Comparison of angiomyofibroblastoma and aggressive angiomyxoma in both sexes: four cases composed of bimodal CD34 and factor XIIIa positive dendritic cell subsets

Aggressive angiomyxoma (AA) is a distinctive, locally aggressive, fibromyxoid tumor of the pelvic and genital soft tissues. AA is of unknown histogenesis but the cytologically bland spindled tumor cells, which surround characteristic variegated blood vessels, show fibroblastic or myofibroblastic features. AA may be related to angiomyofibroblastoma (AMF), another cytologically bland fibromyxoid genital spindle cell tumor with variable myoid differentiation that does not, as a rule, recur. Recently, CD34+ primitive fibroblasts and factor XIIIa+ dendritic histiocytes have been found in varying combination in many fibrovascular, fibrohistiocytic, and myxoid soft tissue tumors. Both cells belong to the microvascular unit, a tissue responsible for stromal repair and remodeling and angiogenesis. To determine if these ubiquitous stromal cells participate in the histogenesis of AA and AMF, we examined two scrotal tumors, one AA with multiple recurrences and one AMF, for the presence of CD34+ and FXIIIa+ dendritic cell subsets. For comparison, a vaginal AMF and a pararectal AA in a woman were included. We also studied actins and desmin to detect myofibroblastic differentiation, and, through double labeling studies, assessed hormone receptors and the cell cycle marker Ki 67 in the different cell subsets. The AA showed unusual cytologic atypia and was initially diagnosed as liposarcoma. It massively recurred four times over 12 years, the first time after seven years. The histologic appearance was fairly constant over the years. The scrotal AMF was a circumscribed 6 cm mass in a 37 year old man. In both cases, most tumor cells were wavy and fibrillar, spindled, stellate, or polygonal fibroblast-like CD34+ dendritic cells. Depending on the area examined, a 20-50% subset of dendritic cells showed both nuclear and cytoplasmic staining for FXIIIa. Actin+ cells were rare but vessels had actin+ myopericytes, although a small focus of the initial male AA was desmin positive. The recurring AA expressed androgen receptors and had Ki 67 index of 10-20% in "hot spots" of the primary and up to 30% in recurrent tumors. The scrotal AMF widely expressed androgen and progesterone receptors with focal estrogen receptor positivity and the Ki 67 index was 10%. Both CD34+ fibroblasts and FXIIIa+ histiocytes were present in the Ki 67+ cycling fraction in both the male AA and AMF and both cell types expressed androgen receptors. The female pararectal AA had more focal CD34 reactivity, particularly in perivascular fibroblasts and these cells were admixed with small FXIIIa+ cells. The vaginal AMF was strongly desmin+ and variably to weakly CD34+ with 20% FXIIIa+ dendritic cells and Ki 67 index of 2%. The vaginal AMF strongly expressed estrogen, progesterone, and androgen receptors. In conclusion our data suggest that at least some AA and AMF are myxoid fibrohistiocytic tumors composed of CD34+ fibroblasts and FXIIIa+ dendritic histiocytes. In our tumors, neoplastic CD34+ dendritic fibroblasts showed predominantly myxo-collagenous differentiation with prominent myofibroblastic differentiation in only one desmin+ vaginal AMF. Our results support the notion that AMF and AA are part of a morphologic and histogenetic continuum of myxofibrous and myoid tumors that may arise due to interactions between microvascular CD34+ fibroblasts and FXIIIa+ histiocytes. CD34 and FXIIIa reactivity may be underappreciated in these tumors and is more important when considered histogenetically and biologically rather than in classifying individual neoplasms. Hormonal stimulation of proliferating pelvico-gential microvascular dendritic cells appears to play a role in the morphogenesis of both tumors.     

Gestational hypertension plasma and human umbilical vein endothelial cells: an in vitro study

A case of metastatic dermatofibrosarcoma protuberans (DFSP) in a 47-year-old woman is presented. Dermatofibrosarcoma protuberans occasionally recurs, but rarely metastasizes. The patient underwent local removal of the nuchal tumor by a general practitioner, followed by a rapid recurrence. She underwent total removal of the tumor and a diagnosis of spindle cell sarcoma was made after an incisional biopsy was performed. This lesion had both a typical DFSP-like area and a fibrosarcoma (FS)-like area. After 7 years, an abnormal lung shadow was observed and a segmental lung resection was performed. Histologically, the lung tumor was similar to the FS-like area in the nuchal tumor. Confirming CD34 expression in the tumor cells, this lung tumor was diagnosed as metastatic DFSP. Usually CD34 expression is unique to DFSP but almost negative in FS-like areas. In the present case, the FS-like area in the nuchal tumor showed decreased CD34 reactivity, as previously reported, but the FS-like area in the metastatic tumor still widely preserved CD34 expression. The presented case suggests that the FS-like area in DFSP is histogenetically different from typical FS or malignant fibrous histiocytoma.     

