Hereditary lymphedema is a developmental disorder characterized by chronic swelling of the extremities due to dysfunction of the lymphatic vessels. Two responsible genes have been identified: the vascular endothelial growth factor receptor 3 (VEGFR3) gene, implicated in congenital lymphedema, or Milroy disease, and the forkhead-related transcription factor gene FOXC2, causing lymphedema-distichiasis. We describe three families with an unusual association of hypotrichosis, lymphedema, and telangiectasia. Using microsatellite analysis, we first excluded both VEGFR3 and FOXC2 as causative genes; we then considered the murine ragged phenotype, caused by mutations in the Sox18 transcription factor, as a likely counterpart to the human disease, because it presents a combination of hair and cardiovascular anomalies, including symptoms of lymphatic dysfunction. Two of the families were consanguineous; in affected members of these families, we identified homozygous missense mutations in the SOX18 gene, located in 20q13. The two amino acid substitutions, W95R and A104P, affect conserved residues in the first alpha helix of the DNA-binding domain of the transcription factor. In the third family, the parents were nonconsanguineous, and both the affected child and his brother, who died in utero with hydrops fetalis, showed a heterozygous nonsense mutation that truncates the SOX18 protein in its transactivation domain; this substitution was not found in genomic DNA from either parent and hence constitutes a de novo germline mutation. Thus, we show that SOX18 mutations in humans cause both recessive and dominant hypotrichosis-lymphedema-telangiectasia, suggesting that, in addition to its established role in hair and blood vessel development, the SOX18 transcription factor plays a role in the development and/or maintenance of lymphatic vessels.

A new red emitting fluorophore, TO-PRO-3 iodide (TP3), which is best excited by an HeNe laser (633 nm), has been compared with propidium iodide (PI) for measuring relative DNA content. TP3, which has a peak absorbance at 642 nm and emission at 661 nm, has been tested on peripheral blood lymphocytes (PBL) and keratinocytes in a two-laser system. As an example, we present a three-color flow cytometric application utilizing TP3 in combination with fluorescein-isothiocyanate (FITC) and phycoerythrin (PE) conjugated to monoclonal antibodies in this paper.A subequilibrium concentration of 1 pM TP3, most preferably used in combination with RNase treatment, proved to be a powerful alternative for DNA amount determination. In humanand mouse-Balb/MK-keratinocyte populations with different S-phase fractions, PI and TP3 showed a good correlation.Finally, in the triple labelling experiment we clearly demonstrated that TP3 is readily applied to the analysis of binding of two antibodies and relative DNA content simultaneously. 0 1994 Wiley-Liss, Inc.

Multi para meter flow cytometric characterization of epidermal cell suspensions prepared from normal and hyperproliferative human skin using an optimized thermolysin-trypsin protocol

Multi para meter flow cytometric characterization of epidermal cell suspensions prepared from normal and hyperproliferative human skin using an optimized thermolysin-trypsin protocol

SummaryObjective comparison of different antipsoriatic therapies requires quantitative assessment of disease severity. However, clinical assessment with the widely used Psoriasis Area and Severity Index (PASI) inaccuracy. An alternative is the quantitative analysis of different epidermal cell parameters using multiparameter flow cytometry. Our aim in the present study was to compare the clinical and flow cytometric approach to monitor disease activity and to evaluate antipsoriatic efficacy. Clinical scores for erythema, induration and scaling were assessed and biopsies for flow cytometric analysis were obtained from the psoriatic plaques of 89 patients before and after treatment with different therapeutic regimens consisting of vitamin D3 analogues and cortico steroids. In total, 219 epidermal cell suspensions were analysed using triple-labelling, with the simultaneous staining of markers for epidermal proliferation (DNA dye TO-PRO-3), differentiation