting in potassium depletion. Medical therapy with steroids presents troublesome side-effects (e.g. hypertension). Conn's syndrome, caused by unilateral aldosterone-producing adenoma, is characterised by clinical features including hypokalaemia and hypertension. Thus, CD and Conn's syndrome may have an overlap of manifestations, and up to now, the simultaneous occurrence of these conditions has not been described. We report here 2 cases of association between CD and Conn's syndrome.

Expression of the CD31 antigen in normal B-cells and non Hodgkin's lymphomas

The role cell adhesion molecules play in the biological and clinical behaviour of non Hodgkin's lymphomas (NHL) has been reported in several studies. This study reports the findings on B-cells taken from various healthy control tissues and compared them to B-cells from 83 malignant B-lymphomas, that had been classified according to the WHO classification. Flow cytometry was used to investigate the surface expression of CD31, an adhesion molecule involved in B-cell development and vascular adhesion mechanisms. Quantification of the fluorescence signals showed specific patterns of CD31 expression on normal B-cell subpopulations and different NHL groups. Our results demonstrate that CD31 expression is modulated during the differentiation process in normal B-cells, high in pre-B-I cells, low in pre-B-II precursors, intermediate in the mature B-cell subpopulations or, depending on the functional state absent in activated follicular centre cells, present in pre- and post- germinal centre cells. When the CD31 expression is evaluated as fluorescence intensity in NHL, it reveals a heterogeneous pattern related to histogenetic derivation (high in small lymphocytic lymphoma, low in follicular lymphoma, intermediate in marginal zone and large cell lymphomas). These observations suggest that CD31 might well play a critical role in the ontogeny and physiology of B-lymphocytes. Therefore, on the basis of these observations we propose the CD31 molecule as an interesting additional useful parameter to be used for the differential diagnosis of NHL and hypothese that it has a pathophysiologic role in NHL evolution.

Point mutations of the BCL-6 gene: clinical and prognostic correlation in B-diffuse large cell lymphoma

Although point mutations of the 5' noncoding regions of the BCL-6 proto-oncogene are frequently detected in B-diffuse large cell lymphoma (B-DLCL), a thorough analysis of the clinical correlation of these mutations has not been performed to date. In this study, BCL-6 mutations were examined by DNA direct sequencing in 103 patients with B-DLCL. BCL-6 mutations were found in 53/103 patients, including 38/76 treated with standard chemotherapy and 15/27 treated with autologous stem cell transplantation (ASCT) up front. The presence of BCL-6 mutations was correlated with clinical features at diagnosis and outcome. Mutated patients had a significantly higher LDH level (66% vs 38%, P < 0.05), and bulky disease (51% vs 32%, P = 0.05). In the whole series of patients BCL-6 mutations did not affect CR and OS. Patients with BCL-6 mutations tended to have a prolonged 5-years DFS and FFS compared to those without mutations (DFS 82% vs 63%, FFS 63% vs 49%). Among B-DLCL treated with standard chemotherapy, mutated patients showed a significantly improved 5-year DFS (85% vs 61%, P < 0.05) and, notably, the only four relapses observed among mutated patients occurred in less than 8 months. The multivariate regression analysis (P < 0.01) with DFS as endpoint confirmed the independent prognostic value of BCL-6 mutations. There was a trend for 5-year failure-free survival to be better for patients with BCL-6 mutations (63% vs 43%, P = 0.09). In the 27 patients treated with ASCT, BCL-6 mutations did not correlate with outcome. These results suggest that BCL-6 mutations may predict a higher chance of being free of disease in B-DLCL treated with standard chemotherapy. Larger series of patients need to be analyzed to evaluate the clinical relevance of BCL-6 mutations properly.

Overweight as an adverse prognostic factor for non-Hodgkin's lymphoma patients receiving high-dose chemotherapy and autograft

Despite detailed evaluation of disease-associated prognostic factors, little is known about the impact of overweight in autograft programs for non-Hodgkin's lymphoma (NHL) patients. In order to address this issue, 121 NHL patients were retrospectively evaluated. They had been upfront (92 patients) or in relapse (29 patients) and received high-dose sequential (HDS) chemotherapy including peripheral blood progenitor cell (PBPC) autograft. Body mass index (BMI) was calculated as weight in kilograms divided by the square of the height in meters; overweight was defined as BMI > or = 28. Univariate and multivariate analyses were used to determine the prognostic implication of overweight and other known prognostic indicators on overall (OS) and event-free (EFS) survival for the entire group and overweight and non-overweight (reference) subgroups. With a median follow-up of 3 years, the estimated 5-year OS and EFS for the entire group were 58% and 49%, respectively. Twenty-eight patients (23%) had BMI > or = 28. Their median OS and EFS were 2.2 and 1.4 years, respectively, whereas median OS and EFS for the reference group have not been reached, with a 5-year projection of 65 and 55%, respectively (P < 0.002). On multivariate analysis, the risk of death among overweight patients was 2.9 (CI, 1.3-6.2) times that of the reference group; using EFS as the end point, a similar association between overweight and survival was observed. In conclusion, in high-risk NHL patients undergoing intensive chemotherapy and PBPC autografting overweight is associated with a poorer outcome.

