Sunday, January 23, 2011

Hairy Cell Leukemia Trivia

Thought I'd put together a few trivia questions for those of you who want to test your hairy cell leukemia knowledge:

1) What causes hairy cell leukemia?
2) Who discovered hairy cell leukemia?
3) In what year was hairy cell leukemia discovered?
4) Where was hairy cell leukemia discovered?
5) What is the formal name of hairy cell leukemia?
6) What protein is overexpressed on hairy cells and the main target of monoclonal antibody therapy?
7) What does the "CD" in "CD20" stand for?
8) Name the primary chemotherapies for hairy cell leukemia?
9) When is Pentostatin typically used in lieu of Cladribine?
10) What's the term for treatment with a monoclonal antibody (mAb)?
11) What is the primary mAb used to treat hairy cell?
12) What other surface proteins are also targeted in hairy cell?
13) Name a well known HCL immunotoxin?
14) Who is Ira Pastan?
15) What is the bacterial toxin used in HA22, and what's its origin?
16) What is the typical cause of fever after treatment with Cladribine (commonly misdiagnosed as "a mystery infection")?
17) What are the three modes of cell death mediated by Rituxan?
18) Who invented Cladribine?
19) Which is the more effective approach for administering Cladribine?
              5 day x 2 hour IV
              or 24x7 drip?
20) At what stage of cellular development is the malignant mutation of hairy cell believed to occur?
21) What is the median age of an HCL patient at diagnosis?
22) Is HCL more prevalent in men or women?
23) What type of cells are hairy cells from?
24) What is the average period of remission for HCL after Cladribine chemotherapy?
25) What percentage of patients receiving Cladribine have a complete remission, partial remission, and no response?
26) How rare is hairy cell leukemia?
27) What does MRD stand for?
28) Is there a cure for hairy cell leukemia?
29) The first case of patient/doctor genetic rights involved hairy cell leukemia and what university?
30) What's the life expectancy of the average hairy cell leukemia patient?
31) When should hairy cell leukemia be treated?
32) What is Hairy Cell Leukemia?
33) What is Bruton's Tyrosine Kinase (BTK)?
34) What Hairy Cell Leukemia (HCL) treatment options are available to multiply relapsed and refractory patients who don't respond to chemotherapy?

