Shrimp Allergy: Analysis of Commercially Available Extracts for In Vivo Diagnosis.

BACKGROUND AND OBJECTIVE: Skin prick testing (SPT) with commercial extracts is the first step in the diagnosis of shrimp allergy, although its clinical efficiency is unknown. Objective: To analyze the clinical usefulness of all commercial crustacean extracts available for SPT in Italy. METHODS: We performed a multicenter study of 157 shrimp-allergic patients who underwent SPT with 5 commercial crustacean extracts and with house dust mite (HDM) extract. Commercial extracts were analyzed using SDS-PAGE and compared with a freshly prepared in-house shrimp extract. IgE to Pen a 1/Pen m 1, Pen m 2, and Pen m 4 was determined, and immunoblot analysis was performed on a large number of sera. RESULTS: The skin reactions caused by commercial crustacean extracts were extremely heterogeneous, resulting in 32 clinical profiles, with marked differences in protein content and missing proteins at molecular weights corresponding to those of major shrimp allergens. Only strong Pen a 1/Pen m 1 reactors reacted to both HDM and all 5 commercial extracts in SPT. Most patients, including those who were tropomyosin-negative, reacted to HDM. Patients reacted to a large and variable array of proteins, and IgE reactivity was common at high molecular weights (>50 kDa). CONCLUSIONS: The in vivo diagnosis of shrimp allergy must continue to be based on SPT with fresh material. Shrimp-allergic patients frequently react to a number of ill-defined high-molecular-weight allergens, thus leaving currently available materials for component-resolved diagnosis largely insufficient. Mites and crustaceans probably share several allergens other than tropomyosin.

Acute kidney injury during colistin therapy: a prospective study in patients with extensively-drug resistant Acinetobacter baumannii infections.

The study aimed to prospectively assess incidence and risk factors for colistin-associated nephrotoxicity. This is a secondary analysis of a multicentre, randomized clinical trial, comparing efficacy and safety of colistin versus the combination of colistin plus rifampicin in severe infections due to extensively drug-resistant (XDR) Acinetobacter baumannii. The primary end point was acute kidney injury (AKI) during colistin treatment, assessed using the AKI Network Criteria, and considering death as a competing risk. A total of 166 adult patients without baseline kidney disease on renal replacement therapy were studied. All had life-threatening infections due to colistin-susceptible XDR A. baumannii. Patients received colistin intravenously at the same initial dose (2 million international units (MIU) every 8 h) with predefined dose adjustments according to the actual renal function. Serum creatinine was measured at baseline and at days 4, 7, 11, 14 and 21 (or last day of therapy when discontinued earlier). Outcomes assessed were 'time to any kidney injury' (AKI stages 1-3) and 'time to severe kidney injury' (considering only AKI stages 2-3 as events). When evaluating overall mortality, AKI occurrence was modelled as a time-dependent variable. AKI was observed in 84 patients (50.6%, stage 1 in 40.4%), with an incidence rate of 5/100 person-days (95% CI 4-6.2). Risk estimates of AKI at 7 and 14 days were 30.6% and 58.8%. Age and previous chronic kidney disease were significantly associated with any AKI in multivariable analysis. Neither 'any' nor 'severe AKI' were associated with on-treatment mortality (p 0.32 and p 0.54, respectively). AKI occurs in one-third to one-half of colistin-treated patients and is more likely in elderly patients and in patients with kidney disease. As no impact of colistin-associated AKI on mortality was found, this adverse event should not represent a reason for withholding colistin therapy, whenever indicated.

Alternative normalization methods demonstrate widespread cortical hypometabolism in untreated de novo Parkinson's disease.