Primary renal angiosarcoma: a case report with immunohistochemical, ultrastructural, and cytogenetic features and review of the literature

Primary angiosarcoma of the kidney is a rare tumor for which fewer than 10 case reports appear in the English literature. A case of primary renal angiosarcoma is reported, in which the tumor showed poorly differentiated spindled sarcoma admixed with typical angiomatous differentiation. Antibodies against CD31, CD34, Ulex europeus lectin type I, factor VIII-related antigen, cytokeratin (AE1/AE3), vimentin, S100 protein, epithelial membrane antigen, carcinoembryonic antigen, desmin, and smooth muscle actin were examined. CD31 showed strong diffuse membranous staining of cells in the well-differentiated areas and strong membranous staining in the spindled, poorly differentiated areas. CD34 showed strong cytoplasmic and membranous staining in both the poorly differentiated and well-differentiated areas. Staining for factor VIII-related antigen and Ulex europeus was less intense and was limited to the well-differentiated areas. Staining for cytokeratin (AE1-AE3), S100, carcinoembryonic antigen, epithelial membrane antigen, desmin, and smooth muscle actin were negative. Electron microscopy showed spindle cells containing abundant pinocytotic vesicles, vimentin-type intermediate filaments, and rare Weibel-Palade bodies. A complex karyotype was found. Our findings suggest that CD31 and CD34 are useful in defining endothelial differentiation in poorly differentiated angiosarcomas in which reactions for Ulex europeus lectin type I and factor VIII-related antigen may be equivocal.     

A comparison of frozen and paraffin sections in dermatofibrosarcoma protuberans

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a tumor with a high local reoccurrence rate. Mohs micrographic surgery offers the highest cure rate. However, differentiating minimal residual tumor from normal skin can be difficult during Mohs surgery. OBJECTIVE: To clarify the problem of determining when a tumor-free plane had been achieved during Mohs surgery for a DFSP. METHODS: In two patients with DFSPs, we compared frozen and paraffin-embedded sections extending from tumor to normal skin, using both H&E and CD34 stains. RESULTS: On frozen, but not paraffin-embedded, sections scattered dermal spindle cells were seen in normal skin. CONCLUSIONS: Scattered dermal spindle cells in the dermis of normal skin make it difficult to differentiate minimal residual tumor from normal dermis during Mohs surgery. A biopsy of normal skin can be useful as a control in this setting.     

Juvenile and adult xanthogranuloma. A histological and immunohistochemical comparison

Thirteen cases of juvenile xanthogranuloma (JXG) and 13 cases of adult-type xanthogranuloma (AXG) were compared at the light and immunohistochemical levels. Histologically, four main cell types (vacuolated, xanthomatized, spindle-shaped, and "oncocytic") were seen in variable proportions (from monomorphous to mixed variants) with different types of giant cells (nonspecific, foreign body, Touton, and "ground-glass"). Giant cells were more prominent in AXG than in JXG; oncocytic cells (characterized by an eosinophilic, slightly granular cytoplasm similar to thyroid oncocytic cells) and mostly periodic acid-Schiff (PAS) negative giant cells with a ground-glass appearance (6 of 26) were not observed in classic JXG (i.e., occurring in children < 2 years old). Immunohistochemically, JXG and AXG gave similar results: most xanthogranuloma cells labeled strongly with KiM1P and vimentin, while HHF35 and HAM56 stained less intensively. Factor-XIIIa (FXIIIa), KP1 (CD68), and HAM56 stained mostly in the periphery of the lesions. Some markers gave variable results: peanut agglutinin (PA), 60%; alpha-1-antitrypsin, 50%; lysozyme, 25%; LN3 (HLA-DR), < 10% of cells positive. Others were negative: S-100, MAC387 (L1 antigen), LeuM1 (CD15), desmin, smooth muscle-specific actin, and QBEND10 (CD34). This profile helps to delineate xanthogranuloma from histological stimulants such as dermatofibroma (which is FXIIIa+, LN3+, KP1-, and PA-) and multicentric reticulohistiocytosis (which is FXIIIa-, KP1+, PA-, and HHF35-).     

