👤 Vineeta Bal

The combination of acute pancreatitis (AP), severe hypertriglyceridemia (HTG), and diabetic ketoacidosis (DKA) poses a life-threatening triad. Although DKA is a frequent complication in children, this triad is rare. We report a 10-year-old girl with type 1 diabetes mellitus (T1DM) for 10 months, who presented with DKA, severe HTG, and AP. Her serum was lipemic. She had HTG (1733 mg/dl, 19.5 mmol/L; reference range, 90-129 mg/dl, 1,016-1,456 mmol/L) and severe abdominal pain that did not improve despite treatment for ketoacidosis. She had high lipase levels (1581 U/L, reference range 28-100 U/L), and pancreatitis was detected on abdominal tomography. She recovered with a combination of hydration and insulin therapy. A heterozygous p.N318S (c.953A>G) variant was detected in her lipoprotein lipase (LPL) gene. Her apolipoprotein B (ApoB) was elevated at 1.44 g/L (reference range, 0.6-1.17 g/L, 60-117 mg/dl). It is well established that both the likely pathogenic LPL variants and high ApoB concentrations contribute to an increased risk of cardiovascular complications. Therefore, it is recommended to evaluate for a pathogenic variant in the LPL gene in children with T1DM who do not have dyslipidemia but exhibit the rare triad of AP, HTG, and DKA. Show less

As individual naïve CD4 T lymphocytes circulate in the body after emerging from the thymus, they are likely to have individually varying microenvironmental interactions even in the absence of stimulation via specific target recognition. It is not clear if these interactions result in alterations in their activation, survival and effector programming. Naïve CD4 T cells show unimodal distribution for many phenotypic properties, suggesting that the variation is caused by intrinsic stochasticity, although underlying variation due to subsets created by different histories of microenvironmental interactions remains possible. To explore this possibility, we began examining the phenotype and functionality of naïve CD4 T cells differing in a basic unimodally distributed property, the CD4 levels, as well as the causal origin of these differences. We examined separated CD4hi and CD4lo subsets of mouse naïve CD4 cells. CD4lo cells were smaller with higher CD5 levels and lower levels of the dual-specific phosphatase (DUSP)6-suppressing micro-RNA miR181a, and responded poorly with more Th2-skewed outcomes. Human naïve CD4lo and CD4hi cells showed similar differences. Naïve CD4lo and CD4hi subsets of thymic single-positive CD4 T cells did not show differences whereas peripheral naïve CD4lo and CD4hi subsets of T cell receptor (TCR)-transgenic T cells did. Adoptive transfer-mediated parking of naïve CD4 cells in vivo lowered CD4 levels, increased CD5 and reactive oxygen species (ROS) levels and induced hyporesponsiveness in them, dependent, at least in part, on availability of major histocompatibility complex class II (MHCII) molecules. ROS scavenging or DUSP inhibition ameliorated hyporesponsiveness. Naïve CD4 cells from aged mice showed lower CD4 levels and cell sizes, higher CD5 levels, and hyporesponsiveness and Th2-skewing reversed by DUSP inhibition. Our data show that, underlying a unimodally distributed property, the CD4 level, there are subsets of naïve CD4 cells that vary in the time spent in the periphery receiving MHCII-mediated signals and show resultant alteration of phenotype and functionality via ROS and DUSP activity. Our findings also suggest the feasibility of potential pharmacological interventions for improved CD4 T cell responses during vaccination of older people via either anti-oxidant or DUSP inhibitor small molecules. Show less