A distinct innate lymphoid cell population regulates tumor-associated T cells

Antitumor T cells are subject to multiple mechanisms of negative regulation. Recent findings that innate lymphoid cells (ILCs) regulate adaptive T cell responses led us to examine the regulatory potential of ILCs in the context of cancer. We identified a unique ILC population that inhibits tumor-infiltrating lymphocytes (TILs) from high-grade serous tumors, defined their suppressive capacity in vitro, and performed a comprehensive analysis of their phenotype. Notably, the presence of this CD56+CD3- population in TIL cultures was associated with reduced T cell numbers, and further functional studies demonstrated that this population suppressed TIL expansion and altered TIL cytokine production. Transcriptome analysis and phenotypic characterization determined that regulatory CD56+CD3- cells exhibit low cytotoxic activity, produce IL-22, and have an expression profile that overlaps with those of natural killer (NK) cells and other ILCs. NKp46 was highly expressed by these cells, and addition of anti-NKp46 antibodies to TIL cultures abrogated the ability of these regulatory ILCs to suppress T cell expansion. Notably, the presence of these regulatory ILCs in TIL cultures corresponded with a striking reduction in the time to disease recurrence. These studies demonstrate that a previously uncharacterized ILC population regulates the activity and expansion of tumor-associated T cells.

Role of CD56 in Normal Kidney Development and Wilms Tumorigenesis

The cell-surface glycoprotein CD56 has three major isoforms that play important roles in cell adhesion and signaling, which may promote cell proliferation, differentiation, survival, or migration. It is an important molecule in normal kidney development and acts as a key marker in Wilms tumor stem and progenitor cells. Here, we review the structural and genetic features of the CD56 glycoprotein, and summarize its roles in the normal versus diseased metanephric blastema. We discuss areas of CD56-related research that may complement or improve existing Wilms tumor treatment strategies, including the antibody-drug conjugate lorvotuzumab mertansine that binds to CD56.

Isolation and Characterization of Vessel-Associated Stem/Progenitor Cells from Skeletal Muscle

More than 10 years ago, we isolated from mouse embryonic dorsal aorta a population of vessel-associated stem/progenitor cells, originally named mesoangioblasts (MABs ) , capable to differentiate in all mesodermal-derived tissues, including skeletal muscle. Similar though not identical cells have been later isolated and characterized from small vessels of adult mouse and human skeletal muscles. When delivered through the arterial circulation, MABs cross the blood vessel wall and participate in skeletal muscle regeneration , leading to an amelioration of muscular dystrophies in different preclinical animal models. As such, human MABs have been used under clinical-grade conditions for a Phase I/II clinical trial for Duchenne muscular dystrophy , just concluded. Although some pericyte markers can be used to identify mouse and human MABs , no single unequivocal marker can be used to isolate MABs . As a result, MABs are mainly defined by their isolation method and functional properties. This chapter provides detailed methods for isolation, culture, and characterization of MABs in light of the recent identification of a new marker, PW1 /Peg3, to screen and identify competent MABs before their use in cell therapy.

Antithymocyte Globulin Plus G-CSF Combination Therapy Leads to Sustained Immunomodulatory and Metabolic Effects in a Subset of Responders With Established Type 1 Diabetes

