King H. Lam

Reclassification of 300 Primary Cutaneous B-Cell Lymphomas According to the New WHO–EORTC Classification for Cutaneous Lymphomas: Comparison With Previous Classifications and Identification of Prognostic Markers

PURPOSE In the new WHO-European Organisation for Research and Treatment of Cancer (WHO-EORTC) classification for cutaneous lymphomas three major groups of primary cutaneous B-cell lymphoma (CBCL) are distinguished: primary cutaneous marginal zone B-cell lymphoma (PCMZL) and primary cutaneous follicle center lymphoma (PCFCL) with a good prognosis, and primary cutaneous large B-cell lymphoma, leg type (PCLBCL-LT), with an intermediate-level prognosis. This study aimed to assess the clinical significance of the new classification compared with previous classification schemes (EORTC 1997; WHO 2001) and to define prognostic factors within the newly defined categories. PATIENTS AND METHODS In the present study clinical data and histologic sections of 300 patients with CBCL, formerly classified according to the EORTC classification, were reviewed and reclassified according to the WHO and the new WHO-EORTC classification schemes. RESULTS After reclassification, the study comprised 71 patients with PCMZL, 171 patients with PCFCL, and 58 patients with PCLBCL-LT, showing 5-year disease-specific survivals of 98%, 95%, and 50%, respectively. When compared with the EORTC and WHO schemes, 5.3% and 36.3% of patients with CBCL were reclassified into another prognostic category. Multivariate analysis of PCFCL revealed localization on the leg and expression of FOXP1 as independent parameters associated with a poor prognosis. Expression of Bcl-2 or MUM-1 had no significant effect on survival in this group. In PCLBCL-LT, no independent prognostic parameters were found. CONCLUSION These results emphasize the clinical significance of the WHO-EORTC classification, but suggest that within the group of PCFCL, distinction should be made between lymphomas presenting on the legs and lymphomas presenting at other sites.

BIOMED-2 multiplex immunoglobulin/T-cell receptor polymerase chain reaction protocols can reliably replace Southern blot analysis in routine clonality diagnostics

To establish the most sensitive and efficient strategy of clonality diagnostics via immunoglobulin and T-cell receptor gene rearrangement studies in suspected lymphoproliferative disorders, we evaluated 300 samples (from 218 patients) submitted consecutively for routine diagnostics. All samples were studied using the BIOMED-2 multiplex polymerase chain reaction (PCR) protocol. In 176 samples, Southern blot (SB) data were also available, and the two types of molecular results were compared. Results of PCR and SB analysis of both T-cell receptor and immunoglobulin loci were concordant in 85% of samples. For discordant results, PCR results were more consistent with the final diagnosis in 73% of samples. No false-negative results were obtained by PCR analysis. In contrast, SB analysis failed to detect clonality in a relatively high number of samples, mainly in cases of low tumor burden. We conclude that the novel BIOMED-2 multiplex PCR strategy is of great value in diagnosing patients with suspected B- and T-cell proliferations. Because of its higher speed, efficiency, and sensitivity, it can reliably replace SB analysis in clonality diagnostics in a routine laboratory setting. Just as with SB results, PCR results should always be interpreted in the context of clinical, immunophenotypical, and histopathological data.

Interphase fluorescence in situ hybridization for detection of 8q24/MYC breakpoints on routine histologic sections: Validation in Burkitt lymphomas from three geographic regions

A chromosomal translocation involving the MYC gene is characteristic of Burkitt lymphoma (BL) and represents a molecular disease marker with diagnostic and clinical implications. The detection of MYC breakpoints is hampered by technical problems, including the distribution of the breakpoints over a very large genomic region of approximately 1,000 kb. In this article, we report on the testing and validation of a segregation fluorescence in situ hybridization (FISH) assay for MYC breakpoints on a large series of BLs. A contig of overlapping genomic clones was generated, and two probe sets flanking the MYC gene were selected. Both probe sets were tested in an interphase FISH segregation assay on 8 B‐cell lymphoma cell lines and 32 lymphoma samples with proved 8q24/MYC abnormalities and validated in 47 BLs from The Netherlands, Brazil, and Uganda. MYC translocation breakpoints were identified in 98% of the tumors of the test series and in 89% of the cases of the validation series. In 89% of all positive samples, the breakpoints were located between 190 kb 5′ and 50 kb 3′ of MYC. Nine cases had more distant breakpoints, and in one patient an insertion of MYC into the IGH region was detected. In two of the three BLs lacking CD10 expression, no breakpoint could be detected, suggesting that CD10 is a discriminative marker of BL. We did not find consistent differences between BL and atypical BL in incidence of an MYC breakpoint.

