Diagnosis of rare entity CD138 negative plasma cell multiple myeloma: the synergy between laboratory and clinician makes the difference

Plasma cell multiple myeloma (MM) is a multiform clinical entity characterized by different laboratory hallmarks. This case shows a rare entity of plasma cell myeloma: the entire plasma cell population lack the CD138 expression. In this case, a careful analysis of laboratory finding, particular flow cytometry gating strategies and the use of other ancillary laboratory tests, guide the clinicians to correct diagnosis. The correct evaluation of pre-analytical phase and the correct gating strategy are the necessary conditions to produce robust and solid flow cytometric results. The diagnostic implications of CD138-negative plasma cell are strictly linked to stem cell-like clonogenic features, such as possible more aggressive clinical behaviour and increasing probability of chemotherapy resistance. At this time, clinical laboratory remains the main reference point to MM diagnosis.

High intratumoral plasma cells content in primary prostate cancer defines a subset of tumors with potential susceptibility to immune-based treatments

BACKGROUND

Data on advanced prostate cancer (PCa) suggest more prior systemic therapies might reduce tumor immune responsiveness. In treatment-naïve primary PCa, recent work correlated intratumoral plasma cell content with enhanced tumor immune-responsiveness. We sought to identify features of localized PCa at a high risk of recurrence following local treatment with high plasma cell content to help focus future immune-based neoadjuvant trials.

METHODS

We performed retrospective analyses of molecular profiles from three independent cohorts of over 1300 prostate tumors. We used Wilcoxon Rank Sum to compare molecular pathways between tumors with high and low intratumoral plasma cell content and multivariable Cox proportional hazards regression analyses to assess metastasis-free survival.

RESULTS

We validated an expression-based signature for intratumoral plasma cell content in 113 primary prostate tumors with both RNA-expression data and digital image quantification of CD138+ cells (plasma cell marker) based on immunohistochemisty. The signature showed castration-resistant tumors (n = 101) with more prior systemic therapies contained lower plasma cell content. In high-grade primary PCa, tumors with high plasma cell content were associated with increased predicted response to immunotherapy and decreased response to androgen-deprivation therapy. Master regulator analyses identified upregulated transcription factors implicated in immune (e.g. SKAP1, IL-16, and HCLS1), and B-cell activity (e.g. VAV1, SP140, and FLI-1) in plasma cell-high tumors. Master regulators overactivated in tumors with low plasma cell content were associated with shorter metastasis-free survival following radical prostatectomy.

CONCLUSIONS

Markers of plasma cell activity might be leveraged to augment clinical trial targeting and selection and better understand the potential for immune-based treatments in patients with PCa at a high risk of recurrence following local treatment.

MUM-1 immunohistochemistry has high accuracy and reliability in the diagnosis of chronic endometritis: a multi-centre comparative study with CD-138 immunostaining

PURPOSE

The current gold standard for chronic endometritis (CE) diagnosis is immunohistochemistry (IHC) for CD-138. However, IHC for CD-138 is not exempt from diagnostic limitations. The aim of our study was to evaluate the reliability and accuracy of MUM-1 IHC, as compared with CD-138.

METHODS

This is a multi-centre, retrospective, observational study, which included three tertiary hysteroscopic centres in university teaching hospitals. One hundred ninety-three consecutive women of reproductive age were referred to our hysteroscopy services due to infertility, recurrent miscarriage, abnormal uterine bleeding, endometrial polyps or myomas. All women underwent hysteroscopy plus endometrial biopsy. Endometrial samples were analysed through histology, CD138 and MUM-1 IHC. The primary outcome was to evaluate the diagnostic accuracy of MUM-1 IHC for CE, as compared with CD-138 IHC.

RESULTS

Sensitivity and specificity of CD-138 and MUM-1 IHC were respectively 89.13%, 79.59% versus 93.48% and 85.03%. The overall diagnostic accuracy of MUM-1 and CD-138 IHC were similar (AUC = 0.893 vs AUC = 0.844). The intercorrelation coefficient for single measurements was high between the two techniques (ICC = 0.831, 0.761-0.881 95%CI). However, among CE positive women, MUM-1 allowed the identification of higher number of plasma cells/hpf than CD-138 (6.50 [SD 4.80] vs 5.05 [SD 3.37]; p = 0.017). Additionally, MUM-1 showed a higher inter-observer agreement as compared to CD-138.

CONCLUSION

IHC for MUM-1 and CD-138 showed a similar accuracy for detecting endometrial stromal plasma cells. Notably, MUM-1 showed higher reliability in the paired comparison of the individual samples than CD-138. Thus, MUM-1 may represent a novel, promising add-on technique for the diagnosis of CE.

Hypertonic sodium lactate improves microcirculation, cardiac function, and inflammation in a rat model of sepsis

BACKGROUND

Hypertonic sodium lactate (HSL) may be of interest during inflammation. We aimed to evaluate its effects during experimental sepsis in rats (cecal ligation and puncture (CLP)).

METHODS

Three groups were analyzed (n = 10/group): sham, CLP-NaCl 0.9%, and CLP-HSL (2.5 mL/kg/h of fluids for 18 h after CLP). Mesenteric microcirculation, echocardiography, cytokines, and biochemical parameters were evaluated. Two additional experiments were performed for capillary leakage (Evans blue, n = 5/group) and cardiac hemodynamics (n = 7/group).

RESULTS

HSL improved mesenteric microcirculation (CLP-HSL 736 [407-879] vs. CLP-NaCl 241 [209-391] UI/pixel, p = 0.0006), cardiac output (0.34 [0.28-0.43] vs. 0.14 [0.10-0.18] mL/min/g, p < 0.0001), and left ventricular fractional shortening (55 [46-73] vs. 39 [33-52] %, p = 0.009). HSL also raised dP/dtmax slope (6.3 [3.3-12.1] vs. 2.7 [2.0-3.9] 103 mmHg/s, p = 0.04), lowered left ventricular end-diastolic pressure-volume relation (1.9 [1.1-2.3] vs. 3.0 [2.2-3.7] RVU/mmHg, p = 0.005), and reduced Evans blue diffusion in the gut (37 [31-43] vs. 113 [63-142], p = 0.03), the lung (108 [82-174] vs. 273 [222-445], p = 0.006), and the liver (24 [14-37] vs. 70 [50-89] ng EB/mg, p = 0.04). Lactate and 3-hydroxybutyrate were higher in CLP-HSL (6.03 [3.08-10.30] vs. 3.19 [2.42-5.11] mmol/L, p = 0.04; 400 [174-626] vs. 189 [130-301] μmol/L, p = 0.03). Plasma cytokines were reduced in HSL (IL-1β, 172 [119-446] vs. 928 [245-1470] pg/mL, p = 0.004; TNFα, 17.9 [12.5-50.3] vs. 53.9 [30.8-85.6] pg/mL, p = 0.005; IL-10, 352 [267-912] vs. 905 [723-1243] pg/mL) as well as plasma VEGF-A (198 [185-250] vs. 261 [250-269] pg/mL, p = 0.009).

