Phenotypic pattern of B cells in the appendix: reduced intensity of CD19 expression

The lymphoid tissue of the appendix is considered as part of the gut-associated lymphoid tissue (GALT). In order to understand better the immunological significance of the appendix we analyzed the cellular composition of normal and inflamed human appendix tissue by flow cytometer with special attention to expression of the CD19 and CD5 markers on B cells. Cellular analysis was also performed on peripheral and appendical vein blood samples as well as on omentum and peritoneal fluid samples. The study population included seventeen patients aged 2-15 yr. (mean age - 11.5 yr.) undergoing appendectomy. Ten children were diagnosed with acute appendicitis while 7 had a normal appendix. RESULTS: Compared to the peripheral blood, the appendix contained a significantly higher percentage of CD19 cells (47.6% of total lymphocytes versus 15%, p<0.0001), and B1 cells (4.98% of total lymphocytes versus 2.42%, p=0.001). In addition, the intensity of CD19-staining was markedly decreased in the appendix (mean - 395.7), and also in the omentum (mean - 398.2) as compared to peripheral lymphocytes (mean - 497.7, p<0.0001 for both comparison). Comparison between the inflamed and the non-inflamed appendices revealed that the inflamed appendix contained a significantly higher proportion of B1 cells (5.64% of total lymphocytes versus 3.53%, p=0.032), and also a higher B1/b cell ratio (0.13 vs. 0.07, p=0.01). CONCLUSIONS: These results indicate that the appendix tissue contains higher number of B1 (and B) cells compared to the peripheral blood and that these cells play a role in the primary immune response to acute infection/inflammation in the appendix. Appendiceal B cell population is unique in term of CD19 intensity expression on their surface.     

Plasma HIV-1 RNA decline within the first two weeks of treatment is comparable for nevirapine, efavirenz, or both drugs combined and is not predictive of long-term virologic efficacy: A 2NN substudy

BACKGROUND: The initial rate of plasma HIV-1 RNA (pVL) decline has been proposed as a marker of early efficacy of antiretroviral therapy (ART) and a possible predictor of late efficacy. We compared the rate of pVL decline in patients starting ART with nevirapine (NVP), efavirenz (EFV), or both drugs combined in addition to lamivudine (3TC) and stavudine (d4T). METHODS: Analysis of the viral decay constant (VDc) during the first 2 weeks of treatment in patients enrolled in the 2NN study who remained on allocated treatment. RESULTS: The median VDc (log10 copies per day, [interquartile range]) was similar for NVP (0.30 [0.25-0.36], EFV (0.31 [0.27-0.37]), and NVP + EFV (0.30 [0.27-0.36]). Patients with a baseline pVL >100,000 copies/mL were 8.7 (95% confidence interval [CI]: 6.2-12.3) times more likely to have a VDc >75th percentile. A high VDc was not associated with plasma drug concentration or with a decreased risk of virologic failure at week 48 after the start of therapy (hazard ratio = 0.8, 95% CI: 0.6-1.2). CONCLUSION: NVP, EFV, or NVP + EFV in combination with 3TC and d4T show similar rates of pVL decline during the first 2 weeks of treatment. The VDc with these regimens is not predictive of late virologic efficacy.     

PFAPA syndrome: new clinical aspects disclosed.

BACKGROUND: The recently described PFAPA (Periodic Fever, Aphthous stomatitis, Pharyngitis and Adenitis) syndrome is characterised by periodic fever, aphthous stomatitis, pharyngitis and adenitis. However, there are currently relatively few data on the natural history of this syndrome. OBJECTIVE: To describe the presentation, clinical course, doctors' awareness, therapeutic response and long-term follow-up of children with PFAPA syndrome. METHODS: Children with PFAPA syndrome referred over a 5-year period (from January 1999 to January 2004) were enrolled in the study. Data were gathered from medical records, parents' interviews, physical examination and telephone calls. RESULTS: 54 patients with PFAPA syndrome were evaluated. Our patients had a higher rate of abdominal pain (65%) and a lower rate of aphthous stomatitis (39%) than those in previous reports. Four different patterns of disease evolution were identified, including the relatively common (n = 14, 26%) and newly described course of alternating remissions and relapses. The remissions lasted 8.5 months on average (range 4-36 months). Diagnosis was established by primary paediatricians in 30 of 54 (56%) patients. However, a substantial delay in diagnosis was apparent (mean 15 months). Episodes were curtailed by a much lower dose of prednisone or equivalent corticosteroid (mean 0.6 mg/kg/day, range 0.15-1.5 mg/kg/day) than reported previously. Tonsillectomy was successful in the prevention of recurrence of further episodes in all six patients who underwent the procedure. CONCLUSIONS: We describe several new characteristics of PFAPA syndrome in children, contributing to our knowledge of this relatively unrecognised but troublesome syndrome. Early diagnosis and appropriate treatment can markedly improve the quality of life of both patients and families.     

Coronavirus Disease Spread during Summer Vacation,Israel, 2020

The relative increase in coronavirus disease incidence during summer 2020 in Israel was most prominent in young children. This finding contrasts with the lower increase in incidence observed in children than in adults during the school attendance period. School closure without lockdown conditions might not be independently effective at reducing spread.     

