Guillaume Dighiero

Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines

Standardized criteria for diagnosis and response assessment are needed to interpret and compare clinical trials and for approval of new therapeutic agents by regulatory agencies. Therefore, a National Cancer Institute-sponsored Working Group (NCI-WG) on chronic lymphocytic leukemia (CLL) published guidelines for the design and conduct of clinical trials for patients with CLL in 1988, which were updated in 1996. During the past decade, considerable progress has been achieved in defining new prognostic markers, diagnostic parameters, and treatment options. This prompted the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) to provide updated recommendations for the management of CLL in clinical trials and general practice.

Chlorambucil in Indolent Chronic Lymphocytic Leukemia

A BSTRACT Background To determine whether chlorambucil treatment benefits patients with indolent chronic lymphocytic leukemia (CLL), we conducted two randomized trials in 1535 patients with previously untreated stage A CLL. Methods In the first trial, 609 patients were randomly assigned to receive either daily chlorambucil or no treatment; in the second trial, 926 patients were randomly assigned to receive either intermittent chlorambucil plus prednisone or no treatment. Median follow-up for the first and second trials exceeded 11 and 6 years, respectively. The end points were overall survival, response to treatment, and disease progression. Results Treatment of indolent CLL did not increase survival in either trial. In the treated group, as compared with the untreated group, the relative risk of death was 1.14 (95 percent confidence interval, 0.92 to 1.41; P=0.23) in the first trial and 0.96 (95 percent confidence interval, 0.75 to 1.23; P=0.74) in the second trial, with 76 percent and 69 percent of patients, respectively, having a response to therapy. Although chlorambucil slowed disease progression, there was no effect on overall survival. In the untreated group in the first trial, 49 percent of patients did not have progression to more advanced disease and did not need therapy after follow-up of more than 11 years; however, 27 percent of patients with stage A CLL died of causes related to the disease. Conclusions Chlorambucil does not prolong survival in patients with stage A CLL. Since deferring therapy until the disease progresses to stage B or C does not compromise survival, treatment of indolent CLL is unnecessary. (N Engl J Med 1998;338:1506-14.)

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia is the commonest form of leukaemia in Europe and North America, and mainly, though not exclusively, affects older individuals. It has a very variable course, with survival ranging from months to decades. Major progress has been made in identification of molecular and cellular markers that could predict disease progression in patients with chronic lymphocytic leukaemia. In particular, the mutational profile of immunoglobulin genes and some cytogenetic abnormalities are important predictors of prognosis. However, these advances have raised new questions about the biology, prognosis, and management of chronic lymphocytic leukaemia, some of which are addressed here. In particular, we discuss how better understanding of the function of the B-cell receptor, the nature of genetic lesions, and the balance between proliferation and apoptosis have affected our ability to assess prognosis and to manage chronic lymphocytic leukaemia. Available treatments generally induce remission, although nearly all patients relapse, and chronic lymphocytic leukaemia remains an incurable disease. Advances in molecular biology have enhanced our understanding of the pathophysiology of the disease and, together with development of new therapeutic agents, have made management of chronic lymphocytic leukaemia more rational and more effective than previously. Unfortunately, we know of no way that chronic lymphocytic leukaemia can be prevented. Early detection is practised widely, but seemingly makes no difference to the patients eventual outcome.

When and How to Treat Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL), the most common form of leukemia in adults, is usually recognized first by the patients primary care physician. When the patient has other medical problems — wh...

VH gene usage by family members affected with chronic lymphocytic leukaemia

The excess risk of chronic lymphocytic leukaemia (CLL) in the first‐degree relatives of affected patients suggests that familial CLL might constitute a useful model to study the pathogenesis of this disease, as has been demonstrated in numerous other neoplastic disorders. Previous studies have shown non‐random utilization of immunoglobulin genes in CLL, some germline in sequence and others containing numerous somatic mutations. To investigate whether familial cases of CLL exhibit similarities in the composition of the B‐cell receptor repertoire to the pattern expressed by CLL patients as a whole, we have studied 25 CLL patients belonging to 12 different families (four French and eight Italian), each of which contained at least two affected members.

Defective assembly of the B-cell receptor chains accounts for its low expression in B-chronic lymphocytic leukaemia

Summary. B‐cell chronic lymphocytic leukaemia (B‐CLL) characteristically displays low amounts of B‐cell receptor (BCR), which mainly consists of the heterodimer CD79a/CD79b bound non‐covalently with the surface immunoglobulin (SIg). This heterodimer is required for SIg expression and BCR signalling. To better define the mechanisms related to low BCR expression, we have investigated transcription, protein synthesis, assembly and transport of the BCR in B‐CLL cells. Our results demonstrated that: (1) there was no major defect in transcriptional expression of the B29 (CD79b) gene; (2) the BCR components were intracellularly detected, thus adequately synthesized, in almost all patients; (3) neither a genetic defect in the transmembrane region of SIg, which associated with CD79a/CD79b, nor a genetic abnormality in the chaperone protein calnexin that is involved in folding and assembly of the BCR were found; (4) a constant defect in the assembly of IgM and CD79b chains occurred leading to abnormal accumulation of both chains in different intracellular compartments; (5) in a majority of CLL patients all of the nascent IgM failed to be processed into mature chains and remained unsuitable for transport. These findings demonstrated that a post‐transcriptional defect located at the BCR intracellular assembly and/or trafficking levels could be involved in its low surface expression in B‐CLL.

