Samer Z. Al-Quran

MyD88-dependent expansion of an immature GR-1+CD11b+ population induces T cell suppression and Th2 polarization in sepsis

Polymicrobial sepsis alters the adaptive immune response and induces T cell suppression and Th2 immune polarization. We identify a GR-1+CD11b+ population whose numbers dramatically increase and remain elevated in the spleen, lymph nodes, and bone marrow during polymicrobial sepsis. Phenotypically, these cells are heterogeneous, immature, predominantly myeloid progenitors that express interleukin 10 and several other cytokines and chemokines. Splenic GR-1+ cells effectively suppress antigen-specific CD8+ T cell interferon (IFN) γ production but only modestly suppress antigen-specific and nonspecific CD4+ T cell proliferation. GR-1+ cell depletion in vivo prevents both the sepsis-induced augmentation of Th2 cell–dependent and depression of Th1 cell–dependent antibody production. Signaling through MyD88, but not Toll-like receptor 4, TIR domain–containing adaptor-inducing IFN-β, or the IFN-α/β receptor, is required for complete GR-1+CD11b+ expansion. GR-1+CD11b+ cells contribute to sepsis-induced T cell suppression and preferential Th2 polarization.

Cutting Edge: Bacterial Infection Induces Hematopoietic Stem and Progenitor Cell Expansion in the Absence of TLR Signaling

Bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs) can be activated by type I IFNs, TLR agonists, viruses, and bacteria to increase hematopoiesis. In this study, we report that endotoxin treatment in vivo induces TLR4, MyD88, and Toll/IL-1 resistance domain-containing adaptor-inducing IFN-β (TRIF)-dependent expansion of BM HSPCs. Bacterial infection by Staphylococcus aureus or cecal ligation and puncture also induces HSPC expansion, but MyD88, TRIF, type I IFN, cytokine, PG, or oxidative stress pathways are not required for their expansion. S. aureus-induced HSPC expansion in MyD88−/−TRIF−/− mice is also normal, but is associated with BM remodeling as granulocyte stores are released peripherally. Importantly, reduction in BM cellularity alone can reproduce HSPC expansion. These data show in vivo HSPC responses to bacterial infection are complex and not absolutely dependent upon key inflammatory signaling pathways.

Identification of c-kit gene mutations in primary adenoid cystic carcinoma of the salivary gland.

The CD117 (KIT) protein is overexpressed in many human neoplasms including adenoid cystic carcinoma of salivary glands. To evaluate the function of c-kit-activating mutations in adenoid cystic carcinoma of the salivary gland, we studied 14 cases (13 primary, 1 cervical lymph node metastasis) from our institution. KIT protein expression was evaluated by immunohistochemistry using formalin-fixed paraffin-embedded tissue. Mutational analyses of c-kit extracellular (exon 9), juxtamembrane (exon 11) and tyrosine kinase domains (exons 13 and 17) were performed by polymerase chain reaction, clonal selection and DNA sequencing. All 14 cases demonstrated strong KIT expression by immunohistochemistry. Molecular analysis was successful in 8 of 14 cases, and c-kit missense point mutations were detected in seven of eight cases (88%) including seven in exon 11, two in exon 9, two in exon 13 and two in exon 17. Eight silent point mutations were detected in five cases. Two cases contained missense mutations in more than one exon. Different mutations were found in the primary tumor and the cervical lymph node metastasis of one patient. Point mutations in domains similar to those described in gastrointestinal stromal tumors were detected, including Pro551Leu and Lys558Glu (5′ end of exon 11), Leu576Phe (3′ end of exon 11), Val643Ala (exon 13) and Asn822Ser (exon 17). Additional novel point mutations in exons 9, 11, 13 and 17 were also identified. This study is the first to report c-kit gene mutations in primary adenoid cystic carcinoma of the salivary gland. Identification of such potential gain-of-function mutations in exon 11, and less frequently in exons 9, 13 and 17, suggests that KIT may be involved in the pathogenesis of adenoid cystic carcinoma of salivary glands. Our study raises a prospect of correlation of c-kit mutation and a potential treatment of adenoid cystic carcinoma with tyrosine kinase inhibitor (imatinib).

Acral myxoinflammatory fibroblastic sarcomas: are they all low-grade neoplasms?

