技术资料

Essential thrombocythemia (ET) and polycythemia vera (PV) are clonal myeloproliferative disorders that are often difficult to distinguish from other causes of elevated blood cell counts. Assays that could reliably detect clonal hematopoiesis would therefore be extremely valuable for diagnosis. We previously reported 3 X-chromosome transcription-based clonality assays (TCAs) involving the G6PD,IDS,and MPP1 genes,which together were informative in about 65% of female subjects. To increase our ability to detect clonality,we developed simple TCA for detecting the transcripts of 2 additional X-chromosome genes: Bruton tyrosine kinase (BTK) and 4-and-a-half LIM domain 1 (FHL1). The combination of TCA established the presence or absence of clonal hematopoiesis in about 90% of female subjects. We show that both genes are subject to X-chromosome inactivation and are polymorphic in all major US ethnic groups. The 5 TCAs were used to examine clonality in 46 female patients along with assays for erythropoietin-independent erythroid colonies (EECs) and granulocyte PRV-1 mRNA levels to discriminate polycythemias and thrombocytoses. Of these,all 19 patients with familial polycythemia or thrombocytosis had polyclonal hematopoiesis,whereas 22 of 26 patients with clinical evidence of myeloproliferative disorder and 1 patient with clinically obscure polycythemia were clonal. Interestingly,interferon alpha therapy in 2 patients with PV was associated with reversion of clonal to polyclonal hematopoiesis. EECs were observed in 14 of 14 patients with PV and 4 of 12 with ET,and increased granulocyte PRV-1 mRNA levels were found in 9 of 13 patients with PV and 2 of 12 with ET. Thus,these novel clonality assays are useful in the diagnosis and follow-up of polycythemic conditions and disorders with increased platelet levels. View Publication

The expression and function of the NK cell receptor KIR2DL4 are controversial. Two common alleles of the transmembrane domain of KIR2DL4 exist. The 10A allele with 10 adenines at the end of the transmembrane exon encodes a full length receptor,whereas the 9A allele has only 9 adenines resulting in a frame shift which in turn generates a stop codon early in the first cytoplasmic exon. The possibility that the 10A and 9A alleles might result in differences in expression and function of KIR2DL4 was explored using mAbs to KIR2DL4. Transfection experiments with cDNA from the 10A and 9A alleles revealed significant membrane expression only with the protein encoded by the 10A allele. Analysis of peripheral blood NK cells demonstrated that only in subjects with at least one 10A allele was cell surface expression of KIR2DL4 detectable,and then only on the minor CD56(bright) NK cell subset. The major CD56(dim) NK cell subset did not cell surface express KIR2DL4 but,interestingly,did so after in vitro culture. Functional analysis using cultured NK cells in redirected lysis assays demonstrated that KIR2DL4 is an activating receptor for NK cells with at least one 10A allele. No significant activity was detected for NK cells generated from subjects homozygous for the 9A allele. These data show that genotype influences cell surface expression and function of KIR2DL4 which may account for reported differences in KIR2DL4 expression and function. View Publication