Numerical simulation of experimental tests performed on ZAO® non-evaporable-getter pump designed for neutral beam injector applications.

Vacuum systems of neutral beam injectors have very demanding requirements in terms of pumping speed, throughput, and capacity. Due to their high affinity to hydrogenic species, porous sintered Non-Evaporable Getters (NEG) are a possible candidate for deployment in giant hydrogen ion sources and neutral beam injectors for fusion. This paper presents the numerical interpretation of experimental tests on a recently developed NEG cartridge, that is part of a modular pump under development for neutral beam injectors. The cartridge is composed of six stacks of ZAO® porous sintered NEG disks and a heater. It was tested under hydrogen loads relevant for neutral beam injectors, namely, at constant pressure or constant flow, such that the hydrogen pressure was in the range of 20 mPa-40 mPa. The result of the sorption test was reproduced by a three dimensional flow simulation in molecular regime to determine the actual pumping speed, the effective sticking coefficient, and the uniformity of the gas load on the various NEG disks. The procedure developed and the results obtained provide the basic understanding for interpreting the large-scale tests on the modular pump, consisting of 34 of these cartridges.

Comparing the performance of three panels rules of blood smear review criteria on an Italian multicenter evaluation.

BACKGROUND: The aims of this study were to compare the diagnostic accuracy of blood smear review criteria, by means of three different panel rules, those proposed by: the International Consensus Group for Hematology [41-ICGH rules], the Italian Survey [IS rules] and the Working Group on Hematology-SIBioC (WGH) consensus rules (WGH rules). METHODS: This study is based on 2707 peripheral blood (PB) samples referred for routine hematological testing to the WGH-associated laboratories displaced all over the Italian territory. The PB samples were processed on seven different hematology analyzers (HAs): Advia 2120i, XE-2100, BC-6800, ABX Pentra, XN-1000, Cell-DYN Sapphire, and DxH800, respectively. All the results provided by the HAs were analyzed through the application of three different blood smear review criteria: that is, the 41-ICGH, IS, and WGH rules. Finally, data were compared with those obtained by optical microscopy (OM), as the current gold standard. RESULTS: The overall the agreement OM classification with ICGH, IS, and WGH panel rules is 0.83, 0.83, and 0.85, respectively. The false negatives are 2.1%, 3.0%, and 2.9%, while false positives are 15.1%, 13.7%, and 11.7%, respectively. All the seven HAs showed variable interinstrument performance, as three different criteria for OM review were adopted on each of them from time to time. CONCLUSION: These results presented show that the customization of validation rules is necessary for enhancing the quality of hematological testing and optimizing workflow.

Life span history of non-fatal suicidal behaviours in a large sample of general practitioners' patients: data from Rovigo, Northern Italy.

A survey about history of non-fatal suicidal behaviour was performed on 1,171 subjects in the waiting room of general practitioners' practices in the territory of Rovigo (Northern Italy). The mean age of interviewed subjects was 52.9 ± 17.0, with a majority of female individuals. Two and two percent admitted previous experience of non-suicidal self-injury, 4.7 % admitted having had serious suicidal thoughts/plans, and 1.8 % reported at least one suicide attempt. Compared to the rest of the sample, people with history of suicidal behaviours resulted to be of younger age (p < .05), whilst their level of well-being was poorer (p < .001). When compared to the results of the Italian arm of the European Study of the Epidemiology of Mental Disorders, carried out on general population samples, the present study produces higher rates of suicidality, despite the much higher mean age of the interviewed subjects compared to the general population.

Molecular characterization of a mariner-like element in the Atta sexdens rubropilosa genome.