Low-dose antithymocyte globulin (ATG) plus pegylated granulocyte colony-stimulating factor (G-CSF) preserves β-cell function for at least 12 months in type 1 diabetes. Herein, we describe metabolic and immunological parameters 24 months following treatment. Patients with established type 1 diabetes (duration 4-24 months) were randomized to ATG and pegylated G-CSF (ATG+G-CSF) (N = 17) or placebo (N = 8). Primary outcomes included C-peptide area under the curve (AUC) following a mixed-meal tolerance test (MMTT) and flow cytometry. "Responders" (12-month C-peptide ≥ baseline), "super responders" (24-month C-peptide ≥ baseline), and "nonresponders" (12-month C-peptide < baseline) were evaluated for biomarkers of outcome. At 24 months, MMTT-stimulated AUC C-peptide was not significantly different in ATG+G-CSF (0.49 nmol/L/min) versus placebo (0.29 nmol/L/min). Subjects treated with ATG+G-CSF demonstrated reduced CD4⁺ T cells and CD4⁺/CD8⁺ T-cell ratio and increased CD16⁺CD56^hi natural killer cells (NK), CD4⁺ effector memory T cells (Tem), CD4⁺PD-1⁺ central memory T cells (Tcm), Tcm PD-1 expression, and neutrophils. FOXP3⁺Helios⁺ regulatory T cells (Treg) were elevated in ATG+G-CSF subjects at 6, 12, and 18 but not 24 months. Immunophenotyping identified differential HLA-DR expression on monocytes and NK and altered CXCR3 and PD-1 expression on T-cell subsets. As such, a group of metabolic and immunological responders was identified. A phase II study of ATG+G-CSF in patients with new-onset type 1 diabetes is ongoing and may support ATG+G-CSF as a prevention strategy in high-risk subjects.

A long noncoding RNA positively regulates CD56 in human natural killer cells

Natural killer (NK) cells are innate immune lymphocytes that play critical roles in host defense against viral infection and surveillance against malignant transformation. Long noncoding RNAs (lncRNAs) are important immune system regulators. Here, we analyzed human primary lymphocyte lncRNA expression profiles to identify NK-lncRNA signatures. We detected numerous novel NK-specific lncRNAs with potential roles in regulating human NK cell differentiation and function. Expression of lnc-CD56, an NK-specific lncRNA, was positively correlated with that of CD56, a classical human NK cell surface marker. We showed that lnc-CD56 may function as a positive regulator of CD56 in primary human NK cells and differentiated NK cells from human CD34+ hematopoietic progenitor cells. Our data provide an annotated human NK cell lncRNA expression catalog and demonstrate a key role for lncRNAs in NK cell biology.

Evaluation of interleukin 12 and CD56+ lymphocyte cells in pediatric hematopoietic stem cell transplantation for early diagnosis of acute graft versus host disease

The present study tried to explain CD56+ lymphocyte cells activities and possible prognostic role of these cells in Graft-Versus-Host-Disease (GVHD). The role of IL-12 activation and function is of interest in this study. Peripheral blood samples of 51 Hematopoietic Stem Cell Transplantation (HSCT) recipients collected at before (day -8) and after (days 7 and 14). PBMC were collected by Ficoll separation and analyzed by Flow Cytometry using triple antibody (CD45-PerCP, CD56-FITC, and CD69-PE staining and control antibody. Levels of the cytokine IL-12 in the patient's serum were evaluated by ELISA. Percentage of CD56+ lymphocytes (CD56+^bright) cells was significantly increased at day 14 in patients with acute GVHD and percentage of lymphocytes expressing CD69 was significantly increased at days 7 and 14 posts HSCT in patients with acute GVHD in comparison to those in non-GVHD patients. Baseline serum IL-12 levels (pre-HSCT, day -8) were significantly higher in those HSCT recipients who did not develop GVHD. This study showed that post-transplant CD56+ lymphocytes and pre-transplant serum levels of IL-12 play significant roles in the induction of and protection against GVHD, respectively. The increase in the percentage of CD69+ cells indicates the activation of lymphocyte in acute GVHD group.

Cytomorphologic and Immunophenotypic Profile of a Cohort of Small Cell Carcinoma of the Urinary Bladder

BACKGROUND

The incidence of primary small cell carcinoma (SCC) of the urinary bladder is extremely rare. We sought to analyze the cytologic and immunophenotypic features of SCC of the urinary bladder in urine and reassert the importance of cytologic examination of urine specimens for diagnosis of this tumor.

METHODS

We studied the clinical and cytomorphologic features in the presurgical urine specimens (4 voided urine and 2 bladder-washing specimens) of histopathologically and immunohistochemically proven cases of SCC of the urinary bladder.

