|
|
| Line 27: |
Line 27: |
|
| |
|
|
| |
|
| cd45 gating
| | Image: typical positions of cell populations using CD45 gating |
|
| |
|
| cd45boxedpops.png
| | Links: Examples of the position for different malignant populations using CD45 plots |
| A typical flow plot illustrating the position of different cell types in a normal individual
| |
| y-axis side scatter of light:light is scattered at an angle to cells ssc differently according to granularity cytoplasmic outline or nuclear complexity
| |
| x-axis cd45 expression log scale the level of cd45 expression is variably different normal or malignant cell types
| |
| | |
| | |
| population a: nucleated red cells others & debris these round agranular cells scatter very little light and do not express cd45. debris and platelet aggregates may also appear here; in such cases the cell populations and distribution may indicate poor sample quality. note that blast cells particularly all blasts non-haematopoietic tumours or plasma cells may appear in this area.
| |
| | |
| population b: mature and maturing granulocytes high granularity irregular outline and nuclear complexity all cause high light scatter cd45 expression is moderate but increases with maturity. the many different forms with differing ssc and cd45 mean that the population forms a spread cloud. note the position of the cloud may be altered in myelodysplasia where cell form is changed or more primitive forms are present
| |
| | |
| | |
| population c monocytes the size and nuclear irregularity give these cells light scatter properties intermediate between lymphocytes and granulocytes. the requirement to engage in immune responses means that they have high cd45 expression generally a little lower than that of lymphocytes . note abnormal or more primitive forms e.eg. cmml may have lower cd45 expression
| |
| | |
| population d lymphocytes & basophils smaller cells - all with relatively low light scatter which seems odd for basophils but is true . all engage in immune responses and cytokine interactions mediated by their high cd45 activity. note that lymphocytes may have varied cd45 expression with weaker expression on b-cells and particularly precursor b-cells haematogones . neoplastic cells may have weak e.eg.ecll or strong e.eg. hcl expression of cd45 ---- file cd45wksscwk.epng left 200px caption
| |
| | |
| population e blasts and maturing precursor cells primitive blast cells have low and sometimes absent cd45 expression the cells tend to have round nuclei and few granules so have low light scatter but this can vary considerably according to their differentiation. note normal maturing cells in this area are few in number and have a wide range of light scatter reflecting their variable maturation. blast cells in leukaemia may form a tighter population in greater number but may also vary in ssc depending on their maturation.
| |
|
| |
|
|
| |
|
|
| |
|
| ----- | | ----- |
Revision as of 15:42, 14 June 2023
- Summary
- CD45 is expressed by almost all mature or maturing leucocytes: hence the name leukocyte common antigen.
- Usefully, the level of expression of CD45 differs according to both the cell type it is expressed on, and the maturation stage of that cell. Generally the expression for any cell type is quite consistent. This means that, when combined with other markers (particularly light scatter parameters) CD45 can be used to make a provisional identification of the different leukocyte types, allow different populations to be analysed individually.
- Most frequently therefore the use of this antigen is for CD45 gating
- Background
CD45 is a transmembrane protein that de-phosphorylates signalling molecules associated with immunological receptors to change their activation state. Expression is typically highest in cells actively involved in immune proceses lymphocytes and monocytes and lower in other populations including blast cells.
- Diagnostic Use
When combined with side scatter in two-dimensional dot plots CD45 expression can allow different leukocyte types to be separately identified and analysed. This can be very useful for analysis of individual populations of interest e.g. blast cells; lymphocytes etc.
Some cell types - particularly plasma cells are not easy to identify using CD45 gating since their expression of CD45 can be variable even within a single case.
Image: typical positions of cell populations using CD45 gating
Links: Examples of the position for different malignant populations using CD45 plots