Polarization of Th-cell responses: a phylogenetic consequence of nonspecific immune defence?

CD4⁺ T helper (Th)-cell responses are polarized into Th1 and Th2 types. Here, Paul Garside and Allam McI. Mowat propose that this is an evolutionary consequence of the relationship between specific adaptive immunity, individual components of the nonspecific inflammatory response and different types of infection. This concept has important implications both for understanding protective immunity and for vaccine design and delivery.     

Aging of the immune system: a risk factor for autoimmunity?

Aging of the immune system, or immunosenescence, is characterized by changes in T cell subsets, cellular and molecular level alterations and thymic atrophy, resulting in a decline of T and B cell function. These alterations have been shown to be accompanied by a loss of ability to recognize "self" and "foreign" antigens. Therefore the development of autoimmune responses like production of autoantibodies has been hypothesized to be secondary to thymus involution with a decline of na?ve T cells and accumulation of clonal T cells with activation due to "neoantigens" during the aging process. Altered apoptosis and altered T cell homeostasis have been emphasized to promote a chronic inflammatory state and lead to the concept of a immune-risk phenotype. However, it has to be proven which kinds of mechanisms turn the immune system to manifest autoimmune disease and how speculated defects in T cell differentiation and interaction leading to premature aging of the immune system may contribute to the development of autoimmune diseases.     

Exercise and the immune system: a model of the stress response?

Exercise influences natural immunity, T- and B-cell functions, and cytokine responses, through circulatory (hemodynamic) changes and by endocrine hormones secreted in response to physical stress. The magnitude of the effects on the immune system reflects the intensity, duration and chronicity of the exercise. In this review, Laurie Hoffman-Goetz and Bente KlarlundPedersen suggest that exercise-immune interactions can be viewed as a subset of stress immunology.     

Are there differences in immune responses following delivery of vaccines through acutely or chronically sun-exposed compared with sun-unexposed skin?

The majority of human vaccines are administered above the deltoid muscle of the arm, a site that is chronically sun-exposed in many people. It is known that exposure of the skin to the UV wavelengths in sunlight stimulates systemic immunosuppression, an outcome that is associated with reduced immunity to microbial infections in animal models. Here we consider whether immunization of humans through a UV-irradiated skin site will lead to a less effective immune response compared with immunization through an unexposed site. Studies showing that the efficacy of vaccination can be reduced when surrogates of increased levels of sun exposure, such as latitude of residence and season of the year, are considered. Results from a limited number of intervention experiments in humans demonstrate a similar pattern. To provide an explanation for these findings, changes in the number and functional potential of immune cells in chronically sun-exposed compared with unexposed skin are outlined. UV radiation-induced changes to skin cells are also relevant when considering skin sites for administration of immune-tolerizing peptides. The review provides the basis for further research into the effects of acute and chronic UV radiation exposure on skin cells in the context of vaccination.     

Phosphorylcholine: friend or foe of the immune system?

Phosphorylcholine (PC) is a structural component of a variety of prokaryotic and eukaryotic pathogens. In some cases, PC in infectious agents can benefit the infected host due to its targeting by both the innate and adaptive immune responses. However, as discussed here, PC exhibits a surprising range of immunomodulatory properties that might be to the detriment of the host.     

HIV-exposed uninfected children: a growing population with a vulnerable immune system?

Through the successful implementation of policies to prevent mother-to-child-transmission (PMTCT) of HIV-1 infection, children born to HIV-1-infected mothers are now much less likely to acquire HIV-1 infection than previously. Nevertheless, HIV-1-exposed uninfected (HEU) children have substantially increased morbidity and mortality compared with children born to uninfected mothers (unexposed uninfected, UU), predominantly from infectious causes. Moreover, a range of phenotypical and functional immunological differences between HEU and UU children has been reported. As the number of HEU children continues to increase worldwide, two questions with clear public health importance need to be addressed: first, does exposure to HIV-1 and/or ART in utero or during infancy have direct immunological consequences, or are these poor outcomes simply attributable to the obvious disadvantages of being born into an HIV-affected household? Secondly, can we expect improved maternal care and ART regimens during and after pregnancy, together with optimized infant immunization schedules, to reduce the excess morbidity and mortality of HEU children?     

