This was the opinion of my haematologist. Is it a drug? Is it a herb? Was it found in a jungle or a coral reef? No, it is a scientific discovery first reported in 1999.

Two teams discovered that CLL appeared to be two different diseases. Looking at the cancerous B Cell lymphocytes some could be seen to have unmutated Vh genes and others to their Vh genes mutated. It was suggested that the difference arose because the latter cells was derived from a cell that had passed through the germinal centre whereas the former, unmutated cells derived from a cell that was naive.

What made this discovery important? The investigators were able to show that patients with the mutated version of the malignant lymphocytes had a dramatically more benign future than those with the unmutated version.

Traditionally CLL has always been described as an heterogeneous disease. This meant that the course of the disease varied between patients with some rapidly becoming ill whilst others went many years without any sign of the disease. As a result the accepted clinical practice was "Watch and Wait". It was clearly unwise to subject patients, many of whom will be elderly, to chemotherapy if the disease was asymptomatic. Indeed many patients could be expected to die from other causes before the CLL became a serious clinical problem. Therefore the doctors would observe the patient, waiting until the disease started to cause serious problems. Whilst this was sound practice, major studies had shown that generalised early treatment offered no survival advantage, it is unusual not to treat cancer as soon as possible. This discovery gave a scientific basis to the suspicion that there are several underlying disorders that require different treatment strategies.

Mutational status of Ig V(H) genes provides clinically valuable information in B-cell chronic lymphocytic leukemia.

Naylor M, Capra JD.

Oklahoma Medical Research Foundation, Oklahoma City, OK; and the University of Oklahoma Health Sciences Center, Oklahoma City, OK.

PMID: 10477711

A general introduction to the findings. It discusses the underlying biology and the clinical significance of the discovery.  The full article can be read at

http://www.bloodjournal.org/cgi/content/full/94/6/1837

Ig V gene mutation status and CD38 expression as novel prognostic indicators in chronic lymphocytic leukemia.

Damle RN, Wasil T, Fais F, Ghiotto F, Valetto A, Allen SL, Buchbinder A, Budman D, Dittmar K, Kolitz J, Lichtman SM, Schulman P, Vinciguerra VP, Rai KR, Ferrarini M, Chiorazzi N.

Department of Medicine, North Shore University Hospital, Manhasset, NY, USA.

PMID: 10477712

One of the two key papers. It reported that Cellular immunophenotypic studies were performed on a cohort of randomly selected IgM(+) B-chronic lymphocytic leukemia (B-CLL) cases for which Ig V(H) and V(L) gene sequences were available. The cases were categorized based on V gene mutation status and CD38 expression and analyzed for treatment history and survival. The B-CLL cases could be divided into 2 groups. Those patients with unmutated V genes displayed higher percentages of CD38(+) B-CLL cells (>/=30%) than those with mutated V genes that had lower percentages of CD38(+) cells (<30%). Patients in both the unmutated and the >/=30% CD38(+) groups responded poorly to continuous multiregimen chemotherapy (including fludarabine) and had shorter survival. In contrast, the mutated and the <30% CD38(+) groups required minimal or no chemotherapy and had prolonged survival. Thus, Ig V gene mutation status and the percentages of CD38(+) B-CLL cells appear to be accurate predictors of clinical outcome in B-CLL patients. These parameters, especially CD38 expression that can be analyzed conveniently in most clinical laboratories, should be valuable adjuncts to the present staging systems for predicting the clinical course in individual B-CLL cases. Future evaluations of new therapeutic strategies and drugs should take into account the different natural histories of patients categorized in these manners.

A full copy of the paper can be found in

 http://www.bloodjournal.org/cgi/content/full/94/6/1840

Unmutated Ig V(H) genes are associated with a more aggressive form of chronic lymphocytic leukemia.

Hamblin TJ, Davis Z, Gardiner A, Oscier DG, Stevenson FK.

Department of Haematology, Royal Bournemouth Hospital, Bournemouth, UK. terjoha@aol.com

PMID: 10477713

The second of the two key papers.