Distinct Expression Profiles of the Peripheral Cannabinoid Receptor in Lymphoid Tissues Depending on Receptor Activation Status

Using two distinct anti-CB2 receptor Abs, we investigated the expression patterns of the peripheral cannabinoid receptor CB2 in human secondary lymphoid organs. Immunohistochemical analysis using an N-terminal specific anti-CB2 Ab revealed high protein expression in the germinal centers (GCs) of secondary follicles. A C-terminal specific anti-CB2 Ab, which only recognizes a nonphosphorylated inactive receptor, showed positivity in the mantle zones (MZs) and marginal zones (MGZs) of the secondary follicles where resting cells reside, and in the primary follicles. In contrast, no positivity was observed in GCs using the C-terminal Ab, suggesting that active CB2 receptors are mainly present on cells in the GCs. Dual immunohistochemical analysis revealed that B lymphocytes express the CB2 protein abundantly. In contrast to B cells in the MZ or MGZ, CB2-expressing cells in the GCs coexpress the costimulatory membrane protein CD40, which is mainly expressed in the GCs and at very low levels in the MZs and MGZs and the proliferation marker Ki-67. Using the human Raji B cell line as a model, we demonstrate in a transwell assay that moderate migration occurs upon stimulation of the CB2 receptor with the endocannabinoid 2-arachidonoylglycerol, which is enhanced by CD40 costimulation. Our findings, that GC-related cells express active CB2 and that CB2-dependent migration requires CD40 costimulation, suggest that CB2 is involved in B cell activation.

Acquired lysosomal storage caused by frequent plasmapheresis procedures with hydroxyethyl starch.

BACKGROUND: Hydroxyethyl starch (HES) solutions have largely replaced conventional plasma expanders such as human albumin and colloidal fluids. Only a few side effects have been reported and mainly concern pruritus or blood coagulation disorders. Excessive HES exposure can result in diffuse tissue storage and accumulation with foamy appearing macrophages which produce the enzyme chitotriosidase (CT). In case of massive tissue storage, this enzyme activity can reach levels comparable to those of Gaucher disease.

Perigranuloma localization and abnormal maturation of B cells: emerging key players in sarcoidosis?

RATIONALE Recent observations of abnormal immunoglobulin responses and case reports describing successful B-cell ablative therapy suggest involvement of B cells in the pathogenesis of sarcoidosis. OBJECTIVES To investigate how abnormal B-cell maturation and function in patients with sarcoidosis contribute to disease. METHODS Patients with sarcoidosis (n = 32) were included for detailed analysis by immunohistochemistry of tissue, flow cytometry of blood B-cell subsets, and serum immunoglobulin levels. Vaccination responses in patients with sarcoidosis to influenza virus and encapsulated bacteria and molecular analysis of immunoglobulin heavy chain transcripts were studied for functional analysis of immunoglobulin responses. MEASUREMENTS AND MAIN RESULTS Perigranuloma localization of IgA-producing plasma cells and numerous B cells were found in affected tissues. Total blood B-cell numbers were normal, CD27(+) memory B cells were significantly reduced, and CD27(-)IgA(+) B cells were significantly increased; the results are normalized in patients treated with TNF-α blockers. Despite this, patients had normal serum immunoglobulin levels and normal antigen-specific immunoglobulin responses. IgA and IgG transcripts, however, showed high frequencies of somatic hypermutations and increased usage of downstream IgG subclasses, suggestive for prolonged or repetitive responses. CONCLUSIONS The large B-cell infiltrates in granulomatous tissue and increased molecular signs of antibody maturation are indicative of direct involvement of B cells in local inflammatory processes in patients with sarcoidosis. Moreover, CD27(-)IgA(+) B cells could be a marker for treatment with TNF-α blockers. These findings of B cells as emerging key players provide a rationale for a systematic study on B-cell ablative therapy in patients with sarcoidosis.

Reducing colorectal anastomotic leakage with tissue adhesive in experimental inflammatory bowel disease.

Background:Anastomotic leakage after gastrointestinal surgery remains a challenging clinical problem. This study aimed to investigate the effectiveness of TissuCol (fibrin glue), Histoacryl Flex (n-butyl-2-cyanoacrylate), and Duraseal (polyethylene glycol) on colorectal anastomotic healing during experimental colitis. Methods:We first performed colectomy 7 days after 10 mg trinitrobenzene sulfonic acid (TNBS)-induced colitis to validate a rat TNBS-colitis-colectomy model. Subsequently, this TNBS-colitis-colectomy model was used in 73 Wistar rats that were stratified into a colitis group (CG, no adhesive), a TissuCol group (TG), a Histoacryl group (HG), and a Duraseal group (DG). Anastomotic sealant was applied with one adhesive after constructing an end-to-end hand-sewn anastomosis. Clinical manifestations, anastomotic bursting pressure, and immunohistochemistry of macrophage type-one (M1) and type-two (M2) was performed on postoperative day (POD)3 or POD7. Results:TNBS-caused mucosal and submucosal colon damage and compromised anastomotic healing (i.e., abscess formation and low anastomotic bursting pressure). On POD3, higher severity of abscesses was seen in CG. Average anastomotic bursting pressure was 53.2 ± 35.5 mm Hg in CG, which was significantly lower than HG (134.4 ± 27.5 mm Hg) and DG (95.1 ± 54.3 mm Hg) but not TG (83.4 ± 46.7 mm Hg). Furthermore, a significantly higher M2/M1 index was found in HG. On POD7, abscesses were only seen in CG (6/9) but not in other groups; HG had the lowest severity of adhesion. Conclusions:We describe the first surgical IBD model by performing colectomy in rats with TNBS-induced colitis, which causes intra-abdominal abscess formation and compromises anastomotic healing. Anastomotic sealing with Histoacryl Flex prevents these complications in this model. Alternative activation of macrophages seems to be involved in its influence on anastomotic healing.