Why did the acquired immune system of vertebrates evolve?

Rapidly expanding genomic information offers important insights into the mechanisms of acquired immunity and has fostered progress in comparative immunology. However, the question of why the acquired immune system, a trait restricted to jawed vertebrates, evolved has rarely been addressed. Here, I will examine three unique features of early vertebrate evolution, during the 50 million years when the acquired immune system evolved: co-evolution with specialised parasites, increased metabolic rates and genomic instability. These combine to shape a powerful multi-level and multi-causal selective scenario that I propose could have moulded the acquired immune system.     

Premature ageing of the immune system: the cause of AIDS?

The reasons for the failure of the immune system to control HIV-1 infection, and the resulting immunodeficiency, remain unclear. HIV-1 persists in its host despite vigorous immune responses, including a strong, and probably functional, HIV-specific cytotoxic T-lymphocyte response. Interestingly the immunological features of HIV-1-infected individuals show many similarities to those seen in elderly people without HIV infection. We propose that, through a process of continuous immune activation, HIV-1 infection leads to an acceleration of the adaptive immune system ageing process, resulting in premature exhaustion of immune resources, which participates in the onset of immunodeficiency. This hypothesis might shed new light on HIV-1 pathogenesis and could suggest the need to reconsider current immunotherapeutic strategies to fight the virus.     

Are spouses of chronically ill partners burdened by exerting health-related social control?

Spouses often seek to influence the health behaviors of chronically ill partners, but little research has examined whether spouses find such involvement to be burdensome. The current study examined this question in a sample of 191 nondiabetic spouses whose partners had type 2 diabetes. Results revealed that spouses who attempted to exert more control over their partners' dietary behavior experienced greater burden, particularly when their partners exhibited poor dietary adherence and reacted negatively to spouses' involvement. The findings contribute to a sparse body of knowledge on how spouses are affected by efforts to influence their chronically ill partners' disease management.     

Promise of uterine transplant – Myth or a reality?

The scientific basis of uterus transplantation has been developing in parallel to other organ transplants throughout the modern period of transplant medicine. Immunosuppression and surgical techniques have been adequate for at least a decade; ethics and society have been less clearly developed. To many observers, it is still unclear if the endeavor is an overall positive or negative. Although scientific and technical challenges have been overcome, the ethical determinations will be a dynamic process while more experience continues to be gained. The most significant experience still lacking is a term gestation. Undoubtedly during a nine-month gestation, unforeseen challenges will test scientific processes and ethical assumptions. Despite dozens of animal experiments and a few animal births, no human birth has occurred to allow any definitive conclusions.     

Warty carcinoma of the uterine cervix: a virus-induced disease?

IntroductionWarty carcinoma (WC) of the uterine cervix is a rare subtype of squamous-cell carcinoma (SCC), and its frequency, clinical behaviour, and aetiology are obscure. It originates from condylomas, and a viral carcinogenesis seems logical.Material and methodsRetrospective analysis was performed of all cervical carcinomas (CC), diagnosed at a single institution for a 10-year period. Analysed patients had stage I carcinoma. Patients with WC were identified, and their tumour samples were tested for high-risk HPV (hr-HPV) and EBV, using PCR and ISH. Clinical characteristics and WC rates across all stage I CC patients were assessed. All patients had minimum 3-year follow-up, and overall survival (OS) and 5-year survival rates were calculated.ResultsWC comprised 2.2% of all stage I CC (n = 630). The mean age of the patients was 48 years (range: 29–72). The primary tumour size was 2 cm in 4 (28.6%) patients, 2–4 cm in 2 (14.3%) patients, and 4 cm in 8 (57.1%) patients. Lymph node metastasis was found in 1 (7.1%) patient. EBV or hr-HPV were detected in 2 (18.2%) patients using ISH, with no coinfection reported. Hr-HPV was detected in 2 (18.2%) patients; EBV in 4 (36.4%) cases, and in 2 of them (18.2%) there was a co-infection. Thirteen patients had a follow-up of ≥ 5 years and their 5-year OS was 100%.ConclusionsWC is a rare subtype of SCC with good prognosis, regardless of viral status. In contrast to SCC, its aetiology is not related to hr-HPV. The role of EBV remains unclear and cannot currently be denied.     

