Allergy-immunology glossary

Interleukin-5 [IL5] is a Th2 homodimeric cytokine involved in the differentiation, maturation, migration, development, survival, trafficking and effector function of blood and local tissue eosinophils, in addition to basophils and mast cells. IL 5 and IL-5R drive allergic and inflammatory immune responses characterizing numerous diseases, such as asthma, atopic dermatitis, chronic obstructive pulmonary disease, eosinophilic gastrointestinal diseases, hyper-eosi nophilic syndrome, Churg-Strauss syndrome and eosinophilic nasal polyposis. IL-5 has been proposed as a potential molecular target in the treatment of these diseases. In studies of asthmatics, anti-IL-5 showed minimal efficacy in patients with moderate, controlled asthma. In patients with severe, refractory asthma associated with eosinophilia, however, clinical trials have demonstrated significant reductions in asthma exacerbations. IL-6 is a pleotropic cytokine that, together with TNF-alpha and IL-lp, has been traditionally considered as a biomarker of ongoing inflammation more than as a regulatory cytokine with potential to modulate the immune response. Specifically, IL-6 has been shown to promote Th2 differentiation of CD4+ T cells while suppressing Thl differentiation through independent pathways, IL-6 can also modulate the intensity of the immune response by inhibiting T regulatory [Treg] cell development. Some studies suggest that IL'6 synergizes with IL4 [3 to promote Thl 7 differentiation. Thus, IL6 may be a key factor in determining the balance of CD4+ T cells in becoming Treg or inflammatory Thl 7 cells

Allergy-immunology glossary

Mast cells VEGF is a highly specific mitogen for vascular endothelial cells. Five VEGF isoforms are generated as a result of alternative splicing from a single VEGF gene. The expression of VEGF is potentiated in response to hypoxia, by activated oncogenes, and by a variety of cytokines. VEGF induces endothelial cell proliferation, promotes cell migration, and inhibits apoptosis. In vivo VEGF induces angiogenesis as well as permeabilization of blood vessels, and plays a central role in the regulation of vasculogenesis. Deregulated VEGF expression contributes to the development of solid tumors and to several additional diseases by promoting tumor angiogenesis. Consequently, inhibition of VEGF signaling abrogates the development of a wide variety of tumors. The various VEGF forms bind to two tyrosine-kinase receptors, VEGFR-1 [flt-1] and VEGFR-2 [KDR/flk-1], which are expressed almost exclusively in endothelial cells Vascular endothelial growth factor [VEGF] New blood vessel formation regulated by a number of protein factors elaborated by cells of the innate and adaptive immune systems.3 Excessive angiogenesis occurs in diseases such as cancer, diabetic blindness, rheumatoid arthritis, psoriasis. Insufficient angiogenesis occurs in diseases such as coronary artery disease, stroke, and chronic wounds. Angiogenic growth factors [GF] include angiogenin, angiopoietin-1, VEGF, fibroblast GF, follistatin, proliferin, transforming GFs and others. Angiogenic inhibitors include angioarrestin, angiostatin [plasminogen fragment], chondromodulin, CD59 complement fragment, heparinases, human chorionic gonadotropin [hCG], interleukin-12, platelet factor-4 [PF4], thrombospondin-1 and -2, vasostatin, etc[4]

Evaluation of Banana Hypersensitivity Among a Group of Atopic Egyptian Children: Relation to Parental/Self Reports

PURPOSE: To evaluate the frequency of banana sensitization and allergy among a group of atopic Egyptian children in relation to parental/self reports. METHODS: This is a case-control study included 2 groups of allergic children with and without history of banana allergy, each included 40 patients. They were subjected to skin prick test (SPT) using commercial banana allergen extract and prick-prick test (PPT) using raw banana, in addition to measuring the serum banana-specific IgE. Oral banana challenge was performed in suspected cases. RESULTS: Banana allergy was diagnosed in 3 (7.5%) patients based on positive history of allergy on exposure to banana, positive SPT/PPT and elevated banana-specific IgE. The 3 patients had bronchial asthma with exacerbation upon banana exposure. The PPT results conform with those of SPT both in diagnosis of banana allergy and in the skin reactivity to banana. Serum banana-specific IgE was detectable in the whole studied sample with higher serum level among those without history of banana allergy (P=0.005). Oral banana challenge was negative for 20 patients with history of banana allergy and positive serum banana-specific IgE but negative SPT and PPT. CONCLUSIONS: Self/parental reports of banana allergy is high while the actual banana allergy is uncommon. The PPT seems as reliable as SPT in diagnosis of banana allergy unlike specific IgE which reflects sensitization rather than allergy. Oral food challenge remains the most helpful tool for diagnosis of food allergy in suspected cases.