Reproducibility of histologic classification in nonfibrotic myeloproliferative neoplasia

Early phases of polycythemia vera, essential thrombocythemia, and primary myelofibrosis (PMF) can be difficult to distinguish by morphologic studies alone because they share many morphologic characteristics. Histologic criteria according to the 2008 World Health Organization (WHO) classification are part of the myeloproliferative neoplasia (MPN) diagnosis. Our aim was to assess the reproducibility of morphologic characteristics and determine their relative importance for histologic diagnoses on selected trephine biopsy sections. For the study, 56 prefibrotic MPN trephine specimens were blindly reviewed by 4 hematopathologists using a scoring list of 16 histologic characteristics mentioned in the WHO classification. Consensus was defined as agreement by 3 of 4 hematopathologists. High degrees of consensus were reached for individual major morphologic features used in the WHO classification, especially for the nuclear features of megakaryocytes (83%). Some of the features correlated positively or negatively with the histologic diagnosis of PMF. Consensus for the histologic classification of MPN was reached in 39 (70%) of 56 cases without knowledge of clinical data. This finding indicates a difference in the relative importance assigned to individual histologic characteristics by different hematopathologists.

High relapse rate in children with non-advanced nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL or nodular paragranuloma) treated with chemotherapy only

Nodular lymphocyte predominant Hodgkins lymphoma (NLPHL) is a rare variant of Hodgkins lymphoma (HL) in children. Since specific immunohistochemical staining has become available, NLPHL can be separated from classical Hodgkins lymphoma (cHL) more accurately. Scarce information is available about pediatric NLPHL treated with chemotherapy only. Therefore, clinical characteristics, treatment, response and outcome of seven pediatric NLPHL patients, median age 9.2 years (range 7.5 – 14.2 years), diagnosed between 1986 – 2003 among 58 HL patients, uniformly treated in a single center with chemotherapy only, were evaluated. The median follow-up time was 4.2 years (range 2.1 – 10.2 years). NLPHL patients were stage I (n = 5), II (n = 2), whereas cHL, median age 11.4 years (range 3.3 – 15.9 years), were stage I (n = 8), II (n = 17), III (n = 9), IV (n = 1). Upfront treatment of NLPHL patients consisted of six courses of epirubicin, bleomycin, vinblastine and dacarbazine (EBVD) without radiotherapy, whereas cHL patients received six courses of EBVD (n = 14) or 4 – 6 courses of EBVD/MOPP (mitoxin, oncovin, procarbazine, prednison; n = 21). Chemotherapy was used as primary treatment thereby aiming to avoid radiotherapy with potential serious side effects to growing jaws and thyroid. All seven patients reached complete remission (CR). Four patients relapsed, of which three locally. These three were salvaged with second-line chemotherapy without radiation therapy (RT) and are in second CR. One patient relapsing with stage III disease was salvaged by EBVD/MOPP followed by autologous BMT and is also in second CR for 36 months. The event-free survival (EFS) is 43% and overall survival (OS) 100%. This study shows that apart from histology, immunohistochemistry (ICH) is required for diagnosing NLPHL. Moreover, it illustrates that although cure of pediatric NLPHL is feasible with chemotherapy only, high dosages of cytotoxic drugs are necessary as salvage treatment in a relatively high proportion of patients after relapse.

Prognostic relevance of immunohistochemical subclassification of diffuse large B-cell lymphoma in two prospective phase III clinical trials.

PURPOSE Until now molecular biologic techniques have not been easily used in daily clinical practice to stratify patients for therapeutic purposes. Therefore, we have investigated the prognostic relevance of the immunohistochemical (IHC) germinal center B-cell (GCB) versus non-GCB diffuse large B-cell lymphoma (DLBCL) subtypes. PATIENTS AND METHODS We have analyzed tumor samples from patients treated in 2 prospective multicenter phase III trials, ie HOVON 25 (patients≥65 years, n=153) and HOVON 26 (patients<65 years, n=144) using whole sections (WS) or tissue microarray (TMA). CD10, BCL6, and MUM1 were applied in a specific IHC algorithm. The effect on clinical outcome using WS or TMA and variations in cut-off levels of these markers was also investigated. RESULTS The GCB subtype was not associated with a better OS in either trial. Small differences were observed in the HOVON 25 trial between techniques, with TMA showing a better outcome for GCB than did WS. Variation of cut-off levels in the specific algorithm did not improve the prediction of clinical outcome. CONCLUSION We did not observe a consistent predictive power of the GCB and non-GCB classification by IHC in this large series of DLBCL patients treated with CHOP. This underscores the need to determine the biologic variation and the standardization of the protein expression levels and to further study the relevance of prognostic IHC classifications, preferably in phase III clinical trials.