Clinical,immunological, and molecular analysis in a large cohort of patients with X-linked agammaglobulinemia: an Italian multicenter study

A questionnaire-based retrospective clinical and immunological survey was conducted in 73 males with a definite diagnosis of X-linked agammaglobulinemia based on BTK sequence analysis. Forty-four were sporadic and 29 familial cases. At December 2000, the patients' ages ranged from 2 to 33 years; mean age at diagnosis and mean duration of follow-up were 3.5 and 10 years respectively. After the mid-1980s all but 2 were on intravenous immunoglobulin (IVIG) substitution therapy, with residual IgG >500 mg/dl in 94% of the patients at the time of enrollment. Respiratory infections were the most frequent manifestation both prior to diagnosis and over follow-up. Chronic lung disease (CLD) was present in 24 patients, in 15 already at diagnosis and in 9 more by 2000. The cumulative risk to present at diagnosis with CLD increased from 0.17 to 0.40 and 0.78 when the diagnosis was made at the ages of 5, 10, and 15 years respectively. For the 9 patients who developed CLD during follow-up, the duration of follow-up, rather than age at diagnosis; previous administration of intramuscular immunoglobulin; and residual IgG levels had a significant effect on the development of CLD. Chronic sinusitis was present in 35 patients (48%), in 15 already at diagnosis and in 20 by 2000. Sistemic infections such as sepsis and meningitis/meningoencephalitis decreased over follow-up, probably due to optimal protection provided by high circulating IgG levels reached with IVIG.     

Deletion of the mental retardation gene Gdi1 impairs associative memory and alters social behavior in mice

Non-specific mental retardation (NSMR) is a common human disorder characterized by mental handicap as the only clinical symptom. Among the recently identified MR genes is GDI1, which encodes alpha Gdi, one of the proteins controlling the activity of the small GTPases of the Rab family in vesicle fusion and intracellular trafficking. We report the cognitive and behavioral characterization of mice carrying a deletion of Gdi1. The Gdi1-deficient mice are fertile and anatomically normal. They appear normal also in many tasks to assess spatial and episodic memory and emotional behavior. Gdi1-deficient mice are impaired in tasks requiring formation of short-term temporal associations, suggesting a defect in short-term memory. In addition, they show lowered aggression and altered social behavior. In mice, as in humans, lack of Gdi1 spares most central nervous system functions and preferentially impairs only a few forebrain functions required to form temporal associations. The general similarity to human mental retardation is striking, and suggests that the Gdi1 mutants may provide insights into the human defect and into the molecular mechanisms important for development of cognitive functions.     

Asymmetrical hemispheric EEG activation evoked by stimulus position during the Simon task

The Simon effect has been previously shown to be asymmetric at both the behavioral and electrophysiological levels. The present investigation was aimed to clarify whether, during a Simon task, hemispheric asymmetry is also observed in the early phases of stimulus processing. In a group of healthy subjects performing the Simon task, we analyzed scalp potentials evoked by the first lateralized cue (left or right), instead of the classical readiness potential preceding the motor response. ERP results showed a significant left cortical activation to stimuli presented in the right visual field at the 140–160 ms time window. Instead, left stimuli elicited a significant activation of the right versus left hemisphere starting at the next 160–180 ms time interval. We linked this asymmetry to that observed in behavioral data: the Simon effect recorded with left stimuli is smaller than the Simon effect recorded with right stimuli. Results confirm the hypothesis that in right handed subjects, left hemisphere is specialized for motor response selection and is able to process right stimuli faster than the right hemisphere does for left stimuli.     

Warthin-like tumour of the thyroid gland: RET/PTC expression indicates it is a variant of papillary carcinoma

AIMS: Three cases with features of so-called 'Warthin-like tumour' of the thyroid (WaLTT) are described, in order to evaluate its relationship with papillary carcinoma (PC). METHODS AND RESULTS: We performed an histological and immunohistochemical study with emphasis on RET/PTC expression. The most striking features are represented by marked lymphocytic infiltration in the stalks of papillae and by oxyphilic metaplasia of epithelium, resembling Warthin tumour of the salivary gland. In all cases, we found nuclear features reminiscent of PC. The neoplastic cells were strongly positive for Leu M1 and epithelial membrane antigen (EMA), less for thyroglobulin and negative for calcitonin. The lymphocytic infiltrate was composed of a mixed population of B and T-cells with sparse S100-positive Langerhans cells. An interesting finding was the strong positivity with the antibody against RET/PTC. CONCLUSION: All clinicopathological data along with the presence of the extensive lymphocytic infiltrate could imply a more favourable prognosis. The expression of RET/PTC fusion gene adds support to the hypothesis that this tumour is a variant of PC, probably related to the oncocytic variant of PC.     