Despite having several characteristics of naive B cells, chronic lymphocytic leukemia (CLL) cells have been shown in some cases to have somatically mutated Ig variable region genes, indicating that the cell of origin has passed through the germinal center. A previous study of patients with CLL found an association between lack of somatic mutation and trisomy 12 and, therefore, possibly with a less favorable prognosis. We have sequenced the Ig V(H) genes of the tumor cells of 84 patients with CLL and correlated our findings with clinical features. A total of 38 cases (45.2%) showed >/= 98% sequence homology with the nearest germline V(H) gene; 46 cases (54.8%) showed >2% somatic mutation. Unmutated V(H) genes were significantly associated with V1-69 and D3-3 usage, with atypical morphology; isolated trisomy 12, advanced stage and progressive disease. Survival was significantly worse for patients with unmutated V(H) genes irrespective of stage. Median survival for stage A patients with unmutated V(H) genes was 95 months compared with 293 months for patients whose tumors had mutated V(H) genes (P =.0008). The simplest explanation is that CLL comprises 2 different diseases with different clinical courses. One, arising from a memory B cell, has a benign course, the other, arising from a naive B cell, is more malignant.

A full copy of the paper will be found at

http://www.bloodjournal.org/cgi/content/full/94/6/1848

TJ Hamblin, Royal Bournemouth Hospital

A discussion intended for GP's on the current treatment options that covers this topic.

Drugs 2001;61(5):593-611

Medline ID number: 11368285

DG Oscier, Royal Bournemouth Hospital

A paper by a colleague of Professor Hamblin. It gives a clear picture of the significance of the IGVH status in prognosis and hence its importance in the management of CLL.

Blood, 15 August 2002, Vol. 100, No. 4, pp. 1177-1184

Medline ID number: 12149195

First: All CLL experts worldwide are agreed that the mutations/no
mutations separation of CLL is valid. However, no test is absolute
and among the 300+ cases of CLL that we have tested in my lab, I have
had one 20 year survivor with unmutated V genes. There have also been
a small number of patients with mutated V genes who have needed
treatment. The biggest group of exceptions to the rule are those
patients who use the V3-21 gene. (There are 51 possible V genes and
this one gene, V3-21, is something special. It seems that whether it
is mutated or not it is associated with a poor prognosis. This is from
work by Richard Rosenquist from Sweden, but it has been confirmed by
Stephan Stilgenbauer in Germany and by ourselves.)

Second: FISH is a means by which chromosomal abnormalities can be
detected. It is less expensive than formal cytogenetic analysis and
can be done by less experienced scientists. In the context of CLL it
is used to detect one of the following abnormalities:-

1] a missing part of the long arm of chromosome 13 (you may see this
written as del 13q14). This is the commonest abnormality in the
mutated subset and implies a good prognosis;

2] an extra chromosome 12 (you see this as trisomy 12 or 12+). This is
seen more commonly in the unmutated subset and most patients who have
this will need treatment;

3] a missing part of the long arm of chromosome 11 (del 11q23). This
is virtually never seen except in the unmutated subset and picks out
those with no mutations that do worse than average for that subset.
These patients tend to have large abdominal lymph node. Of course no
biological finding is absolute, and I have seen a couple of patients
who have done very well.

4] a missing part of the short arm of chromosome 17 (del 17p). These
patients who are almost confined to the unmutated subset tend to have
the worse prognosis of all. They are quite rare and I have seen one
whose disease was non-progressive. In these patients something has
gone wrong with the p53 gene, and treatment may need to be geared to
that finding. Conventional treatment may not work.

Other than the associations that I mention in the last paragraph, FISH
will not tell you anything about the V gene mutations in CLL.

Third: There are a few research labs doing V gene mutations in
the USA but it is not available as a routine test. I can offer it as a
service in England if patients care to visit me, but we are hoping
that a surrogate test will soon be available. We hoped that CD38 by
flow would be useful, and to some degree it is. Generally having a low
CD38 is a good thing and high one a bad thing, but it does not tell
you the same thing as V gene mutations. About 30% of patients have
different results for V genes and CD38. This finding of ours has been
confirmed by the German group. There are other tests such as
beta-2-microglobulin, serum CD23 and serum thymidine kinase that may
be helpful in separating the two subsets, but they have not been
tested as rigorously as CD38 and V genes and therefore cannot yet be
relied upon.