RESULTS

There were 6 cases, all males, with an age range of 61-81 years. On cytologic and histopathologic examination, typical SCC morphology was present in all cases. On immunohistochemistry, synaptophysin and CD56 were positive in all 6 cases, while chromogranin was positive in only 3. The Ki-67 labeling index ranged from 30 to 100%.

CONCLUSIONS

SCC should be kept in the differential diagnosis, when high-grade urothelial carcinoma is suspected in a urine cytology specimen, as this distinction has important therapeutic and prognostic implications. Therefore, a careful observation and, if required, the use of an appropriate immunocytochemical panel on the presurgical urine specimens can lead to a correct diagnosis.

Ocular manifestation in myeloid/NK cell precursor acute leukemia: a case report. Diagnosed by flow cytometry and PCR from aqueous humor

BACKGROUND

Myeloid/NK cell precursor acute leukemia (MNKL) is a rare type of leukemia, and ocular complications have not previously been reported. We now report a patient with MNKL who developed intraocular infiltrates during follow-up.

METHODS AND RESULTS

A 13-year-old boy diagnosed with MNKL developed left eye pain 3 months after starting treatment. Examination of the left eye revealed a visual acuity of counting fingers at 20 cm, ciliary hyperemia, small corneal keratic precipitates, hypopyon, grade 4 vitreous opacities, and an obscured fundus. The differential diagnosis was between an opportunistic infection associated with immunodeficiency and an intraocular leukemic cell infiltrate. Therefore, a sample of aqueous humor was aspirated. Multiplex PCR/broad-range PCR of the aqueous humor was below detection limits for viruses, bacteria, and fungi. Flow cytometry (FCM) detected NK-related CD56-positive cells, thus leading to a diagnosis of ocular infiltrates due to MNKL. With treatment of the ocular infiltrates by consolidation systemic chemotherapy including intrathecal methotrexate (MTX), there was clearing of the vitreous opacities; and optic disc swelling, retinal hemorrhages, exudates, and protuberant lesions were now seen. With the addition of local radiation therapy to the eye, there was a dramatic treatment response, with regression of the optic disc findings and retinal lesions, and an improved visual acuity of 1.5.

CONCLUSION

We encountered the first case of MNKL in which ocular infiltrates developed during follow-up. Multiplex PCR and FCM of the aqueous humor were useful in rapidly distinguishing leukemic cell infiltrates from an opportunistic infection. This case highlights the usefulness of intrathecal MTX and local radiotherapy in treating ocular infiltrates in patients with MNKL.

Ossifying Fibromyxoid Tumor May Express CD56 and CD99: A Case Report

Ossifying fibromyxoid tumor (OFMT) is an uncommon soft tissue neoplasm characterized by a combination of myxoid and/or fibrous stroma with areas of ossification. Although most authors postulate a neuroectodermal origin for this peculiar tumor, there is no agreement in the literature regarding its histogenesis. In this article, we present the immunohistochemical findings of a case of a 39-year-old white male with an OFMT of the soft tissue in the mandibular region. The tumor was positive to S-100 protein, glial fibrillary acidic protein, CD99, CD56 and negative to smooth muscle actin, cytokeratins AE1/AE3, epithelial membrane antigen, and CD68. To the best of our knowledge, this is the first case reported to be positive to CD56 and CD99. Immunoreactivity to these two antibodies, together with reactivity for S-100 protein and glial fibrillary acidic protein, suggests that OFMT is of a neuroectodermal origin. In our opinion, in the absence of reactivity to at least one neuroectodermal marker one should seriously question a diagnosis of OFMT.