Mobile elements are widely present in eukaryotic genomes. They are repeated DNA segments that are able to move from one locus to another within the genome. They are divided into two main categories, depending on their mechanism of transposition, involving RNA (class I) or DNA (class II) molecules. The mariner-like elements are class II transposons. They encode their own transposase, which is necessary and sufficient for transposition in the absence of host factors. They are flanked by a short inverted terminal repeat and a TA dinucleotide target site, which is duplicated upon insertion. The transposase consists of two domains, an N-terminal inverted terminal repeat binding domain and a C-terminal catalytic domain. We identified a transposable element with molecular characteristics of a mariner-like element in Atta sexdens rubropilosa genome. Identification started from a PCR with degenerate primers and queen genomic DNA templates, with which it was possible to amplify a fragment with mariner transposable-element homology. Phylogenetic analysis demonstrated that this element belongs to the mauritiana subfamily of mariner-like elements and it was named Asmar1. We found that Asmar1 is homologous to a transposon described from another ant, Messor bouvieri. The predicted transposase sequence demonstrated that Asmar1 has a truncated transposase ORF. This study is part of a molecular characterization of mobile elements in the Atta spp genome. Our finding of mariner-like elements in all castes of this ant could be useful to help understand the dynamics of mariner-like element distribution in the Hymenoptera.

Normal and defective mariner-like elements in Rhynchosciara species (Sciaridae, Diptera).

Mariner-like elements are widely present in diverse organisms. These elements constitute a large fraction of the eukaryotic genome; they transpose by a "cut-and-paste" mechanism with their own transposase protein. We found two groups of mobile elements in the genus Rhynchosciara. PCR using primers designed from R. americana transposons (Ramar1 and Ramar2) were the starting point for this comparative study. Genomic DNA templates of four species: R. hollaenderi, R. millerii, R. baschanti, and Rhynchosciara sp were used and genomic sequences were amplified, sequenced and the molecular structures of the elements characterized as being putative mariner-like elements. The first group included the putative full-length elements. The second group was composed of defective mariner elements that contain a deletion overlapping most of the internal region of the transposase open reading frame. They were named Rmar1 (type 1) and Rmar2 (type 2), respectively. Many conserved amino acid blocks were identified, as well as a specific D,D(34)D signature motif that was defective in some elements. Based on predicted transposase sequences, these elements encode truncated proteins and are phylogenetically very close to mariner-like elements of the mauritiana subfamily. The inverted terminal repeat sequences that flanked the mariner-like elements are responsible for their mobility. These inverted terminal repeat sequences were identified by inverse PCR.

Analysis of expressed sequence tags from Rhynchosciara americana salivary glands.

The diptera Rhynchosciara americana (sciaridae) is an important model organism in polyteny and gene amplification research, but up to now a limited amount of data regarding DNA sequences and molecular aspects of this species is available. Considering the importance of going further on the DNA puffs biological meaning, we proposed to generate EST sequences from a DNA library constructed from salivary glands. After their categorization in gene ontology terms, they were used to construct an 'electronic Northern' that represents a general view of the salivary gland metabolic status in an important phase of larval development: the spinning of communal cocoon. In this phase occurs the last polytene DNA replication cycle concomitantly with the specific loci amplification related to protein secretion.

Cluster-beam deposition and in situ characterization of carbyne-rich carbon films.

Nanostructured carbon films produced by supersonic cluster beam deposition have been studied by in situ Raman spectroscopy. Raman spectra show the formation of a sp2 solid with a very large fraction of sp-coordinated carbyne species with a long-term stability under ultrahigh vacuum. Distinct Raman contributions from polyyne and cumulene species have been observed, as well as different stabilities under gas exposure. Our experiments confirm theoretical predictions and demonstrate the possibility of producing a carbyne-rich pure carbon solid. The stability of the sp2-sp network has important implications for astrophysics and for the production of novel carbon-based systems.

External Quality Assessment of stat test intralaboratory turnaround times. Pilot study from the Members of the Working Group for the Standardization and Promotion of Turnaround Time Control under the Auspices of the Comitato Italiano per la Standardizzazione dei Metodi Ematologici e di Laboratorio.