Long-term follow-up of advanced-stage low-grade lymphoma patients treated upfront with high-dose sequential chemotherapy and autograft

Long-term outcome, after first line intensified high-dose sequential (i-HDS) chemotherapy, was evaluated in 46 patients, aged < or =65 years, with advanced low-grade lymphoma. Seventeen patients had small lymphocytic lymphoma (SLL), 29 had follicular lymphoma (FL), 10 of them with histologic transformation. I-HDS included: (1) tumor debulking, by 2 APO+2 DHAP courses; (2) sequential administration of high-dose (hd) etoposide, methotrexate, and cyclophosphamide, followed by peripheral blood progenitor cell (PBPC) harvest; (3) hd-mitoxantrone + melphalan with PBPC autograft. Ten FL patients had their PBPC immunologically purged ex vivo. There were two treatment-related deaths; five FL patients had short-lasting response followed by disease progression, five SLL reached a stable PR; overall, 34 patients (74%) reached CR. At a median follow-up of 4.3 years, the estimated 9-year OS and EFS were 84% and 45%, respectively. No significant differences were observed in the OS among patients at low, intermediate or high IPI score, with an estimated OS projection of 95%, 78%, and 75%, respectively. FL had longer survival without evidence of residual disease (9-year EFS: 59%) as compared to SLL patients (8.8-year EFS: 17%); however, both groups had prolonged survival and no need of salvage treatment, as shown by the time to disease progression curve, projected to 66% and 62% for SLL and FL, respectively. The results indicate that hd-approach in low-grade lymphoma: (1) is associated with longer progression-free survival as compared to conventional therapies; (2) may imply higher tumor mass reduction in FL as compared to SLL patients; (3) offers long life expectancy, with potential survival benefits at least for patients at intermediate/high IPI score.

Idiotype vaccination in human myeloma: generation of tumor-specific immune responses after high-dose chemotherapy

Igs contain unique portions, collectively termed idiotypes (Id), that can be recognized by the immune system. Id expressed by tumor cells in B-cell malignancies can be regarded as tumor-specific antigens and a target for vaccine immunotherapy. We have started a vaccination trial in multiple myeloma (MM) using Id-specific proteins conjugated to keyhole limpet hemocyanin (KLH) as immunogens and low doses of subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-2 (IL-2) as immunoadjuvants. Twelve patients who had previously been treated with high-dose chemotherapy followed by peripheral blood progenitor cell (PBPC) transplantation entered this study from August 1995 to January 1998. All patients were in first remission at the time of vaccination. They received subcutaneous injections of Id vaccines and immunoadjuvants in an outpatient setting. The generation of Id-specific T-cell proliferative responses was documented in 2 patients, whereas a positive Id-specific delayed-type hypersensitivity (DTH) reaction was observed in 8 of the 10 patients studied. DTH specificity was confirmed in 1 patient by investigating the reactivity to synthetic peptides derived from the VDJ sequence of the tumor-specific Ig heavy chain. None of the patients generated soluble immune responses to Id, whereas the generation of soluble and cellular immune responses to KLH was observed in 100% and 80%, respectively. Eleven patients completed the treatment, whereas 1 patient failed to finish owing to progression of disease. Freedom from disease progression (FFDP), measured from the date of first Id/KLH injection to the date of first treatment after vaccination or last follow-up, ranged from 9 to 36 months. These data indicate that the immune competence status of MM patients is still susceptible to specific immunization after high-dose chemotherapy and PBPC transplantation. It remains to be determined whether generation of Id-specific immune responses can reduce the relapse rate of patients with minimal residual disease.

Mantle cell lymphoma: a retrospective study on 27 patients. Clinical features and natural history

BACKGROUND AND OBJECTIVE

Mantle cell lymphoma (MCL) is a separate histological and clinical entity recently recognized in the new revised European-American Lymphoma Classification. Little information exists regarding its therapy. We report the results of a retrospective study of 27 patients affected by MCL evaluating the clinical characteristics and the results of different therapeutical options used during the period of observation.

DESIGN AND METHODS

From 1983 to 1993, we observed 27 patients affected by MCL according to the criteria proposed by European Lymphoma Task Force in a revision of 55 cases classified as NHL E according to Working Formulation (WF) criteria. We analyzed the clinical characteristics, the prognostic factors and the O.S. of these patients.

