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Biomedical subjects

Francisco Lozano

Publications and source records attributed to Francisco Lozano.

At least 19 recordsLinked to original sources

Association between mannose-binding lectin deficiency and septic shock following acute pyelonephritis due to Escherichia coli.

Structural and promoter MBL2 gene polymorphisms responsible for low MBL levels are associated with increased risk of infection. The objective of this study was to assess the possible association between polymorphisms of the MBL2 gene and the incidence of septic shock and bacteremia in patients with acute pyelonephritis due to Escherichia coli. The study included 62 female patients with acute pyelonephritis due to E. coli who required hospital admission, as well as 133 healthy control subjects. Six single-nucleotide polymorphisms (-550 G/C, -221 C/G, +4 C/T, codon 52 CGT/TGT, codon 54 GGC/GAC, and codon 57 GGA/GAA) in the MBL2 gene were genotyped by using a sequence-based typing technique. No significant differences were observed in the frequencies for low-expression MBL2 genotypes (O/O and LXA/O) between patients with acute pyelonephritis and healthy controls. Patients with acute pyelonephritis and septic shock had a higher incidence of low-expression MBL2 genotypes than patients with acute pyelonephritis without septic shock (odds ratio = 9.019, 95% confidence interval = 1.23 to 65.93; P = 0.03). No association was found between bacteremic acute pyelonephritis and low-expression MBL2 genotypes. We found that low-expression MBL2 genotypes predispose to septic shock but not to bacteremia in patients with E. coli-induced acute pyelonephritis. Determination of MBL2 polymorphisms could be useful for assessing the risk of septic shock in women undergoing acute pyelonephritis.

Acute Disease↗

Identification and functional characterization of the hepatic stellate cell CD38 cell surface molecule.

The activation of hepatic stellate cells (HSCs) is a critical event in hepatic fibrosis, because these cells are the main producers of extracellular matrix proteins in the liver and contribute to the modulation of inflammatory responses via the secretion of several cytokines and the expression of adhesion molecules. The goal of the present study was to characterize cell surface proteins that regulate HSC activation. To this end, a panel of monoclonal antibodies (mAbs) was generated. mAb 14.27 recognized a protein of 45 kd that was highly expressed on HSCs. Affinity purification of this protein followed by sequencing revealed that protein to be CD38. We subsequently demonstrated that CD38 was constitutively expressed by HSCs and that its expression increased after in vitro and in vivo activation. mAb 14.27 induced an increase in cytosolic Ca2+ levels in HSCs, showing that it functions as an agonistic antibody. Moreover, the effects mediated by the CD38 mAb included induction of the proinflammatory cytokine interleukin-6 and up-regulation of the adhesion molecules intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and neural cell adhesion molecule. Collectively, our data suggest that CD38 can act as a regulator of HSC activation and effector functions.

ADP-ribosyl Cyclase↗

Mitogen-activated protein kinase pathway activation by the CD6 lymphocyte surface receptor.

CD6 is a cell surface receptor primarily expressed on immature thymocytes and mature T and B1a lymphocytes. Through its binding to activated leukocyte cell adhesion molecule (ALCAM/CD166), CD6 is considered to play an important role in lymphocyte development and activation. Accordingly, CD6 associates with the TCR/CD3 complex and colocalizes with it at the center of the mature immunological synapse on T lymphocytes. Moreover, the CD6-ALCAM interaction has been shown to be critical for proper immunological synapse maturation and T cell proliferative responses. However, the precise biological effects of CD6 ligation and its signaling pathway are still not well understood. The present study shows that CD6 ligation with three different specific mAbs (161.8, SPV-L14.2, and MAE1-C10) induces time- and dose-dependent activation of ERK1/2 on normal and leukemic human T cells. This effect was also observed upon CD6 ligation with a chimerical ALCAM protein (ALCAM-Fc). The C-terminal cytoplasmic region of CD6, as well as Src tyrosine kinases, was critical for CD6-induced ERK1/2 activation. Synergistic effects were observed upon coligation of the TCR/CD3 complex with CD6. The ligation of CD6 induced the transcriptional activation of reporter genes under the control of the c-Fos serum responsive element and AP-1. Accordingly, CD6-mediated activation of p38 and JNK was also observed. These findings indicate that the CD6-ALCAM interaction results in activation of the three MAPK cascades, likely influencing the dynamic balance that determines whether resting or activated lymphocytes survive or undergo apoptosis.

