Chronic Lymphocytic Leukaemia and its Relationship to Other Lymphoproliferative Disorders

Detection and Characterization of Paraproteinemia in Canine Chronic B-cell Lymphocytic Leukemia Using Routine and Free Light Chain Immunofixation

BACKGROUND

Hyperglobulinemia is reported in 26% of canine chronic B-cell lymphocytic leukemia (B-CLL) cases. However, few cases have been characterized by protein electrophoresis and immunofixation (IF), and the incidence of a monoclonal protein (M-protein) is unknown using these techniques.

OBJECTIVE

To characterize and determine the proportion of canine B-CLL cases with an M-protein using plasma protein electrophoresis (PPE), routine and free light chain (fLC) IF, and to assess if productive B-CLL cases express MUM1/IRF4 by cell tube block (CTB).

METHODS

PPE, routine (targeting IgG, IgA, IgM, IgG4, and light chain) and fLC IF were performed using 48 dog B-CLL plasma samples from patients diagnosed via peripheral blood flow cytometry. CTB was performed on a separate cohort of 15 patients.

RESULTS

Hyperproteinemia (>7.5 g/dL) was present in 17/48 cases (35%). An M-protein was detected in 32/48 cases (67%). Of these, 19/32 cases (59%) had only complete (monoclonal heavy and light chain) M-proteins detected, 10/32 cases (31%) had both complete and fLC M-proteins detected, and 3/32 cases (9%) had only an fLC M-protein detected. IgM was the most common clonal immunoglobulin isotype detected (23 cases). CD21⁺ cell counts were higher in cases with detectable M-protein. Plasma fLC IF suggested β-γ region interference, likely caused by clotting proteins. All B-CLL cases consistently expressed PAX5 and did not express MUM1/IRF4.

CONCLUSIONS

Most B-CLL cases had an M-protein and were not hyperproteinemic. Most cases with paraproteins had a complete IgM monoclonal gammopathy; a subset had documented fLCs. The prognostic significance of heavy and fLC presence should be evaluated.

The effect of cytosine-arabinoside treatment on the overexpression of c-myc protooncogene in a case of prolymphocytic leukemia

An unusually high level of expression of the c-myc protooncogene was observed in peripheral blood lymphocytes of a patient with prolymphocytic leukemia (atypical chronic lymphocytic leukemia). The overexpression of c-myc could not be attributed to a high level of proliferating activity of the leukemic cells in the blood. Treatment with cytosine-arabinoside at high doses abolished this altered expression of c-myc and resulted in a twofold increase in the expression of a gene sequence encoding the invariant gamma-chain of class II histocompatibility antigens, preferentially expressed in resting B lymphocytes. These observations suggest that the leukemic cells may have been arrested in the cell cycle outside the G0 phase. Our findings demonstrate that growth-regulated genes can be useful molecular markers of diseases with altered mechanisms of cellular proliferation.

The incidence, clonal origin and secretory nature of serum paraproteins in chronic lymphocytic leukaemia

Immuno-isoelectric focusing (IIEF) showed a 61% incidence of serum paraproteinaemia in 56 patients with chronic lymphocytic leukaemia (CLL). A strong correlation between the serum paraprotein heavy chain isotypes and those of the cytoplasmic heavy chain immunoglobulins was observed with no discrepancy noted in light chain expression. Density gradient ultracentrifugation analysis of selected sera containing monoclonal IgM showed that the IgM paraproteins were mostly 19S, secretory IgM but one patient was found to have both 19S and 8S monoclonal IgM. When the cellular origin of the IgM and IgD paraproteins found in one patient was investigated, both paraproteins were found to share the same idiotype and originate from the neoplastic clone. These findings confirm the view that there is an incomplete maturation block in chronic lymphocytic leukaemia and that in vivo secretion of paraproteins by the neoplastic cells is a relatively common occurrence.

