Immunological aspects of endometriosis

The immune system probably plays a role in the onset and development of endometriosis. A general picture can be proposed. In some women refluxing endometrial cells are not destroyed, either because the patient is genetically programmed not to respond to endometrial antigens, or because the reflux is so abundant that the scavenging capacity of the peritoneal immune cells is overloaded. Refluxing cells could be protected due to an abnormal adherence to the mesothelium which exceptionally expresses certain adhesive molecules. Undestroyed, these endometrial cells would cause an inflammation with activation of macrophages. Not only does the peritoneum protect these endometrial cells, but it also produces abnormal quantities of chemotactic and angiogenic cytokines (interleukin-8). Macrophages facilitate development via growth factors such as transforming growth factor P. Immunosuppressive factors block the cytotoxic activity of natural killer (NK) cells. Activated macrophages present antigens of endometrial cells to T cells which will co-operate with B cells to synthesize autoantibodies. Synthesized antibodies protect the ectopic endometrium and could worsen the dysfunction of local NK cells. A vicious circle is set up involving all the partners of the immune system. It is as yet impossible to pinpoint the triggering mechanism. The primary defect could be localized on the endometrium, macrophages already activated by an extrinsic factor (infection, spermatozoa, chemical substances), the uterus or the tubo-uterine junction. The two pathophysiological theories put forward to explain endometriosis are linked by a defective immune system. Indeed, once the vicious circle is set up, growth and angiogenic factors could induce metaplasia of the already irritated mesothelium.     

Immunological aspects of atherosclerosis

Atherosclerosis is a complex chronic inflammatory and metabolic disease that involves the collaboration of several cellular components of the immune system and results in thickening of the arterial wall. Atherosclerosis is also the primary cause of coronary artery and cerebrovascular diseases. A multitude of immune cell subsets, soluble molecules such as chemokines and cytokines, and circulating lipids play pivotal roles in atherosclerosis development. In this review, we highlight the role of the immune system in the course of atherosclerotic disease development and discuss the mechanisms involved.     

Stemming the tide of thymic aging

The establishment and replenishment of thymic epithelium and the persistence of epithelial progenitor cells into adult life were discussed at ThymOz-V 2006.     

Immunological aspects of new quinolones

The effects of new quinolones on the immune system have been mainly studied in vitro. Despite some conflicting results due to variations in study methodologies, certain conclusions can be drawn. Clinically relevant concentrations of most quinolones seem to have no direct effect on isolated immune parameters such as phagocytic cell functions, lymphocyte proliferation, immunoglobulin production, gamma-interferon secretion and bone-marrow progenitor cell proliferation. In contrast, the production of certain cytokines (IL-1, IL-2) and colony stimulating factors by stimulated lymphocytes and splenocytes is enhanced in the presence of clinically achievable concentrations of the drugs. IL-2 production is also enhanced when higher concentrations of quinolones are added to stimulated lymphocytes. However, most other functions such as IL-1 and TNF production, and proliferation of lymphocytes and bone marrow progenitor cells are inhibited in vitro by concentrations of quinolones exceeding 50 µg/ml. In vivo studies on immunomodulatory effects of new quinolones are few and are generally in agreement with the in vitro findings. Only very high dosages administered to experimental animals cause suppressive effects, while therapeutic doses are usually not associated with measurable alterations in immune functions. Recent reports on stimulatory effects of therapeutic doses of ciprofloxacin on bone marrow myeloid progenitor cells in irradiated, neutropenic mice, warrant further investigations in experimental animals as well as in neutropenic and bone marrow transplant patients treated with the new quinolones.     

Immunological aspects of Goodpasture''s syndrome

A typical case of Goodpasture's syndrome is reported. Immunofluorescence studies disclosed linear deposition of γ- and β_1c-globulins on the glomerular and pulmonary basement membranes. The possibility that this indicates a common pathogenesis is suggested by these findings and an hypothesis in support of this view is presented.     