Activated-Leukocyte Cell Adhesion Molecule↗

Assessment of diagnostic tools for eradication of bovine tuberculosis in cattle co-infected with Mycobacterium bovis and M. avium subsp. paratuberculosis.

The intradermal tuberculin (IDTB) test and the interferon-gamma (IFN-gamma) assay are used worldwide for detection of bovine tuberculosis in cattle, but little is known about the effect of co-infecting agents on the performance of these diagnostic tests. This report describes a field trial conducted in a cattle herd with dual infection (bovine tuberculosis and paratuberculosis) during 3.5 years. It has been based on a strategic approach encompassing serial parallel testing (comparative IDTB test, the IFN-gamma assay and serology of paratuberculosis) that was repeated 8 times over the period, and segregation of animals into two herds. The IDTB test detected 65.2% and the IFN-gamma test detected 69.6% of the Mycobacterium bovis culture-positive cattle. However, the IDTB test performed better during the first part of the trial, while the IFN-gamma test was the only method that detected infected animals during the following three samplings. The number of false positive reactors with the IDTB and/or the IFN-gamma tests was remarkably high compared to other reports, and could be caused by cross-reactivity with M. avium subsp. paratuberculosis. Also, the M. bovis isolates from cattle and wildlife from the same property were characterised using molecular techniques to disclose an epidemiological link. The IDTB test may not be appropriate to eradicate bovine tuberculosis in herds with dual mycobacterial infections. This report highlights the need to use several diagnostic techniques for the accurate detection of M. bovis infected animals in these herds.

Animals↗

Mannan-binding lectin pathway deficiencies and invasive fungal infections following allogeneic stem cell transplantation.

OBJECTIVE: The Mannan-binding lectin (MBL) pathway involves recognition of fungal surfaces by MBL and cleavage of C2 and C4 by MBL-associated serine protease (namely, MASP-2). Recent data show that MBL pathway deficiency might result not only from polymorphisms of the MBL2 gene but also of MASP2. The aim of the study was to assess whether polymorphisms of these genes are associated with invasive fungal infections (IFIs) following allogeneic stem cell transplantation (allo-SCT). METHODS: The promoter and the exon 1 of MBL2 and the exon 3 of MASP2 were sequenced in 106 donor-recipient pairs from HLA-identical sibling allo-SCTs performed in a single institution. RESULTS: Ten percent of the donors and 11% of the recipients carried the MBL-low (O/O, LXA/O) genotypes; 7% of the donors and 3% of the recipients were heterozygous for the MASP2 Asp105Gly variant. Factors associated with a higher probability of IFIs were donor's MBL-low genotype (38% vs 12%, p = 0.01), recipient's MASP2 variant (67% vs 14%, p = 0.01), and acute graft-versus-host disease (GVHD) grades II to IV (27% vs 11%, p = 0.04); in the multivariate analysis MBL-low genotype (relative risk [RR] 7.3, p = 0.003), MASP2 variant (RR 6.4, p = 0.002), and acute GVHD II to IV (RR 3.8, p = 0.02) retained independent prognostic value. CONCLUSION: These results show for the first time that polymorphisms responsible for not only MBL but also MASP-2 deficiency are independent predictive factors for IFI after allo-SCT.

Acute Disease↗

Risk of recurrent venous thrombosis in patients with G20210A mutation in the prothrombin gene or factor V Leiden mutation.

The impact of the G20210A prothrombin mutation, factor V Leiden and 677T mutation of methylene tetrahydrofalate reductase (MTHFR) in recurrent deep venous thrombosis (DVT) is not so clear. We have prospectively monitored 259 patients following a first episode of DVT in order to determine which factors influence the development of a recurrent event. Several clinical and biological factors together with the genetic polymorphisms of factor V Leiden, G20210A prothrombin and 677T MTHFR were assessed. During a median follow-up of 786 patient-years, 27 patients (14%) developed one objective episode of recurrent venous thrombosis. The carriers of a double defect, homozygous or double heterozygous for factor V Leiden and G20210A, had an increased risk after a first episode of DVT, while patients who were isolated heterozygous for factor V Leiden or G20210 had a risk of recurrent DVT similar to patients who had neither mutation (annual incidence of 12.1, 3.1, 2.9 and 2.8%). The 677T MTHFR mutation alone or combined with hyperhomocysteinemia was not associated with an increased risk of recurrent events. The development of proximal DVT (P=0.01) and the presence of a double defect (P=0.01) were the only two risk factors independently associated with a high recurrence ratio in the multivariate analysis. Thus, the annual incidence of DVT recurrence in patients without any of these two risk factors was only 0.6% (95% confidence interval, 0.2-0.9). We have identified a group of patients with DVT but at very low risk of re-thrombosis in whom an extended secondary thromboprophylaxis should be carefully considered.