We describe procedures, results and prospects of a pilot program in External Quality Assessment (EQA) of the stat test intralaboratory turnaround times. Our goals are to promote quality by systematic monitoring and comparison of performances by laboratories, continuous investigation into the state of the art of the processes from receipt of sample to transmission of results and creation of a data base for standardization of measures and definition of consensus values for turnaround time. Of 30 laboratories invited to participate, 25 took part, agreeing to record times of arrival and transmission for all determinations of three analytes (blood hemoglobin, serum/plasma potassium and plasma prothrombin time) for seven consecutive days and to continue for one or more further periods of seven days as necessary if there were less than 300 determinations for each analyte. Within a preset time limit, data were sent by e-mail on an Excel file and we sent back two reports per analyte, showing: i) the graph for time vs. percentage of tests completed and several measures of turnaround time; ii) results of all laboratories in graph form, allowing each laboratory to identify only its own data. The high proportion of participating laboratories among those invited (83%) encourages us to implement the EQA program systematically, on a half-yearly basis, extending it to all laboratories wishing to participate in Italy or elsewhere in Europe.

Soluble forms of p55-IL-2R alpha, CD8, and CD30 molecules as markers of lymphoid cell activation in infectious mononucleosis.

BACKGROUND: Epstein-Barr virus (EBV) infection in infectious mononucleosis (IM) is associated with lymphocyte activation leading to the expansion of cells expressing activation-associated antigens. Most of these antigens are released as soluble molecules in vitro and in vivo. METHODS: We investigated the serum levels of the soluble forms of the CD8 (sCD8), p55-IL-2R alpha (sIL-2R alpha), and CD30 (sCD30) molecules in 55 patients following primary EBV infection. These data were compared with the phenotypic pattern of circulating lymphoid subsets. RESULTS: In all cases at presentation, lymphocytosis, mainly characterized by the expansion of a CD8+, HLA-DR+, p75-IL-2R beta+, p55-IL-2R alpha- population, was associated with high levels of the investigated soluble molecules. Their mean values (+/- SD) were: 17,172 +/- 12,885 U/mL for sCD8 (vs 334 +/- 95 in controls), 2,922 +/- 2,813 U/mL for sIL-2R alpha (vs 331 +/- 115 in controls), and 477 +/- 451 U/mL for sCD30 (vs 4.9 +/- 6.4 in controls). Follow-up study (15 cases, up to 60 days) showed a progressive decline of all soluble molecules, associated with a reduction of activated CD8+/HLA-DR+/p75-IL-2R beta+ T-cells. By the 30th day, values of sIL-2R alpha and sCD30 (729 +/- 333 U/mL and 20 +/- 21 U/mL, respectively) were only slightly higher than in normal controls, whereas sCD8 levels remained consistently higher (1,777 +/- 1,385 U/mL, p < .001). CONCLUSIONS: sCD8, sIL-2Ra and sCD30 serum levels in IM reflect the total bulk and/or the activation-related events of infected and reactive cells. The variations in these soluble molecules during the follow-up provide useful information on the in vivo biological modifications occurring after EBV infection.

Serum levels of tumour necrosis factor-alpha in patients with B-cell chronic lymphocytic leukaemia.

Serum levels of tumour necrosis factor-alpha (TNF-alpha) have been evaluated in the peripheral blood of 91 patients with B-cell chronic lymphocytic leukaemia (B-CLL), and have been correlated with the clinical stage (according to Rai's staging system) and relevant haematological and immunological data. Increased values were detected, compared to 36 normal age-matched controls (36 pg/ml +/- 5 versus 0.11 pg/ml +/- 0.08; P < 0.05). An increase of TNF-alpha serum levels was observed in all stages including stage 0, with a progressive increase in relation to the stage of the disease. A significant relationship between serum TNF-alpha levels and the number of circulating monocytes (P < 0.002) and an inverse correlation with the level of the haemoglobin (P < 0.001) was established, as defined by the Pearson's correlation test. In contrast, no correlation was observed between TNF-alpha serum levels and the other parameters taken into account, including the white blood cell and platelet counts, the absolute number of peripheral blood (PB) lymphocytes, CD5+ B lymphocytes, CD57+ lymphocytes, serum levels of lactic dehydrogenase, total serum immunoglobulins and the serum levels of IgG, IgA and IgM. These data suggest that, in addition to the B-CLL neoplastic cells, the PB monocytes may be involved in the release of TNF-alpha.