CONCLUSIONS

Hypertonic sodium lactate fluid protects against cardiac dysfunction, mesenteric microcirculation alteration, and capillary leakage during sepsis and simultaneously reduces inflammation and enhances ketone bodies.

Endometrial CD138 count appears to be a negative prognostic indicator for patients who have experienced previous embryo transfer failure

OBJECTIVE

To explore the predictive value of endometrial CD138 expression in the natural cycle preceding frozen embryo transfer in patients with normal endometrial dating and histopathologic features, who previously failed the transfer of two high-quality fresh embryos.

DESIGN

Retrospective analysis.

SETTING

University-affiliated hospital.

PATIENT(S)

Women with normal endometrial dating and histopathologic features who previously failed the transfer of two high-quality fresh embryos, and who then underwent an endometrial scratching operation preceding a natural cycle.

INTERVENTION(S)

Paraffin-embedded endometrial samples cut into sections for immunohistochemistry staining of CD138 (syndecan-1) expression, then clinical information for these patients reviewed and analyzed.

MAIN OUTCOME MEASURE(S)

Clinical rates of pregnancy and implantation.

RESULT(S)

A total of 141 women met the inclusion criteria. Of these patients, about 31.2% (44 of 141) were positive for CD138 expression, with CD138 counts ranging from 0 to 33. Receiver operating characteristic (ROC) curves were analyzed to determine whether the number of cells expressing CD138 (CD138⁺ cells) predicted a successful pregnancy. The areas under the ROC curves based on CD138⁺ cell density and CD138⁺ cell count were 0.660 and 0.658, respectively. The clinical pregnancy and embryo implantation rates in patients not expressing CD138 (80.04% and 64.9%, respectively) were statistically significantly higher than rates in CD138⁺ patients (52.7% and 46.8%, respectively). In addition, the higher the number of cells expressing CD138, the worse the outcome of the pregnancy. Finally, clinical data showed that free pelvic fluid on the day of endometrial sampling (identified using transvaginal ultrasound) might be a risk factor for CD138 expression.

CONCLUSION(S)

Endometrial CD138⁺ count might be a valuable marker predicting pregnancy outcomes after frozen embryo transfer in patients with normal endometrial dating and histopathologic features who previously failed the transfer of two high-quality fresh embryos.

Rare Breast Carcinoma with Paradoxical Plasma Cell Immunoprofile: A Case Report

Plasma cell features are encountered in a variety of non-plasma cell neoplasias, especially carcinomas of a discohesive type, such as those occurring in the digestive tract and breast. Lobular carcinomas of the breast present themselves in a variety of architectural patterns and many cell morphologies, including plasmacytoid types. A matching plasma cell phenotype is sometimes an associated feature. We report a case of a moderate grade invasive lobular carcinoma with focal plasmacytoid morphology and aberrant expression of plasma cell markers in a patient previously diagnosed with multiple myeloma. Paradoxical plasma cell immunoprofiles can be encountered in many malignancies, causing serious diagnostic problems, even more so with those occurring in discohesive carcinomas in multiple myeloma patients.

The potential diagnostic power of CD138+ microparticles from the plasma analysis for multiple myeloma clinical monitoring

Multiple myeloma (MM) is malignant tumor with abnormal proliferation of bone marrow plasma cells. The existing clinical tools used to determine treatment response and tumor relapse are limited in sensitivity. We investigated the CD138+ microparticles (MPs) of MM patients to find out whether MPs could provide a novel means to monitor the malignant cells in MM patients. Our study showed that the levels of MPs were significantly elevated in MM patients. The MP counts in peripheral blood from new diagnosed MM patients were significantly higher than patients in CR and HD. Consist with the total MPs, the number of the PC-derived MPs (CD138+) increased in BM from MM patients compared with CR and HD. The ratio of the PC-derived MPs (CD138+) in BM increased in MM patients compared with CR and HD. The correlation test revealed that the CD138+ MPs in BM and PB were all positively correlated with the plasmacyte ratio in bone marrow (BMPC) and the β₂ -MG. New diagnosed MM patients and controls were compared, and ROC curves were used to identify cutoff points with optimal sensitivity and specificity concerning the ratios and counts of CD138+ MPs in BM and PB. The AUC of the CD138+ MP counts in BM was 0.767, and in PB was 0.680. The AUC of the CD138+ MP ratios in BM was 0.714, and in PB was 0.666. According to this, the counts of CD138+ MPs in BM showed to be a powerful marker of diagnosis. We demonstrated that CD138+ MPs from the plasma provide support for a potential monitoring biomarker of MM.

CD3+ CD56+ EBER1+ atypical extraosseous plasmacytoma of the nasal cavity

We present a case of atypical extraosseous plasmacytoma (EP) with a plasmablastic morphology and CD3⁺ CD56⁺ Epstein-Barr virus-encoded RNA-1 (EBER1)⁺ phenotypes of the nasal cavity. A 51-year-old male attended a local hospital with a tumor located in his left nasal cavity that was histologically diagnosed as extranodal NK/T cell lymphoma, nasal type. We reviewed the specimens and re-biopsied the tumor, and confirmed that the tumor was positive for CD3, CD56, and EBER1; however, the tumor showed a plasmablastic morphology without necrosis and angiocentricity, and was positive for CD138, but negative for CD20 and PAX5. Given a plasmablastic morphology and EBER1 positivity, but a relatively low Ki67 index (30%), we diagnosed the case as atypical EP. The CHOP regimen was administered and complete remission achieved. This case indicated that EP should be considered as a differential diagnosis even when a tumor shows large cell morphology and is positive for CD3, CD56, and EBER1.

Evidence for Cell Adhesion-Mediated Drug Resistance of Multiple Myeloma Cells in Vivo

Background/Aims

Multiple myeloma is an incurable disease and patients eventually die of disease progression due to drug resistance. VLA-4 (very late antigen 4), VCAM (vascular adhesion molecule), LFA-1 (leukocyte function-associated antigen 1), and ICAM-1 (intercellular adhesion molecule 1)-mediated adhesion of myeloma cells to bone marrow stromal cells induces primary multidrug resistance in vitro. Based on these preclinical data we hypothesized that myeloma cells with strong adhesion - due to strong expression of adhesion molecules on the cell surface - are selected by chemotherapy in patients. To prove this hypothesis we determined the expression levels of adhesion molecules in 31 multiple myeloma patients by flow cytometry.

Methods

A 3-color stain with CD38, CD138 and antibodies against VLA-4, ICAM-1, LFA-1, and VCAM was performed. The patients were either at diagnosis (chemo-naive; n=17) or at relapse (pre-treated; n=15). Furthermore, the response to the next chemotherapy of chemo-naive patients was correlated with the expression levels of adhesion molecules.

Results

ICAM-1, VLA-4, and VCAM expression was higher in pre-treated patients than in chemo-naive patients and the expression levels increased with the number of chemotherapy regimens. Primarily multidrug-resistant patients had significantly higher expression levels of VLA-4 and ICAM-1 than responders.

Conclusion

This study suggests that multiple myeloma cells expressing high levels of VLA-4 and ICAM-1 are drug resistant and that such a subpopulation of cells is selected by chemotherapy.