ZAP-70 is more promising. This molecule was found to be important in
CLL by Dr Staudt's group at NIH using the genechip. We have been
collaborating with him and have developed a Flow test that should be
available for all labs very shortly. A similar test has been developed
by Dr Montserrat in Spain. This test gives very similar results to the
V gene test. As with all biological systems that are small
discrepancies at the margins. Sometimes V genes give the right answer,
sometimes ZAP-70, but we have been impressed that ZAP-70 picks out the
mutated V3-21 cases as poor prognosis.

Fourth: There is probably an intermediate group between smoldering
and progressive. We call it the slowly progressive group. Most of
these have mutated V genes, and we think that these patients can be
satisfactorily treated with small doses of chlorambucil given
intermittently, and repeated when the disease relapses. However, no
one has done a formal study on this group and it remains a question
for more research.

Fifth: ZAP-70 is a signalling molecule in T lymphocytes and NK cells.
This means that it carries a message from receptors on the cell
surface to the DNA in the nucleus. It is not used by B cells that tend
to use the molecule syk instead. CLL cells with mutated V genes seem
unable to use syk, and there is some evidence that those with
unmutated V genes use both syk and ZAP-70. Work is in progress to sort
this out further.

Sixth: Research in CLL is a collaborative effort. The new knowledge
on CLL comes from interaction between experts in the US (such as Drs
Rai, Byrd, Staudt, Keating, Kay and Kipps) and those in Europe (in
Spain, Sweden, Italy, France, Germany and the UK). We are a close knit
community of researchers, all keen to discover more about this disease
and do the best for our patients. We have to remember that what is new
is not necessarily better than what is old. On the other hand, when we
find new things that are better than they were, we are keen that
penny-pinching bureaucracy should not delay their availability to the
patient.

Kind regards,

Terry Hamblin MD
 

Guillaume Dighiero

Institut Pasteur, Paris, France

A report of a paper given at a recent conference. It presents evidence that suggests that CLL is one underlying disease but that their results show that gene expression profiling can distinguish CLL cases with a stable evolution and mutated Ig genes from those with unmutated Ig genes and progressive disease. Thus, monitoring the expression of a very limited number of genes might suffice to identify patients displaying an indolent disease from patients exhibiting an aggressive one.

A full copy of the paper can be found at:

http://www.haematologica.org/2002_12/1233.htm

Terry Hamblin

Royal Bournemouth Hospital

Another from the same conference. It states that the most obvious reason for thinking that chronic lymphocytic leukemia (CLL) comprises two diseases, similar to each other but distinguishable, is the fact that some patients are killed by it and some are not. Furthermore, this heterogeneity is not a gradual blend from one to the other, but a distinct demarcation. Even more convincing is the fact that the allocation to one camp or the other is predictable from the date of diagnosis.

A full copy of the paper can be found at:

http://www.haematologica.org/2002_12/1235.htm

Zap70 expression is a distinctive feature of B-CLL cells with unmutated immunoglobulin genes and can be useful for diagnostic application

Adrian Wiestner, NHLBI

A further development with the unmutated status findings. There are several distinctive populations of CLL patients with very different outcomes and treatment requirements. Unfortunately, the ability to sequence Ig genes is not available in most clinical laboratories. This report shows that a gene, Zap 70, can act as a more easily diagnosed surrogate.

ZAP-70 Expression Is a Reliable Surrogate for Immunoglobulin Variable Region Mutations in Chronic Lymphocytic Leukemia

Francesc Bosch, Hematology, Hospital Clinic, Barcelona

One of a number of papers that proposes the expression of ZAP-70 gene as a cheap and quick surrogate for measuring the mutational status of the IgVH gene.
 

ASH 2002 abstract 633

Neil E. Kay, Terry J. Hamblin, Diane F. Jelinek, Gordon W. Dewald, John C. Byrd, Sherif Farag, Margaret Lucas and Thomas Lin

An ASH educational book bringing together the latest thinking on the early stages of CLL. It includes another account of the significance of this research.

http://www.asheducationbook.org/cgi/content/full/2002/1/193