CD47-blocking immunotherapies stimulate macrophage-mediated destruction of small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly aggressive subtype of lung cancer with limited treatment options. CD47 is a cell-surface molecule that promotes immune evasion by engaging signal-regulatory protein alpha (SIRPα), which serves as an inhibitory receptor on macrophages. Here, we found that CD47 is highly expressed on the surface of human SCLC cells; therefore, we investigated CD47-blocking immunotherapies as a potential approach for SCLC treatment. Disruption of the interaction of CD47 with SIRPα using anti-CD47 antibodies induced macrophage-mediated phagocytosis of human SCLC patient cells in culture. In a murine model, administration of CD47-blocking antibodies or targeted inactivation of the Cd47 gene markedly inhibited SCLC tumor growth. Furthermore, using comprehensive antibody arrays, we identified several possible therapeutic targets on the surface of SCLC cells. Antibodies to these targets, including CD56/neural cell adhesion molecule (NCAM), promoted phagocytosis in human SCLC cell lines that was enhanced when combined with CD47-blocking therapies. In light of recent clinical trials for CD47-blocking therapies in cancer treatment, these findings identify disruption of the CD47/SIRPα axis as a potential immunotherapeutic strategy for SCLC. This approach could enable personalized immunotherapeutic regimens in patients with SCLC and other cancers.

Prion Protein Deficiency Causes Diverse Proteome Shifts in Cell Models That Escape Detection in Brain Tissue

A popular method for studying the function of a given protein is to generate and characterize a suitable model deficient for its expression. For the prion protein (PrP), best known for its role in several invariably fatal neurodegenerative diseases, a natural choice, therefore, would be to undertake such studies with brain samples. We recently documented the surprising observation that PrP deficiency caused a loss or enhancement of NCAM1 polysialylation, dependent on the cell model used. To identify possible causes for this disparity, we set out to systematically investigate the consequence of PrP deficiency on the global proteome in brain tissue and in four distinct cell models. Here we report that PrP deficiency causes robust but surprisingly divergent changes to the global proteomes of cell models but has no discernible impact on the global brain proteome. Amongst >1,500 proteins whose levels were compared in wild-type and PrP-deficient models, members of the MARCKS protein family exhibited pronounced, yet cell model-dependent changes to their steady-state levels. Follow-up experiments revealed that PrP collaborates with members of the MARCKS protein family in its control of NCAM1 polysialylation. We conclude that the physiological function of PrP may be masked in analyses of complex brain samples but its cell-type specific influence on a lipid raft-based NCAM1-related cell biology comes to the fore in investigations of specific cell types.

Up-regulation of Proinflammatory Genes and Cytokines Induced by S100A8 in CD8+ T Cells in Lichen Planus

Lichen planus (LP) is a chronic inflammatory mucocutaneous disease. The inflammatory status of LP may be related to S100A8 (myeloid-related protein 8; MRP8) activation of cytotoxic cells. The aims of this study were to evaluate S100A8 expression in skin lesions and the in vitro effects of S100A8 on CD8+ T cells and natural killer (NK) cells in LP. Increased levels of S100A8/S100A9 were detected in the skin lesions as well as in the sera of subjects with LP. S100A8 expression induced an increased cytotoxic response by peripheral blood CD8+CD107a+ T cells as well as by NK CD56bright cells in patients with LP. Increased expression of interleukin (IL)-1?, tumour necrosis factor (TNF) and IL-6 in the CD8+ T cells of patients with LP was induced by S100A8, in contrast to the control group that produced IL- 10 and interferon type I genes. These data suggest that, in individuals with LP, S100A8 may exert distinct immunomodulatory and cytotoxicity functions.

Natural killer cell immunosenescence in acute myeloid leukaemia patients: new targets for immunotherapeutic strategies?

Several age-associated changes in natural killer (NK) cell phenotype have been reported that contribute to the defective NK cell response observed in elderly patients. A remodelling of the NK cell compartment occurs in the elderly with a reduction in the output of immature CD56(bright) cells and an accumulation of highly differentiated CD56(dim) NK cells. Acute myeloid leukaemia (AML) is generally a disease of older adults. NK cells in AML patients show diminished expression of several activating receptors that contribute to impaired NK cell function and, in consequence, to AML blast escape from NK cell immunosurveillance. In AML patients, phenotypic changes in NK cells have been correlated with disease progression and survival. NK cell-based immunotherapy has emerged as a possibility for the treatment of AML patients. The understanding of age-associated alterations in NK cells is therefore necessary to define adequate therapeutic strategies in older AML patients.