Soluble syndecan-1 (SDC1) serum level as an independent pre-operative predictor of cancer-specific survival in prostate cancer

BACKGROUND

PSA-screening detects many cases of clinically non-aggressive prostate cancer (PC) leading to significant overtreatment. Therefore, pre-operatively available prognostic biomarkers are needed to help therapy decisions. Syndecan-1 (SDC1) is a promising prognostic tissue marker in several cancers including PC but serum levels of shedded SDC1-ectodomain (sSDC1) have not been assessed in PC.

METHODS

A total of 150 patients with PC were included in this study (n = 99 serum samples, n = 103 paraffin-embedded samples (FFPE), n = 52 overlap). SDC1 protein expression and cellular localization was evaluated by immunohistochemistry (IHC), while sSDC1 serum concentrations were measured by ELISA. Serum sSDC1 levels were compared to those of MMP7, which is known to be a protease involved in SDC1 ectodomain-shedding. Clinico-pathological and follow-up data were collected and correlated with SDC1 tissue and serum levels. Disease (PC)-specific (DSS) and overall-survival (OS) were primary endpoints.

RESULTS

Median follow-up was 167 months in the serum- and 146 months in the FFPE-group. SDC1-reactivity was higher in non-neoplastic prostate glands compared to PC. In addition, cytoplasmatic, but not membranous SDC1 expression was enhanced in PC patients with higher Gleason-score >6 PC (P = 0.016). Soluble SDC1-levels were higher in patients with Gleason-score >6 (P = 0.043) and metastatic disease (P = 0.022) as well as in patients with progressed disease treated with palliative transurethral resection (P = 0.002). In addition, sSDC1 levels were associated with higher MMP7 serum concentration (P = 0.005). In univariable analyses, only sSDC1-levels exhibited a trend to unfavorable DSS (P = 0.077). In a multivariable pre-operative model, high pre-operative sSDC1-level (>123 ng/ml) proved to be an independent marker of adverse OS (P = 0.048) and DSS (P = 0.020).

CONCLUSIONS

The present study does not confirm the prognostic relevance of SDC1-IHC. The significant higher sSDC1 serum levels in advanced cases of PC, suggest that SDC1 shedding might be involved in PC progression. Additionally, high sSDC1-level proved to be an independent factor of adverse OS and DSS in a multivariable pre-operative model, making evaluation of sSDC1-levels a promising tool for pre-operative risk-stratification and/or therapy monitoring. Prostate 76:977-985, 2016. © 2016 Wiley Periodicals, Inc.

Syndecan-1, Epithelial-Mesenchymal Transition Markers (E-cadherin/β-catenin) and Neoangiogenesis-related Proteins (PCAM-1 and Endoglin) in Colorectal Cancer

The Syndecan-1 protein plays a crucial role in cell proliferation, cell adhesion, cell migration and angiogenesis and, at the same time, its co-expression with E-cadherin is regulated during epithelial-mesenchymal transition (EMT). In colorectal cancer (CRC), the expression of syndecan-1, E-cadherin/β-catenin complex is frequently disturbed. Angiogenesis is critical for the growth and metastatic spread of tumors. In the present study, we focused on the expression of these biological molecules and their prognostic significance in human CRC. Formalin-fixed paraffin-embedded surgical specimens from 69 patients with CRC were immunostained for syndecan-1, E-cadherin, β-catenin, endoglin (CD105) and CD31 (platelet cell adhesion molecule (PCAM-1)). A significant association was found between syndecan-1 with E-cadherin (p<0.0001), as well with β-catenin (p<0.0001). High β-catenin expression appeared to reduce the risk of poor outcome. Endoglin microvascular density (MVD) count was correlated significantly with Dukes' stage (p<0.0001), vessel invasion (p<0.0001), lymph node metastasis (p=0.039), liver metastasis (p<0.0001), recurrence of disease (p=0.010) and poor survival rate (p<0.0001). Endoglin tumor epithelial cell expression was associated with E-cadherin, β-catenin and syndecan-1 (p=0.001, p=0.068 and p=0.005, respectively). In conclusion, changes in the pattern of expression of syndecan-1, EMT markers, E-cadherin/β-catenin, in association with endoglin (CD105), may be involved in tumor progression and prognosis of CRC patients. Further studies are needed to clarify the interaction between these proteins and tumor initiation and progression.

Syndecan-1 serves as a marker for the progression of epithelial ovarian carcinoma

PURPOSE

Syndecan-1 (SDC-1) promotes the proliferation of cancer cells and plays a role in angiogenesis by binding to a variety of extracellular effectors. The present study was designed to compare the expression of SDC-1 in the normal ovary and in ovarian tumors, to better understand its roles in the progression of epithelial ovarian carcinoma (EOC).

MATERIALS AND METHODS

The expression of SDC- 1, fibroblast growth factor 2 (FGF-2), and FGF receptor 1 (FGFRI) and their transcripts in 65 samples including the normal ovary, benign tumors, borderline ovarian tumors, and EOC was assessed using immunohistochemistry and the reverse transcription-polymerase chain reaction. The influence of FGF-2 on the expression of SDC-1 mRNA syndecan-1 in a human ovarian carcinoma cell line was determined using an FGF-2-neutralizing antibody.

RESULTS

SDC-l was not detected in normal ovarian tissue but was present in the epithelial cells of benign or borderline tumors and in ovarian adenocarcinomas. The levels of expression were significantly different in ovarian tissues derived from benign or malignant cases. Coordinate stromal expression of SDC-1 and its mRNA was detected at the original site of the tumor, as well as in metastatic foci in the greater omentum of ovarian adenocarcinomas. FGF-2 reduced the level of expression of SDC-1 mRNA when added exogenously to SKOV3 cells. This effect was abolished in the presence of an FGF-2-neutralizing antibody.

CONCLUSION

SDC-l contributes to the role of FGF-2 in proliferation and angiogenesis but may also play a role in the invasive properties of EOC. To the present authors' knowledge, this study is the first to report the presence of distinct patterns ofexpression of SDC-1 in local and metastatic foci in the greater omentum in patients with EOC. These data reinforce the role of the tumor stroma in the invasive properties of ovarian adenocarcinoma and suggest that stromal changes in the expression of SDC-1 may originate from the stroma and contribute to the pathogenesis and metastatic potential of EOC.

Expression patterns of B cells in acute kidney transplant rejection

OBJECTIVES

To evaluate B-cell expression patterns and association with function and survival in dysfunctional kidney allografts.

MATERIALS AND METHODS

There were 110 kidney transplant recipients included who had for-cause biopsies. Demographic and transplant data were collected. Immunostaining for B cells, plasma cells, and C4d was performed by the immunoperoxidase technique in paraffin-embedded samples. Circulating antihuman leukocyte antigen donor-specific antibodies were detected in a single-antigen assay at biopsy. The main outcomes were kidney graft survival and function. The patients were evaluated in 3 groups according to the Banff classification: no rejection (40 patients), T-cell-mediated rejection (50 patients), and antibody-mediated rejection (20 patients).

