Association of granulocyte-macrophage colony-stimulating factor with the crystalloid granules of human eosinophils

We have previously shown that normal-density human peripheral blood eosinophils transcribe and translate mRNA for granulocyte-macrophage colony-stimulating factor (GM-CSF) and that the intracellular distribution was granular as assessed by light microscopy immunocytochemistry. The present study was conducted to confirm this apparent association between GM-CSF and the crystalloid granule using a subcellular fractionation method for human eosinophils and immunogold electron microscopy (EM). Highly purified (> 99%, by negative selection using anti-CD16 immunomagnetic microbeads) human peripheral blood eosinophils were obtained from four asthmatic subjects (not taking systemic medication), homogenized and density fractionated (5 x 10(7) cells/subject) on linear Nycodenz gradients. Twenty-four fractions were collected from each cell preparation and analyzed for marker enzyme activities as well as total protein. Dot blot analysis with specific monoclonal antibodies (MoAbs) was used to detect the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP). An anti-CD9 MoAb was used as an eosinophil plasma membrane marker. Lactate dehydrogenase (LDH) was used as a cytosolic marker. Immunoreactivity for GM-CSF was detected by a specific enzyme-linked immunosorbent assay using a polyclonal antihuman GM-CSF antibody and confirmed by dot blot. GM-CSF coeluted with the cellular fractions containing granule markers (MBP, ECP, eosinophil peroxidase, hexosaminidase, and arylsulphatase), but not those containing cytoplasm (LDH+) or membrane (CD9+) markers. EM examination of pooled fractions associated with the peak of GM-CSF immunoreactivity confirmed that they contained crystalloid and small granules, but not plasma membrane. In addition, quantification, using immunogold labeling with an anti/GM-CSF MoAb, indicated preferential localization of gold particles over the eosinophil granule cores of intact cells. Thus, our results indicate that GM-CSF resides as a granule-associated, stored mediator in unstimulated human eosinophils.     

Donor‐Derived Strongyloides stercoralis Infection in Solid Organ Transplant Recipients in the United States, 2009–2013

Infection with Strongyloides stercoralis is typically asymptomatic in immunocompetent hosts, despite chronic infection. In contrast, immunocompromised hosts such as solid organ transplant recipients are at risk for hyperinfection syndrome and/or disseminated disease, frequently resulting in fatal outcomes. Infection in these recipients may result from reactivation of latent infection or infection through transmission from an infected donor. We describe the Centers for Disease Control and Prevention's experience with seven clusters of donor‐derived infection from 2009 to 2013. Six of the seven (86%) donors were born in Latin America; donor screening was not performed prior to organ transplantation in any of these investigations. Eleven of the 20 (55%) organ recipients were symptomatic, two of whom died from complications of strongyloidiasis. We also describe the New York Organ Donor Network (NYODN) experience with targeted donor screening from 2010 to 2013. Of the 233 consented potential donors tested, 10 tested positive for Strongyloides antibody; and 18 organs were transplanted. The majority (86%) of the donors were born in Central or South America. Fourteen recipients received prophylaxis after transplantation; no recipients developed strongyloidiasis. The NYODN experience provides evidence that when targeted donor screening is performed prior to transplantation, donor‐derived infection can be averted in recipients.     

Placental Hofbauer cells assemble and sequester HIV-1 in tetraspanin-positive compartments that are accessible to broadly neutralizing antibodies

Introduction

Within monocyte-derived macrophages, HIV-1 accumulates in intracellular virus-containing compartments (VCCs) that are inaccessible to the external environment, which implicate these cells as latently infected HIV-1 reservoirs. During mother-to-child transmission of HIV-1, human placental macrophages (Hofbauer cells (HCs)) are viral targets, and have been shown to be infected in vivo and sustain low levels of viral replication in vitro; however, the risk of in utero transmission is less than 7%. The role of these primary macrophages as viral reservoirs is largely undefined. The objective of this study is to define potential sites of viral assembly, accumulation and neutralization in HCs given the pivotal role of the placenta in preventing HIV-1 infection in the mother-infant dyad.

Methods

Term placentae from 20 HIV-1 seronegative women were obtained following caesarian section. VCCs were evaluated by 3D confocal and electron microscopy. Colocalization R values (Pearson''s correlation) were quantified with colocalization module of Volocity 5.2.1. Replication kinetics and neutralization studies were evaluated using p24 ELISA.