Acral myxoinflammatory fibroblastic sarcoma (AMIFS) is a low‐grade sarcoma that presents mostly in distal extremities of middle‐aged patients. The clinicopathologic features, immunohistochemical profile and follow‐up data of five cases (three men and two women; age 39–65 years) are presented. The tumors presented as a slow‐growing, poorly circumscribed, subcutaneous masses in the hands (three), foot (one) and calf (one), with dermal involvement in two cases. They had myxoid and hyaline stroma with dense acute and chronic inflammation. Spindle cells, large bizarre ganglion‐like cells and multivacuolated cells were seen. Variable reactivity in lesional cells were noted for vimentin, Alpha‐1‐antitrypsin (A1AT), factor XIIIa, CD68, CD95, CD117, Alpha‐1‐antichymotrypsin (A1ACT), CD34, AE1/3, S‐100 protein, EBER, CD63 and CD15. MIB‐1 showed 5–30% nuclear labeling. They were negative for cytokeratin AE1/3, smooth muscle actin, CD30, ALK‐1, EMA, desmin, CMV, HMB‐45 and Melan‐A. Follow up ranged from 2 weeks to 95 months (mean 54). One patient was lost to follow up; three underwent excision and one patient had below the knee amputation. Two patients developed metastases (one died of disease), and two patients are alive without evidence of disease. AMIFS are rare tumors that may involve joints and tendons leading to clinical diagnosis of ganglion cyst or tenosynovitis.

Developing aptamer probes for acute myelogenous leukemia detection and surface protein biomarker discovery.

BackgroundThe majority of patients with acute myelogenous leukemia (AML) still die of their disease. In order to improve survival rates in AML patients, new strategies are necessary to discover biomarkers for the detection and targeted therapy of AML. One of the advantages of the aptamer-based technology is the unique cell-based selection process, which allows us to efficiently select for cell-specific aptamers without knowing which target molecules are present on the cell surface.MethodsThe NB4 AML cell line was used as the target cell population for selecting single stranded DNA aptamers. After determining the affinity of selected aptamers to leukocytes, the aptamers were used to phenotype human bone marrow leukocytes and AML cells in clinical specimens. Then a biotin-labelled aptamer was used to enrich and identify its target surface protein.ResultsThree new aptamers were characterized from the selected aptamer pools (JH6, JH19, and K19). All of them can selectively recognize myeloid cells with Kd in the low nanomole range (2.77 to 12.37 nM). The target of the biotin-labelled K19 aptamer probe was identified as Siglec-5, a surface membrane protein in low abundance whose expression can serve as a biomarker of granulocytic maturation and be used to phenotype AML. More importantly, Siglec-5 expression can be used to detect low concentrations of AML cells in human bone marrow specimens, and functions as a potential target for leukemic therapy.ConclusionsWe have demonstrated a pipeline approach for developing single stranded DNA aptamer probes, phenotyping AML cells in clinical specimens, and then identifying the aptamer-recognized target protein. The developed aptamer probes and identified Siglec-5 protein may potentially be used for leukemic cell detection and therapy in our future clinical practice.

PTK7: A new biomarker for immunophenotypic characterization of maturing T cells and T cell acute lymphoblastic leukemia

Protein tyrosine kinase-7 (PTK7) was recently identified as a surface protein expressed on hematopoietic cells. To determine if PTK7 is a useful biomarker in clinical practice for acute leukemia immunophenotyping and detection, we examined the PTK7 expression in human bone marrow and thymic specimens. Our results show that PTK7 expression in normal thymic T cells is tightly regulated during the maturational process, but in T cell acute lymphoblastic leukemia (T-ALL) the expected temporal relationship of expression between PTK7 and other maturational T cell markers is lost or disrupted. In addition, nearly all T-ALL cases expressed higher PTK7 levels than mature T cells in the human bone marrow specimens. Therefore, in conjunction with other T cell markers, PTK7 has utility as a biomarker for detecting minimal residual disease of T-ALL in the bone marrow.

