The immunologic mechanisms of sublingual immunotherapy are less established. In Cochrane analysis, the authors concluded that there was an increase in IgG4 but no stable effect on IgE levels in adults. In addition, the induction of allergen-specific IgA has been reported. There are conflicting data concerning lympho-proliferative responses. So far the evidence on changes in Th1/Th2/Treg activity induced by sublingual immunotherapy need to be confirmed. The effects on T-cell reactivity and cytokine secretion show strong variation in a number of studies. (more…)

The response to injury usually begins with dilatation of small blood vessels in and around the injured site (figure bellow). This response (called vasodilatation) results from relaxation of smooth muscle in the vascular walls. It can begin within seconds after an acute injury or develop over hours or days of low-grade irritation or infection. Vasodilatation initially results in increased blood flow through arterioles, capillaries, and venules of the affected region, leading to redness (erythema) and warmth. As the vessels dilate, endothelial cells lining some of the vessels actively retract away from one another to create temporary, microscopic gaps in the endothelial lining. Endothelial retraction occurs only in the smallest venules (often called postcapillary venules), which are thin-walled vessels with lumenal diameters of 20 - 60 µm. (more…)

The overlapping functions of cytokines largely reflect the properties of the cell surface receptors to which they bind. All cytokine receptors function as multiprotein complexes made up of two or more integral membrane polypeptides, called subunits (Figure 1 bellow). A typical subunit polypeptide has an extracellular domain that participates in cytokine binding, a transmembrane region, and an intracellular domain (also called a cytoplasmic tail gp41) involved in signal transduction the molecular events that transmit signals to the cell interior and induce specific cellular responses when the receptor binds its appropriate cytokine ligand. Some receptors (eg, EPO-R) function as homodimers of a single type of subunit; others (eg, GM-CSFR) function as heterodimers, and still others (eg, IL-2R) as heterotrimers. (more…)

A few of the best known humoral effectors of innate immunity are listed in Table 1 bellow, along with the types of target molecules they recognize. Some are enzymes that can directly injure or kill microbial pathogens. An example is lysozyme, an endoglycosidase found in human saliva, mucus, tears, and other secretions, which attacks the protective cell wall encasing every bacterial cell. Lysozyme acts by digesting the peptidoglycan meshwork formed by long carbohydrate chains of alternating N-acetylmuramic acid and N-acetylglucosamine residues, crosslinked covalently by short oligopeptide sidechains which is a major constituent of all bacterial cell walls but is not found in mammalian tissues. (more…)

Although it is commonly imagined that hematopoiesis takes place in a liquid environment resembling the blood, with progenitors responding mainly to soluble hormone-like cytokines, this is in fact not the case at all. It is much more accurate to think of the bone marrow as a solid tissue in which different types of hematopoietic cells develop in physically different locations. These microenvironments are visible in histologic sections of bone marrow, which reveal a patchwork of microscopic foci, each devoted to the production of a particular cell type (Figure bellow). The bone marrow microenvironment is set up and maintained by bone marrow stromal cells. Within each microenvironment, contact of cells with one another or with proteins and other substances that make up the extracellular matrix (ECM) greatly facilitates cell division and differentiation. (more…)

The process by which blood cells grow, divide, and differentiate in the bone marrow is called hematopoiesis. Three general classes of cells are produced:

(1) red blood cells (erythrocytes), responsible for oxygen transport;
(2) platelets, responsible for the control of bleeding; and
(3) white blood cells (leukocytes), the vast majority of which are involved in host defense. (more…)

The final stage of the disease process (although it may not be the final stage of the infection) is the actual production of disease. Many microorganisms live in or on the body without causing disease. These organisms are called commensal organisms and may be beneficial to the host: the production of lactic and lactobacilli proprionic acidophilus in the vagina inhibits the growth of many other bacteria and many commensal organisms compete with pathogens for ‘living space’ in the gut. Microbial pathogens differ in that they cause dis- ease by one or more mechanisms like picture bellow. These include the following: (more…)

Routes by which infectious organisms gain entry into the body include the skin, respiratory tract, gastro-intestinal (GI) tract and GU tract. There are fundamentally two ways in which infectious agents cross the physical and chemical barriers: either they are able to penetrate the intact barriers at one or more anatomical sites, or the physical barriers are damaged and breached, allowing entry of the organism.

Bellow are some possibles pathogens entry into human body:

Penetration of intact skin or mucosa

• Skin. Few organisms are able to penetrate intact skin. However, some parasites (e.g. hookworm) or their larvae (e.g. schistosoma) can do this. Other agents, such as wart viruses, set up infection in the skin and do not enter further into the body.

• Mucosa. Mucosa, being softer and damper than skin, are much more frequent sites of entry and all intact mucosa can be penetrated by some organisms. Examples are shown in table bellow. Pathogens can cross epithelia by passing through epithelial cells, as in the case of the meningococcus (a bacteria causing meningitis), or by passing between the epithelial cells, seen with Haemophilus influenzae.

Mucosal Sites of Entry for Pathogens

Penetration of damaged skin or mucosa

There are many ways in which skin or mucosa can be damaged, allowing entry of infectious organisms that could not cross intact skin or mucosa. Damage to skin is a particularly important route of infection and can occur in a number of ways:

• Burns. Burns, especially severe ones, pose a major risk for infection, particularly with Staphylococcus, Streptococcus, Pseudomonas and Clostridium tetanus.

• Cuts and wounds. These can allow entry of similar organisms to those seen after burns.

• Insect bites. Numerous infections pathogenesis are transmitted via insect bites. These include malaria, typhus and plague.

• Animal bites. Animal bites can provide direct transmission of infection, such as in rabies. Because they cause significant damage to the skin, bites can allow the entry of the same environmental pathogens as burns, cuts and wounds (see above).

• Human behaviour. Various aspects of uniquely human behaviour can result in the skin being penetrated. Sharing of syringes by intravenous (IV) drug users exposes them to risk of hepatitis and human immunodeficiency virus (HIV). A number of viral infections (hepatitis, HIV) have been transmitted by blood transfusion and blood products (e.g. factor VIII for haemophiliacs) before appropriate screening procedures were developed. Transplantation has also resulted in transmission of infection before the introduction of appropriate donor screening.

Damage to mucosa may not increase the likelihood of infection to the same extent as damage to the skin. However, physical or chemical damage may allow entry of some organisms (e.g. smoking increases the risk of respiratory bacterial infections or respiratory allergies). Furthermore, infection of the mucosa with a virus may cause damage and facilitate the entry of bacterial pathogens spread.

An allergic patient’s history may point the clinician’s assessment to a specific area or organ system during allergy testing. In general, physical examination may be standard; shortage of findings isn’t going to rule out allergy.

Essential indicators are a starting point in any physical examination of allergic patients. Respiratory rate is essential as well, but hyperventilation is more a representation of minute ventilation (respiratory rate × tidal volume) than respiratory rate on it’s own. (more…)

Atopic Dermatitis is considered to be one of the first manifestations in the atopic march. The aim of this study was to investigate prospectively the natural course of Atopic Dermatitis to determine factors influencing its prognosis and to analyse the relationship of Atopic Dermatitis with childhood asthma. The Multicenter Allergy Study, a German birth cohort, followed 1314 children from birth to age 7 years. Physical examinations, parental interviews on atopic symptoms and diagnoses, and determination of specific immunoglobulin (Ig)E levels were performed regularly. (more…)