RESULTS

The clinical characteristics of our patients (pts) are similar to those observed in other series: male prevalence, median age 62 years, B symptoms in 9 cases, P.S. > 2 in 11 cases, 3 pts were in stage I and II, 4 in stage III, 20 in stage IV; 18 pts had a bone marrow involvement, 13 pts had spleen enlargement and 14 had extranodal localization; 8 pts had bulky tumor and 5 had LDH above normal. The CR rate was 51.8%, the median O.S. was 43 months, and DFS was 18 months; the pts without bulky disease and with localized disease had a better CR rate. The inclusion of an anthracycline in the regimen did not affect the results.

INTERPRETATION AND CONCLUSIONS

Our results were not divergent from those present in literature. The mantle cell lymphoma is an incurable and highly aggressive disease. Autologous bone marrow transplantation as support of high dose chemotherapy or allogenic bone marrow transplantation may be a chance for some patients, but not for the majority of patients, which are older than 65 years. Studies of a larger series and different therapeutical approaches, i.e. using biological modifiers in association or as maintenance after chemotherapy are essential.

Rearrangements of bcl-6, bcl-2, c-myc and 6q deletion in B-diffuse large-cell lymphoma: clinical relevance in 71 patients

BACKGROUND

B-diffuse large-cell lymphomas (DLCL) have been associated with some molecular lesions, but the role of such lesions as prognostic markers is still controversial. This report concerns an investigation of the frequency and clinical correlation of bcl-6, bcl-2, c-myc rearrangements and 6(q) deletions in B-DLCL.

PATIENTS AND METHODS

The presence of these genetic lesions was analyzed in samples of lymph nodes or bone marrow collected at diagnosis in 71 patients with B-DLCL, all treated with an anthracycline-containing chemotherapy regimen.

RESULTS

Rearrangement of bcl-6 was found in 11 patients (15%), rearranged bcl-2 in 12 (17%), 6(q) deletions in 10 patients (14%) and c-myc rearrangement in four (6%). Patients with rearranged bcl-6 tended to have a more aggressive disease than patients with germ-line bcl-6 (intermediate-high/high risk according to IPI criteria: 73% vs. 43%), but there were no differences in three-year survival rates (62% vs. 42%) between the two groups. The numbers of involved extranodal sites were similar in patients with rearranged and those with germ-line bcl-6. Patients with bcl-2 rearrangement appeared to have a less aggressive disease than those with germ-line bcl-2 (low/ low-intermediate risk 75% vs. 47%) and a slightly better three-year survival rate (70% vs. 41%) but again the difference was not significant. Both groups with or without 6(q) deletion had similar clinical characteristics and outcomes. The four patients with c-myc rearrangement had aggressive disease and did poorly.

CONCLUSIONS

The analysis of molecular lesions in B-DLCL may be useful for a better diagnostic definition; however, in this study we were unable to show that the evaluated genetic lesions had a significant impact on clinical outcome.

Cell proliferation, bcl-2, c-myc, p53 and apoptosis as indicators of different aggressiveness in small lymphocytic lymphoma (SLL)

Cell proliferation activity, by MIB1 mAb, expression of bcl-2, c-myc and p53 gene proteins and apoptotic index (AI) were assessed in 54 cases of SLL and compared to the morphological subtypes of this disorder, defined by Lennert on the basis of amount and distribution of small and larger activated lymphocytes as diffuse, tumor-forming and pseudofollicular subtypes (DS, TFS, PFS). MIB1 scores showed significant differences between DS, PFS and TFS (5.5%, 16.61% and 24.14%, respectively; p < 0.0001). Worth noting, the MIB1 score did not differ significantly when comparing DS with the diffuse areas of PFS, or TFS with the pseudofollicles of PFS. The mean bcl-2 gene protein score was displayed to a high extent in all subtypes, but less extensively by larger activated lymphocytes that, conversely, expressed c-myc. MIB1 score correlated negatively with bcl-2 and positively with c-myc protein scores. These findings suggest that lymphocytes protected from apoptosis by bcl-2 would be exponed to cell activation and growth acceleration provided by c-myc. This condition would account for a different aggressiveness of morphologically activated subtypes, such as TFS and PFS with larger pseudofollicles. The survival analysis, performed in 23 cases, showed a trend of association of cell proliferation and c-myc expression with a more aggressive progression of the disease. Overexpression of p53 and apoptosis were found only in a minority of cases, unrelated to the subtypes. In conclusion, cell growth fraction, bcl-2 and c-myc assessment may be of help in predicting the aggressiveness of different subtypes of SLL. This approach should be most conveniently applied to PFS, which represents a continuum between DS and TFS, in order to distinguish, in this heterogeneous subtype, more indolent from more aggressive disorders.