Cutaneous findings in hairy cell leukemia

Hairy cell leukemia is a distinctive clinicopathologic entity that is histologically characterized by infiltration of the spleen, bone marrow, and blood by uniform mononuclear cells--"hairy cells." We reviewed the prevalent cutaneous findings, specific and nonspecific, in 113 cases of hairy cell leukemia. Only one patient had specific lesions (skin infiltration by leukemic cells). Nonspecific cutaneous findings included recurrent infections, ecchymoses, petechiae, pallor, drug reactions and reactions to transfusions, and nonherpetic ulcerations. Although leukemic infiltration of the skin in hairy cell leukemia is rare, cutaneous histopathologic features may be diagnostic, particularly when cytomorphologic examination is coupled with staining of a fresh specimen with tartrate-resistant acid phosphatase. Cutaneous and extracutaneous infections, often extensive and with opportunistic organisms, were the most common nonspecific findings and demonstrated severely deficient immunologic responsiveness. Associated malignant diseases, cutaneous and extracutaneous, were few in number and are of uncertain significance.

Patterns of bone marrow involvement in chronic lymphocytic leukemia and small lymphocytic (well differentiated) non-Hodgkin's lymphoma. Its clinical significance in relation to their differential diagnosis and prognosis

Forty-eight patients with chronic lymphocytic leukemia (CLL), and 12 patients with small (well differentiated) lymphocytic lymphoma (WDL) were histologically evaluated for their pattern of bone marrow (BM) involvement. Four different types of BM infiltration were recognized: nodular (N), interstitial (I), nodular and interstitial (mixed) and diffuse (D). The pattern of BM involvement was compared with the clinical, laboratory, and survival status in all patients. The extent of the disease in CLL patients, was determined by the Rai and the International Workshop on CLL Staging Systems, while in WDL patients the Ann Arbor staging system was used. In the CLL group the N pattern was found in 8%, the I in 33%, the mixed in 31%, and the D in 27% of the patients. Based on the International Workshop on CLL Staging System, the I pattern of BM involvement was more frequently found in Stage A (56%), the mixed in Stage B (68%), and the D in Stage C disease (90%). All CLL patients with D pattern required treatment from the beginning, contrary to CLL patients with the other patterns, in whom therapy was required in less than 50%. Similarly, deaths were more common in the D pattern in whom therapy pattern than in the other patterns. In the WDL patients BM involvement was found in 4 of 12, (33%) and its pattern of positivity was always nodular, although most patients (10 of 12) had advanced disease. It is concluded that the frequency of BM involvement may contribute in the differential diagnosis of WDL from CLL. In addition, the pattern of BM infiltration correlates very well with the International Staging System for CLL, and the pattern of BM positivity in CLL patients also has prognostic significance.

Serum paraproteins in chronic lymphocytic leukaemia

The presence of paraproteins in the sera of 10 patients with chronic lymphocytic leukaemia (CLL) was investigated using immunoisoelectric focusing. Monoclonal immunoglobulins were found in nine of these 10 sera. Five sera contained a single monoclonal IgM paraprotein, one serum contained a single monoclonal IgG paraprotein, while three sera contained more than one monoclonal paraprotein--namely, IgM + IgD, IgM + IgG, and IgM + IgD + IgG. The results indicate that the malignant B cells of CLL may be at a later stage of differentiation than previously assumed and serum monoclonal immunoglobulin could be of value as a tumour marker.

Interaction of Epstein-Barr virus with leukaemic B cells in vitro. II. Cell line establishment from prolymphocytic leukaemia and from Waldenström's macroglobulinaemia

Leukaemic B-cell populations were prepared from six patients with high-count prolymphocytic leukaemia (PLL) as well as from one patient with Waldenström's macroglobulinaemia (WM) in frankly leukaemic phase, and their response to in vitro Epstein-Barr (EB) virus infection was monitored in terms of expression of the virus-associated nuclear antigen EBNA and of virus-induced transformation to continuous cell lines. The individual leukaemic populations, tested on several occasions, gave reproducibly different responses one from another which were not obviously related to differences either of surface immunoglobulin phenotype or of immunoglobulin secretor status in vivo. After infection, four out of six PLL populations showed either transient or a more persistent expression of EBNA, always involving a minority of the cells, with no evidence of any virus-induced transformation up to six weeks. In contrast, two out of six PLL samples as well as the WM sample rapidly gave rise to EBNA-positive cell lines which, on the evidence both of restricted immunoglobulin class expression and of abnormal marker chromosomes, were clearly derived from the leukaemic cells. Further comparative studies of such leukaemic B-cell populations may help to define host cell components necessary for the triggering of EB-virus-induced cellular transformation.