RESULTS

The CD138-positive plasma cell-rich infiltrates predominated in antibody-mediated rejection and were associated with stronger reactivity against panel antibodies (r = 0.41; P ≤ .001) and positive donor-specific antibodies (r = 0.32; P ≤ .006). The CD20-positive lymphocytes were associated with T-cell-mediated rejection, increased human leukocyte antigen mismatch, and frequency of retransplant. The CD138-positive cell infiltrates also were significantly greater in patients who had late than early rejection. There was no correlation between cellular CD20 and CD138 expression, and neither CD20 nor CD138 predicted worse graft function or survival. Other markers of antibody-mediated rejection such as C4d and donor-specific antibodies were associated with worse graft function and survival at 4 years after transplant. In multivariate analysis, C4d was the only risk factor associated with graft loss.

CONCLUSIONS

After kidney transplant, CD20-positive B-cell infiltrates were associated with T-cell-mediated rejection, and CD138-positive plasma cells were associated with antibody-mediated rejection. Graft loss was associated with the presence of C4d.

[Detection for therapeutic targets specifically expressed in myeloma side population cells]

ATP binding membrane transporter such as multi drug resistant protein (MDR1) and breast cancer resistance protein (BCRP) are highly activated in side population (SP) of various normal organs. It has been demonstrated that various primary as well as cancer cell lines also possess SP. Since SP cells have been also known as the cancer initiating cell rich population in various cancers, the population might play a crucial role in the pathogenesis of multiple myeloma. Recent our works demonstrated that G2/M (e.g. CCNB1, CDC2), centrosome (e.g.AURKB, CENP), polycomb (e.g. EPC1, EZH2) and proteasome (e.g. UBE3C, PSMA5) related genes were upregulated in the SP of myeloma cell lines and CD138-positive primary samples. Although myeloma has been known as incurable disease, discovery of new agents such as immunomodulatory drugs (lenalidomide) and proteasome inhibitor (bortezomib) provide improvement of prognosis of the tumor entity. These drugs might be effective to downregulate aforementioned aberrantly upregulated gene products in myeloma SP. Here we show some evidences of use of these drugs for targeting myeloma-SP cells.

Expression of cereblon protein assessed by immunohistochemicalstaining in myeloma cells is associated with superior response of thalidomide- and lenalidomide-based treatment, but not bortezomib-based treatment, in patients with multiple myeloma

Cereblon (CRBN) is essential for the anti-myeloma (MM) activity of immunomodulatory drugs (IMiDs), such as thalidomide and lenalidomide. However, the clinical implications of CRBN in MM patients are unclear. Using immunohistochemical (IHC) staining on paraffin-embedded bone marrow sections, the expression of CRBN protein in myeloma cells (MCs) was assessed in 40 relapsed/refractory MM (RRMM) patients who received lenalidomide/dexamethasone (LD) and 45 and 22 newly diagnosed MM (NDMM) patients who received thalidomide/dexamethasone (TD) and melphalan/bortezomib/prednisolone (MVP), respectively. IHC staining were scored on a scale representing the diffuseness and intensity of positive-staining MCs (range, 0–8) and a score ≥4.5 was used for CRBN positivity (CRBN⁺) on a cut-point analysis of all possible scores and response of TD and LD. Compared to CRBN⁺ NDMM patients, CRBN⁻ NDMM patients had more international staging system (ISS) III (26 vs. 61 %, respectively; P = 0.006). In the LD and TD cohorts, the response rate (RR) was higher in CRBN⁺ patients than CRBN⁻ patients (LD 79 vs. 33 %, respectively; P = 0.005) (TD 75 vs. 29 %, respectively; P = 0.005); however, this trend was not observed in the MVP cohort. In the LD and TD cohorts, the positive and negative prediction value of CRBN⁺ for treatment response was 79 and 67 % and 75 and 71 %, respectively. Multivariate analysis showed that CRBN⁺ was a significant factor associated with superior RR for LD and TD. The data suggest that expression of CRBN protein in MCs assessed using the IHC is a feasible approach to predict the response of IMiDs in MM patients.

Incidence of cytogenetic aberrations in two B lineage subpopulations in multiple myeloma patients analyzed by combination of whole-genome profiling and FISH

Multiple myeloma (MM) is an incurable malignant disease of the terminal developmental stage of B-lymphocytes. While genetic heterogeneity of MM is widely described, little is known about its genetic basis as well as primary damage during plasma cells (PC) development. In this study, we focused on genome-wide screening of DNA copy number changes using oligonucleotide-based array-CGH together with I-FISH of the IgH locus rearrangements in pair samples of bone marrow B-cells (CD19+) and CD138+ PC from newly diagnosed MM patients. The IgH disruption was found in 8.9% (4/45) of CD19+ samples and in 57.8% (26/45) of CD138+ samples. The genomic profiling using array-CGH identified copy number alterations (CNAs) in 10% (2/20) of CD19+ samples in regions known to be important for MM pathogenesis. In contrast, we found CNAs in 100% (16/16) of CD138+ samples. Most common chromosomal abnormalities were trisomies of odd-numbered chromosomes (3, 5, 7, 9, 11, 15, 19 and 21), gain 1q, gain Xq and monosomy of chromosome 13. We did not find any correlation between incidence of CNAs in CD19+ and CD138+ cells. In conclusion, effective utilization of FISH and array-CGH can identify genetic lesions in premalignant stages leading to better understanding and characterization of MM.

Metastatic plasmacytoid urothelial carcinoma: a case report and review of the literature

Plasmacytoid urothelial carcinoma is a rare form of invasive urothelial carcinoma first described in 1991 by Sahin et al. [Acta Cytol 1991;35:277-280]. Since this original publication, over 70 cases of plasmacytoid urothelial carcinoma have been described. A small number of cytologic descriptions have been published, including cases involving cerebrospinal fluid cytology, bladder washings and urine cytology. To our knowledge, we describe the first fine needle aspiration of metastatic plasmacytoid urothelial carcinoma in a 75-year-old man who presented with a pathologic fracture of the L4 vertebral body. One of the diagnostic pitfalls in the cytologic evaluation of this rare malignancy is the positive staining with CD138. While CD138 is a marker for plasma cell differentiation, it is also positive in plasmacytoid urothelial carcinoma. In addition to recognizing the cytomorphologic details, a full immunohistochemical panel is helpful in properly characterizing this entity. A brief discussion of long-term prognosis and treatment benefit is provided.

The evaluation of minimal residual disease in multiple myeloma by fluorescent molecular beacons in real time PCR of IgH gene rearrangements and correlation with flow cytometry

PURPOSE

Multiple myeloma (MM) patients relapse after a period of time despite longer disease-free survival due to novel treatment options. In this study we aimed to assess the value of real-time polymerase chain reaction (RT-PCR) for detecting the immunoglobulin heavy chain (IgH) gene rearrangement using allele-specific molecular beacons as fluorescence probes to quantify minimal residual disease (MRD) and also to correlate post-treatment flow cytometric detection of plasma cells' (PCs) expression of CD19, CD38, CD45, CD56 and CD138 in MM.

