Detection of precursor Th cells in mesenteric lymph nodes after oral immunization with protein antigen and cholera toxin

We have characterized the earliest antigen-specific Th cells in murine mesenteric lymph nodes (MLN), following oral immunization with the hen egg lysozyme (HEL) as antigen and cholera toxin (CT) as adjuvant. We did this by analyzing in vitro proliferation and cytokine production in response to HEL by the MLN T cells. MLN cells taken 5 days after a single oral immunization with HEL and CT provided the earliest source of proliferating HEL-specific T cells. This proliferation was completely inhibited by anti-IL-2, but not inhibited by anti-IL-4 antibody. IL-2 protein was detected in culture supernatants but not IL- 4 using ELISA or bioassays. IL-4 mRNA was not found in responding cells using RT-PCR. Some of the day 5 MLN cultures produced IFN-gamma in response to HEL, but isolated T cells from the same MLN did not. Exogenous IL-4 alone did not stimulate day 5 MLN T cells, but IL-4 did synergize with HEL to induce a large proliferative response. The data indicate that the HEL-specific CD4 T cell pool in MLN 5 days after oral immunization is composed of undifferentiated precursor Th cells. These cells have the potential for IL-2 production and IL-4R expression upon re-stimulation in vitro.      

Lung oxidative stress as related to exercise and altitude. Lipid peroxidation evidence in exhaled breath condensate: a possible predictor of acute mountain sickness

Lung oxidative stress (OS) was explored in resting and in exercising subjects exposed to moderate and high altitude. Exhaled breath condensate (EBC) was collected under field conditions in male high-competition mountain bikers performing a maximal cycloergometric exercise at 670 m and at 2,160 m, as well as, in male soldiers climbing up to 6,125 m in Northern Chile. Malondialdehyde concentration [MDA] was measured by high-performance liquid chromatography in EBC and in serum samples. Hydrogen peroxide concentration [H₂O₂] was analysed in EBC according to the spectrophotometric FOX₂ assay. [MDA] in EBC of bikers did not change while exercising at 670 m, but increased from 30.0±8.0 to 50.0±11.0 nmol l⁻¹ (P<0.05) at 2,160 m. Concomitantly, [MDA] in serum and [H₂O₂] in EBC remained constant. On the other hand, in mountaineering soldiers, [H₂O₂] in EBC under resting conditions increased from 0.30±0.12 μmol l⁻¹ at 670 m to 1.14±0.29 μmol l⁻¹ immediately on return from the mountain. Three days later, [H₂O₂] in EBC (0.93 ±0.23 μmol l⁻¹) continued to be elevated (P<0.05). [MDA] in EBC increased from 71±16 nmol l⁻¹ at 670 m to 128±26 nmol l⁻¹ at 3,000 m (P<0.05). Changes of [H₂O₂] in EBC while ascending from 670 m up to 3,000 m inversely correlated with concomitant variations in HbO2 saturation (r=−0.48, P<0.05). AMS score evaluated at 5,000 m directly correlated with changes of [MDA] in EBC occurring while the subjects moved from 670 to 3,000 m (r=0.51, P<0.05). Lung OS may constitute a pathogenic factor in AMS.     

Critical appraisal of the revised Ghent criteria for diagnosis of Marfan syndrome

Radonic T, de Witte P, Groenink M, de Bruin‐Bon RACM, Timmermans J, Scholte AJH, van den Berg MP, Baars MJH, van Tintelen JP, Kempers M, Zwinderman AH, Mulder BJM. Critical appraisal of the revised Ghent criteria for diagnosis of Marfan syndrome. Marfan syndrome (MFS) is a connective tissue disorder with major features in cardiovascular, ocular and skeletal systems. Recently, diagnostic criteria were revised where more weight was given to the aortic root dilatation. We applied the revised Marfan nosology in an established adult Marfan population to define practical repercussions of novel criteria for clinical practice and individual patients. Out of 180 MFS patients, in 91% (n = 164) the diagnosis of MFS remained. Out of 16 patients with rejected diagnosis, four patients were diagnosed as MASS (myopia, mitral valve prolapse, borderline non‐progressive aortic root dilatation, skeletal findings and striae) phenotype, three as ectopia lentis syndrome and in nine patients no alternative diagnosis was established. In 13 patients, the diagnosis was rejected because the Z‐score of the aortic root was <2, although the aortic diameter was larger than 40 mm in six of them. In three other patients, the diagnosis of MFS was rejected because dural ectasia was given less weight in the revised nosology. Following the revised Marfan nosology, the diagnosis of MFS was rejected in 9% of patients, mostly because of the absence of aortic root dilatation defined as Z‐score ≥2. Currently used Z‐scores seem to underestimate aortic root dilatation, especially in patients with large body surface area (BSA). We recommend re‐evaluation of criteria for aortic root involvement in adult patients with a suspected diagnosis of MFS.     

Value of allohaemagglutinins in the diagnosis of a polysaccharide antibody deficiency

Polysaccharide antibody deficiency is characterized by a poor or absent antibody response after vaccination with an unconjugated pneumococcal polysaccharide vaccine. Allohaemagglutinins (AHA) are antibodies to A or B polysaccharide antigens on the red blood cells, and are often used as an additional or alternative measure to assess the polysaccharide antibody response. However, few studies have been conducted to establish the clinical significance of AHA. To investigate the value of AHA to diagnose a polysaccharide antibody deficiency, pneumococcal polysaccharide antibody titres and AHA were studied retrospectively in 180 subjects in whom both tests had been performed. Receiver operating characteristic curves for AHA versus the pneumococcal vaccine response as a marker for the anti-polysaccharide immune response revealed an area under the curve between 0·5 and 0·573. Sensitivity and specificity of AHA to detect a polysaccharide antibody deficiency, as diagnosed by vaccination response, were low (calculated for cut-off 1/4–1/32). In subjects with only low pneumococcal antibody response, the prevalence of bronchiectasis was significantly higher than in subjects with only low AHA (45·5 and 1·3%, respectively) or normal pneumococcal antibody response and AHA (2·4%). A logistic regression model showed that low pneumococcal antibody response but not AHA was associated with bronchiectasis (odds ratio 46·2). The results of this study do not support the routine use of AHA to assess the polysaccharide antibody response in patients with suspected immunodeficiency, but more studies are warranted to clarify the subject further.     

Caveolin-3 in muscular dystrophy

The dystrophin-glycoprotein complex (DGC) serves as a link between cytoplasmic actin, the membrane and the extracellular matrix of striated muscle. Genetic defects in genes encoding a subset of DGC proteins result in muscular dystrophy and a secondary decrease in other DGC proteins. Caveolae are dynamic structures that have been implicated in a number of functions including endocytosis, potocytosis and signal transduction. Caveolin (VIP-21) is thought to play a structural role in the formation of non-clathrin-coated vesicles in a number of different cell types. Caveolin-3, or M-caveolin, was identified as a muscle- specific form of the caveolin family. We show that caveolin-3 co- purifies with dystrophin, and that a fraction of caveolin-3 is a dystrophin-associated protein. We isolated the gene for human caveolin- 3 and mapped it to chromosome 3p25. We determined the genomic organization of human caveolin-3 and devised a screening strategy to look for mutations in caveolin-3 in patients with muscular dystrophy. Of 82 patients screened, two nucleotide changes were found that resulted in amino acid substitutions (G55S and C71W); these changes were not seen in a control population. The amino acid changes map to a functionally important domain in caveolin-3, suggesting that these are not benign polymorphisms and instead are disease-causing mutations.