AIM: Previous positron emission tomography (PET) [18F]fluorodeoxyglucose ([18F]FDG) studies in Parkinson's disease (PD) demonstrated that moderate to late stage patients display widespread cortical hypometabolism, whereas early stage PD patients exhibit little or no cortical changes. However, recent studies suggested that conventional data normalization procedures may not always be valid, and demonstrated that alternative normalization strategies better allow detection of low magnitude changes. We hypothesized that these alternative normalization procedures would disclose more widespread metabolic alterations in de novo PD. METHODS: [18F]FDG PET scans of 26 untreated de novo PD patients (Hoehn & Yahr stage I-II) and 21 age-matched controls were compared using voxel-based analysis. Normalization was performed using gray matter (GM), white matter (WM) reference regions and Yakushev normalization. RESULTS: Compared to GM normalization, WM and Yakushev normalization procedures disclosed much larger cortical regions of relative hypometabolism in the PD group with extensive involvement of frontal and parieto-temporal-occipital cortices, and several subcortical structures. Furthermore, in the WM and Yakushev normalized analyses, stage II patients displayed more prominent cortical hypometabolism than did stage I patients. CONCLUSION: The use of alternative normalization procedures, other than GM, suggests that much more extensive cortical hypometabolism is present in untreated de novo PD patients than hitherto reported. The finding may have implications for our understanding of the basic pathophysiology of early-stage PD.

Giant dilatations of virchow-robin spaces in the midbrain. MRI aspects and review of the literature.

Virchow-Robin spaces are lesions often seen in the brain parenchyma but their etiopathogenesis remains unsettled. Giant Virchow-Robin spaces placed in the midbrain are extremely rare. We describe three patients with a diagnosis of giant Virchow-Robin spaces in the midbrain, and their clinical and radiologic findings. We reviewed the literature in terms of the etiopathology, anatomic and radiologic appearance and differential diagnosis of the giant Virchow-Robin spaces. The diagno-stic role of the high Tesla magnetic resonance devices and new sequences techniques such as three dimensional isotropic acquisition and diffusion tensor imaging were also evaluated in this case series.

Hippocampal asymmetry with hippocampal sulcus remnants in a patient with mild cognitive impairment. A case report.

A 65-year-old woman underwent MRI for a mild cognitive impairment (MCI) at Mini-Mental State Examination (MMSE). MRI showed hippocampal sulcus remnants bilaterally, although they were larger on the right, and left hippocampal atrophy with increased left fimbriosubicular distance (right side: 1.2 mm; left side: 2.0 mm). The meaning of these findings in relation to clinical aspects is discussed and reviewed according to data from the literature.

Peripheral nervous system involvement in Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a rare congenital malformation of unknown etiology characterized by cutaneous hemangiomas, venous varicosities and bony and soft tissues hypertrophy usually affecting one limb. Several complex anomalies involving various organs and systems have been described, whereas involvement of the peripheral nervous system has rarely been reported in KTS. We describe the case of a 67-year-old woman with KTS and peripheral neuropathy related to the presence of epineurial microscopic arteriovenous anastomoses (AVA) and endoneurial vascular coils in sural nerve biopsy from both hypertrophic and non-hypertrophic limb. The maintenance of AVA has been proposed to be the cause of the hypertrophy. The observation in our patient of AVA in non-hypertrophic limb contrasts with this hypothesis.

Metabolic interaction between ApoE genotype and onset age in Alzheimer's disease: implications for brain reserve.

