ABSTRACT
Ras-associated lymphoproliferative disease (RALD) is an autoimmune lymphoproliferative syndrome (ALPS)-like disease caused by mutations in Kirsten rat sarcoma viral oncogene homologue (KRAS) or neuroblastoma RAS viral (V-Ras) oncogene homologue (NRAS). The immunological phenotype and pathogenesis of RALD have yet to be studied extensively. Here we report a thorough immunological investigation of a RALD patient with a somatic KRAS mutation. Patient lymphocytes were analysed for phenotype, immunoglobulin levels and T cell proliferation capacity. T and B cell receptor excision circles (TREC and KREC, respectively), markers of naive T and B cell production, were measured serially for 3 years. T and B cell receptor repertoires were studied using both traditional assays as well as next-generation sequencing (NGS). TREC and KREC declined dramatically with time, as did T cell receptor diversity. NGS analysis demonstrated T and B clonal expansions and marked restriction of T and B cell receptor repertoires compared to healthy controls. Our results demonstrate, at least for our reported RALD patient, how peripheral T and B clonal expansions reciprocally limit lymphocyte production and restrict the lymphocyte receptor repertoire in this disease. Decreased naive lymphocyte production correlated with a clinical deterioration in our patient's immune status, suggesting that TREC and KREC may be used as an aid in monitoring disease progression. Both the methodologies used here and the conclusions regarding immune homeostasis may be applicable to the research of ALPS and other immune dysregulation syndromes.
Subject(s)
Autoimmune Lymphoproliferative Syndrome/genetics , Autoimmune Lymphoproliferative Syndrome/immunology , B-Lymphocytes/physiology , Genes, ras , Mutation , T-Lymphocytes/physiology , B-Lymphocytes/immunology , Child , Female , High-Throughput Nucleotide Sequencing , Humans , Phenotype , Receptors, Antigen, B-Cell/genetics , Receptors, Antigen, B-Cell/immunology , Receptors, Antigen, T-Cell/genetics , Receptors, Antigen, T-Cell/immunology , T-Lymphocytes/immunologyABSTRACT
Von Willebrand Factor (VWF) has a central role in primary hemostasis. Its biological activity is related to the size of VWF multimers, spontaneously binding to platelets and inducing circulating microthrombi formation. This process is down-regulated by the VWF cleaving protease ADAMTS13 (A Disintegrin and Metalloprotease with ThromboSpondin motif). To date, information regarding the levels of ADAMTS13 in neonates and preterm infants is scarce. Our aim was to study ADAMTS13, VWF antigen (Ag) and Ristocetin cofactor (RiCof) activity in neonates and evaluate potential correlations with perinatal complications. Our cohort consisted of 128 (48/128: born preterm) neonates, born in Sheba Medical Center and followed until hospital discharge. Control group consisted of 20 healthy adults. As expected, a significant elevation of VWF:Ag was observed in preterm and term infants compared to adults. VWF:Ag levels were highest in full term infants (Median 129.0 IQR 33.8) and lowest in adults (Median 119.0 IQR 58.5) (p<0.05), and RiCoF levels in neonates were higher than in adults. ADAMTS13 was significantly (p<0.05) higher in preterm babies in comparison to full term and adult controls. Neonates that underwent stressful conditions or experienced vascular complications such as IUGR, ROP, NEC, had lower levels of ADAMTS13 in our study. Further studies are required to validate and asses potential significance of these findings.
