Just the FACS m'aam

FACS: Fluorescence-Activated Cell Sorting

FACS is a precise technique which is able to individually differentiate cells taken from the peripheral blood stream. It examines each cell individually, then categorizes it. It works by aiming a beam of light at a droplet containing a single cell and then examines the reflected light pattern. The light pattern is unique to the various types of cells in the bloodstream; thus, each cell can be categorized. It's able to examine millions of cells over the course of several hours.

One of the advantages of participating in the NIH HCL clinical trial is that in addition to the weekly CBCs, my blood is periodically examined using this form of flow cytometry. It's able to identify the individual hairy cells and determine the hairy cell numeric density in my peripheral bloodstream (the blood in my veins, not the marrow).

Because of the number of patients and hours required, it takes awhile to prepare, run and get the results of this test. I just got the latest results from blood drawn on 5/20, and the results are very promising. The table below gives a summary of the hairy cell numeric density before treatment, on Day 4, and 3 weeks post-treament.

Date FACS HCL count
4/20/2009 78.5
4/27/2009 40.1
5/20/2009 4.1

This means the density of hairy cells in my bloodstream is almost 1/20th what it was prior to treatment. The cladribine has definitely had an impact on the blood in my veins. Let's hope it's only a matter of time before the marrow shows similar progress!

The hope is that in 3 weeks, the number of cells will be immeasurable using FACS and a cloning technique known as polymerase chain reaction (PCR) will be required to find the hairy cells. The PCR technique being used at NIH is very sensitive -- able to find 1 hairy cell from 1 million regular blood cells. Prior to accepting me into the trial, Dr. K had to verify that they could develop PCR primers specific to my cells and then clone my cells in a reasonable amount of time. This highly sensitive technique will allow them to identify the faintest amount of minimal residual disease (MRD) and treat it with Rituxan at the 6 month post-chemo epoch or any time MRD is detected thereafter, according to the protocol.

Side Note: Interesting news for those of you dealing with solid tumors. I read another article on Grape Seed Extract today. This one discussed how it has anti-angiogenic properties. It arrests signals that solid tumors use to grow veins to nourish themselves, thus causing the tumors to starve to death. Here's the link.