CD34+CD38dim cells in the human thymus can differentiate into T, natural killer, and dendritic cells but are distinct from pluripotent stem cells

Recently we reported that the human thymus contains a minute population of CD34+CD38dim cells that do not express the T-cell lineage markers CD2 and CD5. The phenotype of this population resembled that of CD34+CD38dim cells present in fetal liver, umbilical cord blood, and bone marrow known to be highly enriched for pluripotent hematopoietic stem cells. In this report we tested the hypothesis that the CD34+CD38dim thymocytes constitute the most primitive hematopoietic cells in the thymus using a combination of phenotypic and functional analyses. It was found that in contrast to CD34+CD38dim cells from fetal liver and bone marrow, CD34+CD38dim cells from the thymus express high levels of CD45RA and are negative for Thy-1. These data indicate that the CD34+CD38dim thymocytes are distinct from pluripotent stem cells. CD34+CD38dim thymocytes differentiate into T cells when cocultured with mouse fetal thymic organs. In addition, individual cells in this population can differentiate either to natural killer cells in the presence of stem cell factor (SCF), interleukin-7 (IL-7), and IL-2 or to dendritic cells in the presence of SCF, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha(TNFalpha), indicating that CD34+CD38dim thymocytes contain multi-potential hematopoietic progenitors. To establish which CD34+ fetal liver subpopulation contains the cells that migrate to the thymus, we investigated the T-cell-developing potential of CD34+CD38dim and CD34+CD38+ fetal liver cells and found that the capacity of CD34+ fetal liver cells to differentiate into T cells is restricted to those cells that are CD38dim. Collectively, these findings indicate that cells from the CD34+CD38dim fetal liver cell population migrate to the thymus before upregulating CD38 and committing to the T-cell lineage.     

Diagnostic value of CD34 immunostaining in desmoplastic trichilemmoma

Desmoplastic trichilemmoma (DT) is a variant of trichilemmoma, characterized by a central prominent desmoplastic component which may simulate invasive carcinoma. We have studied the morphologic and immunohistochemical features of seven cases of DT. Immunohistochemistry was performed on paraffin sections using monoclonal antibodies to CD34 (QBEND/10), vimentin and GCDFP-15. CD34 was also tested in seven cases of basal cell carcinoma (BCC), three with outer root sheath differentiation and four with morphea-form features, and five squamous cell carcinomas. Histologically, features of conventional trichilemmoma were seen at the periphery of the seven lesions. In contrast, at the center, the epithelial cells tended to cluster in narrow irregular cords and nests entrapped in a dense collagenous stroma. One case of DT coexisted with a BCC. In all cases of DT, epithelial tumor cells showed CD34 immunostaining. All cases of BCC, including the one contiguous to a DT, were CD34 negative. CD34 immunodetection in the epithelial cells of the pseudoinvasive component of DT may be of great value in the differential diagnosis with other desmoplastic tumors of the skin, and particularly with BCC.     

Expression of the human progenitor cell antigen CD34 (HPCA-1) distinguishes dermatofibrosarcoma protuberans from fibrous histiocytoma in formalin-fixed, paraffin-embedded tissue

BACKGROUND: Histologic distinction of dermatofibrosarcoma protuberans (DFSP) from fibrous histiocytoma (FH) may be difficult. In addition, differential diagnosis is hampered by the lack of appropriate immunohistochemical markers that reliably distinguish between these two entities. OBJECTIVE: This study is aimed at the introduction of a monoclonal antibody (anti-human progenitor cell antigen-1; anti-CD34) that distinguishes between DFSP and FH in formalin-fixed, paraffin-embedded tissue. METHODS: Paraffin-embedded specimens of DFSP, FH, and other soft-tissue tumors were investigated for CD34 expression by anti-human progenitor cell antigen-1/alkaline phosphatase-antialkaline phosphatase immunostaining. RESULTS: Strong CD34 reactivity was present in each DFSP (n = 19) but was consistently absent from FH (n = 45) and other soft-tissue tumors (n = 47). CONCLUSION: CD34 immunostaining of paraffin-embedded specimens may be useful in differentiating between DFSP and FH.     