Adolescent↗

Polymorphisms in the interleukin-4 receptor alpha chain gene influence susceptibility to HIV-1 infection and its progression to AIDS.

Interleukin (IL) 4 is a key T helper-2 cytokine that downregulates and upregulates CCR5 and CXCR4, respectively, the main coreceptors for HIV. Our objective is to investigate whether single-nucleotide polymorphisms (SNPs) in the IL-4 receptor alpha chain gene (IL4RA) affect HIV infection and its progression to AIDS. The I50V SNP in exon 5 and the haplotypes of six SNPs in exon 12 (E375A, C406R, S411L, S478P, Q551R, and V554I) were studied by polymerase chain reaction and sequencing in 30 HIV+ long-term nonprogressors (LTNP), 36 HIV+ typical progressors (TP), 55 highly exposed but uninfected individuals (EU), 25 EU-sexuals (EU-Sex; mostly women) and 30 EU-hemophiliacs (EU-Hem; hepatitis C virus+), and 97 healthy controls (HC), all Caucasians and lacking CCR5Delta32 homozygosity. V50 homozygosity was increased in LTNP (44%) compared with the other groups [p = 0.005; relative risk ratio = 3.4, 95% confidence interval (CI) = 1.12-10.6, p = 0.03]. The most common (C) exon 12 haplotype, ECSSQV, predominated in all groups, but uncommon (U) haplotypes were increased in HIV+ individuals (n = 64), especially in those (51 of 64) infected via parenteral exposure (35.3%) compared with HC (20.4%) and EU-Hem (18.4%) [p = 0.01; odds ratio (OR) = 2.14, 95% CI = 1.25-3.67, p = 0.01]. EU-Sex also had an increased frequency of U-haplotypes (34.8%) (OR = 2.10, 95% CI = 1.03-4.21, p = 0.01) as well as an increased frequency of CU + UU genotypes (60.9%) compared with HC (38.2%) and EU-Hem (26.6%) (p = 0.043). Distributions of genotypes fitted Hardy-Weinberg equilibrium. Data suggest that V50 homozygosity associates with slow progression and that exon 12 U-haplotypes might be associated with both susceptibility to infection via parenteral route and resistance to infection via sexual exposure. Further studies are required to confirm these findings.

Acquired Immunodeficiency Syndrome↗

The lymphocyte receptor CD6 interacts with syntenin-1, a scaffolding protein containing PDZ domains.

CD6 is a type I membrane glycoprotein expressed on thymocytes, mature T and B1a lymphocytes, and CNS cells. CD6 binds to activated leukocyte cell adhesion molecule (CD166), and is considered as a costimulatory molecule involved in lymphocyte activation and thymocyte development. Accordingly, CD6 partially associates with the TCR/CD3 complex and colocalizes with it at the center of the mature immunological synapse (IS) on T lymphocytes. However, the signaling pathway used by CD6 is still mostly unknown. The yeast two-hybrid system has allowed us the identification of syntenin-1 as an interacting protein with the cytoplasmic tail of CD6. Syntenin-1 is a PDZ (postsynaptic density protein-95, postsynaptic discs large, and zona occludens-1) domain-containing protein, which functions as an adaptor protein able to bind cytoskeletal proteins and signal transduction effectors. Mutational analyses showed that certain amino acids of the most C-terminal sequence of CD6 (-YDDISAA) and the two postsynaptic density protein-95, postsynaptic discs large, and zona occludens-1 domains of syntenin-1 are relevant to the interaction. Further confirmation of the CD6-syntenin-1 interaction was obtained from pull-down and co-immunoprecipitation assays in mammalian cells. Image analyses also showed that syntenin-1 accumulates at CD6 caps and at the IS. Therefore, we propose that syntenin-1 may function as a scaffolding protein coupling CD6 and most likely other lymphocyte receptors to cytoskeleton and/or signaling effectors during IS maturation.

Amino Acid Sequence↗

A role for human Sp alpha as a pattern recognition receptor.