Studies on natural antibodiesand autoantibodies

Summary A serum pool from 800 healthy donors and individual samples from three healthy donors were passed through tubulin, actin, thyroglobulin, myoglobin, fetuin, transferrin albumin, cytochrome C and collagen immunoadsorbents. The proteins eluted were mainly composed of the three major Ig classes and were shown to bind specifically to the antigens via the F (ab′)2 fragment. When these isolated antibodies were examined by competitive assay, they fell into three groups. Antibodies in the first group, consisting of anti-tubulin and anti-thyroglobulin antibodies, were inhibited only by their homologous antigens. The second group was comprised of anti-actin, anti-myoglobin and anti-fetuin: these antibodies were inhibited mainly by their homologous antigens, but also to a significant degree by two or three additional antigens; although the reaction between anti-actin antibodies and immobilized actin was inhibited mainly by actin, both tubulin and thyroglobulin inhibited it to a lesser, but still significant extent. The third group consisted of anti-albumin, anti-transferrin, anti-collagen and anti-cytochrome C antibodies, which all bound specically to the antigens but were inhibited only slightly or not at all by their respective antigens. These results prompted us to study 612 monoclonal Ig (MIg) for their antibody activity against the above-mentioned antigens, plus myosin and double-stranded DNA (dsDNA). Of these 612 MIg, 36 (5.7 %) were shown to possess antibody activity. Of these 36, 32 (5.2 % of the total) were directed mainly against actin, but also reacted with tubulin and thyroglobulin, and sometimes with myosin. One MIg reacted mainly with myosin, but also with actin and tubulin, while the 3 others reacted with tubulin, thyroglobulin and dsDNA, respectively. The results produced by the fusion of splenocytes from non-immunized BALB/c mice with a non-secreting myeloma cell line indicated that a significant number of the induced clones produced monoclonal antibodies directed against the above panel of antigens, and that most of the clones obtained bound two or more antigens simultaneously. Three main conclusions emerged: o 1) the above results strongly suggest that natural antibodies againstthe antigens examined are present in normal human serum, and also indicate that natural antibodies directed against a great variety of antigens—often self antigens—might be present in normal serum; 2) at least in some patient sera, MIg seem to share antibody specificities with natural antibodies, and these MIg may consequently correspond to the expansion of a clone producing a natural antibody; 3) results obtained with normal unimmunized mice prove the existence of autoreactive Ig-synthesizing clones which bind to more than two antigens. The above points are discussed in connection with the role of naturalantibodies in terms of self tolerance and recognition, as well as their relationship to induced antibodies.

Gene expression profiling of chronic lymphocytic leukemia can discriminate cases with stable disease and mutated Ig genes from those with progressive disease and unmutated Ig genes

Gene expression profiling of chronic lymphocytic leukemia can discriminate cases with stable disease and mutated Ig genes from those with progressive disease and unmutated Ig genes

Functional monocyte‐derived dendritic cells can be generated in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) remains an incurable disease. Although modern available treatments are able to induce disease regression, relapse almost inexorably occurs. Therefore, novel therapeutic strategies aimed at reducing the disease relapse rate are very much needed. Among these, the induction of tumour‐associated antigen‐specific cytotoxic T lymphocytes (CTL), through either DNA vaccines or injection of idiotype pulsed dendritic cells (DCs), has been actively investigated with encouraging preliminary results in B‐cell malignancies. As the CLL B lymphocyte characteristically expresses low amounts of surface immunoglobulin (Ig) and T cells from these patients have been reported to display impaired functional activity, there are concerns related to the possibility of generating specific cytotoxic antitumoral T cells in this disease. In addition, no information is presently available regarding the functional ability of CLL‐derived DCs. In the present work, freshly purified monocytes from CLL patients and normal donors were induced to differentiate in granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and interleukin (IL)‐4 serum‐free medium and compared for their morphological, phenotypic and functional characteristics. Our results demonstrate that: (1) functional DCs can be generated from CLL patients with similar phenotype and function to those observed from normal donors; (2) in contrast to normal control subjects, monocyte‐derived DCs from CLL patients spontaneously secrete endogenous IL‐10; and (3) interferon (IFN)‐γ in combination with CD40L plays a major role in priming DCs from CLL patients for IL‐12 and IL‐15 production. Overall, these results indicate that it is possible to derive functionally competent DCs from circulating monocytes in CLL patients.

Can isotype switch modulate antigen-binding affinity and influence clonal selection?

Four different monoclonal Ig (MIg) (IgA1κ, IgG1κ, IgG2κ and IgG4κ) displaying anti‐tubulin activity were detected in the serum from a lymphoma patient. The complete sequence of three of these MIg showed identical VH and VL domains and the presence of mutations compatible with an antigen‐driven process. Surprisingly, despite complete homology in their variable domains, IgA1κ, IgG1κ, or their Fab fragments bound to a common motif recognized in β tubulin, with significant differences in affinity (IgA1κ 1.52×10–8 M, and IgG1κ 2.09×10–7 M). To substantiate these results, the VH and VL domains from IgA1κ were cloned and introduced into expression vectors containing the constant κ exon and either the μ or the γ1 constant exon, and complete recombinant IgMκ and IgG1κ were obtained. Like the IgA1κ, the IgMκ construction bound to the tubulin epitope with consistent affinity (7.7×10–9 M), whereas the IgG1κ construction displayed a significantly lower affinity (3.28×10–7 M). These results provide definitive evidence that isotype can influence binding affinity to antigen and suggest that malignant transformation occurred at the germinal center once the mutational process was achieved and the switch process was still active.