Allelic Diversity and Affinity Variants of MICA are Imbalanced in Spanish Patients with Behcet's Disease

The aetiology of Behçet's disease (BD) is still unknown, but genetic and environmental factors are involved. HLA-B*51 is considered a susceptibility marker and some MICA alleles have also been associated. Cytotoxic T lymphocytes have been suggested as responsible for BD lesions by engaging MICA through NKG2D surface molecules. In the present study, HLA-B and MICA alleles were typed by polymerase chain reaction using sequence-specific primers, in 165 healthy Spanish controls and 42 BD patients. In the healthy group, MICA*008 (28.48%), MICA*004 (17.58%), MICA*002 (14.24%) and MICA*009 (9.39%) were the predominant alleles and the most common haplotype was MICA*004-B*44 (12.12%). MICA*001 (5.15%), MICA*004, MICA*011 (4.54%) and MICA*018 (5.15%) were more frequent, and MICA*010 (1.81%) and MICA*008 were less prevalent than in other Caucasoid populations. Similar results have been reported in North African individuals and this could support the hypothesis of a common ancestral origin of both populations. The frequencies of MICA*009 and MICA*019 were significantly increased in our BD patients in comparison with controls: 22.62% versus 9.39% and 10.71% versus 1.81% respectively. The increase of MICA*019 had not been described in other BD cohorts, and it corroborates the genetic heterogeneity at MICA locus in BD patients. High-affinity MICA alleles for NKG2D were more frequent in controls than in patients. Moreover, high-affinity alleles were not found in homozygous BD patients. These results argue against the hypothesis of an autoaggressive response in BD patients through MICA-NKG2D interactions.

Blunted gamma delta T-lymphocyte response in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterised by an excessive inflammatory response to inhaled particles, mostly tobacco smoking. Although inflammation is present in all smokers, only a percentage of them develop COPD. T-lymphocytes are important effector and regulatory cells that participate actively in the inflammatory response of COPD. They comprise the T-cell receptor (TCR)-alpha beta (CD4+ and CD8+) and TCR-gamma delta T-lymphocytes. The latter represent a small percentage of the total T-cell population, but play a key role in tissue repair and mucosal homeostasis. To investigate TCR-alpha beta (CD4+ and CD8+) and TCR-gamma delta T-lymphocytes in COPD, the present authors determined, by flow cytometry, the distribution of both subpopulations in peripheral blood and bronchoalveolar lavage (BAL) samples obtained from patients with COPD, smokers with normal lung function and never-smokers. The present study found that: 1) the distribution of CD4+ and CD8+ lymphocytes in blood and BAL was similar in all three groups; 2) compared with nonsmokers, gamma delta T-lymphocytes were significantly increased in smokers with preserved lung function; and 3) this response was blunted in patients with COPD. These results highlight a novel, potentially relevant, pathogenic mechanism in chronic obstructive pulmonary disease.

The role of chitosan in wool finishing

The application of the biopolymer chitosan as an alternative to the conventional contaminating processes in textiles was studied. As chitosan is produced by biomass, it is biodegradable and bioadsorbable. These properties are increasingly important given the current environmental legislation. The main aim of chitosan treatment of oxidised wool fabrics is to improve felting properties and dyeing behaviour.

Small cytoplasmic antigens from Pseudomonas aeruginosa stimulate gammadelta T lymphocytes

Gammadelta T lymphocytes respond to different bacterial antigens and transformed cells. The antigenic molecules responsible for this activity have been studied extensively in antigenic preparations from Mycobacterium. We describe here the in vitro effect of Pseudomonas aeruginosa on gammadelta T lymphocytes and the properties of the implicated compounds. We found a preferential gammadelta T-cell expansion when we used heat-treated P. aeruginosa preparations and a dose-dependent inhibition of proliferation of peripheral blood mononuclear cells (PBMC) when non-heat-treated antigens were studied. This expansion corresponded to a Vgamma9-positive subpopulation. In contrast to alphabeta T lymphocytes, the highest stimulatory activity was restricted to very small cytosolic compounds. This activity was protease resistant and phosphatase sensitive and always dependent on interleukin (IL)-2 or alphabeta T-cell activation. We concluded that the antigenic molecules from P. aeruginosa that activated gammadelta T lymphocytes were small, non-peptidic, phosphorylated compounds, similar to those previously described from Mycobacterium.