A Rare Association Between Leukocyte Adhesion Deficiency Type I and Psoriasis in Humans

The beta2 integrins are expressed exclusively on leukocytes and participate in many immune and inflammatory processes. This subfamily comprises four heterodimeric glycoproteins with a common beta-subunit, designated beta2 (CD18). Spontaneous mutations of the CD18 gene result in leukocyte adhesion deficiency type I (LAD-I). Low level of CD18 expression has also been implicated in the pathogenesis of psoriasis. We here describe a child with recurrent skin infections without pus formation, persistent gingivitis and periodontitis. His blood counts showed persistent leukocytosis (neutrophilia). CD11b expression was defective on neutrophils, while that of CD18 was normal. So, our patient represents a mild variant of LAD-I with possible dysfunctional CD18. Moreover, he developed psoriasis with reduced CD18 expression on CD4+ T-cells. Psoriasiform dermatitis has been described before in association with LAD-I, however, clinically and histologically confirmed psoriasis in association with LAD-I has been described only in CD18 hypomorphic mice. Therefore, our patient represents the first clinically and histopathologically documented association between LAD-I and psoriasis in humans. It lends support to the role of beta2 integrins in the etiopathogenesis of psoriasis.

Allergy-Immunology Glossary

A retrovirus is any virus belonging to the viral family Retroviridae. The family Retroviridae comprises a variety of enveloped RNA viruses, such as endogenous retroviruses, leukemia viruses, and HIV-1, the replicative strategy of which includes as essential steps reverse transcription of the virion RNA into linear double-stranded DNA and the subsequent integration of this DNA into the genome of the cell[1]. It is a DNA polymerase that is able to make genetic transcriptase information flow in the reverse [RNA ->DNA] of its normal [RT] direction [DNA -> RNA][3], HIV-1 RT is responsible for the production of a double stranded DNA copy of the single stranded RNA genome that is contained in the HIV- 1 virus particle. HIV-1 RT is of tremendous medical interest as it is the target enzyme for the best known of anti-AIDS drugs, zidovudine, which acts by causing chain termination of the polymerase reaction[4]. CD4 [cluster of differentiation 4] is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells. CD4 is also a primary receptor used by HIV-1 to gain entry into host T cells. The CD4 gene is on chromosome 12. CD4 functions to initiate or augment the early phase of T-cell activation[5. Human CD4 may function as an important mediator of indirect neuronal damage in infectious and immune-mediated diseases of the central nervous system[6]

Allergy-Immunology glossary

Mast cells are normally present in small numbers in the connective tissue of all organs, but particularly in the dermis. They have been considered the tissue equivalent of basophils but there is evidence that both arise from common precursor cell in the bone marrow. The two cell types are readily distinguished by their morphology on light microscopy and the presence of chloroacetate esterase activity in mast cells. Mast cells are specifically involved in type I hypersensitivity reactions where they release their granule contents of histamine and heparin, and synthesize and secrete other mediators into the surrounding tissues. Although serotonin is not normally present, it has been demonstrated in mast cells in the stronia of carcinoid tumours and in mastocytosis[1]. Mast cells are also involved in delayed hypersensitivity, cytotoxicity, immunoregulation and inflammation[2]. Recently, mast cells were reported to be essential in regulatory T-cell-dependent peripheral tolerance[3]. It is a biogenic monoamine found in plant and animal tissue and is released from mast cells as part of an allergic reaction in humans. It stimulates gastric secretion and causes dilation of capillaries, constriction of bronchial smooth muscles, and decreased blood pressure[5]. Histamine, like many other transmitters, mediates responses via receptors [Rs], which are divided into three subtypes H1, H2 and H1. H1Rs are found in the smooth muscle of the intestines, bronchi, and blood vessels. The H2Rs are found in gastric parietal cells and in the vascular and central nervous systems. H3Rs are found in the brain and in the periphery and regulate histamine release[5]. Most recently, a novel orphan G-protein coupled receptor, named H4R [GPRv53, human 390 aa] has been cloned and characterized. It is most closely related to H3R. Unlike H3R, H4R has a distinct tissue distribution and it is localized in the peripheral blood leukocytes, spleen, thymus and colon[6]

School-age children's surgical fears

The study included 100 school-age children hospitalized for abdominal surgery and were unaccompanied by their parents. Each child was hospital environment, hospital personnel and surgery itself. The findings showed that the highest percentages of children expressed different fears in relation to surgical operations which were fear of death, pain, change body image, surgical gown, abdominal incision and anesthesia. Children also expressed their fears of injection and laboratory investigations. Hospital environment was a source of fear for the children, where they were afraid of hospital as a strange place, the general view of the hospital at night, darkness and noises. Also, the majority of children expressed their fears of doctors and nurses. The study revealed that females expressed more fears than