1) Most cases of classic HCL have a BRAF V600E DNA mutation, caused by a photon from sunlight inducing an RNA translation error in a B-cell (a type of white blood cell) during replication.  This mutation is also common to 50% of melanoma cases, but in that case, it affects a skin cell.  The causes of other variants of HCL are unknown.
2) Bertha A. Bouroncle, MD
3) 1958
4) Ohio State University
5) Reticuloendotheliosis
6) CD20
7) "Cluster of Differentiation"
8) Cladribine and Pentostatin
9) When a patient's counts are so low or health is so weak that a less sudden drop in counts is needed; however, it is sometimes used if a patient doesn't respond to Cladribine.  Pentostatin is administered over several weeks whereas Cladribine is administered in 5 or 7 days.
10) mAb therapy
11) Rituximab (aka: Rituxan)
12) CD25, CD22
13) HA22
14) Head of NCI laboratory of molecular biology and immunotoxin development
15) Pseudomonas Exotoxin from Pseudomonas aeruginosa
16) Tumor Lysis (hairy cells dying)
17) Apoptosis (cell suicide), antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC)
18) Dr. Dennis Carson
19) Both are considered equally effective
20) Later in the differentiation process at the level of the germinal center B-cells, likely in the process of differentiating to a Memory B-cell (per Basso, et al, p.62, col 1).
21) 52
22) Men, by a ratio of 4:1
23)  B-cells, a type of lymphocyte.
24) Ten years.
25) 80%, 15% and 5% respectively.
26) HCL accounts for only 2% of diagnosed/reported cases of leukemia.  However, it may be more prevelant since it can remain "in-check" in many people without ever being diagnosed.
27) Minimal Residual Disease.
28) Not yet, but there are hairy cell clinical trials trying to establish a cure curve.
29) UCLA (link to court case)
30) The average patient will have a normal life expectancy.
31) In general, HCL should be treated when blood counts indicate one of the following conditions:
                 Platelets (PLT) < 100 K/uL
                 Hemoglobin (HGB) < 10 g/dL
                 Absolute Neutrophils (ANC) < 1.0 K/uL
       however, Dr. Michael Grever, in his paper "How I treat Hairy Cell Leukemia (Blood, 10/2009)" states the following:
                   "Therefore, I recommend that therapy be initiated when a declining trajectory predicts that the patient will reach a platelet count less than 100,000/uL or an absolute granulocyte count consistently below 1,000/uL."
32)  HCL is an uncommon, chronic, neoplastic (malignant) disorder of B lymphocytes (a type of white blood cell) that predominantly afflicts middle-aged men. The patient usually presents with pancytopenia (broad spectrum reduction in blood counts -- low platelets, low white blood cells, low red blood cells). In the U.S., there are 500 to 800 cases of HCL annually, representing just 2% of all leukemias. Although it is incurable, it is highly treatable, with an average remission of 10 years.
33) BTK is an enzyme that's critical to the maturation of B-cells.  Inhibiting it, with drugs like Ibrutinib, has proven to be a well-tolerated and effective means of targeting a variety of leukemias and lymphomas.  Clinical trials using Ibrutinib to target hairy cell leukemia in relapsed and refractory patients are now underway.
34)  Multiply relapsed and refractory Hairy Cell Leukemia (HCL) patients should consider the moxetumomab (moxe) clinical trial at NIH.  A majority of patients have achieved complete remissions and in many cases eliminated MRD.

Tuesday, January 18, 2011


A lot has happened since my last post:
  •        Christmas
  •        New Years
  •        Birthdays (Howard Recombinant DNA Experiment #1 turned 3, and my wife had a birthday too)
  •        4 Rounds of Rituxan

The Rituxan treatments have gone well, although I've had to deal with several failed IV placements (including 3 blown veins).  The only significant change in my blood counts so far has been a dramatic increase in monocytes as shown below, but this has me very excited.  It's believed that monocytes may mediate the antibody-dependent cell-mediated cytotoxicity (ADCC) by Rituximab, and a cursory analysis of my counts leads me to believe this may be the case.  Specifically, my monocyte counts increased dramatically after both Rituxan treatments were initiated (see highlighted areas).

I believe this increase in monocytes is directly correlated to the administration of the Rituxan as they begin to kill the hairies through antibody attack (see picture below).  The monocytes increase in numbers as Rituxan (RTX) is introduced into the bloodstream and then they level off as they morph into phagocytes and ADCC is evoked.  As you can see in the highlighted areas above, the pattern for this cycle (RTX #2)  is similar to the first RTX treatment in 2009, but the initial level of monocytes is much higher.  Given that my spleen is now 40% of its prior volume (no longer infiltrated with hairies), and the monocyte level is 9 times higher than when I started RTX treatment #1, I think this round may have a much bigger impact in reducing the hairy cell burden in my marrow aspirate!  

Monocyte Mediated ADCC

Starting in week 5 of RTX treatment #1, my neutrophil level increased dramatically as the monocyte levels began to top off.  Hopefully, the same increase will occur over the next few weeks.  If so, I think the response correlation with RTX treatment #1 will be another strong indicator of monocyte mediated ADCC.  It may take awhile for it to complete the job, but fortunately Rituxan's half-life is two weeks, so it will remain in my bloodstream for months and during that time > 99% remains in the peripheral blood looking for B-cells and hairies to destroy, so it's readily available for quite awhile as the layers of the hairy clumps are peeled away.