Schwann cells induce cancer cell dispersion and invasion

Nerves enable cancer progression, as cancers have been shown to extend along nerves through the process of perineural invasion, which carries a poor prognosis. Furthermore, the innervation of some cancers promotes growth and metastases. It remains unclear, however, how nerves mechanistically contribute to cancer progression. Here, we demonstrated that Schwann cells promote cancer invasion through direct cancer cell contact. Histological evaluation of murine and human cancer specimens with perineural invasion uncovered a subpopulation of Schwann cells that associates with cancer cells. Coculture of cancer cells with dorsal root ganglion extracts revealed that Schwann cells direct cancer cells to migrate toward nerves and promote invasion in a contact-dependent manner. Upon contact, Schwann cells induced the formation of cancer cell protrusions in their direction and intercalated between the cancer cells, leading to cancer cell dispersion. The formation of these processes was dependent on Schwann cell expression of neural cell adhesion molecule 1 (NCAM1) and ultimately promoted perineural invasion. Moreover, NCAM1-deficient mice showed decreased neural invasion and less paralysis. Such Schwann cell behavior reflects normal Schwann cell programs that are typically activated in nerve repair but are instead exploited by cancer cells to promote perineural invasion and cancer progression.

Cancer's got nerve: Schwann cells drive perineural invasion

The invasion of cancer cells around and into nerves is associated with increased cancer aggression and poor patient outcome. As this perineural invasion increases disease severity, a better understanding of how the process is regulated may help in the development of therapeutics to target neuronal involvement in cancer. In this issue of the JCI, Deborde and colleagues show that direct contact between Schwann cells and cancer cells promotes cancer cell dissociation, migration, and invasion. Moreover, their data specifically suggest NCAM1 as an important molecular mediator of this Schwann cell-directed regulation of cancer cells in perineural invasion. The results of this study provide new insight into the cellular and molecular mechanisms of perineural invasion.

Distinctive Leukocyte Subpopulations According to Organ Type in Cynomolgus Macaques

Cynomolgus macaques (CYNO; Macaca fascicularis) are a well-established NHP model used for studies in immunology. To provide reference values on the baseline cell distributions in the hematopoietic and lymphoid organs (HLO) of these animals, we used flow cytometry to analyze the peripheral blood, bone marrow, mesenteric lymph nodes, spleen, and thymus of a cohort of male, adult, research-naïve, Mauritian CYNO. Our findings demonstrate that several cell distribution patterns differ between CYNO and humans. First, the CD4(+):CD8(+) T-cell ratio is lower in CYNO compared with humans. Second, the peripheral blood of CYNO contains a population of CD4(+)CD8(+) T cells. Third, the CD31 level was elevated in all organs studied, suggesting that CD31 may not be an accurate marker of recent thymic emigrants within the CD4(+) T cells of CYNO. Finally the B-cell population is lower in CYNO compared with humans. In summary, although the majority of immune cell populations are similar between cynomolgus macaques and humans, several important differences should be considered when using CYNO in immunologic studies. Our current findings provide valuable information to not only researchers but also veterinarians working with CYNO at research centers, in zoos, or in the wild.

Defining the value of CD56, CK19, Galectin 3 and HBME-1 in diagnosis of follicular cell derived lesions of thyroid with systematic review of literature

BACKGROUND

Nodular follicular lesions of thyroid gland comprise benign and malignant neoplasms, as well as some forms of hyperplasia. "Follicular" refers to origin of cells and in the same time to growth pattern - building follicles. Nodular follicular thyroid lesions have in common many morphological features, therefore attempts were made to define additional criteria for distinction between follicular adenoma, follicular carcinoma and follicular variant of papillary carcinoma. Increasing number of immunohistochemical markers is in the continual process of evaluation.

METHODS

Tissue microarrays incorporating, total 201 cases, out of which 122 malignant and 79 benign follicular lesions, including neoplastic and non-neoplastic, were constructed and immunostained with antibodies to CD56, CK19, Galectin-3, HBME-1. Tissue cores were exclusively being acquired from tumour/lesion on interface with normal thyroid tissue. A systematic review of literature was done for period from the year 2001 to present time.

