A Useful Flow Cytometry Panel To Exclude Myelodysplastic Syndrome.
Authors: Zhang Ling , Lopatequi Jean R. , Kelly Sharron E. , Neer Tobi , Lee Stephen 
Published: April 2020

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:

normal, not morphologically suspicious for MDS, 46 cases, equivocal, morphologically suggestive but not diagnostic of MDS, 20 cases, morphologically diagnostic of MDS, 25 cases.

10 FCM paremeters were performed and scored: hypogranularity,aberrant expression of CD56,lack of CD10 expression,decreased CD64 expression,&lack of CD13 or CD33 expression,&abnormal CD13/CD16 or CD16/CD11b pattern,increase of CD 34 expression gating on all cells excluding erythrocytes,decreased expression of CD71/Glycophorin gating on erythroid precursors. Karyotypings were analyzed.

Results:

and (see Table 1 and 2). 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 &gt;=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 &gt;=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.

Table 1. Comparison of FCM Parameters in Patients with/without MDS Parameters/Group Normal Group(A)(n=46) Equivocal Group(B)(n=20) MDS Group(C)(n=25) CHITEST(P value)(GRoup A vs C) * These two parameters were deleted in the 8-parameter panel due to their high frequency seen in normal group. Hypogranularity 4 (8.7%) 6 (30%) 18 (72%) 0.0001 CD56 0 (0.0%) 1 (5%) 6 (24%) 0.0005 CD10 7 (15.2%) 7 (35%) 15 (60%) 0.0001 CD64 6 (13.1%) 2 (10%) 6 (24%) 0.2396 CD13 0 (0.0%) 0 (0.0%) 2 (8.0%) 0.0516 CD33 0 (0.0%) 2 (10 %) 0 (0%) 0 CD13/CD16* 23 (50.0%) 7 (35%) 21 (84%) 0.0047 CD34 8 (17.4%) 7 (35%) 13 (52%) 0.0026 CD71 2 (4.3%) 5 (25%) 12 (48%) 0.0001 CD16/CD11b* 27 (58.7%) 8 (40%) 22 (88%) 0.0107 Table 2. Scoring with 8 FCM Parameters in Patients with/without MDS Score/Group Normal Group (A)* (n=46) Equivocal Group (B)* (n=20) MDS Group (C)* (n=25) * Fish Exact T Test: Group A vs C: p&lt;0.0001, A vs B: p=0.0006, B vs C: p=&lt;0.0001 Score=0 21 (45.7%) 3 (15%) 0 (0.0%) Score=1–2 25 (543 %) 14 (70%) 8 (32 %) Score&gt;3 0 (0.0%) 3 (15%) 17 (68%) *Mean score +/− SD 0.65+/−1.06 1.55+/−1.54 2.8+/−1.65