Then again, since neutrophils are the first to attack (neutrophils are microphages, ie: small eaters), they may be pulled out of the peripheral blood stream to mediate Rituxan-induced complement-dependent cytoxicity (CDC) and attach to C3b proteins -- causing a drop in their blood levels.  Perhaps the monocytes are being released into my blood stream in response to the transient decrease in neutrophils. Monocytes are held in reserve in the splenic red pulp for just such an emergency.  As the monocytes morph into macrophages (ie: big eaters) to mediate ADCC induced by Rituxan, the neutrophils are no longer needed as much and stay in the blood and increase in numbers as marrow function improves. 

I watched the Dr. Najeeb lecture series on the complement system, and now I'm wondering if an overzealous complement system response to Rituxan aggregates immune complexes (Ig's, anaphylatoxins like C3a, mast cell activation products, etc.) in the skin that lead to the non-itchy rashes often seen in patients who take Rituxan.  I had several during my first round in 2009.  This cycle I noticed a small dime-sized one on my left arm a couple days after the first round that's still there.  They're small patches that usually take 5 to 8 weeks to clear.

Here's a video on Rituxan's mode of action that covers direct cell death, ADCC and complement.  However, the video indicates NK cells are responsible for ADCC whereas I'm postulating that monocytes may also play a significant role.

Rituxan Method of Action

My fascination with GA101 continues to grow.  It's a third generation monoclonal antibody (mAb) that mediates ADCC 5 to 100 times more effectively than Rituxan.  Not only is this antibody humanized, but it's elbow region has been engineered to provide better cross-linking of CD-20 antigens, which appears to dramatically improve apoptosis (cell suicide) as stated in a citation from a prior post.  This mAb has now undergone Phase II trials in indolent/refractory non-Hodgkin's lymphoma with very good results.  I'm lobbying and anxious for in-vitro studies to occur in HCL. 

[Credit: Robert Marcus, Kings College Hospital, London]

Aside from that, I've become quite a gadget geek.  I bought a PS3 to support my hobby and an Xbox Kinect for working out.  It's seems to be doing the trick too.  My creatine kinase levels went from 109 to 315 over the past week.  CK is an enzyme that's secreted when you workout and convert ATP to ADP to release energy.  The Kinect is an imaging sensor that allows you to play games without a controller.  It's truly amazing.  The technology is still in its infancy, but you can use it to workout and keep/manage all your workout metrics, and it provides real-time analysis of your form that's better than a personal trainer's.  I predict it will make P90x obsolete within a year, and I'm anxious for a yoga application to be released.  I'm hoping some yoga and regular stretching will keep things fluid in my marrow and increase the hairy clump surface area to volume ratio, but that's just a WAG.  I figure it can't hurt.

I'm so grateful and glad I'm participating in the NIH clinical trial!  Not treating my somewhat difficult case with Rituxan by monitoring MRD would probably have led to more Cladribine treatments and marrow suppression.  I think that my case shows that just blindly adding Rituxan at 6 months post-Cladribine and taking a wait-and-see approach by monitoring counts to determine relapse is risky -- especially for younger patients.  Rather, monitoring and treating MRD is the way to go, and right now, only NIH has the facilities to do that -- especially the hypersensitive PCR MRD test.  Likewise, NIH provides 2 8-week cycles of Rituxan to treat MRD -- something regular oncologists won't be able to justify to insurance companies until the NIH study is completed.

The family's doing well.  My youngest (8 mo's) is already cruising and lifting herself up on tables, and the eldest is starting to read and play computer games (Dora and Cat in the Hat).  I've had a couple weeks as Mr. Mom over the past month while my wife's been on travel.  The first time was a breeze, but the baby had an earache the second time, so things were a little more exhausting.  I've been working on Ka-band science downlink designs for future Deep Space Discovery Missions and the S-band command and telemetry link for the GEMS program.  Overall, things are going well.
Happy New Year, and here's to a fruitful 2011!