Ryosuke Aoki

Ratio of M2 macrophage expression is closely associated with poor prognosis for Angioimmunoblastic T-cell lymphoma (AITL)

Angioimmunoblastic T‐cell lymphoma (AITL) is a peripheral T‐cell lymphoma characterized by systemic disease with polymorphous infiltrate including macrophages. Although many studies of tumor‐associated macrophage (TAM) populations in various malignant tumors have been published, only a few have dealt with activation of macrophage phenotypes such as M1 and M2 in tumor tissue. Because M2 macrophages highly express CD163, we suspected that CD163 may be a useful marker for identification of activation of macrophage phenotypes in AITL. We performed a retrospective study of immunohistochemical expression using two markers for macrophages [CD68 (PG‐M1), CD163] and of the correlation of these expressions with overall survival of 42 AITL patients. The number of CD68‐positive cells in AITL tissues did not correlate with overall survival (P= 0.59), whereas the number of CD163‐positive cells and overall survival correlated to some extent (P= 0.08). Meanwhile, a higher ratio of CD163‐positive to CD68‐positive cells in AITL significantly correlated with worse overall survival (P= 0.036). Considering that this ratio reflects the proportion of macrophages polarized to the M2 phenotype, our findings indicate that activation of macrophages towards the M2 phenotype correlates with worse prognosis. Our findings indicate that the ratio of M2 macrophages expressed may be a useful marker for prognosis of AITL.

Distribution of malignant lymphoma in Japan: Analysis of 2260 cases, 2001–2006

The World Health Organization classification was used to conduct an analysis of geographic, age, sex, and lesion primarily biopsied/resected distribution of 2260 lymphoid neoplasms diagnosed during 2001–2006 throughout Japan. B‐cell neoplasms accounted for 65% of all lymphoid neoplasms, T/natural killer (T/NK)‐cell neoplasms for 25% and Hodgkin lymphoma for 7%. The most common type was diffuse large B‐cell lymphoma (DLBCL, 33%), followed by follicular lymphoma (18%), and adult T‐cell leukemia/lymphoma (ATLL, 10%). The high rate of 18% for follicular lymphoma was similar to that in Western countries (11–33%). T/NK‐cell neoplasms accounted for a higher percentage of lymphoid neoplasms in Kyushu (30%) and Okinawa (38%) compared with other areas of Japan (18–20%). Among T/NK‐cell neoplasms, ATLL was the most common type in Okinawa (54%) and Kyushu (59%). Extranodal NK/T cell lymphoma was the second most common type of T/NK‐cell neoplasms in Okinawa (15%). This epidemiological study shows that the distribution patterns of malignant lymphoma differ especially in Kyushu and Okinawa, the endemic area of human T‐cell leukemia/lymphoma virus type 1.

Usefulness of flow cytometry for differential diagnosis of precursor and peripheral T-cell and NK-cell lymphomas: analysis of 490 cases.

Although various CD markers have been analyzed in T‐cell and natural killer (NK)‐cell lymphomas, the sensitivity and specificity of these phenotypic features have not been satisfactorily characterized. Flow cytometry (FCM) was used to determine the phenotypic pattern of 490 T/NK‐cell lymphomas with the aid of a set of surface antigens (CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD11c, CD16, CD19, CD20, CD25, CD30, CD34, and CD56). In data obtained from 319 patients, CD10 expression was detected in 57% of angioimmunoblastic T‐cell lymphomas, CD30 in 93% of anaplastic large cell lymphomas, CD34 in 50% of lymphoblastic lymphomas, and CD56 in 100% of extranodal NK/T‐cell lymphomas nasal type. A total of 92% of adult T‐cell leukemia/lymphomas (ATLL) had expression of CD25 and downregulation of CD7. Of special interest is that 92 ATLL (50%) were CD4+CD7‐CD25+ phenotype while only four peripheral T‐cell lymphoma unspecified (9%) and one (9%) cutaneous T‐cell lymphoma had this phenotype. Phenotypic analysis using FCM was thus found to be useful for differential diagnosis of T‐cell and NK‐cell lymphomas.

Gene expression analysis of rheumatoid arthritis synovial lining regions by cDNA microarray combined with laser microdissection: up-regulation of inflammation-associated STAT1, IRF1, CXCL9, CXCL10, and CCL5.