RESULTS

All analysed markers may make a difference between benign lesions/tumours from differentiated thyroid carcinomas (p = <0.01, for all markers). Expression of all markers is significantly higher in papillary carcinoma than in follicular adenoma (p < 0.01). Statistically significant difference in expression of Galectin-3 and CD56 between follicular carcinoma and follicular adenoma was registered (p = 0.043; p = 0.028, respectively). The only marker which expression showed statistically significant difference between adenoma and carcinoma of Hurthle cells was Galectin 3 (p = 0.041). CK19 and HBME-1 were significantly expressed more in papillary carcinoma as compared to follicular carcinoma.

CONCLUSION

Galectin 3 is most sensitive marker for malignancy, while loss of expression of CD56 is very specific for malignancy. Expected co-expression for combination of markers in diagnosis of follicular lesions decreases sensitivity and increases specificity for malignancy.

Chemokine Receptor Expression on Normal Blood CD56(+) NK-Cells Elucidates Cell Partners That Comigrate during the Innate and Adaptive Immune Responses and Identifies a Transitional NK-Cell Population

Studies of chemokine receptors (CKR) in natural killer- (NK-) cells have already been published, but only a few gave detailed information on its differential expression on blood NK-cell subsets. We report on the expression of the inflammatory and homeostatic CKR on normal blood CD56(+low) CD16(+) and CD56(+high)  CD16(-/+low) NK-cells. Conventional CD56(+low) and CD56(+high) NK-cells present in the normal PB do express CKR for inflammatory cytokines, although with different patterns CD56(+low) NK-cells are mainly CXCR1/CXCR2(+) and CXCR3/CCR5(-/+), whereas mostly CD56(+high) NK-cells are CXCR1/CXCR2(-) and CXCR3/CCR5(+). Both NK-cell subsets have variable CXCR4 expression and are CCR4(-) and CCR6(-). The CKR repertoire of the CD56(+low) NK-cells approaches to that of neutrophils, whereas the CKR repertoire of the CD56(+high) NK-cells mimics that of Th1(+) T cells, suggesting that these cells are prepared to migrate into inflamed tissues at different phases of the immune response. In addition, we describe a subpopulation of NK-cells with intermediate levels of CD56 expression, which we named CD56(+int) NK-cells. These NK-cells are CXCR3/CCR5(+), they have intermediate levels of expression of CD16, CD62L, CD94, and CD122, and they are CD57(-) and CD158a(-). In view of their phenotypic features, we hypothesize that they correspond to a transitional stage, between the well-known CD56(+high) and CD56(+low) NK-cells populations.

Effects of Single and Fractionated Irradiation on Natural Killer Cell Populations: Radiobiological Characteristics of Viability and Cytotoxicity In Vitro

BACKGROUND

Natural killer (NK) cells are important in destroying tumor cells. However, they are damaged by radiation therapy. We studied the effects of single and fractionated irradiation on the viability and cytotoxicity of human non-selected NK cells and sub-groups with cluster of differentiation (CD) CD16(+) and CD56(+) in vitro. Only very few studies dealing with the standard radiobiological parameters for characterizing NK cells exist in the literature.

MATERIALS AND METHODS

NK cell populations were isolated from buffy coats using different methods and irradiated with single doses up to 80 Gy and fractionated doses of 10 or 30 Gy with different numbers of applications and at different intervals. The study end-points were viability using propidium iodide (PI), trypan blue and intracellular adenosine triphosphate (ATP) assays, and cytotoxicity using the (51)Cr-release assay. The standard radiobiological parameters α and β of the linear-quadratic (L-Q) model and the mean inactivation dose D̅ taken as the area under the curve (AUC) were calculated to characterize the radiosensitivity of different NK cell populations.