[Lymphadenopathy caused by Toxoplasma in an intramammary lymph node: role of molecular biology in the diagnosis]

We describe a case of Toxoplasma gondii lymphoadenopathy in an intramammary lymph node in a 22 year old woman. Clinical evidence and ultrasound were suggestive for fibroadenoma, while cytology on fine needle aspiration suspected a lymphomatous lesion. The pathological examination demonstrated a lymph node with granulomatous foci with epithelioid histiocytes, consistent with Toxoplasma gondii lymphadenopathy. The pathological finding was confirmed by serological tests and by PCR (Polymerase Chain Reaction) using specific primers designed on ribosomal 18s DNA sequence of Toxoplasma gondii. The aim of this work is to emphasize the role of molecular biology techniques as an aid to pathological diagnosis in parasite diseases.

Analysis of the immunoglobulin heavy-chain gene rearrangement providing molecular evidence of second lymphoma in a patient in apparent relapse after autotransplantation

Development of a second lymphoma after autotransplantation is an unusual event. Its real incidence, however, could be underestimated, since histologic and immunophenotyping techniques are often unable to distinguish it from a relapse. We report a lymphoma patient in apparent relapse after 42 months of molecular remission achieved by autotransplantation. Sequencing analysis of the immunoglobulin heavy-chain genes showed that the rearrangement of variable, diversity and joining segments had changed between diagnosis and relapse and suggested that a second lymphoma had developed.

Recurrent necroinflammatory disease of multiple organs and colon. Systemic presentation of inflammatory bowel disease or gut involvement during systemic disorder

A 30-year-old man with a recurrent febrile illness resembling infection is described. Because he presented with an acute abdomen, he underwent a laparotomy, which showed the paraaortic and mesenteric lymph nodes to be changed into an abscess-like granulomatous tissue made up of necrotized granulocytes. During further flare-ups, the disease affected the spleen, skin, colon, peripheral nerve, and muscle. Histology on the biopsy materials of both the skin and colon, and on the surgically removed spleen showed the same invading pathologic tissue. Exhaustive investigation disclosed no pathogen, and the flare-ups responded repeatedly to high-dose steroids. This patient's picture has recently been defined as a syndrome of chronic granulomatosis based on several published cases. As a distinctive feature, in our patient the granulomas affected also the colon. For the present, and for another previously described similar case we analyzed the factors that might permit the differential diagnosis between the above-mentioned granulomatous syndrome and Crohn's colitis.

Molecular heterogeneity of B-lineage diffuse large cell lymphoma

B-lineage diffuse large cell lymphoma (B-DLCL) arising de novo is characterized by a marked degree of clinical heterogeneity. To determine whether or not the clinical heterogeneity of de novo B-DLCL is reflected by heterogeneity in the molecular features of these tumors, we investigated the pattern of distribution of several genetic lesions in 70 cases of de novo B-DLCL at diagnosis. The panel of genetic lesions tested comprised the molecular alterations most frequently detected in B-DLCL, including rearrangements of BCL2, BCL6, and MYC as well as deletions of 6q and mutations of TP53. One or more genetic lesions were detected in 39/70 cases of B-DLCL. Isolated structural alterations of BCL2, BCL6, 6q or TPS3 were detected in 8/70, 10/70, 11/70, and 3/70 cases, respectively. No isolated MYC lesions were detected. Six cases carried different combinations of two genetic lesions, including lesions of BCL2 + BCL6 (1 case), BCL2 + MYC (1 case), BCL2 + 6q (2 cases), or BCL6 + 6q (2 cases). One case had accumulated three genetic lesions, namely a rearrangement of BCL2 and BCL6 and a mutation of TPS3. Overall, these data show that multiple distinct patterns of genetic lesions may associate with de novo B-DLCL, indicating that the molecular pathogenesis of this group of lymphomas is characterized by a high degree of molecular heterogeneity.

Biological heterogeneity of diffuse mixed small and large cell non-Hodgkin's lymphomas assessed by DNA flow cytometry and Ki67