BACKGROUND: Clinically apparent Alzheimer's disease (AD) is thought to result when brain tissue damage exceeds a critical threshold of "brain reserve", a process possibly accelerated by the apolipoprotein E (ApoE) E4 allele. The interaction between onset age and ApoE genotype was investigated to assess whether early disease onset (<65 years) in patients carrying the E4 allele is associated with greater cerebral metabolic (regional cerebral metabolic rate of glucose utilisation, rCMRgl) reduction. METHODS: AD patients, divided into early (EOAD; 27 patients) and late onset (LOAD; 65 patients) groups, both groups balanced as to the number of E4 carriers (E4+) and non-carriers (E4-), and matched controls (NC; 35 cases) underwent (18)F-FDG PET ([(18)F]fluorodeoxyglucose positron emission tomography) scanning. SPM'99 software was used to compare AD patients to NC and to perform a two way ANOVA with onset age and ApoE genotype as grouping factors. Results were considered significant at p<0.001, uncorrected. RESULTS: AD patients demonstrated rCMRgl reductions compared to NC, with rCMRgl lower in association cortex and relatively higher in limbic areas in EOAD compared to LOAD subjects. rCMRgl was lower in the anterior cingulate and frontal cortex for E4+ compared to E4- subjects. A significant onset age by ApoE interaction was detected in the hippocampi and basal frontal cortex, with EOAD E4+ subjects having the greatest rCMRgl reduction. CONCLUSIONS: The interactive effects of early onset age, possibly reflecting lower brain reserve, and ApoE E4 allele, possibly leading to greater tissue damage, lead to reduced tolerance to the pathophysiological effects of AD in key brain regions.

MCI conversion to dementia and the APOE genotype: a prediction study with FDG-PET.

OBJECTIVES: To investigate whether the combination of fluoro-2-deoxy-d-glucose (FDG) PET measures with the APOE genotype would improve prediction of the conversion from mild cognitive impairment (MCI) to Alzheimer disease (AD). METHOD: After 1 year, 8 of 37 patients with MCI converted to AD (22%). Differences in baseline regional glucose metabolic rate (rCMRglc) across groups were assessed on a voxel-based basis using a two-factor analysis of variance with outcome (converters [n = 8] vs nonconverters [n = 29]) and APOE genotype (E4 carriers [E4+] [n = 16] vs noncarriers [E4-] [n = 21]) as grouping factors. Results were considered significant at p < 0.05, corrected for multiple comparisons. RESULTS: All converters showed reduced rCMRglc in the inferior parietal cortex (IPC) as compared with the nonconverters. Hypometabolism in AD-typical regions, that is, temporoparietal and posterior cingulate cortex, was found for the E4+ as compared with the E4- patients, with the E4+/converters (n = 5) having additional rCMRglc reductions within frontal areas, such as the anterior cingulate (ACC) and inferior frontal (IFC) cortex. For the whole MCI sample, IPC rCMRglc predicted conversion to AD with 84% overall diagnostic accuracy (p = 0.003). Moreover, ACC and IFC rCMRglc improved prediction for the E4+ group, yielding 100% sensitivity, 90% specificity, and 94% accuracy (p < 0.0005), thus leading to an excellent discrimination. CONCLUSION: Fluoro-2-deoxy-d-glucose-PET measures may improve prediction of the conversion to Alzheimer disease, especially in combination with the APOE genotype.

Paradoxical embolism in a preterm infant.

Cerebral paradoxical embolism has not until now been described as a cause of cryptogenic stroke in newborn infants. A male infant was born at 27 weeks 2 days' gestational age by emergency Caesarean section in a twin pregnancy because of intrauterine growth retardation and absence of diastolic flow in the twin. His birthweight was 950g (50th centile). Apgar scores were 7 and 8 at 1 and 5 minutes respectively. At 17 days of life he showed sudden respiratory distress and signs of encephalopathy. Presence of deep venous thrombosis, patent foramen ovale (PFO), and clinical progression suggested paradoxical embolism which were confirmed by neuroradiological findings. The high incidence of PFO and central venous catheter-related deep venous thrombosis in newborn infants suggest that paradoxical embolism is probably a more common complication than has been thought.

Functional interactions of the entorhinal cortex: an 18F-FDG PET study on normal aging and Alzheimer's disease.