CD8 alveolitis in sarcoidosis: incidence, phenotypic characteristics, and clinical features.

PURPOSE: Although the accumulation of CD4 cells in the lung and other involved tissues is regarded as the distinctive immunologic feature of sarcoidosis, a few sarcoid patients can present with CD8 alveolitis. This study evaluates the incidence as well as the clinical and immunologic features of sarcoidosis presenting with CD8 alveolitis. PATIENTS AND METHODS: A total of 2,214 consecutive bronchoalveolar lavage (BAL) specimens obtained from 481 patients with sarcoidosis between January 1985 and December 1991 were retrospectively analyzed. Subjects who entered the study had the following characteristics: (1) lymphocyte alveolitis and (2) lung CD4/CD8 ratio less than 1.0. Only data obtained from patients with a first episode of pulmonary involvement were included in the analysis (394 patients). RESULTS: Fifteen of the 394 patients studied at the time of diagnosis showed CD8 alveolitis as the presenting manifestation; the incidence of this phenomenon was 3.8%. A follow-up study of BAL T-cell subsets demonstrated that patients who showed high-intensity CD8 alveolitis at the onset of the disease maintained the CD8 pattern of alveolitis during relapses. Phenotypic analysis of lung T cells revealed that the accumulation of CD8 lymphocytes was due to the discrete local increase of CD45RO+ "memory" cells equipped with a number of accessory structures, including adhesion molecules and class II major histocompatibility complex-related HLA-DR antigen. CONCLUSIONS: The accumulation of CD8 cells in the sarcoid lung is likely to reflect a homing of memory cells due to the ongoing immunologic response against the unknown antigen causing the disease. Although CD8 alveolitis can be considered a relatively rare event in sarcoidosis, the possibility that an increase of CD8 cells in the BAL fluid might be sustained by an underlying sarcoid inflammatory process should never be dismissed on clinical grounds in patients with interstitial lung disease.

Persistent polyclonal lymphocytosis in human immunodeficiency virus-1-infected patients.

In this study we describe the clinical, morphologic, immunologic, and genetic features of a chronic peripheral blood lymphocytosis associated with posttraumatic splenectomy in patients with human immunodeficiency virus-1 (HIV-1) infection. Among a series of 2,365 consecutive HIV-1 seropositive cases investigated, eight patients were selected for the presence of more than 4,000 lymphocytes/mm3. All cases were characterized by a lymphocytosis with cytoplasmic azurophilic granules; in three patients the hematologic picture was superimposable with that of lymphoproliferative disease of granular lymphocytes. Phenotypic analysis of lymphocytes showed a prevalent CD3+CD8+ pattern. In vitro evaluations, including the response to mitogens and interleukin-2 and the cytotoxic assays, showed an unimpaired lymphocyte function in the majority of our patients, even in those with advanced stages of the syndrome. The analysis of the configuration of the T-cell receptor (TCR) beta and gamma genes showed a polyclonal pattern of rearrangement. At the mean follow-up time of 45 +/- 8 months, one patient died of overdose when the clinical conditions were stable; all the other patients are alive, although disease progression was documented in two. Our results indicate that a chronic polyclonal lymphocytosis may be associated with HIV-1 infection; this finding seems to be restricted to patients who have undergone splenectomy. The demonstration of a still uncompromised immune system together with a silent clinical course in the patients under study also suggest that splenectomy per se does not favor an aggressive clinical behavior of HIV-1 infection.

