Re: New Flow Results

[Guest guest]

Flow cytometry (the most common means for determing CD38 and zap-70) are very

operator dependent, but they are also open to interpretation. Small changes in

the intensity of the staining can result in positive versus negative results

changing.

The percentage of cells positive needs to be the percentage of just the CLL

cells. Some reports might report the percentage of all cells, while some might

report percentage of B cells. (B cells do not normally express zap-70.)

Therefore, one cannot look at just the percentage, especially if the first value

might have been obtained with a low WBC and subsequent analyses done with a

higher WBC.

CD38 is not supposed to change over the course of the disease, but this is a

topic that is debated.

Rick Furman, MD

>

> I have a new hematologist/oncologist while I am in my winter

> home in AZ. He is very knowledgeable, practices at a major

> center at the University and was highly recommended by

> others on the lists. He wanted to do a new flow cytometry at

> his facility. My previous ones were done by US Labs and

> Sloan Kettering in 10-11/2005 at the time of my diagnosis.

> Back in 2005 both labs found that I was CD38 pos. and Sloan

> Kettering did a Zap-70 that was neg.

>

> The results in AZ were that I was CD 38 neg. but Zap-70 pos

> in 62%. My question to our experts is can someone be CD 38

> pos and 5+ yrs later be negative? I am not sure if I have

> heard of this in all my reading. Also, I know more and more

> experts are not in favor of Zap-70 results due to no

> standardization of the test.

>

> I remain indolent and have not had one single illness in the

> past 5 yrs, and no symptoms. My WBC remains around 20,000

> with other results stable. I am Trisomy 12, 13q del and have

> not had mutational testing. Any insights?

>

> R

> Dx Atypical CLL 11/05

>

[Guest guest]

Thanks Dr. Furman. The report says " Flow cytometric analysis

demonstrates a pop. of lambda restricted CD19 pos and CD 20

pos. that coexpress CD5 and CD23. 62% of these cells are Zap

70+. So it is the percentage of my CLL cells that they are

claiming are 62% pos. for Zap 70. I am not worrying about

all this, just find it interesting and always a bit puzzling.

On Sun, Mar 6, 2011 at 9:25 AM, rrfman wrote:

(snipped by moderator)

> The percentage of cells positive needs to be the

percentage of just the CLL cells. Some reports might report

the percentage of all cells, while some might report

percentage of B cells. (B cells do not normally express

zap-70.) Therefore, one cannot look at just the percentage,

especially if the first value might have been obtained with

a low WBC and subsequent analyses done with a higher WBC.

(snipped by moderator)