UNLABELLED: Alzheimer's disease (AD) is a brain disorder characterized by reduced cerebral glucose metabolism (CMRgl) in several cortical regions. Evidence from neuropathology studies, animal models of AD, and (18)F-FDG PET studies on cognitive impairment suggest that disrupted connections with the entorhinal cortex (EC) could be implicated in the emergence of the cortical hypometabolism. This (18)F-FDG PET study assessed the functional interactions-that is, the intercorrelations between the EC and the whole brain in vivo-in normal aging and AD. METHODS: Eighty-seven consecutive clinical AD patients underwent (18)F-FDG PET scanning at rest. Thirty-five sex- and age-matched healthy elderly subjects were studied as controls (NC). A voxel-based correlation analysis was performed with statistical parametric mapping to assess significant correlations between relative CMRgl (rCMRgl) in the EC and the rest of the brain, for NC and AD patients. Results were considered significant at P < 0.001. RESULTS: The pattern of EC functional interactions varies between normal aging and AD patients. In NC, the left and right EC were bilaterally correlated with several cortical and limbic regions, in accord with the major anatomic pathways identified in nonhuman primates. Alternatively, in AD patients, the EC correlations with the contralateral hemisphere were entirely lost, whereas those within the ipsilateral hemisphere were preserved only with the inferior temporooccipital (T-O) areas. CONCLUSION: This (18)F-FDG PET correlation study indicates that AD-related processes lead to an altered functional relationship between the EC and several cortical and limbic regions, with respect to normal aging. Our results suggest that the assessment of coupled rCMRgl reductions between the EC and the ipsilateral T-O cortex, besides the typical pattern of cortical reduction, could increase (18)F-FDG PET diagnostic sensitivity and further motivate its inclusion in the clinical assessment of AD.

Brain metabolic decreases related to the dose of the ApoE e4 allele in Alzheimer's disease.

OBJECTIVES: Declines in brain glucose metabolism have been described early in Alzheimer's disease (AD), and there is evidence that a genetic predisposition to AD contributes to accelerate this process. The epsilon 4 (e4) allele of the apolipoprotein E (ApoE) gene has been implicated as a major risk factor in this process. The aim of this FDG-PET study was to assess the ApoE e4 dose related effect on regional cerebral glucose metabolism (METglc) in clinical AD patients, with statistical voxel based methods. METHODS: Eighty six consecutive mild to moderate AD patients included in the Network for Efficiency and Standardisation of Dementia Diagnosis database underwent FDG-PET scans at rest. PCR was used to determine the ApoE genotype. Patients were grouped as e4 non-carriers (n = 46), e3/e4 (n = 27) and e4/e4 (n = 13) carriers. A voxel-based mapping program was used to compare each AD subgroup with a database of 35 sex and age matched controls (p<0.001, corrected for cluster extent) and also to compare between the subgroups (p<0.001, uncorrected). RESULTS: No difference was found as to age at examination, age at onset, sex, disease duration, educational level, or severity of dementia between AD subgroups. Compared with controls, all AD subgroups had equivalent METglc reductions in the precuneus, posterior cingulate, parietotemporal, and frontal regions. Direct comparisons between AD subgroups indicated that patients with at least one e4 allele had METglc reductions within additional associative and limbic areas compared with e4 non-carriers. CONCLUSIONS: The present FDG-PET study showed different metabolic phenotypes related to the ApoE genotype in clinical AD patients, as revealed with voxel based statistical methods. The results suggest a generalised disorder in e4 carriers impairing metabolism globally, in addition to the more localised changes typical of AD patients.

Brain metabolic differences between sporadic and familial Alzheimer's disease.

This FDG-PET study with SPM99 compared 46 patients with sporadic Alzheimer disease (SAD) to 40 patients with familial AD (FAD) and to 35 matched controls. AD groups had equivalent metabolic (METglu) reductions in several cortical and limbic areas with respect to the controls. Patients with FAD showed decreased METglu in the posterior cingulate, parahippocampal, and occipital cortex as compared to the patients with SAD (p < 0.001). Genetic factors lead to phenotypic differences in AD.

Lymphomononuclear cells from multiple sclerosis patients spontaneously produce high levels of oncostatin M, tumor necrosis factors alpha and beta, and interferon gamma.