Phospholipid and cholesterol differences amongst leukemic cell types with special reference to hairy cell leukemia: a preliminary report

Whole cell cholesterol and phospholipid content was determined for ten patients with hairy cell leukemia (HCL) and 15 patients with chronic lymphocytic leukemia (CLL). Malignant cells from HCL patients contained 0.412 mumol/10(8) whole cells is compared to 0.177 mumol/10(8) whole cells for CLL cells; the total phospholipid concentrations were 0.746 and 0.469 mumol/10(8) whole cells respectively (p less than 0.001). Phospholipid sub-types were determined by thin-layer chromatography. The percentages of sphingomyelin (HCL-16.2%, CLL-8.2%) and phosphatidylcholine (HCL-46.0%, CLL-55.1%) differed significantly between the two diseases (p less than 0.05, respectively). The novel finding in our study is that HCL cells are enriched two- to three-fold in sphingomyelin (expressed on a mumol/g protein basis) at the expense of phosphatidylcholine when compared to Cll cells (a PC/SM ratio of 2.9 in HCL compared to 6.5 in CLL). Increases in the total amount of cholesterol and phospholipid as well as in the selective portions of the individual phospholipids could reflect and, possibly, result in the unique membrane architecture of the hairy cell.

Studies of mixed lymphocyte reactions, surface B cell antigens, and intracytoplasmic immunoglobulins in "null cell" acute lymphocytic leukemia

Lymphoblasts from "null cell" acute lymphocytic leukemia (ALL) were analyzed for the pattern of proliferation displayed in a mixed lymphocyte reaction (MLR), the presence of a B cell surface antigen, and for the presence of intracytoplasmic immunoglobulin (ICIg). "Null cell" ALL was defined by cytologic and cytochemical criteria and by the absence of spontaneous rosette formation and surface membrane immunoglobulin in cell suspensions of the malignant lymphocytes. In eleven of fourteen patients the proliferative characteristics of lymphoblasts in the MLR were similar to those observed with normal B enriched lymphocytes. In eleven cases studied, anti-B cell serum reacted with a majority of the lymphoblasts. None of the ten cases examined displayed ICIg in the lymphoblasts. We conclude that the "null" lymphoblast from most cases of ALL is a B cell in an early stage of development.

Hairy cell leukemia: an unusual lymphoproliferative disease: a study of 24 patients

A laboratory and clinical evaluation of 24 patients with hairy cell leukemia was carried out over a 23-month period. Most patients had splenomegaly without adenopathy or pancyotpenia. Nine of the patients had undergone splenectomy prior to referral; their median WBC count was 6600/mm3. The median WBC count for the 14 patients who had no prior therapy was 3550/mm3, and their median platelet count was 80,500/mm3. Spleen weights ranged from 618 to 3780 g; there appeared to be no relationship between the size of the spleen and the response in the blood counts after splenectomy. Four patients in whom the majority of the WBC were hairy cells underwent splenectomy, which produced no real change in their WBC count; however, there was improvement in the platelet count in three. In contrast, the presence of leukopenia with a low percentage of hairy cells predicted a beneficial response to splenectomy. The study of surface immunoglobulins (SIg) in 16 patients demonstrated that resynthesis had occurred in each case. Phagocytosis of zymosan was studied in 15 patients; in 8 of these, 25% or more of the hair cells were capable of phagocytosis; in 6 others, 0--9%; and in one, 13%. The resynthesis of SIg is a feature usually associated with B-lymphocytes, but the phagocytosis of zymosan is not. Thus, the existence of either a spectrum of functional capabilities of hairy cells or several distinct subtypes is suggested by these data. Platelet aggregation with epinephrine was abnormal in 7 of 14 patients studied but there were no clinically significant bleeding problems. A chromosome abnormality was present in 2 of the 19 patients from whom adequate samples were obtained; the abnormality probably involved chromsome 12 in both patients as well as absent Y and was associated with a rapidly progressive clinical course. The presence of a predominant number of hairy cells with a normal or increased peripheral blood WBC count or of a chromosomal abnormality suggests that splenectomy might not be beneficial as the initial therapy and that chemotherapy should be considered.