BSE: a consequence of cattle feeding with glycated molecules host-unknown?

Although there is much evidence supporting a prion contribution in the pathogenesis of transmissible spongiform encephalopathies, a novel point of view as to the induction of the diseases can be proposed. It is hypothesized that neurodegenerative diseases, such as scrapie in sheep and goats and bovine spongiform encephalopathy in cattle (BSE), originate from the consumption of glycated proteins contained in their feed. These components are obtained during a high-temperature glycation process.     

Are renal microgranulomas related to inflammatory tubular destruction?

Two cases of renal microgranuloma formation are reported, one in a patient with known Crohn's disease and another in a case of acute renal allograft rejection. In both cases, the microgranulomas arose as a result of inflammatory tubular destruction, in a manner analogous to that seen in patients with ulcerative colitis arising adjacent to ruptured epithelial crypts in the large intestine. Microgranulomas may occur at multiple anatomical sites in Crohn's disease, although renal microgranulomas are very rare. Non-specific inflammatory tubular destruction should be considered as a cause of renal microgranuloma formation, in addition to systemic granulomatous diseases, such as tuberculosis, sarcoid, or Crohn's disease, when granulomas are seen in the presence of inflammatory tubular destruction in renal biopsies.     

Can tissue transglutaminase be a marker of idiopathic inflammatory myopathies?

In the normal striated muscle, tissue transglutaminase (TG2) content is vestigial. However, this protein's presence has been reported to occur in myoblasts and myotubes during the fetal period. Its increased expression has been also found in the muscle tissue in the course of sporadic inclusion body myositis, as well as in polymyositis (PM) and dermatomyositis (DM), which are considered to be diseases of immunological origin. Based on in vitro studies, a substantial TG2 role in the infiltration of some T cell subsets into inflamed tissues has been suggested lately. In this study, the immunohistochemical reactions in the guinea pig experimental myositis specimens and in the ones from PM/DM patients were compared. The guinea pig tissue specimens were taken from muscles affected by experimental myositis induced by intramuscular injections of: 1/sera from 30 neoplasm patients with no metastases; 2/sera from 10 healthy people; 3/sera from 2 DM patients; 4/neuropeptides (SP, NPY or VIP) and from 5/the muscles affected by the reversed passive Arthus reaction (RPAR). The immunostaining for TG2 revealed substantial presence of this protein in single, damaged muscle fibers and a weak reaction in regenerating fibers appearing in PM/DM patients' specimens. From among experimental myositis specimens, a very intensive reaction appeared only in the damaged and regenerating muscle fibers present in the slides from guinea pig muscles injected with DM patients' sera. Such results suggest some presence of a specific factor(s) (the one(s) responsible for TG2 expression in the damaged muscle fibers) in DM patients' sera. The results suggest that transglutaminase can be a marker of inflammatory myopathies. A probable correlation between TG2 expression in muscles and organismal immunological factors, including the complement activation status, requires additional studies.     

Limiting dilution analysis of cells of the immune system II: What can be learnt?

Last month (p. 265) Herman Waldmann and Ivan Lefkovits described the principles underlying limiting dilution analysis. In this article they review some experimental approaches which have been useful in resolving some of the complexities of lymphocyte interactions.