El-Hajj Racha, St. Heaps Luke, Clark Alissa and Wright Dale.
Sydney Genome Diagnostics, Cytogenetic Department, The Children’s Hospital at Westmead, NSW, Australia.
Multiple myeloma (MM) is a plasma cell (PC) neoplasm in which the surface antigen CD138 (syndecan-1) is highly expressed. We have previously shown that FISH gives higher abnormalities rates on uncultured CD138+ enriched cells compared to routine cultured bone marrow cells (50.8% vs 7.4%, P<0.001). In our laboratory, CD138+ cell enrichment has subsequently become standard practice for FISH and chromosome microarray testing for MM patients.
To validate and implement the AutoMACS Pro Separator for automated enrichment of CD138+ PCs.
To date, eleven bone marrow samples have been enriched using the MACS whole Blood CD138 MicroBeads human kit (Miltenyi Biotec), which was performed in parallel with manual vs. autoMACS Pro Separator (Miltenyi Biotec) protocols, according to the manufacturer’s instructions. FISH was performed using the probes IGH/CCND1, IGH/FGFR3, IGH/MAF, IGH break-apart, TP53/D17Z1 and/or CKS1B/CDKN2C (Carl Zeiss). The proportion of FISH abnormal cells between the two methods was compared using the paired-means t-test with a significance level α=0.05. Hands-in processing time was also evaluated.
The mean proportion of abnormal cells by FISH for each method was 77.7% vs 86.4% for the manual vs. automated method, respectively. The increased yield (8.8%) was marginally significant (t=2.3, df=10, P=0.0442). Hands-on time taken to perform the manual vs. automated method was 140min vs. 55min, respectively.
Although there was a marginally increased yield of abnormal CD138+ cells (8.8%) using the autoMACS Pro, we considered there to be no real practical difference given the small sample size of the study. More importantly, when processing time was considered, the autoMACS Pro reduced processing by ~45 minutes. Furthermore, up to six samples can be batch processed. Although sample recruitment is ongoing, the results to date indicate the benefits of automation for CD138+ cell enrichment in a busy laboratory.