Proinflammatory cytokines are deemed to play a pivotal role in the pathogenesis of multiple sderosis (MS). They provide signals for T-cell activation and inflammatory cell recruitment in the brain and might directly alter neuroglial and neuronal cell survival and function. We found that peripheral blood mononuclear cells (PBMCs) from MS patents spontaneously produce high levels of TNFalpha, TNFbeta, IFNgamma, and oncostatin M (oncM), a proinflammatory cytokine actng on cells of neural, vascular, hematopoietic, and lymphoid origin. Spontaneous production of these cytokines was significantly higher (p < 0.01) in PBMC short-term culture supernatants from MS patients than in blood donors (HC). On average, lectin-induced production of these cytokines by PBMC was higher in MS patents than in HC significantly so only for TNFalpha (p = 0.013). Determination of TNFalpha, TNFbeta IFNgamma, and oncM in corresponding sera showed that on average, oncM levels were higher in MS patients than in HC, though the results were not statistically significant whereas levels of TNFalpha, TNFbeta and IFNgamma were below the assay threshold in most patients. The finding that MS PBMCs are primed in vivo to produce and release high levels of proinflammatory cytokines suggests the presence of a basal activation of the immune system which, in turn, may play a role in the complex circuitry of molecular and cellular interactions responsible for neurologic damage in MS.

Endogenous cytokine production protects T cells from spontaneous apoptosis during highly active antiretroviral therapy.

BACKGROUND: The availability of therapeutic regimens that effectively interfere with HIV-1 replication provides novel opportunities to investigate mechanisms of T-cell depletion as well as repopulation in infected individuals. METHODS: Nineteen HIV-1-infected individuals were investigated during one-year follow-up of highly active retroviral therapy (HAART). The frequencies of apoptotic T cells, as determined by propidium iodide, staining, TUNEL assay and analysis of annexin V, were assessed either in the absence or in the presence of anti-interleukin (IL)2 and anti-IL-4 neutralizing Ab. Spontaneous and lectin-induced cytokine production were assessed by ELISA. RESULTS: Increments of both naive and memory CD4 and CD8 T cells during HAART are accompanied by a decrease of T-cell apoptosis that, after 12 months of HAART, reaches normal levels. This is associated with increments of both spontaneous and activation-induced production of IL-2 and IL-4 by peripheral blood mononuclear cells (PBMCs), though only the latter was found defective at enrolment. During HAART, blocking of either IL-2 or IL-4 production by PBMCs using neutralizing Ab restores levels of T-cell apoptosis consistent with those determined at enrolment. These data suggest that both IL-2 and IL-4 produced by PBMCs during HAART provide anti-apoptotic signals that can contribute to an increased survival of T cells and may thus play a part in long-term immune reconstitution. CONCLUSIONS: An effective viral suppression and, possibly, effects of PI on molecular targets other than viral components, can support a progressive normalization of T-cell survival that, at least in part, depends upon the restoration of proper soluble signals. These results provide evidence of a supporting role of endogenous cytokine production in peripheral T-cell repopulation during an effective and prolonged viral suppression. This may be relevant for the definition of immune-intervention targets aimed at immune reconstitution in HIV-1-infected patients.

Role of immune-derived diffusible mediators in AIDS-associated neurological disorders.

Neurologic abnormalities are common in HIV-1 infected patients and often represent the dominant clinical manifestation of pediatric AIDS. Although the neurological dysfunction has been directly related to CNS invasion by HIV-1, the pathogenesis of neurologic disorders remains unclear. This review will first discuss the spectrum of potential interactions between HIV-1 and neural (neuronal and glial) cells, in the face of experimental data. Next, we will focus on the role of immune-derived cytokines and other soluble compounds which have been proposed to act as neurotoxic mediators and appear to play a role in the pathogenesis of AIDS-associated neurodegeneration.

Decreased T cell apoptosis and T cell recovery during highly active antiretroviral therapy (HAART).