Human Sp alpha is a soluble protein belonging to group B of the scavenger receptor cysteine-rich (SRCR) superfamily for which little functional information is available. It is expressed by macrophages present in lymphoid tissues (spleen, lymph node, thymus, and bone marrow), and it binds to myelomonocytic and lymphoid cells, which suggests that it may play an important role in the regulation of the innate and adaptive immune systems. In the present study we show that recombinant human Sp alpha (rSp alpha) binds to the surface of several gram-positive and gram-negative bacterial strains. Competition studies indicated that such binding is mediated by the recognition of lipoteichoic acid (LTA) and lipopolysaccharide (LPS), respectively, through nonoverlapping sites on the Sp alpha molecule. The most conserved part of LPS (2-keto-3-deoxyoctulosonic acid and lipid A) was shown to be involved in the recognition by Sp alpha. Bacterial binding studies using the SRCR domain 1 of Sp alpha showed that this domain retains both the LPS and LTA binding activities, indicating that both bacterial interacting sites are retained in a single SRCR domain. Furthermore, rSp alpha induced aggregation of gram-positive and gram-negative bacteria strains. On the other hand, rSp alpha inhibited tumor necrosis factor-alpha secretion by human monocytes stimulated with LPS or LTA. Binding of Sp alpha to conserved components of bacterial surfaces and modulation of the monocyte response indicate that this molecule is an active constituent of the innate immune response of the host.

Amino Acid Sequence↗

Expression of interleukin-8 receptors (CXCR1 and CXCR2) in premenopausal women with recurrent urinary tract infections.

The migration of neutrophils through infected tissues is mediated by the CXC chemokines and its receptors (CXCR1 and CXCR2). It has been proposed that a CXCR1 deficiency could confer susceptibility to acute pyelonephritis in children. The objective of the study is to assess the surface expression of CXCR1 and CXCR2 and the existence of polymorphisms in the CXCR1 gene in premenopausal women with recurrent urinary tract infections. The study included 20 premenopausal women with recurrent urinary infections, with normal urinary tracts, and without diseases potentially associated with relapsing urinary infections and 30 controls without previous urinary infections. The levels of CXCR1 and CXCR2 expression on neutrophils were measured and analyzed by flow cytometry by measuring the mean fluorescence intensity (MFI) channel. The promoter and coding regions of the CXCR1 gene were analyzed for the presence of polymorphisms by a sequence-based typing method. Patients with recurrent urinary tract infections exhibited median levels of CXCR1 expression, determined from MFI values, similar to those of the controls. The analysis of CXCR2 showed that patients with recurrent urinary infections had lower median levels of expression, determined from the MFI values, than the controls (P = 0.002, Mann-Whitney U test). No polymorphisms were detected at the promoter or at the exon 1 region of the CXCR1 gene either in the patients or in the controls. Polymorphisms were detected at the exon 2 of CXCR1, but their frequencies did not differ between patients and controls. We have found a low level of CXCR2 expression in patients with recurrent urinary tract infections. These results suggest that a low level of CXCR2 expression may increase the susceptibilities of premenopausal women to urinary tract infections.

Adult↗

Relevance of CD6-mediated interactions in T cell activation and proliferation.

CD6 is a cell surface receptor expressed on immature thymocytes and mature T and B1a lymphocytes. The ultimate function of CD6 has not been deciphered yet, but much evidence supports a role for CD6 in T cell activation and differentiation. In this study, we show that a fraction of CD6 molecules physically associates with the TCR/CD3 complex by coimmunoprecipitation, cocapping, and fluorescence resonance energy transfer experiments. Image analysis of Ag-specific T-APC conjugates demonstrated that CD6 and its ligand, activated leukocyte cell adhesion molecule (CD166), colocalize with TCR/CD3 at the center of the immunological synapse, the so-called central supramolecular activation cluster. The addition of a soluble rCD6 form significantly reduced the number of mature Ag-specific T-APC conjugates, indicating that CD6 mediates early cell-cell interactions needed for immunological synapse maturation to proceed. This was in agreement with the dose-dependent inhibition of CD3-mediated T cell proliferation induced by soluble rCD6. Taken together, our data illustrate the important role played by the intra- and intercellular molecular interactions mediated by CD6 during T cell activation and proliferation processes.

Activated-Leukocyte Cell Adhesion Molecule↗

Transcriptional regulation of human CD5: important role of Ets transcription factors in CD5 expression in T cells.