METHODS

After diagnosis of 17 MM patients, the CDR1, CDR2 and CDR3 regions of the IgH gene were analysed and sequenced to identify IgH's clonal nature. Unique sequences of the clonal IgH rearrangement were used to design specific molecular beacon probes for each MM patient. Examined were also the co-expression of CD19, CD38, CD45, CD56, and CD138 molecules in bone marrow aspirates of patients with MM by flow cytometry.

RESULTS

Detection of MRD was positive in 13 (76%) of 17 patients by RT-PCR. The infiltration ratio was significantly correlated with CD138 expression (p=0.009). Significant correlation was also found between RT-PCR detection of MRD and CD138 expression (p=0.006). Nevertheless, no correlation was observed among other surface antigens (CD38, CD45, CD56).

CONCLUSION

Our results indicated that RT-PCR with specific molecular beacons provide a feasible, accurate and reproducible method for the determination of MRD in MM. Flow cytometry detection of CD138 expression may be used as a disease marker in addition to RT-PCR.

Targeting tumour-initiating cells with TRAIL based combination therapy ensures complete and lasting eradication of multiple myeloma tumours in vivo

Multiple myeloma (MM) remains an incurable disease despite improvements to available treatments and efforts to identify new drug targets. Consequently new approaches are urgently required. We have investigated the potential of native tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), in combination with doxorubicin, to induce apoptotic cell death in phenotypically distinct populations of myeloma cells in vitro and in vivo. The cytotoxic potential of TRAIL alone, and in combination with DOX, was assessed in vitro in purified CD138(+) and CD138(-) cells from the MM cell lines and samples from patients with MM. Mouse xenografts obtained by implanting CD138(-) MM cells were used to assess the efficacy of TRAIL, alone and in combination with DOX, in vivo. CD138(-) cells were shown to be more resistant to the cytotoxic activity of TRAIL than CD138(+) cells and have reduced expression of TRAIL death receptors. This resistance results in preferential killing of CD 138(+) cells during exposure of MM culture to TRAIL. Furthermore, prolonged exposure results in the appearance of TRAIL-resistant CD138(-) cells. However, when TRAIL is combined with doxorubicin, this results in complete eradication of MM cells in vivo. Most importantly, this treatment successfully eliminates CD138(-) cells implicated in tumour initiation and growth maintenance. These findings may explain the failure of current therapies and offer a promising new approach in the quest to cure MM and disseminated cancers.

Immunophenotyping of classic murine myeloma cell lines used for monoclonal antibody production

Murine myeloma cell lines play an important role in different areas of scientific research and are essential tools for monoclonal antibody production technology. Thus, it is important to understand the biology of these cell lines in order to provide useful information to various research fronts. The present study aims to perform detailed analyses of surface antigens expressed on three major murine myeloma cell lines extensively used for MAb production. The P3X63Ag8.653 cell line expresses molecules associated with T cell interaction (CD40(low), CD80(low)), as well as antigens related to plasma cell phenotype (CD138(high), CD184(low)). The Sp2/0-Ag14 cell line presents molecules associated with BCR activation and regulation (CD79b(low), CD22(low), CD72(med)), molecules related to T cell interaction (CD40(low), CD80(low)), and markers of plasma cell phenotype (CD138(high), CD184(low)). The NS1 cell line presents all molecules of plasma cell phenotype evaluated in this study (CD184(low), CD138(high), CD38(med)) with low expression of CD72 (CD72(low)), a molecule related to BCR activation. Molecules associated with immune response modulation such as CD23 and CD25, as well as CD117, a marker related to undifferentiated cell phenotype, were not observed in any of the three murine myeloma cell lines evaluated. These data show that in spite of their common origin and function, the immunological profiles differ between P3X63Ag8.653, Sp2/0-Ag14, and NS1 cell lines.

Detecting plasma cell precursors in autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis (AIH) is a non-resolving inflammatory liver disease. Inflammation showing plasma cells under hematoxylin-eosin (H&E) stain is typical of AIH. In many cases, however, only lymphocytes and occasional granulocytes are found. It was recently noticed that the antibody to multiple myeloma oncogene 1/IRF4 (MUM1), stained plasma cells and their precursors.

PATIENTS AND METHODS

Liver biopsies from 11 patients were stained with H&E and with anti-MUM1. Clinically, four patients were suspicious of AIH, four had viral hepatitis C, two nonalcoholic steatohepatitis (NASH) and one, fatty liver. Counting was performed in three high-power fields.

RESULTS

In patients having clinical suspicion of AIH, H&E revealed plasma cells in only one of the four cases. On the other hand, MUM1 immunostain revealed such cells in all four cases, MUM1-expressing cells were found in the portal triads, in the zone corresponding to interface inflammation and in the parenchyma surrounding the interface hepatitis. MUM 1-expressing cells ranged from 26 to 44 in AIH, from 2 to 15 in viral hepatitis C, from 1 to 3 in NASH, and from 0 to 2 in the case with fatty liver (AIH vs. viral hepatitis C/NAS/fatty liver, p<0.05).

CONCLUSION

These preliminary results suggest that MUM1 immunostain may be of help in endorsing a presumptive clinical diagnosis of AIH and may add valuable information in the differential diagnosis between AIH and the other liver diseases examined here. This appears to be the first report in which MUM1 immunostain has been applied to assess the presence of plasma cell precursors in AIH.

Sample processing and methodological pitfalls in multiple myeloma research

In this paper, initial processing of biological material, cell separation algorithms and other procedures are discussed. For samples with initial infiltration of plasma cells > 5%, CD138 MicroBeads and Auto-Magnetic-Activated Cell Sorting program are used. Fluorescence-Activated Cell Sorting is used exclusively for cell populations with low-abundance; these samples are detected using fluorescently labeled antibodies only. Isolated plasma cells are further processed for molecular biological studies, for cytogenetics and protein analyses. Furthermore, this work examines the pitfalls of research related to multiple myeloma; some of them we have overcome, while the others are still problematic.

Primary plasma cell leukemia mimicking an adult T-cell leukemia-lymphoma: a case report

BACKGROUND

Malignant plasma cells ofmultiple myeloma (MM), or plasma cell leukemia (PCL), may present highly variable morphologic aspects. Adult T-cell leukemia-lymphoma (ATLL) is a peripheral T-cell neoplasm composed of highly pleomorphic lymphoid cells. We report an unusual case ofprimary PCL with misleading cellular morphology and some clinical and biologic similarities simulating ATLL.

CASE

A 40-year-old Caribbean man presented with asthenia, epistaxis and diffuse bone pain. Blood cell count showed anemia and thrombocytopenia and a hyperleukocytosis composed of deeply basophilic cells with a polylobulated nucleus resembling flower cells. An ATLL diagnosis was given at first, without ruling out the possibility of a PCL diagnosis. Hypercalcemia and lytic bone lesions were compatible with both diagnoses. Immunophenotyping was key to the diagnosis of primary PCL.

CONCLUSION

Some clinical and biological overlap may exist between PCL and ATLL, leading to a false diagnosis or delaying a correct one. An accurate cytologic analysis leading to a rapid detection of plasma cell markers is essential for an early diagnosis.