T cell apoptosis represents a common mechanism of T cell depletion in HIV-1-infected individuals reflecting maturational and functional T cell abnormalities either directly or indirectly induced by the virus. In the present study, the effects of highly active antiretroviral therapy (HAART) on the spontaneous apoptosis of distinct T cell subsets were investigated during a 6-month follow-up in a cohort of HIV-1-infected individuals with CD4(+) cell counts between 100 and 500 cells/microliter and plasma HIV-1 RNA levels >/=10, 000 copies/ml. We determined that the rapid and sustained increase of both naive (CD45RA(+)CD62L(+)) and memory (CD45R0(+) and CD45RA(+)/CD62L(-)) CD4(+) and, to as lesser extent, CD8(+) T cells in peripheral blood was associated with a significant decrease of apoptotic CD4(+) and CD8(+) as well as CD3(+)CD4(-)CD8(-) T cells. Among CD4(+) lymphocytes, at enrollment, the highest frequency of apoptotic cells was observed within the memory compartment, as defined by CD45R0 expression. During HAART, however, the frequency of CD4(+)CD45R0(+) apoptotic T cells progressively decreased in association with a significant downregulation of surface activation markers that indicated decreased levels of systemic immune stimulation. These results indicate that effective viral suppression can contribute to progressive normalization of maturational and functional T cell abnormalities responsible for the high levels of T cell apoptosis in HIV-1-infected individuals. This, in turn, may contribute to a reduced rate of T cell loss and immune reconstitution during HAART.

Use of technetium-99m hexamethylpropylene amine oxime SPET for the study of cerebral blood flow reactivity after acetazolamide infusion in patients with Behçet's disease.

The purpose of this study was to characterise the nature of the baseline perfusion defects found in patients with Behçet's disease using hexamethylpropylene amine oxime single-photon emission tomography in conjunction with acetazolamide test (Acz SPET). Eleven patients underwent both baseline and Acz SPET. Regions of interest (ROIs) were drawn on the areas with decreased perfusion (D-ROI) and, in the same section, on areas with normal perfusion (N-ROI). The ROIs were then repositioned on the corresponding section on Acz SPET. The mean ROI counts were then transformed into a perfusion index value (PIV) with reference to the global brain counts. In total we found 24 D-ROIs (17 in the cortical and 7 in subcortical grey matter). The influence of Acz infusion was selectively registered in the D-ROIs, where PIVs changed from 1.23+/-0.17 (baseline SPET) to 1.63+/-0.23 (Acz SPET) (P<0.001). No significant difference was seen in the N-ROIs (1.46+/-0.21 and 1.40+/-0.17, respectively, on baseline SPET and Acz SPET). Our results demonstrate that Acz infusion increases the regional cerebral blood flow within baseline grey matter perfusion defects. This finding suggests that baseline perfusion abnormalities could reflect a disconnection rather than local vasculitic involvement.

Hypertrophic cardiomyopathy in pediatric patients: effect of verapamil on regional and global left ventricular diastolic function.