The cell proliferative activity of the clinico-pathologically heterogeneous non-Hodgkin's lymphomas (NHL) included in the intermediate grade F category of the Working Formulation (WF) was investigated. S-phase fraction with flow cytometry on cell suspensions, and Ki67 on frozen tissue sections were performed in 42 F NHL. An avidin-biotin immunocomplex method was used and 1000 cells from 10 representative fields were counted. DNA content, S-phase and Ki67 were also detected in 194 NHL covering the whole spectrum of the WF. DNA content anomalies were found in 52 of 194 NHL. Their incidence, like that of S-phase fraction and Ki67 positive cells, progressively increased from low- to high-grade. A linear correlation was found between Ki67 and S-phase (r = .59). Using the median value of proliferating cells obtained with both procedures as a cut off, two very different groups of lymphomas could be distinguished within a series of 42 F-intermediate NHL: with low and high proliferative cell activity (p < .0001) that were termed F(low) and F(high), respectively. A intermediate group was placed between them. It differed significantly from the others if Ki67 was used but only from the F(high) group if the S-phase fraction analysis was applied. No significant differences were seen when comparing F(low) with the single categories of low-grade NHL and F(high) with H high-grade NHL; no significant differences were found between F(high) and G, and between G and H categories. The existence of distinct groups of NHL in the F category, as defined by biological parameters assessing the cell proliferative activity, indicates that this category includes biologically heterogeneous lymphoma subtypes with different grades of aggressiveness. The results also indicate that the G intermediate category displays proliferation indices similar to those of H high grade category.

Intestinal T-cell lymphoma with massive tissue and blood eosinophilia mediated by IL-5

A case of enteropathy associated T-cell lymphoma (EATCL) in a 62-year-old female with a previous history of coeliac disease, complicated during the clinical course by massive blood and tissue eosinophilia is described. The patient's serum contained a factor capable of stimulating the in vitro growth of eosinophilic colonies (CFU-Eo), that was absent in the serum of normal donors. We suggest that such factor was Interleukin-5 (IL-5), as indicated by the presence in the monoclonal tumor T cells of IL-5 encoding mRNA, usually absent in the normal enterocytes of the jejunum.

B-cell chronic lymphocytic leukaemia stage 0. An immunophenotypic study of 66 cases and comparison with B small cell lymphomas

The cells of 66 B-CLL stage 0 patients were analyzed using a large panel of monoclonal antibodies in order to better define the immunophenotype of B-CLL. The data were compared with the immunophenotypes of lymph node cells from 51 patients with diffuse B small cell lymphoma or leukaemia with lymph node enlargement. The most frequent immunophenotype of B-CLL stage 0 was SIgM(D)+ EmR+ CD5+ CD9+ CD21+ CD23+ CD35- CD38-. Among the lymphomas, EmR-positive and EmR-negative cases were identified. The vast majority of the EmR-positive cases usually showed the leukaemic pattern, immunophenotype and lymph node histology of B-CLL. The EmR-negative cases usually had immunophenotypes quite different from those of B-CLL and the histology of indented cell lymphoma (centrocytic or intermediate) or features of lymphoplasmacytoid/cytic lymphoma. More than 20% of EmR-positive cells proved to be the most important marker to distinguish B-CLL from other lymphocytic lymphomas. Indeed this was a sign of better prognosis. Lymphoplasmacytoid/cytic lymphomas were EmR-positive with the immunophenotype of B-CLL or EmR-negative with a definitely different immunological profile. This suggests two morphologically similar but biologically different subgroups of these diseases.

MIB-1, Ki67, and PCNA scores and DNA flow cytometry in intermediate grade malignant lymphomas

AIMS

To verify the correlation between MIB-1, Ki67, and proliferating cell nuclear antigen (PCNA-PC10) scores and S-phase fraction in intermediate grade non-Hodgkin's lymphomas (Working Formulation F); and their reliability in differently processed tissues.

METHODS

Forty one non-Hodgkin's lymphomas were classified as (F) intermediate grade malignant lymphomas according to the Working Formulation; mitotic counts and percentage of large cells were assessed for each case. Sections from formalin fixed, paraffin wax embedded tissues were stained with anti MIB-1 monoclonal antibody, after microwave oven processing, and anti-PCNA (PC10) monoclonal antibody using an avidin-biotin immunoperoxidase (ABC) method. One thousand cells from 10 representative fields were scored. Frozen sections from surgical specimens were stained with Ki67 monoclonal antibody using the ABC method; the fraction of Ki67 positive cells was calculated scoring 1000 cells. Flow cytometry analysis (FCM) was performed on cell suspensions from fresh tissues. Correlations between data were estimated using linear regression.

RESULTS

A linear correlation was found between MIB-1 and Ki67 scores (r = 0.92; p < 0.00001); between MIB-1 and PCNA scores (r = 0.79; p < 0.00001); and between MIB-1 score and S-phase fraction (r = 0.51; p = 0.0006). A linear correlation was also found between Ki67 and PCNA scores (r = 0.85; p < 0.00001); between Ki67 score and S-phase fraction (r = 0.6; p = 0.0002); and between PCNA score and S-phase fraction (r = 0.74; p < 0.00001). A correlation was found between mitotic counts and MIB-1 (r = 0.56; p = 0.0001), PCNA (r = 0.51; p = 0.0007), or Ki67 scores (r = 0.47; p = 0.002); between the percentage of large cells and MIB-1 (r = 0.49; p = 0.0009), PCNA (r = 0.6; p = 0.00003), and Ki67 scores (r = 0.53; p = 0.0003) and S-phase fraction (r = 0.55; p = 0.0002).