Latency in vitro of varicella-zoster virus in cells derived from human fetal dorsal root ganglia.

A potential in vitro model of varicella-zoster virus (VZV) latency was developed. Dissociated human dorsal root ganglion cultures were infected with VZV and maintained for 1 wk in the presence of bromovinyl arabinosyl uracil, a potent inhibitor of VZV. Seven to 21 d after removing the inhibitor (> or = 14 d after infection), the cells were trypsinized, passed to monolayers of human embryonic lung fibroblasts, and observed for VZV reactivation as indicated by typical cytopathic effects and the appearance of VZV antigens. VZV reactivated from 56% of the cultures containing both neurons and satellite cells but not from cultures specifically enriched for either neurons, satellite cells, or ganglion-derived fibroblasts. The failure to isolate VZV from cell suspensions that were sonicated before cocultivation with fibroblasts indicated that infectious VZV was not present before reactivation. Moreover, immunohistochemical and immunoprecipitation studies revealed no VZV-specific antigens in any cultures before the reactivation stimulus. VZV antigens were detected after trypsinization and cocultivation. These findings suggest that cultures containing both neurons and satellite cells provide a model system for VZV persistence that possesses many properties of a latent infection.     

Postappendectomy intra-abdominal abscess: a therapeutic approach

Four hundred and sixty two children were operated on between January 1989 and June 1993 for acute appendicitis; 10 developed an intra-abdominal abscess. Intra-abdominal abscesses were accompanied by fever above 38 degrees C (nine out of 10 patients) and leucocytosis (mean leucocyte count 20.3 x 10(9)/l) and were detected sonographically four to 14 days after operation. Management included intravenous administration of antibiotics effective against both aerobes and anaerobes, and follow up with serial sonographic studies. Eight patients responded favourably to antibiotic treatment without any drainage procedure, with gradual shrinkage and collapse of abscesses. Two patients, in whom enlargement of collection was demonstrated on serial sonographic examination, eventually underwent percutaneous drainage under sonographic control. These results suggest that some paediatric patients with an intra-abdominal abscess after appendicectomy and who are followed up closely by sonography may be managed successfully with appropriate antibiotics alone.     

Effectiveness of the Oka/GSK attenuated varicella vaccine for the prevention of chickenpox in clinical practice in Israel

BACKGROUND: The varicella Oka/Merck vaccine has been shown to be very effective in clinical practice; however, several recent studies reported reduced effectiveness. The varicella Oka/GSK vaccine (Varilrix; GlaxoSmithKline Biologicals), which has been subjected to fewer effectiveness studies, was licensed in Israel for voluntary use in 2000. This study was planned to estimate the effectiveness of the varicella Oka/GSK vaccine among children 1-5 years of age. METHODS: Recent reports of varicella were retrieved from the Tel Aviv Health District. Two age-matched control subjects who attended the same day-care center and/or resided in the same neighborhood and had not contracted varicella in the past were recruited for each varicella case. The parents of case and control subjects were interviewed regarding the history of varicella vaccination and the severity of illness. RESULTS: A total of 151 case subjects (mean age, 2.9 +/-1.1 years) and 298 control subjects (mean age, 3.0 +/-1.1 years) were recruited. Vaccination rates for case and control subjects were 6.6% and 38.3%, respectively (P < 0.001). Disease among vaccinated children was significantly milder, as measured by several indices, including parental perception of the illness, presence of fever, time until the lesions dried and days of day care missed. Vaccine effectiveness against varicella of any severity with these figures was 88% (95% confidence interval, 77-94%), and effectiveness against moderate/severe illness was 100%. CONCLUSIONS: Our data demonstrate that the varicella Oka/GSK vaccine used in clinical practice is highly effective in prevention of varicella (especially moderate/severe disease) among children, including those attending day-care centers.     

The pattern of sesame sensitivity among infants and children

Recently, we found sesame to be a major cause of severe IgE-mediated food allergic reactions among infants and young children in Israel. The purpose of this study was to describe the different patterns of sesame sensitivity. We have identified three subgroups among our patients (n = 32). Group I (n = 23, M/F; 14/9) consisted of cases with IgE-mediated sesame allergy. The mean age of the first allergic reaction was 11.7 months. Although the main clinical manifestation was urticaria/angiedema (n = 14, 60%), anaphylaxis was the presenting symptom in seven (30%) patients; all of them were younger than 1 year. Sixteen (70%) were found to be allergic to other foods, and other atopic diseases were identified in 18 (78%) patients. Three patients 'outgrew' their allergy within 1–2 years. Group II (n = 2) included cases in whom sesame allergy was ruled out based on a negative skin prick test (SPT) together with a negative open oral challenge. Group III (n = 7) consisted of patients that were found to be SPT positive for sesame as part of a screening for other food allergies. Although sesame products have become fashionable in westernized countries, early exposure may cause sesame to share eventually the same 'noteriety and fate' as peanut – a major cause of severe food allergic reactions.