OBJECTIVE: To assess the effects of treatment with verapamil on regional and global left ventricular (LV) diastolic function in paediatric patients with hypertrophic cardiomyopathy (HCM). DESIGN: Twelve patients (age range 5.1 to 12.3 years, median 8.6) with HCM were evaluated during ongoing chronic oral treatment with verapamil (4 mg/kg/day) and four days after withdrawal of therapy. Twelve age- and body surface area-matched normal children served as controls. In an echocardiographic study, global LV diastolic function was evaluated by assessing isovolumic relaxation time (IVRT) and mitral flow indexes, including peak filling rate normalized to mitral stroke volume (PFR/SV). In addition, regional LV diastolic function was assessed by pulsed-wave Doppler tissue imaging at the subendocardial portion of the middle region of the anterior and posterior interventricular septum, and anterolateral and inferior walls to measure the peak velocities and the velocity-time integrals of myocardial excursion in both early diastole and atrial systole. In addition, as an index of diastolic asynchrony (AsyI), the variation in time to peak filling rate, measured as the time from the peak of the R wave on the electrocardiogram to the peak of the regional E wave, among the four myocardial regions was defined by subtracting the smallest value from the greatest and expressing the difference as a percentage of the smallest value. RESULTS: Compared with the controls, patients with HCM without therapy showed a longer IVRT (P<0.01) and a decrease in PFR/SV (P<0.01) without a compensatory increase in filling during atrial systole. Oral administration of verapamil induced a significant shortening of the IVRT (P=0.003) and an increase in PFR/SV (P=0.02). Furthermore, patients with HCM without therapy showed a significantly longer time to peak filling rate (P<0.01) associated with a decreased peak velocity in early diastole without a concomitant increase in peak velocity during atrial systole in each of the myocardial regions. Furthermore, the AsyI was higher in the HCM group than in controls (19% versus 6%, respectively), and this index was inversely correlated with the PFR/SV (r=-0.86, P<0.001). The regional diastolic velocity of the myocardium at each of the four analyzed regions was not significantly different with verapamil, but the AsyI was significantly lower (P<0.05). CONCLUSIONS: Children with HCM show abnormalities of both global and regional LV diastolic function. In these patients, chronic administration of verapamil plays a crucial role in the improvement in global LV filling and, as a consequence, in clinical manifestations. The beneficial effects of verapamil seem to be related to a reduction in diastolic asynchrony more than to significant changes in diastolic velocities of the myocardial fibres.

Cold lesion of a vertebral angioma with Tc-99m-labeled monoclonal antibodies against granulocytes.

Antigranulocyte immunoscintigraphy is indicated for diagnostic imaging to determine the location and extent of infection. We present a case of a focal cold lesion in a vertebra of a patient thought to have a septic focal lesion. Whole-body scanning and dorsal spine SPECT revealed no focal increased uptake. CT and MR studies revealed the presence of a vertebral angioma. Conditions associated with a defect of uptake in immunoscintigraphy are discussed.

CCR5 and CXCR4 chemokine receptor expression and beta-chemokine production during early T cell repopulation induced by highly active anti-retroviral therapy.

Expression of chemokine receptors and beta-chemokine production by peripheral blood mononuclear cells (PBMC) were determined in HIV-1-infected individuals before and after highly active anti-retroviral therapy (HAART) and their relationship to viral load, T cell phenotype and the expression of immunological activation markers was examined. We found that the expression of CCR5 is up-regulated in HIV-1-infected individuals while CXCR4 appears down-regulated on both CD4 and CD8 T cells compared with normal controls. These alterations are associated with the high levels of viral load. In addition, a relationship was observed between the degree of immune activation and chemokine receptor expression on T cells. However, after 3 months of combined anti-retroviral regimen, expression of CXCR4 significantly increased while CCR5 decreased when compared with pretherapy determinations. This was seen in strict association with a dramatic decrease of viral load and an increase of both CD45RA+/CD62L+ (naive) and CD45RA-/CD62L+ or CD45RA+/CD62L- (memory) T cells accompanied by a significant decrease of the expression of immune activation markers such as HLA-DR and CD38. At enrolment, both spontaneous and lectin-induced RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta production by PBMC were higher in HIV-1-infected individuals compared with normal controls, although differences for MIP-1beta were not statistically significant. However, RANTES and MIP-1alpha production decreased during HAART at levels closer to that determined with normal controls, while MIP-1beta production was less consistently modified. These data indicate that the expression of chemokine receptors CCR5 and CXCR4 and the production of beta-chemokines are altered in HIV-infected individuals, and suggest that their early modifications during HAART reflect both the peripheral redistribution of naive/memory T cell compartments and the decrease in levels of T cell activation. Such modifications in the expression of host determinants of viral tropism and the production of anti-viral molecules may play a role in the emergence of virus variants when a failure of HAART occurs.