CONCLUSION

MIB-1, Ki67, and PCNA (PC10) scores and S-phase fraction are highly correlated and equally well represent the proliferative activity of intermediate grade non-Hodgkin's lymphomas in differently processed material. MIB-1 and PCNA stains can be applied even on small biopsy specimens. MIB-1 produces homogenous staining without background; it also strongly stains mitotic figures. It can be performed on routinely processed tissues, permitting the simultaneous evaluation of the morphology and tumour cell kinetics. The wide standard deviations of the proliferative indices found for intermediate grade NHL suggest that this category probably includes various degrees of malignancy.

Unusual eruption of cutaneous metastases from occult gastric carcinoma shortly after HIV-1 infection

We report a case of eruptive metastases to the skin of the face and neck from a hitherto unknown gastric carcinoma, occurring in a fifty-two-year-old man (a regular blood donor), about six months after he contracted human immunodeficiency virus-1 infection. The eruption, consisting of more than thirty pea-sized cutaneous nodules appeared within about twenty days. The patient complained of epigastric pain and weight loss. Histologic examination showed signet-ring cells of gastric carcinoma metastases. Gastroscopic examination showed a widely infiltrating tumor. No metastases were found elsewhere after a careful screening. Immunologic variables were only slightly altered. This case and a brief review suggest that gastric carcinomas, possibly as well as other coincidental tumors, may present atypically during human immunodeficiency virus-1 infection.

Heterogeneous immunoglobulin gene rearrangement in a B-chronic lymphocytic leukemia progressing into non-Hodgkin lymphoma (Richter syndrome)

BACKGROUND

The relationship between chronic lymphocytic leukemia (CLL) and supervening non-Hodgkin lymphoma is debated, as is whether a particular genomic pattern is related to the emergence of the terminal lymphoma. To investigate these features, the molecular organization of the immunoglobulin (Ig) gene region in a case during both the B-CLL and Richter transformation phase was studied.

METHODS

B-CLL and non-Hodgkin lymphoma cells were processed for Southern blot analysis of Ig heavy- and light-chain gene configuration.

RESULTS

Molecular studies of B-CLL cells revealed the presence of a single Ig heavy-chain rearrangement with both kappa and lambda light-chain rearranged genes, which was consistent with the occurrence of multiple mutational events during the development of the B-CLL clone. Molecular analysis of the lymphoma DNA showed new Ig heavy- and kappa light-chain rearrangements in addition to the original ones related to the CLL phase, indicating that the lymphoma tissue consisted of two genotypically distinct populations of cells.

CONCLUSIONS

On the basis of the overall molecular configuration, this heterogeneous pattern of Ig gene rearrangement was interpreted as an inherent genetic instability of the CLL clone, in which multiple mutational events allowed a selective pressure toward more aggressive subclones, resulting in the emergence of the terminal lymphoma.

Stage II large B-cell lymphoma with sclerosis treated with MACOP-B

In a series of 193 patients with advanced stage diffuse large-cell lymphoma (DLCL) treated with MACOP-B, 18 (11%) were defined as having a stage II large B-cell lymphoma with sclerosis of the mediastinum. This type of lymphoma has been reported to have a highly aggressive behaviour and special histological and clinical features. In our series young women were more commonly affected and the most striking clinical feature was the presence of a bulky mediastinal mass in 81%. A comparison was made between stage II patients with DLCL with and without sclerosis. The group of patients with sclerosis had prognostic parameters significantly worse than those of the patients without sclerosis, namely, elevated LDH level and bulky disease. The complete remission rates (89% vs 76%) were similar in the two groups and, with a median follow-up of 23 months, survival and disease-free survival rates were also superimposable. MACOP-B chemotherapy has been proven effective in this subgroup of lymphoma patients with sclerosis that had thus far been reported to have a poor prognosis.