Differential role of dopamine in drug- and lithium-conditioned saccharin avoidance

Rats learn to avoid palatable saccharin solutions that predict the systemic administration of reinforcing drugs as well as malaise-inducing lithium chloride (conditioned saccharin avoidance, CSA). In the present study the involvement of dopamine (DA) transmission in the acquisition of morphine, nicotine and lithium-conditioned CSA was investigated in a two-bottle choice paradigm. Nicotine tartrate (0.2 and 0.4 mg/kg s.c.) administered 15 min after saccharin presentation induced CSA, with a maximum effect at 0.4 mg/kg. The DA D1 receptor antagonist, SCH 39166 (0.1 mg/kg s.c.) and the DA D2 receptor antagonist raclopride (0.3 mg/kg s.c.), administered immediately after saccharin, prevented CSA induced by the lower but not by the higher dose of nicotine. However, combined administration of the two antagonists prevented CSA induced by the higher dose of nicotine. SCH 39166 prevented CSA induced by all morphine doses while raclopride prevented only CSA induced by the lowest dose of morphine (1.75 mg/kg). CSA induced by different doses of lithium given by the same schedule of drug-CSA (i.e. two pairings, 15 min after saccharin) was not affected by SCH 39166. However SCH 39166 impaired the acquisition of lithium-CSA when lithium was given 60 min after saccharin. In contrast, raclopride failed to affect lithium-CSA independently from the delay between saccharin and lithium. These results suggest that DA can play different roles in drug- and in lithium-CSA and are consistent with a different mechanism of drug- as compared to lithium-CSA.     

Polyomavirus BK DNA quantification assay to evaluate viral load in renal transplant recipients.

BACKGROUND: Several studies have disclosed a correlation between polyomavirus BK (BKV) and interstitial nephritis in renal transplant recipients and its quantification in urine and serum is therefore required to assess the role of BKV infection in nephropathy. OBJECTIVE: This paper describes a urine and serum BKV-DNA quantification protocol devised to evaluate the viral load. STUDY DESIGN: Screening of samples containing > or =10(3)/ml viral genome copies by a semi-quantitative polymerase chain reaction (PCR) assay is followed by precise quantification of the samples containing a high number of viral genomes in a quantitative-competitive (QC)-PCR assay. Generation of the competitor construct relied on the different sizes of wild-type and competitor amplicons. RESULTS AND CONCLUSIONS: Screening by semi-quantitative PCR selects samples with a high number of viral genomes for use in the more labor-intensive and -expensive QC-PCR assay and thus provides a handy means for quantitative DNA analysis of large numbers of samples. The results obtained in BKV-DNA quantification in urine and serum samples from 51 renal transplant recipients (22 on treatment with tacrolimus (FK506) and 29 on cyclosporine A (Cy A)) are interesting: BKV-DNA findings (43.1%) in urine samples are in agreement with the BKV urinary shedding reported in literature (5-45%). With regard to immunosuppressive treatment, the percentage of activation of the infection (revealed by BKV-DNA detection in urine samples) in the two groups of therapy is similar (40.9% vs 44.8%). The observation that the viral load in urine is dissociated with that of serum suggests that both parameters should be investigated in evaluation of the pathogenetic role of BKV reactivation in renal transplant recipients. Moreover, our BKV-DNA quantification protocol could be used to monitor viral load in urine and serum samples from renal transplant recipients so as to detect those at risk of nephropathy and monitor their response to immunosuppression reduction therapy if it occurs.     

Identification of the basic subunit of Ara h 3 as the major allergen in a group of children allergic to peanuts.

BACKGROUND: Several proteins have been identified as peanut allergens; among them, Ara h 1 (7S globulin) and Ara h 2 (2S globulin) are usually considered the major allergens. OBJECTIVE: To identify the major allergens in a group of children selected for their specific pattern of immunoreactivity. METHODS: We identified the dominant allergen by using (1) amino acid sequencing of the bands that show the strongest IgE immunoreactivity in 1-dimensional electrophoresis and immunoblotting and (2) specific animal IgGs raised against the dominant immunoreactive band to pinpoint the allergen(s) in peanut proteins separated by 2-dimensional electrophoresis and immunoblotting. To confirm these data, we further examined the peanut proteome using serum samples from the children with the unusual immunoreactivity. RESULTS: We found a group of children with marked peanut allergy who are specifically sensitized to the basic subunit of Ara h 3 (11S globulin family). CONCLUSION: That the dominant immunoreactivity in these patients is in a basic subunit of Ara h 3 was unexpected, because previous studies had indicated that Ara h 3 was only a minor peanut allergen and that the identified allergenic epitopes occurred mainly in the acidic Ara h 3 subunit.     