Culture system for extensive production of CD19+IgM+ cells by human cord blood CD34+ progenitors

We established a co-culture system with a monolayer of the murine bone marrow (BM) stroma cell line, MS-5, in which human cord blood CD34+ cells differentiated to CD19+ cells. The addition of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) highly enhanced the production of CD19+ cells. The expansion of the cell numbers was over 10(3)-fold. Furthermore, a significant proportion (<45%) of the cells expressed surface IgM (sIgM) after 5 weeks of co-culture. CD34+CD19- cells also showed a similar development of CD19+ cells and CD19+sigM+ cells. Filter separation of MS-5 cells and CD34+ cells did not inhibit the growth of CD19+ cells. However, when further purified CD34+CD19-CD13- CD33- cells were cultured in the presence of MS-5 cells with or without a separation filter, CD19+ cells did not appear in the non-contact setting. This result suggested that the highly purified CD34+CD19-CD13-CD33- progenitors require the cell-cell contact for the development of CD19+ cells, whereas other CD34+ fractions contain progenitors that do not require the contact. This co-culture system should be useful for the study of early human B-lymphopoiesis.     

Solitary fibrous tumor of the nasal cavity and orbit

Solitary fibrous tumors (SFT) are rare spindle cell neoplasms generally associated with the serosal surface, especially the pleura. Two SFT are reported arising in the nasal cavity and orbit, occurring in a 33 year old female and a 21 year old male, respectively. The lesions lacked the characteristic features of other recognized neoplasms that occur in these regions. Immunohistochemically, the tumors cells were diffusely and strongly positive for vimentin and CD34 and some or many tumor cells expressed neuron-specific enolase and Leu-7. Ultrastructurally, the tumor cells showed no distinct features although they were suggested to be primitive mesenchymal or fibroblast-like cells. Both tumors were diploid by flow cytometry. The two patients have had benign clinical courses with limited follow-up. Our findings suggest that SFT is of mesenchymal cell origin and support another location for SFT, indicating additional evidence against mesothelial origin. SFT should be included in the differential diagnosis of spindle cell tumors arising in the nasal cavity and orbit.     

In vitro identification of single CD34+CD38- cells with both lymphoid and myeloid potential

Human hematopoietic stem cells are pluripotent, ie, capable of producing both lymphoid and myeloid progeny, and are therefore used for transplantation and gene therapy. An in vitro culture system was developed to study the multi-lineage developmental potential of a candidate human hematopoietic stem cell population, CD34+CD38- cells. CD34+CD38- cells cocultivated on the murine stromal line S17 generated predominantly CD19(+) B-cell progenitors. Transfer of cells from S17 stroma to myeloid-specific conditions ("switch culture") showed that a fraction of the immunophenotypically uncommitted CD19- cells generated on S17 stroma had myeloid potential (defined by expression of CD33 and generation of colony-forming unit-cells). Using the switch culture system, single CD34+CD38- cells were assessed for their lymphoid and myeloid potential. Nineteen of 50 (38%) clones generated from single CD34+CD38- cells possessed both B-lymphoid and myeloid potential. 94.7% of the CD34+CD38- cells with lympho-myeloid potential were late-proliferating (clonal appearance after 30 days), demonstrating that pluripotentiality is detected significantly more often in quiescent progenitors than in cytokine-responsive cells (P = .00002). The S17/switch culture system permits the in vitro assessment of the pluripotentiality of single human hematopoietic cells.     

Fine-needle aspiration biopsy of synovial sarcoma. A cytomorphologic analysis of primary, recurrent, and metastatic tumors

Thirteen fine-needle aspiration specimens from 10 patients with histologically proven synovial sarcoma are described. The aspiration biopsy specimens were obtained from the primary tumor in five cases, locally recurrent tumors in four cases, pulmonary metastases in three cases, and mediastinal metastasis in one case. Patient's ages ranged from 22 years to 65 years; there were four women and six men. All cases had a confirmation biopsy and/or resection specimen that were reviewed. Histologic subtypes included monophasic fibrous (5 cases), monophasic epithelial (1 case), biphasic (3 cases), and poorly differentiated (1 case). The majority of the aspiration biopsy specimens were similar with moderate to marked smear cellularity dominated by cohesive clusters of spindle-shaped cells with ovoid, hyperchromatic nuclei and scanty tapering cytoplasm. Nucleoli were not prominent. Epithelial tumor cells with ovoid to round, mostly regular, centrally to eccentrically located nuclei, surrounded by scant to abundant cytoplasm predominated in one case (monophasic epithelial) and were admixed with spindle cells in a second (classical biphasic). Multi-nucleated tumor giant cells were not observed in any of the tumors. In biphasic synovial sarcoma, the neoplastic spindle cells are generally more numerous and frequent than the epithelial cells, making distinction from monophasic synovial sarcoma or other spindle cell soft tissue tumors difficult. Although synovial sarcoma may be diagnosed by fine-needle aspiration cytology, clinical correlation, especially in monophasic types, is necessary to minimize errors in sarcoma classification.     

