Analysis of circulating gammadelta T cells in children affected by IgE-associated and non-IgE-associated allergic atopic eczema/dermatitis syndrome

Recent studies have suggested that not only alphabeta(+) T cells, but also the less common gammadelta(+) T cells may play a role as effectors and immunoregolatory cells in the development and perpetuation of allergic inflammation. The objective of this study was to focus on the role of gammadelta(+) T cells in atopic dermatitis (AD), a chronic relapsing inflammatory disease of the skin, often associated with allergic bronchial asthma. The present study employed flow cytometric analysis to compare numbers and phenotypic characteristics of gammadelta(+) T cells in the peripheral blood of children with atopic dermatitis and age-matched healthy controls. The percentage of circulating Vgamma 9Vdelta2(+) T lymphocytes was significantly increased in AD patients with respect to the age-matched controls, with a positive correlation with clinical score severity. The prevalent phenotype in both AD patients and controls was CD45RO(+), with no differences observed in the percentage of Vdelta2(+) CD45RO(+) between these groups. Conversely, memory CD45RO(+) CD62L(+) Vdelta2(+) lymphocytes were significantly lower in AD patients. Furthermore, naive circulating Vdelta2(+) T lymphocytes were significantly lower in AD children than in aged-matched controls. No correlation was observed between circulating Vgamma 9Vdelta2(+) expansion and IgE serum levels. It was concluded that an association exists between the levels of circulating gammadelta(+) T lymphocytes and atopic dermatitis, with a positive correlation with clinical score but no link with IgE serum levels. The pathophysiological role of gammadelta T lymphocytes in atopic dermatitis awaits further investigation.     

Two-center collaborative evaluation of the performance of the BD Phoenix automated microbiology system for identification and antimicrobial susceptibility testing of Enterococcus spp. and Staphylococcus spp

The performance of the BD Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, Md.) was assessed for identification (ID) and antimicrobial susceptibility testing (AST) for the majority of clinically encountered bacterial isolates in a European collaborative two-center trial. A total of 469 bacterial isolates of the genera Staphylococcus (275 isolates), Enterococcus (179 isolates), and Streptococcus (15 isolates, for ID only) were investigated; of these, 367 were single patient isolates, and 102 were challenge strains tested at one center. Sixty-four antimicrobial drugs were tested, including the following drug classes: aminoglycosides, beta-lactam antibiotics, beta-lactam-beta-lactamase inhibitors, carbapenems, cephems, folate antagonists, quinolones, glycopeptides, macrolides-lincosamides-streptogramin B (MLS), and others. Phoenix ID results were compared to those of the laboratories' routine ID systems (API 32 Staph, API 32 Strep, and VITEK 2 [bioMérieux, Marcy l'Etoile, France]); Phoenix AST results were compared to those of frozen standard broth microdilution (SBM) panels according to NCCLS guidelines (NCCLS document M 100-S 9, approved standard M 7-A 4). Discrepant results were repeated in duplicate. Concordant IDs of 97.1, 98.9, and 100% were observed for staphylococci, enterococci, and streptococci, respectively. For AST results the overall essential agreement was 93.3%; the category agreement was 97.3%; and the very major error rate, major error rate, and minor error rate were 1.2, 1.9, and 1.3%, respectively. In conclusion, the Phoenix ID results showed high agreement with results of the systems to which they were being compared; the AST performance was highly equivalent to that of the SBM reference method.     

Autosomal dominant inheritance of left ventricular outflow tract obstruction

Most nonsyndromic congenital heart malformations (CHMs) in humans are multifactorial in origin, although an increasing number of monogenic cases have been reported recently. We describe here four new families with presumed autosomal dominant inheritance of left ventricular outflow tract obstruction (LVOTO), consisting of hypoplastic left heart (HLHS) or left ventricle (HLV), aortic valve stenosis (AS) and bicuspid aortic valve (BAV), hypoplastic aortic arch (HAA), and coarctation of the aorta (CoA). LVOTO in these families shows a wide clinical spectrum with some family members having severe anomalies such as hypoplastic left heart, and others only minor anomalies such as mild aortic valve stenosis. This supports the suggestion that all anomalies of the LVOTO spectrum are developmentally related and can be caused by a single gene defect.     

