Effects of Bacille Calmette-Guerin after the first demyelinating event in the CNS

The interplay between bacillus Calmette-Guérin and Treg cells and its role to prevent or cure inflammatory diseases

Clinical evidence indicates that Bacillus Calmette-Guérin (BCG) vaccination exerts anti-inflammatory effects in diseases such as asthma, multiple sclerosis or Type 1 diabetes. Although the exact mechanisms for this activity remain debated, the capacity of mycobacteria to induce regulatory T cells (Tregs) in vivo has been widely reported. However, adverse events associated with live BCG prevent its repeated use, especially in immunocompromised individuals. This article reviews the preclinical data showing a potent, systemic and long-term anti-inflammatory effect in animal models of allergic asthma, inflammatory bowel disease and atherosclerosis with a preparation of BCG inactivated by Extended Freeze-Drying (EFD BCG). It also presents the characteristics of EFD BCG-induced Tregs which play a crucial role in the immunomodulation of various inflammatory diseases. Finally, it compares EFD BCG with other approaches based on the therapeutic use of Tregs in humans.

Evaluation of the humoral response against mycobacterial peptides, homologous to MOG₃₅₋₅₅, in multiple sclerosis patients

Bacillus Calmette-Guérin (BCG) and Mycobacterium avium subspecies paratuberculosis (MAP) have been associated with multiple sclerosis (MS). Clinical data indicates that BCG vaccination exerts anti-inflammatory effects in MS; conversely, MAP is thought to be one of the possible infectious factors responsible of MS through a molecular mimicry mechanism. A peptide-based indirect ELISA was used to detect antibodies against the encephalitogenic myelin oligodendrocyte glycoprotein (MOG)35-55 epitope, and two mycobacterial peptides sharing sequence homology with the latter: MAP_2619c352-361/BCG_1224355-364 and BCG_3329c64-74. Among 40 MS patients and 39 healthy volunteers included in the study, only MOG35-55 was capable of inducing a significantly higher humoral response in MS subjects compared to controls. Indeed, 11 out of 40 MS subjects (27.5%) and only 2 out of 39 controls (5%) were antibody-positive for MOG35-55 (p=0.01, AUC=0.65). These findings strengthen the importance of MOG35-55 in MS pathogenesis. The MAP and BCG MOG-homologues epitopes investigated were not recognized in MS patients. Overall, the results allow us concluding that sharing homology of linear epitopes is necessary but not sufficient to induce antibody-mediated cross-reactivity.

Noise in multiple sclerosis: unwanted and necessary

As our knowledge about the etiology of multiple sclerosis (MS) increases, deterministic paradigms appear insufficient to describe the pathogenesis of the disease, and the impression is that stochastic phenomena (i.e. random events not necessarily resulting in disease in all individuals) may contribute to the development of MS. However, sources and mechanisms of stochastic behavior have not been investigated and there is no proposed framework to incorporate nondeterministic processes into disease biology. In this report, we will first describe analogies between physics of nonlinear systems and cell biology, showing how small-scale random perturbations can impact on large-scale phenomena, including cell function. We will then review growing and solid evidence showing that stochastic gene expression (or gene expression “noise”) can be a driver of phenotypic variation. Moreover, we will describe new methods that open unprecedented opportunities for the study of such phenomena in patients and the impact of this information on our understanding of MS course and therapy.