O-glucuronidation, a newly identified metabolic pathway for topotecan and N-desmethyl topotecan

BACKGROUND AND OBJECTIVE: CD34+ hematopoietic progenitor cells (HPCs) constitute a heterogeneous population both in size and in immunological features. Lack of CD38, HLA-DR and lineage committed antigens as well as the co-expression of Thy-1 (CDw90) and c-kit receptor (CD117), are able to identify the so-called stem cells. A flow cytometric study was carried out to investigate the co-expression of Thy-1 and c-kit receptors, both members of Ig superfamily adhesion molecules, involved in cell to cell and cell to stroma interactions, on bone marrow (BM), mobilized peripheral blood (PB) and human umbilical cord blood (HUCB) CD34+ HPCs. DESIGN AND METHODS: Lysed whole blood from 15 BM, 25 mobilized PB and 25 HUCB samples were used to perform a five-dimensional flow cytometric evaluation of both CDw90 and CD117 on CD34+ cells. RESULTS: Few CD34+ cells co-expressed Thy-1 antigen in all three compartments (BM: 11.2 +/- 7.2%; PB: 6.2 +/- 3.6%; HUCB: 6 +/- 2.9%; BM vs PB < 0.04; BM vs HUCB < 0.008; PB vs HUCB ns). c-kit receptor was detected on the majority of CD34+ HPCs, particularly in HUCB (HUCB: 80.7 +/- 8.2%; BM: 72.3 +/- 13.1%; PB: 64.2 +/- 17%; HUCB vs BM < 0.03; HUCB vs PB < 0.0001; BM vs PB ns). CD34+Thy-1+ and CD34+c-kit+ HPCs generally displayed HLA-DR antigen, as expression of early cell commitment. However, the most immature CD34+Thy-1+HLA-DR- (HUCB: 1 +/- 0.6%; BM: 0.4 +/- 03%; PB: 0.7 +/- 0.5%; HUCB vs BM < 0.0001; BM vs PB < 0.04; HUCB vs PB ns) and CD34+c-kit+HLA-DR- HPCs (HUCB: 6.5 +/- 4.4%; BM: 6.3 +/- 4.8%; PB: 2.2 +/- 1.8%; HUCB vs BM ns; BM vs PB < 0.0001; HUCB vs PB < 0.0001) were mainly detected in HUCB. Finally, the greatest percentage of CD34+Thy-1+c-kit+ cells was found in BM (6.9 +/- 4.1%) followed by leukapheretic samples (4.4% +/- 2.7) and then by HUCB (3.7 +/- 1.2%; BM vs PB ns; BM vs HUCB < 0.001; HUCB vs PB ns). INTERPRETATION AND CONCLUSIONS: Since the blood release or HPCs is probably due to a perturbation of the adhesive interactions between these cells and the marrow stroma, the different pattern of Thy-1 and c-kit receptor expression on CD34+ HPCs found in the three hemopoietic compartments evaluated can lead to new knowledge about the mobilization kinetics in which the Ig superfamily adhesion molecules are involved.     

Characterization of CD34+ thymic stromal cells located in the subcapsular cortex of the human thymus