Expression and functional role of tumor necrosis factor receptors on leukemic cells from patients with type B chronic lymphoproliferative disorders.

Two receptors for tumor necrosis factor (TNF) with different molecular weight (75-Kd and 55-Kd) and binding affinity have been recently discovered. To investigate the distribution and the functional role of these receptors on leukemic B cells from hairy cell leukemia (HCL) and B-cell chronic lymphocytic leukemia (B-CLL) patients, we evaluated: (1) the cytofluorimetric pattern of uncultured and cultured leukemic B cells incubated with utr-1 and htr-9 monoclonal antibodies (MoAbs), which specifically recognize the 75-Kd and 55-Kd TNF receptors (TNFR), respectively; (2) the effect of TNF-alpha and TNF-beta on leukemic B cells in an in vitro proliferation assay; (3) the role of anti-TNFR MoAbs on TNF-alpha and TNF-beta-driven B-cell growth; and (4) the proliferative effect of utr-1 and htr-9 MoAbs on in vitro cultured leukemic cells. Our study shows that the high affinity (75-Kd) but not the low affinity (55-Kd) TNFR molecules are expressed on freshly isolated leukemic B cells recovered from HCL and B-CLL patients. The expression of these receptors was neither upregulated nor downregulated by different stimuli, including TNF-alpha, TNF-beta, B-cell growth factor, and interleukin-2. TNF-alpha efficiently triggers the proliferation of HC and, to a lesser extent, the growth of B-CLL cells. TNF-beta was also able to transduce the proliferative signal in HCL, but not in B-CLL patients. TNF-alpha- and TNF-beta-driven B-cell proliferation was inhibited by the preincubation of leukemic B cells with utr-1 but not htr-9 MoAb. Moreover, anti-75-Kd, but not anti-55-Kd TNFR MoAb, was able to trigger the proliferation of leukemic B cells, and in particular of HC. These results show that leukemic B cells from patients with HCL and B-CLL are equipped with a fully functional high affinity TNFR.

Different mechanisms of activation of proliferating CD3+ cells in patients with lymphoproliferative disease of granular lymphocytes.

To investigate the role of p55 and p75 chains of interleukin-2 receptor (IL-2R) on the activation of granular lymphocytes (GL) in patients with lymphoproliferative disease of granular lymphocytes (LDGL), the cells obtained from 11 LDGL patients (belonging to the CD3+ group) were studied for (a) the surface expression and (b) mRNA transcripts of the p55 and p75 IL-2R after activation with anti-CD3 monoclonal antibody (mAb) or interleukin-2 (IL-2). The effects of mAbs specifically blocking the p55 and p75 IL-2R on the generation of proliferative and cytotoxic functions were studied following anti-CD3 mAb stimulation. A significant difference was observed in the expression of p55 and p75 antigens on LDGL cells under resting conditions: a low number of p55 IL-2R+ (mean 1.2 +/- 0.4%) and high values of p75 IL-2R+ cells (54.9 +/- 7.4%). Accordingly, a barely detectable message for the p55 IL-2R and a strong signal for the p75 IL-2R mRNA were demonstrated. Following activation with anti-CD3 or IL-2, different patterns of IL-2R expression were observed. Anti-CD3 mAb induced an increase in the expression of the p55 IL-2R both at the mRNA and antigen level, whereas the p75 values remained consistently raised. In contrast, IL-2 induced the expression of p55 IL-2R mRNA associated with only a slight expression of this antigen. This finding was associated with a decrease in the cell expression of the p75 IL-2R, whereas the amount of p75 mRNA was unchanged. Both anti-CD3 mAb and IL-2 induced cell proliferation and cytotoxicity against the K-562 target cells. Anti-p55 IL-2R mAb did not affect the cytotoxic activity mediated by anti-CD3, but it markedly inhibited cell proliferation. Anti-p75 mAb did not inhibit either lytic function or cell proliferation mediated by anti-CD3 mAb, suggesting that only the high affinity IL-2R (p55 plus p75) is involved in anti-CD3 mediated cell activation in LDGL patients. This mechanism is different from that responsible for the IL-2 activation of CD3+ GL in LDGL patients, which is achieved through the p75 IL-2R alone. These results provide new insights into the pathophysiology of proliferating GL in LDGL patients and may also contribute to further characterization of the normal CD3+ GL population.