RESULTS

The AUC values of the 51Cr release data in the dose range of 0-40 Gy were as follows: for non-selected NK cells, 23.6-20.9 Gy; for CD16(+) and CD56(+) cells, 14.5-13.2 Gy. The AUC values of ATP, trypan blue and propidium iodide methods equally well described the viability of irradiated NK cells. The α/β ratio for cytotoxicity and viability data in the L-Q model corresponded to the acutely responding tissues. Splitting a 30-Gy dose into two fractions applied at different intervals caused a significant rise in ATP levels and cytotoxicity. Dividing the total dose into four doses applied at fixed intervals also resulted in significant elevations of ATP content and cytotoxicity of NK cells at 10 Gy.

CONCLUSION

According to the L-Q method, irradiated NK cells behaved similarly to acutely responding human tissues with respect to cytotoxicity and viability. The AUC proved very useful for comparing the effects of irradiation on NK cells.

[Expression of p63, p40 and CK5/6 in small cell lung cancer]

OBJECTIVE

To study the expression of squamous cell markers p63, p40 and CK5/6 in small cell carcinoma of lung (SCLC).

METHODS

Immunohistochemical study for squamous cell markers (p63, p40 and CK5/6), neuroendocrine markers (chromogranin A, synaptophysin and CD56) and TTF1 was carried out in 283 cases of SCLC. The diagnostic value of these markers was evaluated.

RESULTS

The expression rate of p63, p40 and CK5/6 were 20.7% (54/261), 7.9% (5/63) and 0.5% (1/221), respectively in the cases of SCLC studied. Amongst the squamous cell markers, CK5/6 had the lowest rate of positivity (P < 0.01). On the other hand, chromogranin A, synaptophysin and CD56 were positive in 61.8% (170/275), 85.5% (242/283) and 89.2% (248/278), respectively. The positivity rate for chromogranin A was lower than that for synaptophysin and CD56 (P < 0.01). TTF1 was expressed in 77.2% (217/281).

CONCLUSIONS

p63 and p40 are expressed in a subset of SCLC. In contrast, CK5/6 is rarely positive in SCLC. An immunohistochemical panel of CK5/6, synaptophysin and CD56 is recommended for differential diagnosis of SCLC.

The Prion Protein Controls Polysialylation of Neural Cell Adhesion Molecule 1 during Cellular Morphogenesis

Despite its multi-faceted role in neurodegenerative diseases, the physiological function of the prion protein (PrP) has remained elusive. On the basis of its evolutionary relationship to ZIP metal ion transporters, we considered that PrP may contribute to the morphogenetic reprogramming of cells underlying epithelial-to-mesenchymal transitions (EMT). Consistent with this hypothesis, PrP transcription increased more than tenfold during EMT, and stable PrP-deficient cells failed to complete EMT in a mammalian cell model. A global comparative proteomics analysis identified the neural cell adhesion molecule 1 (NCAM1) as a candidate mediator of this impairment, which led to the observation that PrP-deficient cells fail to undergo NCAM1 polysialylation during EMT. Surprisingly, this defect was caused by a perturbed transcription of the polysialyltransferase ST8SIA2 gene. Proteomics data pointed toward β-catenin as a transcriptional regulator affected in PrP-deficient cells. Indeed, pharmacological blockade or siRNA-based knockdown of β-catenin mimicked PrP-deficiency in regards to NCAM1 polysialylation. Our data established the existence of a PrP-ST8SIA2-NCAM signaling loop, merged two mature fields of investigation and offer a simple model for explaining phenotypes linked to PrP.

The Role of CD56 in Thyroid Fine Needle Aspiration Cytology: A Pilot Study Performed on Liquid Based Cytology

Background

Fine needle aspiration Cytology (FNAC) fulfills a reliable role in the evaluation of thyroid lesions. Although the majority of nodules are quite easily diagnosed as benign or malignant, 30% of them represent an indeterminate category whereby the application of ancillary techniques (i.e. immunocytochemistry-ICC and molecular testing) has been encouraged. The search for a specific immunomarker of malignancy sheds light on a huge number of ICC stains although none of them attempt to yield 100% conclusive results. Our aim was to define in a pilot study on thyroid FNAC whether CD56 might be a valid marker also in comparison with HBME-1 and Galectin-3.