CD5 is a surface receptor constitutively expressed on thymocytes and mature T and B-1a cells. CD5 expression is tightly regulated during T and B cell development and activation processes. In this study we shown that the constitutive expression of CD5 on human T cells correlates with the presence of a DNase I-hypersensitive (DH) site at the 5'-flanking region of CD5. Human CD5 is a TATA-less gene for which 5'-RACE analysis shows multiple transcriptional start sites, the most frequent of which locates within an initiator sequence. Luciferase reporter assays indicate that a 282-bp region upstream of the initiation ATG displays full promoter activity in human T cells. Two conserved Ets-binding sites (at positions -239 and -185) were identified as functionally relevant to CD5 expression by site-directed mutagenesis, EMSAs, and cotransfection experiments. A possible contribution of Sp1 (-115 and -95), c-Myb (-177), and AP-1-like (-151) motifs was also detected. Further DH site analyses revealed an inducible DH site 10 kb upstream of the human CD5 gene in both T and B CD5(+) cells. Interestingly, a 140-bp sequence showing high homology with a murine inducible enhancer is found within that site. The data presented indicate that the 5'-flanking region of human CD5 is transcriptionally active in T cells, and that Ets transcription factors in conjunction with other regulatory elements are responsible for constitutive and tissue-specific CD5 expression.

5' Flanking Region↗

Angio-Behçet with vertebral erosion: an exceptional Behçet's complication and literature review.

Behçet's disease is a multisystem disorder commonly seen in Japan and in Mediterranean countries characterized by a vasculitis of unknown origin. In this work, we describe a case of a 47-year-old man with Behçet's disease of 28 years evolution who presented with a common lumbago and revealed to have a rare case of destruction of the third lumbar vertebra due to a giant pseudoaneurysm of the right iliac artery. In the discussion, we make a brief review of the literature on the subject and analyze the existence of three similar cases.

Behcet Syndrome↗

The Scavenger Receptor Cysteine-Rich (SRCR) domain: an ancient and highly conserved protein module of the innate immune system.

The Scavenger Receptor Cysteine-Rich (SRCR) domain is an ancient and highly conserved protein module of ~100-110 amino acids, which defines a superfamily (SRCR-SF) of either soluble or membrane-bound receptors expressed by hematopoietic and nonhematopoietic cells, at either embryonic or adult stages. The existence of two types of SRCR domains allows the division of the SRCR-SF into two groups. Members of group A contain SRCR domains with 6 cysteine residues and are encoded by two exons, whereas those of group B usually contain 8 cysteines and are encoded by a single exon. Group A members usually present as multidomain mosaic proteins containing single SRCR domains associated to other functional domains, such as enzymatic (protease) domains or collagenous regions. On the contrary, group B members generally present as proteins exclusively composed of tandem repeats of SRCR domains, with or without the presence of CUB and ZP domains thought to be involved in oligomerization but never associated to protease domains. Representatives of either group are found in different animal species, from low invertebrates (sponges) to high vertebrates (mammals). Although no unifying function has been defined for SRCR-SF members, accumulated data, together with the high degree of structural and phylogenetic conservation of SRCR domains indicates that they might subserve basic homeostatic functions, including innate immune defense.

Agglutinins↗

The accessory molecules CD5 and CD6 associate on the membrane of lymphoid T cells.

CD5 and CD6 are closely related lymphocyte surface receptors of the scavenger receptor cysteine-rich superfamily, which show highly homologous extracellular regions but little conserved cytoplasmic tails. Both molecules are expressed on the same lymphocyte populations (thymocytes, mature T cells, and B1a cells) and share similar co-stimulatory properties on mature T cells. Although several works have been reported on the molecular associations and the signaling pathway mediated by CD5, very limited information is available for CD6 in this regard. Here we show the physical association of CD5 and CD6 at the cell membrane of lymphocytes, as well as their localization at the immunological synapse. CD5 and CD6 co-immunoprecipitate from Brij 96 but not Nonidet P-40 cell lysates, independently of both the co-expression of other lymphocyte surface receptors and the integrity of CD5 cytoplasmic region. Fluorescence resonance energy transfer analysis, co-capping, and co-modulation experiments demonstrate the physical in vivo association of CD5 and CD6. Analysis of T cell/antigen-presenting cells conjugates shows the accumulation of both molecules at the immunological synapse. These results indicate that CD5 and CD6 are structurally and physically related receptors, which may be functionally linked to provide either similar or complementary accessory signals during T cell activation and/or differentiation.

Animals↗

Cloning of S4D-SRCRB, a new soluble member of the group B scavenger receptor cysteine-rich family (SRCR-SF) mapping to human chromosome 7q11.23.