Results

We demonstrate that primary HCs assemble and sequester HIV-1_BaL in intracellular VCCs, which are enriched in endosomal/lysosomal markers, including CD9, CD81, CD63 and LAMP-1. Following infection, we observed HIV-1 accumulation in potentially acidic compartments, which stained intensely with Lysotracker-Red. Remarkably, these compartments are readily accessible via the cell surface and can be targeted by exogenously applied small molecules and HIV-1-specific broadly neutralizing antibodies. In addition, broadly neutralizing antibodies (4E10 and VRC01) limited viral replication by HIV-1-infected HCs, which may be mediated by FcγRI.

Conclusions

These findings suggest that placental HCs possess intrinsic adaptations facilitating unique sequestration of HIV-1, and may serve as a protective viral reservoir to permit viral neutralization and/or antiretroviral drug entry in utero.     

Long-term protection of hematopoiesis against the cytotoxic effects of multiple doses of nitrosourea by retrovirus-mediated expression of human O6-alkylguanine-DNA-alkyltransferase

A human O6-alkylguanine-DNA-alkyltransferase (ATase) cDNA-containing retrovirus was used to infect murine long-term primary bone marrow cultures. High levels of ATase expression were obtained, and colony- forming cells of the granulocyte-macrophage lineage from the cultures transduced with the human ATase retrovirus were three times more resistant to the alkylating agent, N-methyl-N-nitrosourea (MNU), than control cultures. Furthermore, expression of the human ATase protected long-term hematopoiesis, measured as the output of progenitor cells to the nonadherent fraction of the culture, against the cytotoxic effects of repeated exposures to MNU. These results clearly show that a human ATase cDNA-containing retrovirus can be used to infect long-term primary bone marrow cultures and that this attenuates their sensitivity to nitrosoureas.     

High grade endometrial stromal sarcoma on thinprep

High grade endometrial stromal sarcoma (HGESS) is an uncommon malignancy recently re‐defined in the new WHO classification of endometrial stromal tumors. In this article, we discuss the differential diagnoses of metastatic HGESS in a fine needle aspiration (FNA) of a lymph node and compare the cytomorphology of HGESS in ThinPrep [(TP), Hologic Inc., Boxborough, MA] to conventional smears (CS). The patient had a history of stage I HGESS, status‐post supracervical hysterectomy without regional lymph node metastases. Her post‐operative course was complicated by pelvic fluid collections and enlarging para‐aortic lymph nodes. Diff‐Quik (DQ)‐stained and Papanicolaou (Pap)‐stained smears from a para‐aortic lymph node FNA demonstrated a cellular specimen with monomorphic population of plump to oval cells with scant, wispy cytoplasm in aggregates and as single cells. The nuclei showed fine chromatin and small inconspicuous nucleoli. Compared to the CS, HGESS cells in the TP showed similar cytological features, with the exception that the nuclei were slightly smaller, hyperchromatic, and the chromatin pattern was attenuated. In the absence of prior clinical history, the cytomorphology of metastatic HGESS in a lymph node can be difficult to differentiate from a lymphoma, a variety of metastatic spindle cell tumors or metastatic carcinoma. Immunohistochemical analysis and comparison with the primary tumor can be useful in proving the nature of the malignant cells. The cytomorphology of HGESS on TP correlated well in both single cells and aggregates when compared to CS. The differences noted were decreased nuclear size, nuclear hyperchromasia, and slightly attenuated nuclear detail on TP. Diagn. Cytopathol. 2015;43:756–762. © 2015 Wiley Periodicals, Inc.     

Riedel thyroiditis: Fine needle aspiration findings of a rare entity

Riedel thyroiditis is a rare fibrosing disorder characterized by extension of the fibroinflammatory process beyond the thyroid capsule. Due to the nature of this lesion, fine‐needle aspiration often yields scant material and may be interpreted as non‐diagnostic. In this report, we describe cytologic features that allow the cytopathologist to favor a diagnosis of Riedel thyroiditis, thereby guiding appropriate further work‐up and management. Diagn. Cytopathol. 2015;43:747–750. © 2015 Wiley Periodicals, Inc.