Shedding of the soluble form of the CD8 complex by CD8+/HLA-DR+ cells in HIV-1-infected patients.

High levels of the soluble form of the CD8 molecule (sCD8) are detectable in the serum of HIV-1-infected patients. To investigate the mechanisms accountable for the release of this molecule we evaluated the presence of sCD8 in the supernatants obtained from in vitro cultures of highly purified CD8 cells isolated from 20 HIV-1-infected patients. At resting conditions cultured CD8 cells from HIV-1-infected patients released low amounts of sCD8; no statistically significant differences were observed between unstimulated cultures from HIV-1-seropositive patients and from HIV-1-seronegative subjects at risk for HIV-1 infection or normal healthy controls. Following in vitro activation of highly purified CD8 cells with a series of stimulatory agents, including phorbol myristate acetate, phytohemagglutinin (PHA) and recombinant interleukin-2, CD8 cells of HIV-1-infected patients significantly increased the shedding of sCD8. By expressing the results of activation-related release index (ARRI = sCD8 levels detected in the cultures with stimulatory agent/sCD8 levels detected in the unstimulated cultures), significantly higher values were observed upon PHA stimulation in HIV-1-infected patients than in control subjects. In order to identify the cell subset responsible for the enhanced release of sCD8 by PHA-stimulated cultures, we correlated the amounts of sCD8 detected in the supernatants with the phenotypic profile of CD8+ cells recovered from the cultures. A significant relationship was demonstrated between the percentage of CD8+/HLA-DR+ lymphocytes and sCD8 levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytotoxic events taking place in the lung of patients with HIV-1 infection. Evidence of an intrinsic defect of the major histocompatibility complex-unrestricted killing partially restored by the incubation with rIL-2.

To characterize the cytotoxic events taking place in the lung of patients with HIV-1 infection, we studied the cells recovered from the bronchoalveolar lavage (BAL) of nine patients with AIDS, seven patients with AIDS-related complex, and two patients with lymphadenopathy. Phenotypic analysis was coupled to a series of functional evaluations of nonspecific cytotoxic abilities performed on lung effectors, including their property to bind K-562 targets, to release natural killer cytotoxic factor (NKCF), and to become cytotoxic following in vitro activation with rIL-2. Our results demonstrated that lung cells bearing the NK-related CD16, CD56, and CD57 antigens were quantitatively increased, irrespective of the disease stage. The majority of the cells also coexpressed the CD3 molecule and the alpha/beta T cell receptor (TCR), notably the phenotype characterizing MHC-unrestricted cytotoxic T cells. From a functional point of view, a severe impairment of the spontaneous cytotoxic ability was demonstrated in most patients. Evaluation at the single cell level showed a normal percentage of the effector/target conjugates formed by HIV-1 lymphocytes. The release of NKCF was undetectable in patients with AIDS even following lectin stimulation, whereas BAL cells from patients with earlier infection produced and/or could be triggered to release discrete amounts of NKCF by incubation with PHA. Studies designed to activate lung cytotoxic cells with rIL-2 showed that in most patients the stimulation of effector cells with rIL-2 enhanced the spontaneous killing and elicited a lymphokine-activated killer (LAK) phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum levels of soluble CD8 are increased in patients with B chronic lymphocytic leukemia.