Immunological aspects of cellular transplantology

The problem of surmounting the histocompatibility barrier and the mechanisms underlying the immune response to allo- and xenogeneic cells is discussed. Allogeneic grafts are recognized by T cells via direct and indirect pathways, while xenografts are recognized predominantly via the indirect pathway. Rejection of allografts is realized through recognition of foreign antigen by CD8 T cells, while xenografts are rejected after presentation of xenoantigens by host antigen-presenting cells to CD4 T cells. The differences in immune response to allo- and xenografts should be taken into consideration in the strategy of overcoming the histocompatibility barrier. The approaches to suppression of graft rejection are described in detail. Induction of antigen-specific tolerance proved to be the most optimal approach. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 2, pp. 124–129, February, 1998     

Immunological aspects of humidifier fever

An epidemiological investigation was made of eight employees working in a defined section of an office building who complained of febrile reactions accompanied by respiratory tract symptoms and fatigue. Culture of the water from the humidifier for their section yielded strains ofPseudomonas acidovorans and an unidentifiedPseudomonas species. In vitro studies showed that these strains activated the alternative pathway of the complement system in Mg-EGTA supplemented serum, as evidenced by properdin depletion and conversion of C3-proactivator (Factor B) and C3. Whereas the employees with symptoms had significantly reduced properdin values during the symptomatic phase, a slight C3 conversion and antibodies toPseudomonas spp., staff working in another part of the building with a different ventilation system did not. It was concluded that staff with humidifier fever symptoms had been exposed toPseudomonas spp. through the faulty ventilation system, and their symptoms were most likely a result of complement activation.     

Immunological aspects of male infertility

Some immunological aspects of male infertility are discussed, including the mechanism of induction of auto-antibodies to sperm-specific antigens. Tests to determine antispermatozoal antibodies in serum are discussed. Since there is no direct relation with infertility, more attention is focused on the presence of antispermatozoal antibodies in semen. These antibodies affect male fertility by reducing the capacity of the spermatozoa to penetrate cervical mucus. This penetration inhibition is caused by autoagglutination of the spermatozoa in the ejaculate and by the shaking phenomenon. The sperm-cervical mucus contact test, based on the shaking phenomenon is described. The use of the Mixed Antiglobulin Reaction tests, to detect IgG and IgA antibodies on spermatozoa is discussed. Finally, the effect of antispermatozoal antibodies on the fertilization process is reviewed.     

Immunological aspects of fungal pathogenesis

The incidence of infection with the pathogenic fungi continues to escalate, especially in the era of the acquired immune deficiency syndrome. To the clinician, this heterogeneous group of organisms poses both a diagnostic and a therapeutic challenge. Consequently, growing numbers of investigators are seeking to elucidate the pathogenetic mechanisms involved in disease caused by medically important fungi. In this review, many of the recent scientific advances that have been made in the immunological aspects of the pathogenesis of fungal infections are presented. The topics covered include 1) the receptors for fungi on the surface of professional phagocytes; 2) the mechanisms for killing and growth inhibition of fungi by phagocytes; 3) the means by which fungi evade host defenses; 4) the role of humoral immunity in fungal infection; 5) immunoregulation in fungal infections; and 6) the influence of cytokines on host defenses against pathogenic fungi.     

Immunological aspects of Derzsy's disease in goslings

Laying geese naturally infected by the parvovirus agent of Derzsy's disease transmit IgG type maternal immunoglobulins through the eggs to their offsprings. The passively acquired yolk antibodies persisted at a relatively high level until about 12-14 days of age, but were eliminated from the birds during the 3rd week of life. The IgG type immunoglobulins present in the specific hyperimmune sera used for preventive treatment have a half-life, about 6 days, and their blood level falls to a minimal value during the 2nd week following administration. The primary humoral immune response of geese to parvovirus is characterised by the production of initially IgM and then IgG type immunoglobulins. Gosling less than 20 days old began to produce antibodies later after antigenic stimulation and in lower titre than did older birds. The presence of passively acquired antibodies also interfered with the development of an active immune response. It follows that the most efficient approach to the protection of susceptible goslings against Derzsy's disease is to boost their levels of maternal antibodies through active immunisation of the laying flocks.