[Syndecans in the diagnosis and prognosis of prostate cancer]

Syndecans, a family of heparan sulphate proteoglycans that are present in the cellsurface are involved in the control o fcel lproliferation, apoptosis and transfor-mation. Syndecans 1 and 2 have a central role in processes such as position control, invasion, angiogenesis and metastases ofseveral types of cáncer The expression of Syndecan 1 in epithelial cells, decreases when cells are transformed and acquire invasive properties. This decreased expression is associated to a bad prognosis. Syndecan 2, originally described in mesenchymal cells, favors cell apoptosis, increa-ses angiogenesis and controls the death of cáncer cells subjected to chemotherapy Both syndecans are present in basal and epithelial cells of prostate cancer Their lower expression is associated to more undifferentiated tumors. Disturbances in the expression and subcellular location of syndecans predict the relapse of localized tumors. Syndecans 1 and 2 can be considered tumor suppression genes and can be targetsfor new treatments. The detection of circulating fragments of these molecules could be useful for the early detection of prostate cancer.

Expression of syndecan-1 in histologically normal breast tissue from postmenopausal women with breast cancer according to mammographic density

OBJECTIVE

To analyze the expression of Syndecan-1 in dense and non-dense human breast tissue.

METHODS

Specimens of histologically normal tissue were obtained from postmenopausal women undergoing surgery for breast cancer. Each tissue block was subject to radiological examination and pair-wise samples of dense and non-dense tissue were collected. Semi-quantitative assessment of immunohistochemical staining intensity for Syndecan-1 and estrogen receptor subtypes was performed.

RESULTS

The expression of Syndecan-1 in all tissue compartments was significantly higher in dense than in non-dense specimens. The strongest staining was recorded in stromal tissue. There was a strong correlation between epithelial estrogen receptor alpha and stromal cell Syndecan-1 expression in dense tissue (rs = 0.7; p = 0.02). This association was absent in non-dense tissue.

CONCLUSION

An increase of Syndecan-1 in all tissue compartments and a redistribution from epithelium to stroma may be a characteristic feature for dense breast tissue.

The expression of syndecan-1 and -2 is associated with Gleason score and epithelial-mesenchymal transition markers, E-cadherin and beta-catenin, in prostate cancer

The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and beta-catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. beta-Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and beta-catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.

Bortezomib successfully reduces monoclonal serum free light chain levels in a patient with recurrent myeloma and cast nephropathy in the renal transplant

Bortezomib can be used to successfully treat acute kidney injury in the renal transplant allograft due to light chain cast nephropathy from recurrent multiple myeloma.

CD20-negative CD138-positive leukemic large cell lymphoma with plasmablastic differentiation with an IgH/MYC translocation in an HIV-positive patient

A 49-year-old HIV-positive Japanese man was referred to our hospital for multiple skin nodules. Many plasmablastic atypical lymphocytes were observed in the peripheral blood. He was diagnosed with diffuse large B cell lymphoma (DLBCL) by a biopsy of the inguinal lymph node. IgH/MYC translocation was detected by in situ hybridization of the lymph node and chromosomal analysis of bone marrow cells showed 46, XY, t(8 ; 14)(q24 ; q32)add(14)(q32), der(21)t(1 ; 21)(q12 ; p11). He showed a transient response to multi-agent chemotherapy, and during the course of salvage chemotherapy, he died of urinary infection. This case has unique clinical features compared with previously reported DLBCLs with plasmablastic differentiation.

Correlation of plasma cell percentages by CD138 immunohistochemistry, cyclin D1 status, and CD56 expression with clinical parameters and overall survival in plasma cell myeloma

CONTEXT

Plasma cell myelomas (PCMs) are traditionally diagnosed by the percentage (%) of plasma cells (PCs) in the bone marrow aspirate differential combined with clinical parameters and radiographic findings. PCs are most reliably quantitated in bone marrow (BM) tissues by CD138 immunohistochemistry (IHC). However, there are no correlations of % CD138+ cells with clinical parameters or overall survival (OS). The presence of cyclin D1 has correlated with worst prognosis, but cyclin D1 has not been correlated with routine cytogenetics. CD56+, although not significantly reported in reactive plasmacytoses, monoclonal gammopathy of undetermined significance (MGUS), nor in lymphoplasmacytic lymphomas (LPLs), has not been evaluated in borderline diagnostic (borderline) cases.

OBJECTIVES

It includes: (1) correlating the percentages of PCs by CD138 IHC, cyclin D1 status, and CD56 expression with clinical parameters and OS in PCMs, (2) correlating cyclin D1 status with routine cytogenetics in PCMs, borderline cases, and MGUSs, and (3) analyzing CD56 expression in PCMs, borderline cases, MGUSs, and LPLs.

DESIGN

Bone marrow aspirates, BM touch preparations, and BM clot and/or biopsy sections with CD138/kappa/lambda IHC (44-PCMs, 9-MGUSs, 17-borderline cases, 3-LPLs, and 3-reactive plasmacytoses) were reviewed and stained with CD56 and cyclin D1.

RESULTS/CONCLUSIONS

Increased CD138+ cells did not correlate significantly with clinical parameters or OS. Cyclin D1+ did not correlate with the presence of a t(11;14) by routine cytogenetics [although detected in all t(11;14)+ cases], clinical parameters, nor OS. CD56 expression was identified in PCMs, MGUSs, and LPL but not in reactive plasmacytoses. CD56+ did not distinguish PCMs, MGUS, and LPLs, and did not correlate with clinical parameters or OS. CD56 and cyclin D1 IHC were better evaluated in BM clot than biopsy sections.

HHV-8+, EBV+ Multicentric Plasmablastic Microlymphoma in an HIV+ Man: The Spectrum of HHV-8+ Lymphoproliferative Disorders Expands

Human herpesvirus-8 (HHV-8) is associated with several distinct lymphoproliferative disorders: primary effusion lymphoma, multicentric Castleman disease (MCD), MCD-associated plasmablastic lymphoma and HHV-8+, Epstein-Barr virus (EBV)+ germinotropic lymphoproliferative disorder. We report the case of a human immunodeficiency virus (HIV)+ male with fever, generalized lymphadenopathy, and splenomegaly. Two peripheral lymph nodes were excised and showed features of MCD and a prominent proliferation of HHV-8+, EBV+, CD20, CD138, MUM1+, lambda dim+, Ig heavy chain plasmablasts and immunoblasts replacing some follicles. Subsequently, a splenectomy and biopsy of retroperitoneal lymph nodes were performed; the retroperitoneal and splenic hilar lymph nodes showed changes similar to those in the peripheral lymph nodes while the markedly enlarged spleen showed replacement of occasional white pulp by the HHV-8+, EBV+ large cells. The histologic features and coinfection by EBV and HHV-8 suggested a diagnosis of HHV-8+ germinotropic lymphoproliferative disorder. However, the occurrence in an HIV+ individual, the background of MCD, the widespread anatomic distribution and the aggressive clinical course tended to exclude germinotropic lymphoproliferative disorder, and to favor multifocal plasmablastic microlymphoma. The patient died shortly after surgery; postmortem examination showed progression to overt lymphoma. The marrow showed extensive hemophagocytosis, consistent with development of a hemophagocytic syndrome. This unique case has clinical features compatible with a MCD-associated plasmablastic lymphoproliferative disorder, with pathologic features intermediate between HHV-8+ plasmablastic microlymphoma, and HHV-8+ germinotropic lymphoproliferative disorder, although in contrast to both of these, in our case, light chain expression was dim and heavy chain was not detected.

