Bacille Calmette Guerin (BCG) and prevention of types 1 and 2 diabetes: Results of two observational studies.

BACKGROUND: Diabetes is a common disease marked by high blood sugars. An earlier clinical trial in type 1 diabetic subjects (T1Ds) found that repeat BCG vaccinations succeeded in lowering HbA1c values over a multi-year course. Here we seek to determine whether BCG therapy for bladder cancer may improve blood sugar levels in patients with comorbid T1D and type 2 diabetes (T2D). We also investigate whether BCG exposure may reduce onset of T1D and T2D by examining country-by-country impact of BCG childhood vaccination policies in relation to disease incidence. METHODS AND FINDINGS: We first analyzed three large US patient datasets (Optum Labs data [N = 45 million], Massachusetts General Brigham [N = 6.5 million], and Quest Diagnostics [N = 263 million adults]), by sorting out subjects with documented T1D (N = 19) or T2D (N = 106) undergoing BCG therapy for bladder cancer, and then by retrospectively assessing BCG's subsequent year-by-year impact on blood sugar trends. Additionally, we performed an ecological analysis of global data to assess the country-by-country associations between mandatory neonatal BCG vaccination programs and T1D and T2D incidence. Multi-dose BCG therapy in adults with comorbid diabetes and bladder cancer was associated with multi-year and stable lowering of HbA1c in T1Ds, but not in T2Ds. The lack of a similar benefit in T2D may be due to concurrent administration of the diabetes drug metformin, which inhibits BCG's beneficial effect on glycolysis pathways. Countries with mandatory neonatal BCG vaccination policies had a lower incidence of T1D in two international databases and a lower incidence of T2D in one of the databases. CONCLUSIONS: The epidemiological evidence analyzed here suggests that BCG may play a role in the prevention of T1D. It does not support prevention of T2D, most likely because of interference by metformin. Our ecological analysis of global data suggests a role for neonatal BCG in the prevention of T1D and, to a lesser extent, T2D. Randomized clinical trials are needed to confirm these findings.

BCG vaccinations drive epigenetic changes to the human T cell receptor: Restored expression in type 1 diabetes.

The BCG (Bacille Calmette-Guérin) vaccine, introduced 100 years ago for tuberculosis prevention, has emerging therapeutic off-target benefits for autoimmunity. In randomized controlled trials, BCG vaccinations were shown to gradually improve two autoimmune conditions, type 1 diabetes (T1D) and multiple sclerosis. Here, we investigate the mechanisms behind the autoimmune benefits and test the hypothesis that this microbe synergy could be due to an impact on the host T cell receptor (TCR) and TCR signal strength. We show a quantitative TCR defect in T1D subjects consisting of a marked reduction in receptor density on T cells due to hypermethylation of TCR-related genes. BCG corrects this defect gradually over 3 years by demethylating hypermethylated sites on members of the TCR gene family. The TCR sequence is not modified through recombination, ruling out a qualitative defect. These findings support an underlying density defect in the TCR affecting TCR signal strength in T1D.

Multiple BCG vaccinations for the prevention of COVID-19 and other infectious diseases in type 1 diabetes.

There is a need for safe and effective platform vaccines to protect against coronavirus disease 2019 (COVID-19) and other infectious diseases. In this randomized, double-blinded, placebo-controlled phase 2/3 trial, we evaluate the safety and efficacy of a multi-dose Bacillus Calmette-Guérin (BCG) vaccine for the prevention of COVID-19 and other infectious disease in a COVID-19-unvaccinated, at-risk-community-based cohort. The at-risk population is made of up of adults with type 1 diabetes. We enrolled 144 subjects and randomized 96 to BCG and 48 to placebo. There were no dropouts over the 15-month trial. A cumulative incidence of 12.5% of placebo-treated and 1% of BCG-treated participants meets criteria for confirmed COVID-19, yielding an efficacy of 92%. The BCG group also displayed fewer infectious disease symptoms and lesser severity and fewer infectious disease events per patient, including COVID-19. There were no BCG-related systemic adverse events. BCG's broad-based infection protection suggests that it may provide platform protection against new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and other pathogens.

Epigenetic changes related to glucose metabolism in type 1 diabetes after BCG vaccinations: A vital role for KDM2B.

BACKGROUND: A recent epigenome-wide association study of genes associated with type 2 diabetics (T2D), used integrative cross-omics analysis to identify 22 abnormally methylated CpG sites associated with insulin and glucose metabolism. Here, in this epigenetic analysis we preliminarily determine whether the same CpG sites identified in T2D also apply to type 1 diabetes (T1D). We then determine whether BCG vaccination could correct the abnormal methylation patterns, considering that the two diseases share metabolic derangements. METHODS: T1D (n = 13) and control (n = 8) subjects were studied at baseline and then T1D subjects studied yearly for 3 years after receiving BCG vaccinations in a clinical trial. In this biomarker analysis, methylation patterns were evaluated on CD4+ T-lymphocytes from baseline and yearly blood samples using the human Illumina Methylation EPIC Bead Chip. Methylation analysis combined with mRNA analysis using RNAseq. RESULTS: Broad but not complete overlap was observed between T1D and T2D in CpG sites with abnormal methylation. And in the three-year observation period after BCG vaccinations, the majority of the abnormal methylation sites were corrected in vivo. Genes of particular interest were related to oxidative phosphorylation (CPT1A, LETM1, ABCG1), to the histone lysine demethylase gene (KDM2B), and mTOR signaling through the DDIT4 gene. The highlighted CpG sites for both KDM2B and DDIT4 genes were hypomethylated at baseline compared to controls; BCG vaccination corrected the defect by hypermethylation. CONCLUSIONS: Glycolysis is regulated by methylation of genes. This study unexpectedly identified both KDM2B and DDIT4 as genes controlling BCG-driven re-methylation of histones, and the activation of the mTOR pathway for facilitated glucose transport respectively. The BCG effect at the gene level was confirmed by reciprocal mRNA changes. The DDIT4 gene with known inhibitory role of mTOR was re-methylated after BCG, a step likely to allow improved glucose transport. BCGs driven methylation of KDM2B's site should halt augmented histone activity, a step known to allow cytokine activation and increased glycolysis.

The N-Terminal Region of Fibrillin-1 Mediates a Bipartite Interaction with LTBP1.

Fibrillin-1 (FBN1) mutations associated with Marfan syndrome lead to an increase in transforming growth factor ß (TGF-ß) activation in connective tissues resulting in pathogenic changes including aortic dilatation and dissection. Since FBN1 binds latent TGF-ß binding proteins (LTBPs), the major reservoir of TGF-ß in the extracellular matrix (ECM), we investigated the structural basis for the FBN1/LTBP1 interaction. We present the structure of a four-domain FBN1 fragment, EGF2-EGF3-Hyb1-cbEGF1 (FBN1E2cbEGF1), which reveals a near-linear domain organization. Binding studies demonstrate a bipartite interaction between a C-terminal LTBP1 fragment and FBN1E2cbEGF1, which lies adjacent to the latency-associated propeptide (LAP)/TGF-ß binding site of LTBP1. Modeling of the binding interface suggests that, rather than interacting along the longitudinal axis, LTBP1 anchors itself to FBN1 using two independent epitopes. As part of this mechanism, a flexible pivot adjacent to the FBN1/LTBP1 binding site allows LTBP1 to make contacts with different ECM networks while presumably facilitating a force-induced/traction-based TGF-ß activation mechanism.