Vestibular and audiological findings in the Alport syndrome

Alport syndrome (AS) is caused by mutations in collagen IV, which is widespread in the basement membranes of many organs, including the kidneys, eyes, and ears. Whereas the effects of collagen IV changes in the cochlea are well known, no changes have been described in the posterior labyrinth. The aim of this study was to investigate both the auditory and the vestibular function of a group of individuals with AS. Seventeen patients, aged 9–52, underwent audiological tests including pure‐tone and speech audiometry, immittance test and otoacoustic emissions and vestibular tests including video head impulse test, rotatory test, and vestibular evoked myogenic potentials. Hearing loss affected 25% of the males and 27.3% of the females with X‐linked AS. It was sensorineural with a cochlear localization and a variable severity. 50% of the males and 45.4% of the females had a hearing impairment in the high‐frequency range. Otoacoustic emissions were absent in about one‐third of the individuals. A peripheral vestibular dysfunction was present in 75% of the males and 45.4% of the females, with no complaints of vertigo or dizziness. The vestibular impairment was compensated and the vestibulo‐ocular reflex asymmetry was more evident in rotatory tests carried out at lower than higher speeds; a vestibular hypofunction was present in all hearing impaired ears although it was also found in subjects with normal hearing. A posterior labyrinth injury should be hypothesized in AS even when the patient does not manifest hearing disorders or evident signs of renal failure.     

CD34+ Cord Blood Cell-Transplanted Rag2−/− γc−/− Mice as a Model for Epstein-Barr Virus Infection

Recent studies suggest that Epstein-Barr virus (EBV) can infect naïve B cells, driving them to differentiate into resting memory B cells via the germinal center reaction. This hypothesis has been inferred from parallels with the biology of normal B cells but has never been proven experimentally. Rag2^−/− γ_c^−/− mice that were transplanted with human CD34⁺ cord blood cells as newborns were recently shown to develop human B, T, and dendritic cells, constituting lymphoid organs in situ. Here we used this model to better define the strategy of EBV infection of human B cells in vivo and to compare this model system with different conditions of EBV infection in humans. Our results support the model of EBV persistence in vivo in cases that were characterized by follicular hyperplasia and a relatively normal CD4⁺ and CD8⁺ T-cell distribution. Intriguingly, in cases that were characterized by nodular and diffuse proliferation with a preponderance of CD8⁺ T cells, similar to infectious mononucleosis, EBV still infects naïve B cells but also induces clonal expansion and ongoing somatic mutations without germinal center reactions. Our results reveal different strategies of EBV infection in B cells that possibly result from variations in the host immune response. Future experiments might allow understanding of the mechanisms responsible for persistent EBV infection and provide targets for more highly tailored therapeutic interventions.     

Evaluation of the VITEK 2 System for Rapid Identification of Medically Relevant Gram-Negative Rods

The new VITEK 2 system (bioMérieux) was evaluated at two independent sites with the identification card for gram-negative bacilli (ID-GNB card). Of the 845 strains tested, which represented 70 different taxa belonging to either the family Enterobacteriaceae or the nonenteric bacilli, 716 (84.7%) were correctly identified at the species level. Thirty-two (3.8%) additional strains were identified to the species level after the performance of simple, rapid manual tests (oxidase, hemolysis, indole reaction, motility, and pigmentation). For 80 (9.5%) strains, these additional tests did not lead to an identification at the species level but the correct species identification was given among the organisms listed. Only 7 (0.8%) strains were misidentified, and 10 (1.2%) were not identified. Mistakes were randomly distributed over different taxa. Due to the new, more sensitive fluorescence-based technology of the VITEK 2 system, final results were available after 3 h. Since our evaluation was mainly a stress test, it is predicted that the VITEK 2 system in conjunction with the ID-GNB card would perform well under conditions of a routine clinical laboratory in identifying members of the family Enterobacteriaceae and selected species of nonenteric bacteria. This system is a promising, highly automated new tool for the rapid identification of gram-negative bacilli from human clinical specimens.