Bladder defense molecules, urothelial differentiation, urinary biomarkers, and interstitial cystitis

It has long been recognized that interstitial cystitis (IC) is a disease of the urothelium. In this article, we review the results of published studies and present new data concerning the precise role of the bladder epithelium in IC. We discuss bladder defenses against both the penetration of urinary solutes and bacterial adherence, and we present new information about the proteoglycans that are present on the normal bladder. Previously published results and new data presented here support the conclusion that IC involves an aberrant differentiation program in the bladder urothelium that leads to altered synthesis of several proteoglycans, cell adhesion and tight junction proteins, and bacterial defense molecules such as GP51. These findings lend support to the rationale for glycosaminoglycan replacement therapy for the treatment of patients with IC.

Differential expression of syndecans and glypicans in chronically inflamed synovium

BACKGROUND

Membrane-bound heparan sulphate proteoglycans (HSPGs) act as co-receptors and presenters of cytokines and are involved in cell-matrix and cell-cell adhesion.

AIM

To investigate which HSPGs are expressed in knee joint synovia from patients with different forms of arthritis and normal individuals.

METHODS

Synovial samples were obtained from patients with early rheumatoid arthritis (n = 8), longstanding rheumatoid arthritis (n = 13), psoriatic arthritis (n = 7), osteoarthritis (n = 6) and normal joints (n = 12). Expression of syndecan-1, -2, -3 and -4 and glypican-1, -3 and -4 was analysed by immunohistochemistry and dual label immunofluorescence.

RESULTS

The expression of HSPGs in chronically inflamed synovium exhibited a differential distribution. Syndecan-1 was present in the mononuclear infiltrates of synovia from patients with rheumatoid and psoriatic arthritis where it was expressed by plasma cells. Syndecan-2 was present mainly in blood vessels where it occurred on endothelial cells, pericytes and smooth muscle cells. Syndecan-3 stained intensely in endothelial cells but also occurred in sublining macrophages and the lining layer. Glypican-4 occurred in the lining layer and blood vessels. Increased expression of these HSPGs was apparent in rheumatoid and psoriatic compared to osteoarthritic and normal synovia. Little or no staining for syndecan-4, glypican-1 and glypican-3 was seen in all samples.

DISCUSSION

Selected HSPGs, such as syndecan-1, -2 and -3 and glypican-4, could play a part in the pathophysiology of arthritis, such as the migration and retention of leukocytes and angiogenesis in the chronically inflamed synovium.

MUC1 (EMA) expressing plasma cells in bone marrow infiltrated by plasma cell myeloma

MUC1 (also called: epithelial membrane antigen, EMA) represents a mucin molecule strongly expressed in various epithelia and epithelial neoplasms. Its expression correlates with clinical and pathological factors as well as prognosis in some tumor types. Additionally, MUC1 was detected in normal haematopoietic cell lines and neoplasms, especially subgroups of human lymphomas including plasma cell myeloma. Therefore, the expression of MUC1 in trephine biopsies exhibiting infiltrates of plasma cell myeloma were investigated immunohistochemically. An immunoreactivity of two monoclonal antibodies (EMA and HMFG-2) was observed in about 50% of the cases. In cases exhibiting a so-called packed marrow, EMA immunoreactivity was reduced. However, MUC1 positivity did not correlate with the cytologic grade of differentiation, the fibre content of the marrow, or survival probability of the patients. However, its strong expression in a certain percentage of cases of plasma cell myeloma may be of therapeutic impact, since new therapeutic strategies include the enrichment of MUC1-specific T cells or MUC1 vaccination.

Syndecan-1 and Wingless-type protein-1 in human ameloblastomas

BACKGROUND

Aberrant Wingless type 1 glycoprotein (Wnt) pathway in ameloblastomas and a role of syndecan-1 (SDC1) in activating Wnt signalling were perspected. SDC1 shifting from epithelium to stroma was reported in invasive non-odontogenic neoplasms. The aim of this study was to reveal the role of SDC1 and Wnt1 in intraosseous ameloblastomas (IA(s)).

METHODS

SDC1 and Wnt1 expressions were investigated in 29 ameloblastoma subtypes and seven tooth buds.

RESULTS

SDC1 immunostaining strongly depicted stromal cells, extracellular matrix (ECM) and basement membranes of ameloblastomas. It also showed epithelial tumour cells in the acanthomatous and plexiform subtypes, and it often occurred in stellate reticulum cells and basal ameloblasts of tooth buds. Parallel Wnt1 expression occurred in ameloblastomatous epithelial cells, but it was common in basal cells of tooth buds too. Statistically, a significant correlation was found between the percentage of IA(s)-bearing SDC1-positive stromal cells and ECM and the percentage of IA(s)-bearing Wnt1-positive epithelial cells.

CONCLUSIONS

A role of SDC1 in stromal cells and ECM can be hypothesized as a critical factor for carcinogenesis and local invasiveness of IA(s).

Osteoclast nuclei of myeloma patients show chromosome translocations specific for the myeloma cell clone: a new type of cancer-host partnership?

A major clinical manifestation of bone cancers is bone destruction. It is widely accepted that this destruction is not caused by the malignant cells themselves, but by osteoclasts, multinucleated cells of monocytic origin that are considered to be the only cells able to degrade bone. The present study demonstrates that bone-resorbing osteoclasts from myeloma patients contain nuclei with translocated chromosomes of myeloma B-cell clone origin, in addition to nuclei without these translocations, by using combined FISH and immunohistochemistry on bone sections. These nuclei of malignant origin are transcriptionally active and appear fully integrated amongst the other nuclei. The contribution of malignant nuclei to the osteoclast population analysed in this study was greater than 30%. Osteoclast-myeloma clone hybrids contained more nuclei than normal osteoclasts and their occurrence correlated with the proximity of myeloma cells. Similar hybrid cells were generated in myeloma cell-osteoclast co-cultures, as revealed by tracing myeloma nuclei using translocations, bromo-deoxyuridine, or the Y chromosome of male myeloma cells in female osteoclasts. These observations indicate that hybrid cells can originate through fusion between myeloma cells and osteoclasts. In conclusion, malignant cells contribute significantly to the formation of bone-resorbing osteoclasts in multiple myeloma. Osteoclast-myeloma clone hybrids reflect a previously unrecognized mechanism of bone destruction in which malignant cells participate directly. The possibility that malignant cells corrupt host cells by the transfer of malignant DNA may have been underestimated to date in cancer research.

