Hepatitis B and C virus reactivation in immunosuppressed patients with inflammatory bowel disease

In recent years,a number of case reports and clinical studies have highlighted the risk of hepatitis B and C virus reactivation in patients with inflammatory bowel disease who are treated with immunosuppressive drugs.The cases of viral hepatitis reactivation that have been reported are characterized by a wide range of clinical manifestations,from viremia without clinically relevant manifestations to fulminant life-threatening hepatitis.The development and dissemination of biological immunosuppressive drugs have led to a significant increase in the number of reports of interest to physicians in a variety of clinical settings.On this topic,there have been a number of published guidelines and reviews that have collected the available evidence,providing recommendations on prophylactic and therapeutic strategies and methods for monitoring patients at risk.However,it should be noted that,to date,very few clinical studies have been published,and most of the recommendations have been borrowed from otherclinical settings.The published studies are mostly retrospective and are based on very heterogeneous populations,using different therapeutic and prophylactic regimens and obtaining conflicting results.Thus,it seems clear that it is desirable to concentrate our efforts on prospective studies,not conducting further reviews of the literature in the continued absence of new evidence.     

Chemokine-mediated redirection of T cells constitutes a critical mechanism of glucocorticoid therapy in autoimmune CNS responses

Glucocorticoids (GCs) are the standard therapy for treating multiple sclerosis (MS) patients suffering from an acute relapse. One of the main mechanisms of GC action is held to be the induction of T cell apoptosis leading to reduced lymphocyte infiltration into the CNS, yet our analysis of experimental autoimmune encephalomyelitis (EAE) in three different strains of genetically manipulated mice has revealed that the induction of T cell apoptosis is not essential for the therapeutic efficacy of GCs. Instead, we identified the redirection of T cell migration in response to chemokines as a new therapeutic principle of GC action. GCs inhibited the migration of T cells towards CCL19 while they enhanced their responsiveness towards CXCL12. Importantly, blocking CXCR4 signaling in vivo by applying Plerixafor^® strongly impaired the capacity of GCs to interfere with EAE, as revealed by an aggravated disease course, more pronounced CNS infiltration and a more dispersed distribution of the infiltrating T cells throughout the parenchyma. Our observation that T cells lacking the GC receptor were refractory to CXCL12 further underscores the importance of this pathway for the treatment of EAE by GCs. Importantly, methylprednisolone pulse therapy strongly increased the capacity of peripheral blood T cells from MS patients of different subtypes to migrate towards CXCL12. This indicates that modulation of T cell migration is an important mechanistic principle responsible for the efficacy of high-dose GC therapy not only of EAE but also of MS.     

Folding without charges

Surface charges of proteins have in several cases been found to function as “structural gatekeepers,” which avoid unwanted interactions by negative design, for example, in the control of protein aggregation and binding. The question is then if side-chain charges, due to their desolvation penalties, play a corresponding role in protein folding by avoiding competing, misfolded traps? To find out, we removed all 32 side-chain charges from the 101-residue protein S6 from Thermus thermophilus. The results show that the charge-depleted S6 variant not only retains its native structure and cooperative folding transition, but folds also faster than the wild-type protein. In addition, charge removal unleashes pronounced aggregation on longer timescales. S6 provides thus an example where the bias toward native contacts of a naturally evolved protein sequence is independent of charges, and point at a fundamental difference in the codes for folding and intermolecular interaction: specificity in folding is governed primarily by hydrophobic packing and hydrogen bonding, whereas solubility and binding relies critically on the interplay of side-chain charges.     

Pre-vaccination incidence of genital warts in 15-23-year-old women and men attending youth clinics in Stockholm, Sweden

Abstract Background: Human papillomavirus (HPV) vaccines were introduced to the market in 2006 and 2007. The present pilot study was designed to examine the incidence of genital warts in the population up to 23 y of age in the county of Stockholm before the start of mass HPV vaccination. Methods: Data from the electronic health records of 9 youth clinics in the county of Stockholm were collected retrospectively for the y 2006-2008. Results: In total, 49,985 patients visited the study youth clinics during 2006-2008. Of these, 1817 were denoted genital warts patients. An extrapolation of the study data was done in an attempt to estimate the annual number of genital warts cases in the full Stockholm County population aged 15-23 y. Results showed that there were approximately 1792 genital warts patients in the age group 15-23 y each year in Stockholm County. Female cases represented approximately 62% of all cases in the age group 15-23 y. The peak incidence was at around 20 y of age for females, while males had a more flattened peak incidence around 19-23 y of age. Conclusion: This pilot study demonstrates that, compared to other reported data, genital warts are at least as common in Sweden as in other countries among 15-23 y old females and males.     

Tolerance to apoptotic cells is regulated by indoleamine 2,3-dioxygenase

Tolerance to self-antigens present in apoptotic cells is critical to maintain immune-homeostasis and prevent systemic autoimmunity. However, mechanisms that sustain self-tolerance are poorly understood. Here we show that systemic administration of apoptotic cells to mice induced splenic expression of the tryptophan catabolizing enzyme indoleamine 2,3-dioxygenase (IDO). IDO expression was confined to the splenic marginal zone and was abrogated by depletion of CD169(+) cells. Pharmacologic inhibition of IDO skewed the immune response to apoptotic cells, resulting in increased proinflammatory cytokine production and increased effector T-cell responses toward apoptotic cell-associated antigens. Presymptomatic lupus-prone MRL(lpr/lpr) mice exhibited abnormal elevated IDO expression in the marginal zone and red pulp and inhibition of IDO markedly accelerated disease progression. Moreover, chronic exposure of IDO-deficient mice to apoptotic cells induced a lupus-like disease with serum autoreactivity to double-stranded DNA associated with renal pathology and increased mortality. Thus, IDO limits innate and adaptive immunity to apoptotic self-antigens and IDO-mediated regulation inhibits inflammatory pathology caused by systemic autoimmune disease.     

Associations between inflammatory markers, candidate polymorphisms and physical performance in older Danish twins

Inflammation may play an essential role in the decline of physical performance. In this study we investigated the associations between inflammatory markers, candidate polymorphisms and physical performance in elderly people. Plasma levels of TNF-α, IL-6, CRP, fibrinogen, sICAM-1 and candidate polymorphisms were measured in 600 twin individuals aged 73 years and older participating in the Longitudinal Study of Aging Danish Twins. Physical performance was assessed using a self-reported measure. The inclusion of twins allowed both traditional and within-twin-pair analysis which permitted control for shared environment and genetic factors. Higher levels of inflammatory markers were generally associated with a lower level of physical performance. The TNFα-238G/A polymorphism was significantly associated with physical performance in men, with A allele carriers having significantly better performance than GG homozygotes. However, this gene variation seems to have only a minor role in explaining the associations between the levels of inflammatory markers and physical performance. When using twin pair analysis to test whether genetic factors in general account for this association, results showed that the association between the level of fibrinogen and physical performance could be caused by genetic factors. Also the association between the level of TNF-α and physical performance in males could be caused by genetic factors. However, other gene variations than the candidate gene polymorphisms studied here seem to explain the major part of the genetic proportion of this association.