In this paper we report that suspensions of human fetal thymocytes contain cells that express high levels of CD34 and Thy-1. These cells were characterized with regard to location within the thymus, phenotype, and function. Confocal laser scan analysis of frozen sections of fetal thymus with anti-CD34 and Thy-1 antibodies revealed that the double-labeled cells were located in the pericortical area. In addition, it was found that the CD34+Thy-1+ cells lacked CD45 and CD50, indicating that these cells are not of hematopoietic origin; this was confirmed by the finding that these cells could be cultured as adherent cells in a medium with cholera toxin and dexamethasone, but failed to grow in mixtures of hematopoietic growth factors. Further analysis indicated that most cultured CD34+Thy-1+ cells expressed cytokeratin (CK) 14 but lacked CK 13, suggesting that these cells are immature epithelial cells. Cultured CD34+Thy-1+ cells were able to induce differentiation of CD1-CD34+CD3-CD4-CD8- thymic precursors into CD4+CD8+ cells in a reaggregate culture in the absence of exogenous cytokines. The CD4+CD8+ cells that developed in these cultures did not express CD3, indicating that CD34+Thy-1+ thymic stromal cells are not capable of completing full T cell differentiation of thymic hematopoietic progenitor cells.     

Recurrent dermatofibrosarcoma protuberans with myxoid and fibrosarcomatous changes paralleled by loss of CD34 expression

A 38-year-old woman complained of recurrent nodules on her anterior chest wall. She noticed the first nodule at the age of 12 and has since undergone surgical removal a total of 31 times. Finally, wide resection of parts of the rib cartilage and sternum and chest wall reconstruction were required. Histopathological examination of a series of surgical specimens were reevaluated. Immunohistochemical staining of the tumors by anti-CD34 antibody provided a definite diagnosis of dermatofibrosarcoma protuberans (DFSP). A noteworthy result was that her DFSP did not always express CD34; the recurrent tumors with myxoid and fibrosarcomatous changes lost their CD34 expression.     

Magnetic fields elicited by tones and vowel formants reveal tonotopy and nonlinear summation of cortical activation

Hematopoietic stem and progenitor cells express the CD34 antigen. Techniques have been developed that enable purified populations of CD34+ cells to be selected from hematopoietic tissues. These selected CD34+ cells have several potential applications, including CD34 selection to obtain a tumor purging effect in autologous transplantation studies and using CD34+ cells as the starting cells for ex vivo expansion studies and as a vehicle for gene transduction protocols. We have investigated the feasibility of using cryopreserved peripheral blood progenitor cells (PBPC) for CD34 selection. Cells could be recovered from cryopreservation with good yields and high viability. After CD34 selection, the final product was, on average, 84% pure, with a recovery of 54%. These cells retained extensive proliferative potential, as demonstrated by ex vivo expansion culture. We believe that cryopreserved PBPC could be thawed, and CD34+ cells could be selected and used for transplantation following high-dose chemotherapy.     

Inflammatory pseudotumor of the ileum. A report of a multifocal, transmural lesion with regional lymph node involvement

Inflammatory pseudotumor (inflammatory fibroid polyp) of the ileum is a rare, usually solitary and polypoid lesion that frequently presents clinically as small-intestinal intussusception and obstruction. Regional lymph nodes are usually not involved. We describe an inflammatory pseudotumor of the ileum that was multifocal, not polypoid, and involved one regional lymph node. Grossly, two circumferential transmural nodules were separated by 8.5 cm of normal ileum. Microscopically, the lesion extended through the muscularis propria into peri-intestinal adipose tissue and involved one noncontiguous regional lymph node. The pseudotumor was composed of highly vascularized stroma with a mixture of spindle cells and chronic inflammatory cells including numerous eosinophils, lymphocytes, plasma cells, histiocytes, neutrophils, and multinucleated giant cells forming small granulomas. Immunohistochemically, the majority of spindle cells reacted with vimentin but not smooth-muscle, endothelial, or lymphoid markers. Ultrastructurally, the spindle cells had abundant rough endoplasmic reticulum, cytoplasmic filaments, and dense bodies consistent with myofibroblasts, plump endothelial cells (some with Weibel-Palade bodies), and chronic inflammatory cells. We prefer the term inflammatory pseudotumor to inflammatory fibroid polyp for the lesion in this case, since it was not polypoid and shared many histologic features with inflammatory pseudotumors arising at sites other than the gastrointestinal tract.     