Clinically-based determination of safe DNAemia cutoff levels for preemptive therapy or human cytomegalovirus infections in solid organ and hematopoietic stem cell transplant recipients

Transplantation Centers using human cytomegalovirus (HCMV) antigenemia-based preemptive therapy will need to replace in the near future the antigenemia assay with a more standardized and automatable assay, such as a molecular assay quantifying HCMV DNA in blood (DNAemia). Thus, in view of replacing antigenemia with clinically safe cutoff values, DNAemia levels corresponding to antigenemia cutoffs guiding HCMV preemptive therapy were determined retrospectively in solid organ and hematopoietic stem cell transplant recipients (HSCTR) using an "in-house" quantitative PCR (QPCR) method. Since preemptive therapy had prevented appearance of HCMV disease in all patients tested, DNA cutoffs determined retrospectively had to be considered as safe clinically as antigenemia cutoffs used prospectively. However, in solid organ transplant recipients (SOTR), initiating preemptive therapy upon an antigenemia cutoff of 100 pp65-positive leukocytes, a DNAemia cutoff of 300,000 copies/ml blood had positive and negative predictive values of >90%, indicating that a DNAemia cutoff could achieve, in terms of prevention of HCMV disease, the same clinical results as the antigenemia cutoff. In HSCTR, initiating preemptive therapy upon first antigenemia positivity, a DNAemia cutoff of 10,000 copies/ml blood had a positive predictive value of >90%, indicating that the great majority of patients treated under the antigenemia guidance would have been treated also using this DNA cutoff. On the other hand, the negative predictive value of 28.6% indicated that two out of three HSCTR had been treated under the antigenemia guidance having the same levels of viral DNA as the untreated patients. The data suggest that a quantitative cutoff could be adopted as a guiding criterion for preemptive therapy also in HSCTR. Regression analysis allowed to determine the DNAemia (corresponding to QPCR) cutoff values for two commercial assays tested both in solid organ and HSCTR. Retrospective DNAemia cutoff values will be verified for safety in prospective trials.     

Selected pool of peptides from ESAT-6 and CFP-10 proteins for detection of Mycobacterium tuberculosis infection

We have validated a new test for detecting Mycobacterium tuberculosis infection. A pool of synthetic peptides derived from ESAT-6 and CFP-10 proteins was used to detect the number of specific gamma interferon-producing T cells by means of an enzyme-linked immunospot assay. Sixty-eight individuals positive for M. tuberculosis infection, either human immunodeficiency virus-seropositive or -seronegative, were studied. The test results were highly specific (87.5%) and sensitive (93.1%), more so than a classical lymphoproliferative assay (specificity and sensitivity of 77.27%), opening new possibilities for diagnosis and screening of tuberculosis. Moreover, the test allowed us to distinguish individuals infected with M. tuberculosis from those vaccinated with BCG.     

A study of cellular immunity in newborns after prevention of respiratory distress syndrome (RDS)

Cellular immune responsiveness against infections was evaluated in four groups of newborns. The first group was composed of preterm newborns whose mothers had received betamethasone for prevention of RDS, the second group of preterm newborns whose mothers had received ambroxol for prevention of RDS, the third group of preterm newborns whose mothers had not received any drug enhancing surfactant production, and the fourth group were healthy-term infants. A reduction of OKT4+ cells and functional deficits of neutrophils were found in preterm infants born to mothers treated with steroids, whereas no functional abnormalities of immune-competent cells were observed in preterm infants born to mothers treated with ambroxol.     