Serum levels of the soluble form of the CD8 (s-CD8) antigen were evaluated in the peripheral blood of 44 patients with B-CLL, using an enzyme-linked immunosorbent assay, and were correlated with clinical features and relevant hematological and immunological data. Increased values were observed with respect to normal age-matched controls (mean +/- S.E.M. 603 U/ml +/- 81 vs. 315 U/ml +/- 31, respectively; P less than 0.0001). This increase was observed in all stages of the disease, excluding stage 0 (mean 277 U/ml +/- 45). A general trend pointing to lower values overall in patients with less invasive disease was observed. In fact, the rank correlation test showed that the serum levels of s-CD8 correlate significantly with the WBC counts, the CD4/CD8 ratio, and also with the levels of serum immunoglobulins. On the contrary, no correlation was observed between s-CD8 levels and the absolute number of circulating CD8+ cells in individual cases. Therefore, the increase of s-CD8 is unlikely to be a mere expression of the increase of the CD8 cell number, but seems related to an increase of the activation phenomena involving the CD8+ T cell subset.

Lymphoproliferative disease of granular lymphocytes in a patient with concomitant hepatitis B virus infection of CD4 lymphocytes.

In this report we studied a 35-year-old male who developed an abnormal expansion of granular lymphocytes (GL) which spontaneously regressed over a period of 2 years. The immunological and molecular characterizations of expanded cells showed the CD3+,CD8+,HNK-1+ phenotype, a polyclonal organization of the T-cell receptor beta-chain gene and normal natural killer activity. At the time of presentation, spot and blot hybridization techniques revealed the presence of viral hepatitis B virus (HBV) DNA sequences only in highly enriched CD4+ T cells, while proliferating GL were negative. With this as a background, we addressed the question of whether in our case the polyclonal GL proliferation represented an immunoreactive response against CD4+ infected cells. In particular, we tested the possibility that expanded GL could be cytotoxic against autologous infected CD4+ cells. At the time of the first determination, when several of the CD4+ cells harbored HBV, GL showed a minimal degree of cytotoxicity against 51Cr-labeled CD4+ cells; 2 years later, when GL became capable of lysing these targets, the appearance of the specific cytotoxicity was concomitant with the disappearance of the HBV-infected CD4+ cells and with the recovery of granular lymphocytosis. Taken together, our data suggest that in this case GL proliferation could represent an immunoreactive process against CD4+ cells.

Increased levels of soluble CD8 molecule in the serum of patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related disorders.

In this study we investigated the serological levels of the soluble form of the CD8 molecule (s-CD8) in 97 human immunodeficiency virus (HIV) seropositive patients. The control groups included 20 normal heterosexual subjects and 19 healthy seronegative subjects belonging to risk groups for AIDS. Our results show that patients with HIV infection have significantly higher levels of s-CD8 U/ml than the control groups. When the patients were further subdivided according to the Centers for Disease Control (CDC) classification, s-CD8 U/ml values were consistently increased in all HIV patients, irrespective of the CDC stages. No statistically significant correlation was found between the serological levels of s-CD8/ml and the absolute numbers of CD8 lymphocytes/mm3, in both HIV seropositive patients and control groups. Since in the more advanced stages of HIV infection (IV-A, IV-C1) the decrease in the absolute number of CD8+ cells was not followed by a decrease in s-CD8 levels, it is conceivable that an increased release and/or shedding of s-CD8 per cell might occur in these patients. In fact, when the results were expressed as s-CD8 units per CD8 positive cell (s-CD8/absolute number of CD8), the levels of s-CD8/cell were higher in patients belonging to the IV-A and IV-C1 CDC groups (1.94 U/cell +/- 0.33 and 3.39 U/cell +/- 0.5, respectively) compared to normal controls (P less than 0.001), HIV seronegative subjects at risk for AIDS (P less than 0.001), and the other patients' groups (II and III CDC groups, respectively, P less than 0.001 and P less than 0.001). The evidence herein provided that in patients with HIV infection s-CD8 levels are increased suggests a possible pathogenetic role of the cells involved in the release of this molecule.