B-cell activity of polyclonal antithymocyte globulins

Polyclonal antithymocyte globulins (AThG) are a subset of antilymphocyte antibody preparations derived from the sera of rabbits or horses immunized with unfractionated cells isolated from pediatric human thymi. In vivo, AThG preparations have been used to successfully treat antibody mediated rejection in kidney transplant recipients. In vitro, AThG can induce apoptosis of naïve and memory B cells and terminally differentiated plasma cells. The presence of B-cell reactive antibodies in AThG results from a thymic inoculum containing a significant percentage of CD20(+) B cells and CD138(+) plasma cells. In this paper, the experimental and clinical evidence supporting the B-cell activity of AThG preparations, and their mechanisms of action, are reviewed.

Follicular exclusion of autoreactive B cells requires Fc RIIb

In non-autoimmune mice, the 3H9 transgenic Ig heavy chain can pair with endogenous Iglambda1 light chains to generate B cells with specificity for DNA. These autoreactive cells are actively regulated in vivo, as indicated by the exclusion of lambda1 cells from the splenic B cell follicle and the absence of auto-antibody production. To study the role of Fcgamma receptor IIb (FcgammaRIIb) in peripheral B cell tolerance, FcgammaRIIb(-/-) mice were crossed with C57BL/6 mice bearing a site-directed knock-in of the 3H9 transgene. 3H9FcgammaRIIb(-/-) mice become autoreactive, lose the follicular exclusion of anti-DNA B cells and instead have lambda1 B cells located within splenic germinal centers. They have increased frequencies of splenic auto-antibody-producing cells and elevated titers of IgG anti-DNA auto-antibody. The data implicate an FcgammaRIIb-dependent checkpoint that can exclude autoreactive B cells from splenic follicles. By restricting their participation in germinal center reactions, this putative checkpoint helps attenuate the production of potentially pathogenic auto-antibodies. The data further suggest that this FcgammaRIIb-dependent regulation is B cell autonomous.

Multiple Myeloma: Molecular Imaging with C-Methionine PET/CT—Initial Experience

PURPOSE

To prospectively assess molecular imaging of multiple myeloma (MM) by using the radiolabeled amino acid carbon 11 ((11)C) methionine and positron emission tomography (PET)/computed tomography (CT).

MATERIALS AND METHODS

The study was approved by the institutional local ethics committee and the national radiation protection authorities. All patients with MM and control patients gave written informed consent. Nineteen patients with MM (11 women, eight men; age range, 42-64 years) and 10 control patients with hyperparathyroidism without hematologic diseases (six women, four men; age range, 43-75 years) underwent PET/CT 20 minutes after injection of a mean of 1.0 GBq +/- 0.2 (standard deviation) (11)C-methionine. Presence and extent of CT-assessed tumor manifestations and (11)C-methionine bone marrow (BM) uptake were determined on the basis of maximum standardized uptake value (SUV(max)). BM imaging patterns, normal BM, and maximal lesion (11)C-methionine uptake in patients with MM were compared with those in control patients. In two patients with MM, sulfur 35 ((35)S) methionine uptake in freshly isolated BM plasma cells was measured. Values for SUV(max) of groups were compared by using the Mann-Whitney test on a per-patient basis.

RESULTS

(35)S-methionine uptake of plasma cells was five- to sixfold higher than in normal BM cells. (11)C-methionine BM uptake in control patients was homogeneous and low. All patients with MM except one with exclusively extramedullary myeloma had (11)C-methionine-positive lesions. Maximal lesion and normal BM (11)C-methionine mean SUV(max) were 10.2 +/- 3.5 and 4.3 +/- 2.0, respectively, and thus were significantly higher than that of BM in the control group (mean, 1.8 +/- 0.3; P < .001). Extramedullary MM was clearly visible in three patients (mean SUV(max), 7.2 +/- 2.4). Additional (11)C-methionine-positive lesions in normal cancellous bone were found in nearly all patients with MM. In pretreated patients with MM, a moderate fraction of osteolytic lesions had no (11)C-methionine uptake.

CONCLUSION

On the basis of increased methionine uptake in plasma cells, active MM can be imaged with (11)C-methionine PET/CT.

Assessing the potential of immunohistochemistry for systematic gene expression profiling

Immunohistochemistry (IHC) is a powerful technique for identifying sites of protein expression in tissues at the cellular and sub-cellular level. Here we have investigated the potential of using IHC for genome-wide expression screening by measuring the success rate and specificity of a panel of 35 monoclonal antibodies recognizing 5 well characterised CD antigens. Antibodies were pre-screened on acetone fixed frozen sections of spleen, tonsil and colon tissues. 19/35 antibodies gave staining with a success rate of 0/7 for JAM-2, 1/4 for CD99, 3/6 for CD138, 5/8 for CD45 and 10/10 for MHC-class II. 16/19 of these antibodies also gave staining on formalin fixed paraffin embedded tissue sections of tonsil and colon. All antibodies that had given staining were then profiled on tissues presented in human tissue microarrays. In the frozen microarrays 216 cores from 29 normal tissue types were present and in the formalin fixed paraffin array 344 cores from 35 normal and 4 cancers were represented. Where multiple antibodies were positive, there was evidence of consistent staining of the same tissues with several antibodies. In some cases differences in staining were observed potentially due to differential splice variants, polymorphisms or protein modification. With some antibodies there was evidence of cross-reactivity to inappropriate cells or structures. In addition the staining intensity with formalin fixation was changed quantitatively for some antibodies and in a few cases qualitatively, representing differential sensitivity of specific and non-specific epitopes to fixation. Accordingly, whilst IHC has potential for describing protein expression of unknown genes, these results emphasise a need to systematically address issues of specificity and sensitivity if appropriate profiles are to be described.

A Local Antigen-Driven Humoral Response Is Present in the Inflammatory Myopathies

The inflammatory myopathies are putative autoimmune disorders characterized by muscle weakness and the presence of intramuscular inflammatory infiltrates. Although inclusion body myositis and polymyositis have been characterized as cytotoxic CD8(+) T cell-mediated diseases, we recently demonstrated high frequencies of CD138(+) plasma cells in the inflamed muscle tissue of patients with these diseases. To gain a deeper understanding of the role these B cell family members play in the disease pathology, we examined the molecular characteristics of the H chain portion of the Ag receptor. Biopsies of muscle tissue were sectioned and tissue regions and individual cells were isolated through laser capture microdissection. Ig H chain gene transcripts isolated from the sections, regions, and cells were used to determine the variable region gene sequences. Analysis of these sequences revealed clear evidence of affinity maturation in that significant somatic mutation, isotype switching, receptor revision, codon insertion/deletion, and oligoclonal expansion had occurred within the B and plasma cell populations. Moreover, analysis of tissue regions isolated by laser capture microdissection revealed both clonal expansion and variation, suggesting that local B cell maturation occurs within muscle. In contrast, sequences from control muscle tissues and peripheral blood revealed none of these characteristics found in inflammatory myopathy muscle tissue. Collectively, these data demonstrate that Ag drives a B cell Ag-specific response in muscle in patients with dermatomyositis, inclusion body myositis, and polymyositis. These findings highlight the need for a revision of the current paradigm of exclusively T cell-mediated intramuscular Ag-specific autoimmunity in inclusion body myositis and polymyositis.