[Comparative morphological study of the structure of the normal and arteriosclerotic internal mammary, coronary, and renal artery wall]

Morphological comparative study of the normal anatomy of the internal mammary artery, coronary artery and renal artery, and their atherosclerotic alterations. We report in this paper the comparative results of a morphological and morphometrical study of the normal anatomy of the Left Coronary Artery (interventricular descending branch) (LCA), Internal Mammary Artery (IMA) and Renal Artery (RA) and their atherosclerotic alterations in 27 unselected people of both sexes aging from 19 to 76 years (average 59 +/- 14.3). Sections from three different segments of each vessel were examined by measuring the thickness of the intima and media calculated at the maximum intimal thickening. The lumen was also measured at the level of its highest pathological reduction; the same measurements were carried out on sections free from atherosclerotic damage. Then the intima to media ratio was assumed as major indicator of atherosclerosis involvement according to the literature. All these parameters were statistically analysed. With these procedures we found that LCA displayed more severely atherosclerotic changes than IMA. The degree of damage in RA fell in between when compared to the other arteries. The intima to media ratio average was 0.061 mm. (+/- 0.084) in I.M.A.; 0.882 mm. (+/- 0.753) in L.C.A. and 0.272 (+/- 0.315) in RA with statistically significant differences between IMA and LCA (p less than 0.001) and between IMA and RA (p less than 0.001). In the lesion free sections intima to media ratios were 0.178 (+/- 0.90) in LCA, 0.053 (+/- 0.28) in IMA and 0.082 (+/- 0.127) in RA. The difference was statistically significative between LCA and IMA, but not between RA and IMA.(ABSTRACT TRUNCATED AT 250 WORDS)

[Incidence of atherosclerosis of the internal mammary artery compared with the coronary artery. A study of 22 non-selected autopsy cases]

In the present work the examination and comparison of the degree of atherosclerotic involvement of the left coronary artery (CDA) and internal mammary artery (AMI) was performed on 22 unselected subjects at necroscopy examination. The maximum age was 77 and the minimal was 25 (average 62.59 +/- 2.47); 13 were male and 9 female. We macroscopically and microscopically examined three sections obtained from three different segments for each vessel. First we macroscopically evaluated the degree of narrowing of the lumen giving a score (+ to +). (Tab. II). Then the sections, 6 micron thick, stained with Haematoxylin-eosine, Alcian blue, PAS and Van Gieson methods were accurately examined at microscope with a graduated eyepiece. The lumen, the intima and the media were measured at the level of maximum thickness of the intima. Then the thickness of intima and the intima to media ratio, accordingly to the literature, were assumed as major indicators of atherosclerosis involvement. The intima to media ratio average was 5.05 (+/- 5.81) in the CDA vs. 0.44 (+/- 0.29) in the AMI (p less than 0.001). The intima in the CDA was 0.86 mm (+/- 0.76) thick (average) vs. 0.09 mm (+/- 0.07) in the AMI (p less than 0.001). These results show a great difference in atherosclerosis involvement which results to be ten times greater in CDA than in AMI in non selected people. Almost the same result is obtained by the measurement of the intima. On the contrary no detectable difference was found between the media of the two vessels.

Heterogeneous subgroups among malignant diffuse small B cell lymphomas. A combined nucleometric and immunocytologic study

The degree of heterogeneity among subtypes was evaluated in 39 of the most frequent malignant, diffusely growing small B cell lymphomas by a combination of morphometry, automated image analysis, and immunocytologic techniques. Cluster analysis of nuclear profile parameters, including nuclear area, circularity factor, and chromatin distribution pattern, distinguished 3 groups. Each group was characterized by the preponderance of certain nuclear profile types, i.e. (a) small, rather regular (roundish) and dark staining (typical small lymphocytic lymphomas and immunocytomas); (b) small to intermediate size, rather regular (roundish) and pale staining (small to intermediate size variant); or (c) small to intermediate size, irregular, rather pale staining (diffuse follicular small cleaved cell (centrocytic) lymphomas and, probably, polymorphous immunocytomas). Group 3 was clearly distinct from the rest, but groups 1 and 2 also differed significantly. Every case displayed a mixture of the 13 registered nuclear profile types. Lymphoid cells with similar nuclear profile features occurred in B cell zones of non-neoplastic lymph nodes. Frequency distribution of nuclear profile parameters significantly differed from one lymphoma group to another. However, there were considerable overlaps. No clear correlation was found between nuclear profile types and immunophenotypes. Cellular surface antigen patterns showed an extensive intra- and inter-case variability. The findings support the notion of a certain individuality of malignant B cell lymphomas and of a marked heterogeneity among their subtypes.