Objectives: The main histological change in rheumatoid arthritis (RA) is the villous proliferation of synovial lining cells, an important source of cytokines and chemokines, which are associated with inflammation. The aim of this study was to evaluate gene expression in the microdissected synovial lining cells of RA patients, using those of osteoarthritis (OA) patients as the control. Methods: Samples were obtained during total joint replacement from 11 RA and five OA patients. Total RNA from the synovial lining cells was derived from selected specimens by laser microdissection (LMD) for subsequent cDNA microarray analysis. In addition, the expression of significant genes was confirmed immunohistochemically. Results: The 14 519 genes detected by cDNA microarray were used to compare gene expression levels in synovial lining cells from RA with those from OA patients. Cluster analysis indicated that RA cells, including low- and high-expression subgroups, and OA cells were stored in two main clusters. The molecular activity of RA was statistically consistent with its clinical and histological activity. Expression levels of signal transducer and activator of transcription 1 (STAT1), interferon regulatory factor 1 (IRF1), and the chemokines CXCL9, CXCL10, and CCL5 were statistically significantly higher in the synovium of RA than in that of OA. Immunohistochemically, the lining synovium of RA, but not that of OA, clearly expressed STAT1, IRF1, and chemokines, as was seen in microarray analysis combined with LMD. Conclusions: Our findings indicate an important role for lining synovial cells in the inflammatory and proliferative processes of RA. Further understanding of the local signalling in structural components is important in rheumatology.

The relationship of FOXP3 expression and clinicopathological characteristics in adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma is an aggressive malignant disease associated with regulatory T cells as discussed in some recent reports. We analyzed the expression of FOXP3, a key molecule of regulatory T cells, in adult T-cell leukemia/lymphoma and its association with clinicopathological features. Of 169 adult T-cell leukemia/lymphoma cases examined, 60 (36%) showed FOXP3 expression in lymphoma cells. Morphologically, 22 cases were classified as anaplastic large cell variant and 147 as pleomorphic cell variant. Only 1 (5%) of the anaplastic large cell variant cases and 59/147 (40%) of the pleomorphic cell variant cases expressed FOXP3. Epstein–Barr virus-infected cells were significantly more frequently found in FOXP3(+) cases (23/60; 38%) than in FOXP3(−) cases (12/109; 11%) (P<0.0001). Cytogenetic analysis showed that FOXP3(+) cases had simpler chromosomal abnormalities than FOXP3(−) cases. Clinically, FOXP3(+) and FOXP3(−) cases did not differ significantly in age distribution, clinical stage, lactate dehydrogenase and calcium in serum and overall survival. However, 8 of 34 FOXP3(+) cases suffered a severe infectious state, an indication of immunosuppression, while only 2 of 62 FOXP3(−) cases did so (P<0.005). FOXP3 expression in adult T-cell leukemia/lymphoma thus reflects morphological features and is clinically and pathologically associated with an immunosuppressive state.

BCL6 gene amplification/3q27 gain is associated with unique clinicopathological characteristics among follicular lymphoma without BCL2 gene translocation

Although approximately 10–20% cases of follicular lymphoma lack BCL2 gene rearrangement, there are few reports having described the alternative genetic aberrations and their association about clinicopathological features. In this study, analysis by Fluorescence in situ hybridization of BCL6 gene aberrations in 100 follicular lymphoma cases without IGH/BCL2 rearrangement resulted in the identification of four subgroups. Group I: BCL6 gene rearrangement (n=41); Group II: BCL6 gene amplification/3q27 gain (n=30); Group III: the absence of both (n=23); and Group IV: the presence of both (n=6). Group II showed higher grade morphology (Grade 3a/b: 93%), higher bcl2 and MUM1 expression (73 and 57%, respectively), and more frequent combination with BCL2 gene amplification/18q21 gain (90%) than the other groups. BCL6 gene aberration, especially amplification/3q27 gain, indicates the presence of certain morphological and phenotypical findings in follicular lymphoma cases without IGH/BCL2 rearrangement.