Myeloid sarcoma of the urinary bladder and epididymis as a primary manifestation of acute myeloid leukemia with inv(16)

Myeloid sarcoma (MS) of the lower urinary tract is rare. We describe a 47-year-old man with hematuria, who was subsequently found to have MS involving bladder and epididymis. The neoplasm was composed predominantly of blasts that expressed CD68, CD117, myeloperoxidase, and lysozyme, with occasional immature eosinophils. Although blood and bone marrow examinations showed no morphologic evidence of leukemia, conventional cytogenetic studies of marrow demonstrated inv(16)(p13q22) in 4 of 20 metaphases; fluorescence in situ hybridization of the bladder neoplasm also showed inv(16). Following chemotherapy, the patient has been in complete remission for 32 months. In our literature review, we identified 7 cases of MS involving bladder, only 3 without evidence of an associated myeloid neoplasm in marrow, none with cytogenetic data. A high index of suspicion is required to establish the diagnosis of MS involving bladder. Cytogenetic analysis is useful for both demonstrating minimal marrow disease and classifying MS in paraffin-embedded tissue sections.

Cytokeratin and Epithelial Membrane Antigen Expression in Angiosarcomas: An Immunohistochemical Study of 33 Cases

CONTEXT Expression of epithelial cell markers can occur in mesenchymal tumors and has been reported in angiosarcomas with variable frequency. In these situations, establishing the diagnosis becomes problematic. OBJECTIVE To determine the expression of cytokeratin and epithelial membrane antigen in angiosarcoma. DESIGN To address this issue, 33 well-documented cases of angiosarcomas were retrieved from the archival material of Shands Hospital at the University of Florida, Gainesville, and Jackson Memorial Hospital at the University of Miami, Miami, Florida. These cases were all reviewed and studied using a cytokeratin cocktail (CAM 5.2 and AE1/AE3) and epithelial membrane antigen using standard immunohistochemical techniques. All 33 cases had available material for cytokeratin analysis; however, only 20 cases had enough material for epithelial membrane antigen staining. RESULTS In the 33 cases studied, the age range of the patients was 2 to 88 years (mean, 63 years). There were 23 (70%) men and 10 (30%) women. One (3%) of 33 was cytokeratin-immunoreactive and 2 (10%) of 20 were epithelial membrane antigen-immunoreactive. CONCLUSION Cytokeratin and epithelial membrane antigen immunoreactivity in angiosarcomas is infrequent but may be encountered. Interpretation of such expression should be done with caution and in conjunction with the characteristic clinical and morphologic features of the tumor as well as the expression of endothelial cell antigens.

Smoothelin immunohistochemistry is a useful adjunct for assessing muscularis propria invasion in bladder carcinoma

Bovio I M, Al‐Quran S Z, Rosser C J, Algood C B, Drew P A & Allan R W
(2010) Histopathology 56, 951–956 
Smoothelin immunohistochemistry is a useful adjunct for assessing muscularis propria invasion in bladder carcinoma

Thomsen-Friedenreich (T) antigen: a possible tool for differentiating sebaceous carcinoma from its simulators.

The Thomsen–Friedenreich (T) antigen is a cryptic glycoprotein, referred to as tumor antigen or cancer-associated antigen because it is absent or masked by some carbohydrates in normal tissues, but present in many human cancers. The latter include gastrointestinal, lung, pancreatic, mammary, and some ovarian carcinomas. Cancer cells frequently undergo incomplete glycosylation resulting in the appearance of precursor structures that normally would be absent like the case with the T antigen. T antigen can be detected by several different reagents including monoclonal antibodies and several plant lectins–e.g., Arachis hypogea (peanut agglutinin). The aim of the current study was to evaluate the expression of T antigen in sebaceous carcinoma and to compare it with its simulators. The authors studied the immunohistochemical expression of T antigen in 45 skin biopsy and excisional specimens obtained from the archives of their dermatopathology laboratories, including 8 cases of sebaceous carcinoma, 15 cases of sebaceous adenoma, 9 cases of sebaceoma, 1 case of basal cell carcinoma with sebaceous differentiation, and 12 cases of basal cell carcinoma with cytologic atypia. Sebaceous carcinoma was unique in expressing a strong, diffuse cytoplasmic T antigen reactivity (7 of 8 cases) along the immature basaloid cells and the intermediate cells. However, sebaceous adenoma, sebaceoma, and basal cell carcinomas expressed negative reaction in the basaloid cells and mild reactivity in the intermediate cells. Mature sebocytes showed a strong reaction in all cases. The authors concluded that T antigen expression may be a helpful tool in differentiating sebaceous carcinoma from other sebaceous lesions that may simulate it histologically.