Effectiveness of therapeutic plasma exchange in a critically ill child with secondary hemophagocytic lymphohistiocytosis.

Currently, the ASFA has not included TPE in the management of HLH but many cases reports have reported successful role of TPE in HLH. Here we are presenting a case in which HLH was managed successfully with TPE. Diagnosis of HLH is based on the HLH 2004 diagnostic criteria proposed by HLH society. TPE was done using COM. TEC (Fresenius Kabi, Germany). Patient required three sessions of TPE. After three sessions of TPE patient's clinical condition improved remarkably and he was switched to IV Dexamethasone as maintenance treatment. One standard TPE procedure was 1.5 plasma volume exchanges. In view of deranged coagulation profile fresh frozen plasma was used as a replacement fluid. During follow up after one month of discharge, patient was absolutely normal. In developing countries like India, where infections are still a prime concern to the physicians, making an accurate diagnosis of HLH is a great concern. High suspicion, timely diagnosis and early start of TPE can be life saving in such patients.

Production of viable gametes without meiosis in maize deficient for an ARGONAUTE protein.

Apomixis is a form of asexual reproduction through seeds in angiosperms. Apomictic plants bypass meiosis and fertilization, developing offspring that are genetically identical to their mother. In a genetic screen for maize (Zea mays) mutants mimicking aspects of apomixis, we identified a dominant mutation resulting in the formation of functional unreduced gametes. The mutant shows defects in chromatin condensation during meiosis and subsequent failure to segregate chromosomes. The mutated locus codes for AGO104, a member of the ARGONAUTE family of proteins. AGO104 accumulates specifically in somatic cells surrounding the female meiocyte, suggesting a mobile signal rather than cell-autonomous control. AGO104 is necessary for non-CG methylation of centromeric and knob-repeat DNA. Digital gene expression tag profiling experiments using high-throughput sequencing show that AGO104 influences the transcription of many targets in the ovaries, with a strong effect on centromeric repeats. AGO104 is related to Arabidopsis thaliana AGO9, but while AGO9 acts to repress germ cell fate in somatic tissues, AGO104 acts to repress somatic fate in germ cells. Our findings show that female germ cell development in maize is dependent upon conserved small RNA pathways acting non-cell-autonomously in the ovule. Interfering with this repression leads to apomixis-like phenotypes in maize.