Phenotype for activated tissue macrophages in histiocytic necrotizing lymphadenitis

Macrophage polarization is divided into M1 and M2 type based on membrane receptors, cytokines, and chemokines. M1 expresses CD80, interleukin (IL)‐6, IL‐12, and chemokine receptor (CCR)7, while M2 expresses CD163, IL10, and chemokine ligand (CCL)22. The aim of the present study was to identify the properties of infiltrating tissue macrophages in histiocytic necrotizing lymphadenitis (HNL). Twenty patients with HNL were studied, and immunohistochemistry for CD68 (KP1), CD163, CCL22, CCR7, and CD123 was done, along with myeloperoxidase (MPO). To evaluate the phenotypes of tissue macrophages in HNL, the number of cells stained positively for CD163, CCL22, CCR7, CD123 and MPO concurrently with CD68 was counted, and the ratio was calculated for each antibody to CD68+ cells. There was a high rate of co‐expression for CD163 (median, 78%) or CCL22 (80%) and a low rate for CCR7 (5%) in CD68+ cells. It is therefore conceivable that infiltration by M2 macrophages is dominant in HNL. Furthermore, some CD68+ tissue macrophages in HNL co‐express MPO or CD123 (range, 5–80%; median, 23% and 40%, respectively). It is suggested that these characteristic tissue macrophages may be associated with the pathogenesis of HNL and that M2 macrophages may infiltrate to repair the lymphoid tissue injured by cytotoxic T cells in HNL.

Regression of rectal mucosa‐associated lymphoid tissue (MALT) lymphoma after antibiotic treatments

Only a few reports have described regression of rectal mucosa‐associated lymphoid tissue (MALT) lymphoma after antibiotic treatment are generally found to be successful for gastric tumors. We examined eight rectal MALT lymphomas treated with antibiotic treatments to determine whether they regressed after treatment. We also discuss the relationship between rectal MALT lymphomas and MALT1 gene genetic abnormalities. Eight patients who had undergone antibiotic treatments were followed up with colonoscopy after initiation of the treatment. In five of the eight cases (63%) endoscopic examination showed that the rectal tumor had disappeared, which was confirmed histologically. Polymerase chain reaction for immunoglobulin heavy chain identified a monoclonal band in seven of eight cases (88%). Of the eight cases analyzed with fluorescence in situ hybridization (FISH) for MALT1 translocation, two demonstrated MALT1 gene genetic abnormality. These cases tended to be resistant to antibiotic treatment. Investigation and analysis of a large number of rectal MALT lymphomas are needed to establish suitable standards for antibiotic treatment.

FOXP3+ regulatory and TIA-1+ cytotoxic T lymphocytes in HIV-associated Hodgkin lymphoma

Human immunodeficiency virus (HIV) infects CD4+ lymphocytes, leading to a development of malignant lymphomas, such as HIV‐associated Hodgkin Lymphoma (HIV‐HL). This study aimed to assess the differences in cellular composition of the inflammatory reactive background of HIV‐HLs. We examined infiltrating T lymphocytes, specifically regulatory T cells, cytotoxic cells, Epstein‐Barr virus (EBV) related antigens and HIV‐receptor CCR5. In all HIV‐HL cases, Hodgkin and Reed‐Sternberg (HRS) cells showed EBER1 expression, LMP‐1 staining positivity and EBNA‐2 staining negativity, except for one case which showed LMP‐1 staining negativity. Our histological findings indicate the percentage of CD8+, TIA‐1+ lymphocytes was significantly higher in HIV‐HL than in non‐HIV‐HL cases (P < 0.05). On the other hand, the percentage of CD4+, FOXP3+ lymphocytes was significantly lower in HIV‐HL than in non‐HIV‐HL cases (P < 0.05) but present. The percentage of CCR5+ lymphocytes was significantly lower in HIV‐HL than in non‐HIV‐HL cases (P < 0.05). Usually, CD4+ and CCR5+ lymphocytes are reported to be rarely detected in HIV‐associated non‐Hodgkin lymphomas, but the presence of CD4+ and/or FOXP3+ lymphocytes may be implicated in the pathogenesis of HL. In addition, although additional CD8+ lymphocytes are probably not EBV‐LMP specific cytotoxic T‐cells, these lymphocytes may also well be involved in the pathogenesis of HIV‐HL.

Mantle cell lymphoma shows three morphological evolutions of classical, intermediate, and aggressive forms, which occur in parallel with increased labeling index of cyclin D1 and Ki-67

(Cancer Sci 2010; 101: 806–814)