The scavenger receptor cysteine-rich superfamily (SRCR-SF) is a highly conserved group of membrane and/or secreted proteins related to the innate and adaptive immune system. Here, we report the cloning of the gene encoding human S4D-SRCRB, a novel soluble member of the SRCR-SF, which is composed of four group B SRCR domains separated by Pro-, Ser- and Thr-rich polypeptides. The longest cDNA sequence found is 2,806 bp in length and encodes a mature protein of 528 aa, with a predicted molecular mass of M(r) 55,600. The S4D-SRCRB gene is located at Chromosome 7q11.23, telomeric to the Williams-Beuren syndrome deletion. It extends over 20 kb and consists of 11 exons, with each SRCR domain being encoded by a single exon. Northern blot analysis indicated that S4D-SRCRB has a broad tissue distribution and is expressed as two major mRNA species: one of 2.8 kb, with a restricted tissue expression pattern (mainly kidney and placenta), and another of 1.5 kb, with a broader distribution. A similar mRNA expression pattern was observed during the analysis of several tumor cell lines. The highest degree of similarity found between S4D-SRCRB and other group B SRCR-SF members was with human DMBT1 (a mosaic protein composed of fourteen SRCR domains, which is involved in innate defense and epithelia polarization) and chicken 18-B (a turpentine-induced soluble acute-phase protein composed of four SRCR domains). Our data indicate that S4D-SRCRB constitutes a novel SRCR-SF member, which could be involved in basic homeostatic functions such as innate host defense.

Alternative Splicing↗

A novel serine-rich motif in the intercellular adhesion molecule 3 is critical for its ezrin/radixin/moesin-directed subcellular targeting.

Intercellular adhesion molecule 3 (ICAM-3) is a leukocyte-specific receptor involved in primary immune responses. We have investigated the interaction between ICAM-3 and ezrin/radixin/moesin (ERM) proteins and its role in LFA-1-induced cell-cell interactions and membrane positioning of ICAM-3 in polarized migrating lymphocytes. Protein-protein binding assays demonstrated a phosphatidylinositol 4,5-bisphosphate-induced association between ICAM-3 and the amino-terminal domain of ERM proteins. This interaction was not essential for the binding of ICAM-3 to LFA-1. Dynamic fluorescence videomicroscopy studies of cells demonstrated that moesin and ICAM-3 coordinately redistribute on the plasma membrane during lymphocyte migration. Furthermore, overexpression of the amino-terminal domain of moesin, which lacks the consensus moesin actin-binding site, caused the subcellular mislocalization of ICAM-3. A CD4 chimerical protein containing the cytoplasmic tail of ICAM-3 was targeted to the trailing edge. Point mutation of Ser(487), Ser(489), and Ser(496) to alanine in the juxtamembrane region of ICAM-3 significantly impaired both ERM binding and polarization of ICAM-3. ERM-directed polarization of ICAM-3 was also impaired by phosphorylation-like mutation of Ser(487) and Ser(489), but not of Ser(496). Our results underscore the key role of specific serine residues within the cytoplasmic region of ICAM-3 for its ERM-directed positioning at the trailing edge of motile lymphocytes.

Alanine↗

Fine-needle aspiration biopsy of the retroperitoneum: a series of 111 cases not including specific organs.

We report on our experience in fine-needle aspiration (FNA) biopsy of the retroperitoneum: 111 FNA biopsies performed on 99 patients. Cytologic diagnoses were divided into four groups: nondiagnostic (unsatisfactory samples because of a low cellularity and/or improperly prepared smears) aspirates (20%), benign (16%), suspicious for malignancy (13%), and malignant (50%). There were no known false-positive samples. We had two false-negative diagnoses due to sampling errors. Among diagnostic smears, the procedure showed a sensitivity of 97% and a specificity of 100%. The predictive value of a positive result was 100% and the predictive value of a negative result was 90%. The overall accuracy was 98%. Metastatic carcinomas accounted for the largest number of lesions in the group of malignant tumors. A primary tumor site was known for the majority of the cases before the aspiration was performed. In the remaining cases we were unable to suggest an origin. It is therefore important to emphasize the role of ancillary studies in patients that are at the first assessment of the disease or when a second intercurrent malignancy is suspected. In our limited experience, a suggestion of the correct subtype of retroperitoneal sarcoma was not possible. As in the rest of cytopathology, a multidisciplinary approach is mandatory in this setting to improve patient management.

Adult↗