Many common disorders of pregnancy are attributed to insufficient invasion of the uterine lining by trophoblast, fetal cells that are the major cell type of the placenta. Interactions between fetal... Show moreMany common disorders of pregnancy are attributed to insufficient invasion of the uterine lining by trophoblast, fetal cells that are the major cell type of the placenta. Interactions between fetal trophoblast and maternal uterine NK (uNK) cells - specifically interactions between HLA-C molecules expressed by the fetal trophoblast cells and killer Ig-like receptors (KIRs) on the maternal uNK cells - influence placentation in human pregnancy. Consistent with this, pregnancies are at increased risk of preeclampsia in mothers homozygous for KIR haplotype A (KIR AA). In this study, we have demonstrated that trophoblast expresses both paternally and maternally inherited HLA-C surface proteins and that maternal KIR AA frequencies are increased in affected pregnancies only when the fetus has more group 2 HLA-C genes (C2) than the mother. These data raise the possibility that there is a deleterious allogeneic effect stemming from paternal C2. We found that this effect also occurred in other pregnancy disorders (fetal growth restriction and recurrent miscarriage), indicating a role early in gestation for these receptor/ligand pairs in the pathogenesis of reproductive failure. Notably, pregnancy disorders were less frequent in mothers that possessed the telomeric end of the KIR B haplotype, which contains activating KIR2DS1. In addition, uNK cells expressed KIR2DS1, which bound specifically to C2(+) trophoblast cells. These findings highlight the complexity and central importance of specific combinations of activating KIR and HLA-C in maternal-fetal immune interactions that determine reproductive success. Show less
Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and attacks of muscle atonia triggered by strong emotions (cataplexy). Narcolepsy is caused by hypocretin (orexin)... Show moreNarcolepsy is a sleep disorder characterized by excessive daytime sleepiness and attacks of muscle atonia triggered by strong emotions (cataplexy). Narcolepsy is caused by hypocretin (orexin) deficiency, paralleled by a dramatic loss in hypothalamic hypocretin-producing neurons. It is believed that narcolepsy is an autoimmune disorder, although definitive proof of this, such as the presence of autoantibodies, is still lacking. We engineered a transgenic mouse model to identify peptides enriched within hypocretin-producing neurons that could serve as potential autoimmune targets. Initial analysis indicated that the transcript encoding Tribbles homolog 2 (Trib2), previously identified as an autoantigen in autoimmune uveitis, was enriched in hypocretin neurons in these mice. ELISA analysis showed that sera from narcolepsy patients with cataplexy had higher Trib2-specific antibody titers compared with either normal controls or patients with idiopathic hypersomnia, multiple sclerosis, or other inflammatory neurological disorders. Trib2-specific antibody titers were highest early after narcolepsy onset, sharply decreased within 2-3 years, and then stabilized at levels substantially higher than that of controls for up to 30 years. High Trib2-specific antibody titers correlated with the severity of cataptexy. Serum of a patient showed specific immunoreactivity with over 86% of hypocretin neurons in the mouse hypothalamus. Thus, we have identified reactive autoantibodies in human narcolepsy, providing evidence that narcolepsy is an autoimmune disorder. Show less
Gaucher disease (GD; glucosylceramidosis) is caused by a deficient activity of the enzyme glucocerebrosidase (GC). Clinical manifestations are highly variable and cannot be predicted accurately on... Show moreGaucher disease (GD; glucosylceramidosis) is caused by a deficient activity of the enzyme glucocerebrosidase (GC). Clinical manifestations are highly variable and cannot be predicted accurately on the basis of the properties of mutant GC. Analysis of secondary abnormalities, such as elevated plasma levels of some hydrolases, may help to increase insight into the complicated pathophysiology of the disease and could also provide useful disease markers. The recent availability of enzyme supplementation therapy for GD increases the need for markers as early predictors of the efficacy of treatment. We report the finding of a very marked increase in chitotrisidase activity in plasma of 30 of 32 symptomatic type 1 GD patients studied: the median activity being > 600 times the median value in plasma of healthy volunteers. In three GC-deficient individuals without clinical symptoms, only slight increases were noted. Chitotriosidase activity was absent in plasma of three control subjects and two patients. During enzyme supplementation therapy, chitotriosidase activity declined dramatically. We conclude that plasma chitotriosidase levels can serve as a new diagnostic hallmark of GD and should prove to be useful in assessing whether clinical manifestations of GD are present and for monitoring the efficacy of therapeutic intervention. Show less