9q34 loss of heterozygosity in a tuberous sclerosis astrocytoma suggests a growth suppressor-like activity also for the TSC1 gene

Tuberous sclerosis is an autosomal dominant disease whose characteristicfeature is the development of multiple hamartomas in a varietyof organs and tissues. Two major loci have been identified sofar: TSC1 on chromosome 9q34 and TSC2 on chromosome 16p13.3.Loss of heterozygosity at 16p13.3-associated markers has beenrecently observed in hamartomatous lesions of some tuberoussclerosis patients. Here we report the first evidence of lossof heterozygosity at the TSC1 critical region in a giant cellastrocytoma of a familial tuberous sclerosis case. Segregationanalysis showed that the 9q34 haplotype lost carried the putativenormal TSC1 gene. These data support the hypothesis of botha germline and somatic loss-of-function mutation for the developmentof tuberous sclerosis hamartomas and suggest a tumor-suppressor-likeactivity also for the TSC1 gene product. Finally, the possiblesignificance of a second small region of loss of heterozygosityat 9p21, found in the same astrocytoma, is discussed.     

Development and evaluation of a capture ELISA for IgM antibody to the human cytomegalovirus major DNA binding protein.

A new capture ELISA (ELAb) for determination of the IgM antibody response to the human cytomegalovirus major DNA binding protein (p52) was developed by using a p52-specific monoclonal antibody. As a reference test, a capture ELISA using in parallel viral- and cell-control labeled antigens (ELA) was employed. General specificity, which was determined on 180 unselected IgM-negative sera from an adult population was 100%; stringent specificity, which was evaluated on 108 potentially interfering sera from patients with Epstein-Barr virus infectious mononucleosis, autoimmune diseases, rheumatoid factor or treated with radioimmunotherapy, was 96.3%; finally, clinical specificity, determined on 79 IgM-negative sera drawn prior to onset of primary HCMV infection, was 100%. Thus, the overall specificity was 98.9% (363/367 IgM negative tested sera). Sensitivity assayed on 277 IgM-positive sera was 100%. The study of the kinetics of the IgM antibody response in sequential blood samples from 9 immunocompetent and 9 heart transplanted patients showed that, while in the immunocompetent p52-specific IgM titer fell sharply 2-3 months after onset and was virtually undetectable 12 months after onset, in the immunocompromised the IgM response persisted for longer than a year. Recurrent HCMV infections were associated with a high titer IgM response in 6 (30%), and with a low IgM response in another 6 (30%) heart transplanted patients within a group of 20 patients sequentially examined. Finally, IgM antibodies were detected in all 4 infants with congenital infection and in 5 of 6 infants with neonatal infection. The results show that the HCMV p52-specific IgM antibody response parallels that obtained by ELA, thus representing a major component of it. ELAb is highly sensitive, specific and reproducible. It represents a major advance among capture ELISA techniques, allowing detection of IgM antibody reactive to a specific viral protein.     

Immunohistochemical pattern of hMSH2/hMLH1 in familial and sporadic colorectal, gastric, endometrial and ovarian carcinomas with instability in microsatellite sequences

Alterations of DNA mismatch repair (MMR) genes are involved in carcinogenesis of sporadic and inherited human cancers characterised by instability of DNA microsatellite sequences (MSI). MSI tumours are usually identified using molecular analysis. In the present investigation, hMLH1 and hMSH2 immunohistochemistry was tested in order to evaluate the utility of this method in predicting MMR deficiency. Colorectal (72), gastric (68), endometrial (44) and ovarian (17) carcinomas were independently evaluated for familial history, histological type of tumour, MSI status and immunohistochemical results. Loss of expression of either hMLH1 or hMSH2 was observed in 51 of 55 (92.8%) MSI tumours, while 145 of 146 microsatellite stable (MSS) tumours expressed both the hMLH1 and hMSH2 gene products. Independently of tumour site, an overall agreement between immunohistochemical and molecular results was observed in 15 hereditary non-polyposis colorectal cancer-related tumours. Among sporadic tumours, only 2 of 60 colorectal and 2 of 66 gastric carcinomas, displaying MSI, expressed both hMLH1 and hMSH2 gene products. All 39 endometrial and 16 ovarian tumours presented a concordant molecular and immunohistochemical profile. These data show that immunohistochemistry is an accurate and rapid method to predict the presence of defective DNA MMR genes and to identify both sporadic and familial MSI tumours.