Project description:Severe thrombocytopenia can be a determinant factor in the morbidity of Plasmodium vivax (Pv), the most widespread human malaria. Although immune mechanisms may drive Pv-induced severe thrombocytopenia (PvST), the current data on the cytokine landscape in PvST is scarce, and often conflicting. The analysis of the bidirectional circuit of inflammatory mediators and miRNAs would lead to a better understanding of the mechanisms underlying PvST.
Project description:Leprosy is a chronic granulomatous disease caused by infection with Mycobacterium leprae. Genetic association studies indicated that leprosy risk is strongly associated with variation within the major histocompatibility complex (MHC) region, but the full number of variants in this region has yet to be elucidated. To identify further susceptibility loci or loss of function variants for this disease, we performed fine-mapping analysis of the MHC region using a Han Chinese reference panel (n= 10,689 patients, 29,948 genetic markers) in the data sets from our previous leprosy studies. Then, a fixed-effect meta-analysis was carried out separately for Chinese (case=2,901, control=3,801) and North Chinese (case=1,983, control=2,635) participants. The meta-analysis of Chinese participants identified 10 HLA-type or amino acid variants with lower than the genome-wide significant susceptibility signal. Next, gene-by-gene step-wise conditional analysis was performed in the combined dataset of these cohorts. Finally, we identified four new independent susceptibility loci (HLA-DQA1, HLA-C, rs3129063, and rs58327373) and confirmed one previously reported locus (HLA-DRB1) that significantly associated with leprosy in the Chinese Han population. Thus the results of this study increase knowledge about leprosy risk variants and illustrate the value of HLA imputation for fine mapping of causal variants in the MHC.
Project description:Host factors governing mild disease in adults who have developed clinical immunity to Plasmodium falciparum may provide insights for disease altering vaccine or interventions, to prevent severe malaria We used microarrays of whole blood samples during mild malaria and compared them in a paired analysis to whole blood microarray 30 days later. (n=19 pairs)
Project description:Abstract of associated publication: Background: During the latter half of the natural 48-hour intraerythrocytic life cycle of human Plasmodium falciparum infection, parasites sequester deep in endothelium tissues, away from the spleen and inaccessible to peripheral blood. These late-stage parasites may cause tissue damage and likely contribute to clinical disease, and a more complete understanding of their biology is needed. Because these life cycle stages are not easily sampled due to deep tissue sequestration, measuring in vivo gene expression of parasites in the trophozoite and schizont stages has been a challenge. Methods: We developed a custom nCounter® gene expression platform, and used this platform to measure malaria parasite gene expression profiles in vitro and in vivo. We also used imputation to generate global transcriptional profiles, and assessed differential gene expression between parasites growing in vitro and those recovered from malaria-infected patient tissues collected at autopsy. Results: We demonstrate, for the first time, global transcriptional expression profiles from in vivo malaria parasites sequestered in human tissues. We found that parasite physiology can be correlated with in vitro data from an existing life cycle data set, and that parasites in sequestered tissues show an expected schizont-like transcriptional profile, which is conserved across tissues from the same patient. Imputation based on 60 landmark genes generated global transcriptional profiles that were highly correlated with genome-wide expression patterns from the same sample measured by microarray. Finally, differential expression revealed a limited set of in vivo upregulated transcripts, which may indicate unique parasite genes involved in human clinical infections. Conclusions: Our study highlights the utility of a custom nCounter® P. falciparum probe set, validation of imputation within Plasmodium species, and documentation of in vivo schizont-stage expression patterns from human tissues.