Email: [email protected]
Abstract form
Title: How does the absolute MCHbF in adult F-cells correlate with
genomic variants in HPFH?
Presenter: Jeanesse Scerri
Contact address: C1, Sir Leslie Rundle Str. Mtarfa
Tel: 79459473
Email: [email protected]
Presentation date: 26th May, 2014
Around birth, a shift from γ- to β-globin gene expression causes a switch from
foetal haemoglobin (HbF) to adult haemoglobin (HbA). Residual amounts of HbF are
synthesized throughout life and localized in erythrocytes termed F-cells. Increased
HbF levels are known to ameliorate symptoms of β-haemoglobinopathies.
Krüppel-like factor 1 (KLF1) plays a central role in the developmental globin gene
switch; carriers of KLF1 mutations have hereditary persistence of foetal
haemoglobin (HPFH) and show variably elevated (10-40%) HbF. This variation may
be due to differential expression of other modifier genes. The KLF1 interactome can
be further defined by identifying potential molecular targets and observing their
expression at the cellular level in comparison with HbF expression and distribution
in F-cells. While analysing next generation sequencing (NGS) data of a Maltese
family with HPFH, calculated cMCHbF provided an independent classification from
HbF levels, according to which genomic variants were observed.
The mean corpuscular HbF (MCHbF) is normally estimated by dividing the
amount of HbF, determined by HPLC, by the number of F-cells, obtained by flow
cytometry. Since HbF may be unequally distributed among F-cells, an imaging
cytometry protocol enables quantification of HbF per F-cell by fluorescent emission
measurements. A new intracellular anti-HbF antibody-labelling technique was thus
optimized for use with the Nikon Eclipse Ti inverted fluorescence microscope. This
technique resulted in images of superior quality from which the mean HbF could be
determined for each F-cell observed. The technique was applied on blood from six
family members, three of which had HPFH. The data obtained will be used to study
the association of KLF1 and other genes, obtained through NGS data analyses, with
quantitated qMCHbF in normal and HPFH individuals, to identify new potential
therapeutic targets for β-haemoglobinopathies.