Materials and Methods

Inasmuch as this is the largest pilot study using only liquid based cytology (LBC), we selected all the cases only in the categories of benign nodules (BN) and positive for malignancy (PM) for validation purposes. Eighty-five consecutive (including 50 PM and 35 BN) out of 950 thyroid FNACs had surgical follow-up. The ICC panel (HBME-1, Galectin-3 and CD56) was carried out on LBC and histology.

Results

All BNs and PMs were histological confirmed. CD56 was negative in 96% of the PM while 68.5% of the BNs showed cytoplasmic positivity for this marker, with an overall high sensitivity (96%) but lower specificity (69%). In specific, our 96% of the PMs did not show any follicular cell with CD56 expression. Different ICC combinations were evaluated showing that the panel made up of CD56 plus HBME-1 and Galectin-3 had the highest sensitivity (98%) and specificity (86%).

Conclusions

Our pilot study suggests that CD56 may be a good marker for ruling out PTC and its variants. The low specificity suggests that an immunopanel including also HBME-1 and Galectin-3 could obtain the highest diagnostic accuracy in thyroid lesions. Our results suggest that CD56 may be a feasible additional marker for identifying malignancies also in the FNs and SMs.

Practical NK cell phenotyping and variability in healthy adults

Human natural killer (NK) cells display a wide array of surface and intracellular markers that indicate various states of differentiation and/or levels of effector function. These NK cell subsets exist simultaneously in peripheral blood and may vary among individuals. We examined variety among selected NK cell receptors expressed by NK cells from normal donors, as well as the distribution of select NK cell subsets and NK cell receptor expression over time in several individual donors. Peripheral blood mononuclear cells were evaluated using flow cytometry via fluorochrome-conjugated antibodies against a number of NK cell receptors. Results were analyzed for both mean fluorescence intensity (MFI) and the percent positive cells for each receptor. CD56(bright) and CD56(dim) NK cell subsets were also considered separately, as was variation in receptor expression in NK cell subsets over time in selected individuals. Through this effort, we provide ranges of NK cell surface receptor expression for a local adult population as well as provide insight into intra-individual variation.

Invasive Surgery Impairs the Regulatory Function of Human CD56 bright Natural Killer Cells in Response to Staphylococcus aureus. Suppression of Interferon-γ Synthesis

Major surgery increases the risk for infectious complications due to the development of immunosuppression. CD56^bright NK cells play a key role in the defense against bacterial infections through the release of Interferon (IFN) γ upon stimulation with monocyte-derived Interleukin (IL) 12. We investigated whether invasive visceral surgery interferes with the IFN-γ synthesis of human NK cells in response to Staphylococcus aureus. In a prospective pilot study, peripheral blood mononuclear cells (PBMC) were isolated from 53 patients before and 1 to 7 d after elective visceral surgery. The release of IL-12 and IFN-γ from PBMC upon exposure to S. aureus in vitro was quantified. The expression of the IL-12 receptor β1 chain on the surface, the phosphorylation of signal transducer and activator of transcription (STAT) 4, and the synthesis of IFN-γ on/in individual CD56^bright NK cells were investigated using flow cytometry. The modulatory effect of IL-12 on the S. aureus-induced IFN-γ production in CD56^bright NK cells was analyzed. The IFN-γ secretion from purified CD56^bright NK cells was quantified after stimulation with IL-12 and IL-18. After surgery, CD56^bright NK cells among total PBMC were impaired in the release of IFN-γ for at least 5 d. Likewise, the IL-12-induced release of IFN-γ from purified CD56^bright NK cells was abolished. Upon stimulation with S. aureus, PBMC secreted less IL-12 but supplementation with recombinant IL-12 did not restore the capacity of CD56^bright NK cells to produce IFN-γ. CD56^bright NK cells displayed reduced levels of the IL-12Rβ1 chain whereas the phosphorylation of STAT4, the key transcription factor for the Ifng gene was not diminished. In summary, after invasive visceral surgery, CD56^bright NK cells are impaired in S. aureus-induced IFN-γ production and might contribute to the enhanced susceptibility to opportunistic infections.