A Useful Flow Cytometry Panel To Exclude Myelodysplastic Syndrome.

Background: Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic disorders, which can be difficult to diagnose based only on morphologic bone marrow examination. Karyotyping can be useful in diagnosing borderline cases. However, only 40% of patients with MDS have an abnormal karyotype. Flow cytometry(FCM) approaches have been described but not clearly defined in MDS due to use of different criteria. We devised a 10-parameter FCM panel, mainly including myeloid and erythroid maturation markers, to differentiate MDS marrows from normal marrows.

Design: Bone marrow from 91 patients with cytopenia(s) or anemia were included in the study(10/2005–7/2006). Cases were divided into 3 groups:

1. normal, not morphologically suspicious for MDS, 46 cases,

2. equivocal, morphologically suggestive but not diagnostic of MDS, 20 cases,

3. morphologically diagnostic of MDS, 25 cases.

10 FCM paremeters were performed and scored:

1. hypogranularity,

2. aberrant expression of CD56,

3. lack of CD10 expression,

4. decreased CD64 expression,

5. &

6. lack of CD13 or CD33 expression,

7. &

8. abnormal CD13/CD16 or CD16/CD11b pattern,

9. increase of CD 34 expression gating on all cells excluding erythrocytes,

10. decreased expression of CD71/Glycophorin gating on erythroid precursors. Karyotypings were analyzed.

Results:

1. and

2. (see Table 1 and 2).

3. Karyotyping were anlayzed in 86 cases.

Cytogenetic abnormalities were found in 2.2% (1/44) of normal group, 5.3% (1/19) of equivocal group and 34.8% (8/43) of MDS group. In MDS group 7 of 8 patients (87.5%) who had both morphologic and cytogenetic diagnosis of MDS were scored >=3 of 8 FCM parameters.

Conclusions: Study showed the 8-parameter FCM panel was more predictive of MDS than 10-parameters one. Both CD13/CD16 & CD16/CD11b patterns were considered to be non-specific. In 8-parameter panel, zero score tended to rule out MDS, while score >=3 suggested MDS. The most specific FCM parameters were hypogranularity, CD34, aberrant expression of CD56 or lack of CD10 expression by mature granulocytes. CD71/Glycophorin A might be useful in identifying dysplasia in erythroid lineage.