T-lymphoblastic lymphomas expressing the non-disulfide-linked form of the T-cell receptor gamma/delta: characterization with monoclonal antibodies and genotypic analysis

Three cases of T-lymphoblastic lymphomas (T-LL) expressing the T cell antigen receptor gamma delta (TCR gamma delta) are reported. All of them were CD3+/beta F1-/TCR delta 1+. Moreover, neoplastic cells reacted with the delta TCS1 monoclonal antibody (MoAb) which binds to the non-disulfide-linked form of the TCR gamma delta, but not with the BB3 MoAb which recognizes the disulfide-linked form of the TCR gamma delta. All cases showed a stage II cortical phenotype, eg, TdT+/CD1+/CD3+/CD5+/CD7+; two of them coexpressed CD4/CD8, while the other was CD4+/CD8-. Two cases were positive for CALLA and CD25. Immunogenotypic analysis showed evidence of T beta and C gamma 2 gene rearrangements in all three cases and immunoglobulin (Ig) gene rearrangements in two cases. Two patients presented with an anterior mediastinal mass and the third with a solitary inguinal lymphadenopathy. We suggest that these cases of TCR gamma delta+ T-LL may be derived from the small population (approximately 0.5%) of CD3+ cortical thymocytes which, in the normal human thymus, express the delta TCS1-reactive, non-disulfide-linked form of the TCR gamma delta.

Immunologic cell markers of peripheral blood and lymph node lymphocytes in chronic lymphocytic leukemia

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.

Acid hydrolases in B-chronic lymphocytic leukemia (B-CLL): a comparison with normal peripheral B lymphocytes and normal B-cell subset with the phenotype of B-leukaemic cells

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.

Relationship between structure and T-lymphocyte maturation in human thymomas. Enzyme histochemical and immunohistological studies

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.

Immunohistochemical and enzyme histochemical contributions to the problem concerning the role of the thymus in the pathogenesis of myasthenia gravis

Normal fetal and postnatal thymuses, as well as thymuses from patients with myasthenia gravis (MG), were investigated by immunohistochemical and enzyme histochemical techniques and their morphology reviewed. Intrathymic B-cells, detected by ATPase activity, were found to be markedly increased in number in MG thymuses. They were scattered in the medulla and accumulated around the junctional and medullary vessels and Hassall's corpuscles (HCs). Large epithelial cells, singly or within HCs, were found to be unevenly distributed in the medulla of all the thymuses examined. The striated muscle-like nature of some of these cells was revealed by the presence of myoglobin in their cytoplasm. In myasthenics these cells and small developing HCs characteristically surrounded lymph follicles and were in direct contact with the expanded cap of the follicle mantle, without interposition of reticulin fibres. The close association of immune reactive foci (lymphoid follicles, junctional and medullary vessels, and HCs) with structures involved in autoimmune responses in the thymus (muscle-like and true myoid cells, HCs) strongly suggests that the autoimmune reactions against AChR (acetylcholine receptor) and other muscular components, which constitute the basic defects in myasthenia gravis, may begin in the thymus.

Histochemical study on human germinal centre, mantle-zone and extra-follicular area lymphoid cell subpopulations. Immunological and cytochemical correlations with lymphomatous cells, peripheral normal and leukemic lymphocytes

Tissue sections of lymph nodes, appendices and tonsils, together with smears of immunologically separated peripheral lymphoid cells from a B-CLL and lymphomatous cells from an immunocytoma were submitted to combined enzyme cytochemical investigations with acid alpha-naphthyl acetate esterase (ANAE), beta-glucuronidase (B-G), acid phosphatase (AcPh), adenosine triphosphatase (ATPase), a,d 5'nucleotidase (5'N). T-cells were Acph+, ATPase- and 5'N-. The vast majority of T- and B-cells displayed ANAE and B-G activities with two distinct staining patterns (T-like and B-like pattern). A high proportion of lymphoid cells in the germinal centre (G.C.) and the vast majority of lymphoid cells in the mantle-zone (M.Z.) were shown to belong to B-cell system because of the expression of ATPase and 5'N in their membranes. Some lymphoid cells positive for ANAE and B-G with a B-like pattern and for AcPh were recognizable in the G.C. In the M.Z. only a few lymphoid cells being ANAE+, with a T-like pattern, and AcPh+ were shown to belong to the T-cell system. In contrast, in this zone a high proportion of small lymphoid cells (64% +/- 10%) showed ANAE activity, mostly with B-like pattern. Therefore, these findings indicate that in the M.Z. a high proportion of B-cells ATPase+ and 5'N+ also display ANAE activity. By comparison of the results obtained from lymphoid tissue sections, B-CLL and immunocytoma cell suspensions and normal circulating lymphocytes we can conclude that B-ANAE-positive cells of the M.Z. do not usually appear in the peripheral blood. They circulate in large numbers only in some pathological conditions (like our reported B-CLL). Therefore, B-ANAE-positive lymphoid cells of the mantle, with a B-like staining pattern, include a wide range of subsets which exclude large lymphoid cells and plasma cells.

Detection and distribution of alfa-naphthyl acetate esterase activity in thymocytes of normal, myasthenic thymus and thymoma. Histochemical and cytochemical study in relation to E-rosetting

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.

Role of the T-cell system in glomerulonephritis induced in rats by human serum albumin (HSA). An immunological and morphological study

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.