Stromal factors support the expansion of the whole hemopoietic spectrum from bone marrow CD34+DR- cells and of some hemopoietic subsets from CD34+ and CD34+DR+ cells

Ex vivo expanded bone marrow CD34+DR- cells could offer a graft devoid of malignant cells able to promptly reconstitute hemopoiesis after transplant. We investigated the specific expansion requirements of this subpopulation compared to the more mature CD34+ and CD34+DR+ populations. The role of stromal factors was assessed by comparing the expansion obtained when the cells were cultured in (1) long-term bone marrow culture (LTBMC) medium conditioned by an irradiated human BM stroma (CM), (2) medium supplemented with 15% FBS (FBSM) and (3) non-conditioned LTBMC medium (LTM) for 21 days. The effect of the addition of G-CSF (G) and/or of MIP-1alpha (M) to a combination of IL-3, SCF, IL-6 and IL-11 (3, S, 6, 11) was analyzed. Compared to CD34+DR- cells, CD34+ and CD34+DR+ cells gave rise to a similar number of viable cells and to a lower progenitor expansion. The expansion potential of CD34+ and CD34+DR+ cells was equivalent in CM and in FBSM except for both the emergence of CD61 + megakaryocytic cells and LTC-IC maintenance which were improved by culture in CM. In contrast, expansion from CD34+DR- cells was enhanced by CM for all the parameters tested. Compared to FBSM, CM induced a higher level of CFU-GM and BFU-E expansion and allowed the emergence of CD61+ cells. HPP-CFC were maintained or expanded in CM but decreased in FBSM. Compared to input, the number of LTC-IC remaining after 21 days of CD34+DR- expansion culture was strongly decreased in FBSM and variably maintained or expanded in CM. Comparison with LTM indicated that stroma conditioning is responsible for this effect. G-CSF significantly improved CFU-GM and HPP-CFC expansion from CD34+DR- cells without being detrimental to the LTC-IC pool. The growth of CD61+ cells was significantly enhanced by G-CSF in CM. Addition of MIP-1alpha had no significant effect either on progenitor expansion or on LTC-IC, regardless of culture medium. We conclude that factors present in stroma- conditioned medium are necessary to support the expansion of the whole spectrum of hematopoietic cells from CD34+DR- cells and to support the expansion of cell subsets from CD34+ and CD34+DR+.     

Elastase derived elastin peptides: putative autoimmune targets in giant cell arteritis

OBJECTIVE: Histological analysis of giant cell arteritis (GCA) reveals a granulomatous reaction around the internal elastic lamina. Elastolysis by multinucleated giant cells has also been reported. We investigated elastin derived peptides as putative recall antigens for peripheral blood mononuclear cells (PBMC) from patients with GCA. METHODS: PBMC were collected from 17 patients with GCA (Group 1), 17 patients with vascular diseases, connective tissue diseases, or polymyalgia rheumatica without GCA (Group 2), and 17 healthy controls (Group 3). Cultures of PBMC with different elastin derived peptides or elastase were analyzed. RESULTS: A proliferative response was obtained only with elastate derived elastin peptides in 12/13 untreated patients with GCA. Steroid treatment was believed to abolish this proliferative response in 4 patients with GCA. PBMC from only 3/34 non-GCA subjects responded to these antigens. No proliferative response was obtained for other elastin derived peptides or elastase in any subject. CONCLUSION: Degradation of native elastin by leukocyte elastase can provide elastin derived peptides that act as autoimmune targets for T cells in GCA.     

Analysis of cord blood CD34+ cells purified after cryopreservation

Many practical issues regarding processing blood samples for cord blood banking remain. After cryopreservation, a reduction in clonogenicity has been reported, although it is unknown whether this is associated with lower potential for long-term engraftment. CD34+ cell purification of cryopreserved cord blood (CB) may be important for the clinical application of in vitro expansion. We compared purity, yield, clonogenicity, and growth in long-term stromal-based culture of fresh and cryopreserved CD34+ purified cells (n = 12) using the miniMACS separation system. Mean purity of CD34+ cells was 93% when processed before and 73% when processed after cryopreservation. Fresh CD34+ cells had higher clonogenic potential than cryopreserved cells (45 vs 20%, p < 0.05) in CFU-Mix assays, indicating that progenitor cell loss during cryopreservation is due in part to reduced cloning efficiency of viable CD34+ cells. In long-term culture (LTC) on irradiated normal human bone marrow stroma (n = 7), CFU-GM production in the two groups was the same over 12 weeks, suggesting identical long-term culture-initiating cell (LTC-IC) numbers. We conclude that apparent clonogenic cell loss during cryopreservation is associated with relative sparing of the more primitive LTC-ICs. CFU-Mix assays may therefore underestimate the transplant potential of cryopreserved CB. Purification of CD34+ cells following cryopreservation gives sufficient purity for detailed evaluation of CD34+ cells and for stem cell expansion.