B-cell chronic lymphocytic leukaemia: prognostic value of the immunophenotype and the clinico-haematological features

Host virus and pneumococcus-specific immune responses in high-count monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia: implications for disease progression

Patients diagnosed with chronic lymphocytic leukemia (CLL) display a high incidence of infections due to an associated immunodeficiency that includes hypogammaglobulinemia. A higher risk of infections has also been recently reported for high-count monoclonal B-cell lymphocytosis, while no information is available in low-count monoclonal B-cell lymphocytosis. Here, we evaluated the status of the humoral immune system in patients with chronic lymphocytic leukemia (n=58), as well as in low- (n=71) and high- (n=29) count monoclonal B-cell lymphocytosis versus healthy donors (n=91). Total free plasma immunoglobulin titers and specific levels of antibodies against cytomegalovirus, Epstein-Barr virus, influenza and S.pneumoniae were measured by nephelometry and ELISA-based techniques, respectively. Overall, our results show that both CLL and high-count monoclonal B-cell lymphocytosis patients, but not low-count monoclonal B-cell lymphocytosis subjects, present with relatively high levels of antibodies specific for the latent viruses investigated, associated with progressively lower levels of S.pneumoniae-specific immunoglobulins. These findings probably reflect asymptomatic chronic reactivation of humoral immune responses against host viruses associated with expanded virus-specific antibody levels and progressively decreased protection against other micro-organisms, denoting a severe humoral immunodeficiency state not reflected by the overall plasma immunoglobulin levels. Alternatively, these results could reflect a potential role of ubiquitous viruses in the pathogenesis of the disease. Further analyses are necessary to establish the relevance of such asymptomatic humoral immune responses against host viruses in the expansion of the tumor B-cell clone and progression from monoclonal B-cell lymphocytosis to CLL.

The development of marked elevation in white blood cell count does not predict inferior outcome in chronic lymphocytic leukemia

Although elevation of the white blood cell (WBC) count at diagnosis of chronic lymphocytic leukemia (CLL) appears to predict shortened survival, its significance later in the course of the disease remains unclear. We reviewed all cases of CLL seen in our center between 1980 and 1999 to evaluate the frequency and clinical significance of WBC elevation > 100 x 10(9)/L. CLL was confirmed according to standard diagnostic criteria and data was collected from diagnosis, occurrence of WBC > 100 x 10(9)/L, and last follow-up. 235 consecutive patients with CLL were identified; 94 were excluded. 141 included patients had a median age of 61 years and median WBC 19.7 x 10(9)/L at diagnosis. Median follow-up for all patients was 56 months, and median survival was 104 months. 41 patients (29%) had > or = 1 episode of WBC > 100 x 10(9)1/L, occurring at a median of 38 months from diagnosis. Compared to controls matched for modified Rai stage, development of a WBC > 100 x 10(9)/L did not predict inferior survival (median 107 vs. 101 months, p = 0.72). We conclude that the occurrence of a WBC count > 100 x 10(9)/L in patients with CLL does not shorten the survival, and patients require therapy only if other indications for treatment are present.

B-cell chronic lymphocytic leukaemia with CD8 expression: report of 10 cases and immunochemical analysis of the CD8 antigen

We report 10 cases of B-cell chronic lymphocytic leukaemia (B-CLL) with expression of the T-cell antigen CD8. The majority of patients had typical B-cell CLL with stable and non-progressive stage A(O) disease except for more common expression of lambda light chain and CD25. Two patients had progressive disease and required therapy, one with atypical morphological and phenotypic features. The incidence of CD8 expression was approximately 0.5% of B-CLL patients from our institutions. Immunoprecipitation of the CD8 antigen from four of these B-CLLs showed identity to the CD8 antigen expressed on T cells with precipitation of CD8alpha bands of molecular weight approximately 34 kD. In view of the known intracellular signalling mechanism of CD8 using the tyrosine kinase p56-lck, we studied p56-lck expression by Western blot and found lack of consistent expression of the CD8 surface antigen, with most lacking p56-lck. Our report indicates that CD8 expression in B-CLL is probably underrecognized but is not a marker of disease progression. The CD8 on the B-CLL surface is immunochemically identical to the antigen on T cells, but is not accompanied by its usual signalling mechanism of p56-lck tyrosine kinase and therefore is unlikely to be a functionally active receptor.

Clinico-prognostic relevance of quantitative immunophenotyping in B-cell chronic lymphocytic leukemia with emphasis on the expression of CD20 antigen and surface immunoglobulins

Expression of CD20, evaluated as antibody binding capacity (ABC) (i.e. absolute number of molecules of antibody per cell), was analyzed using flow cytometry on leukemic cells of 93 previously untreated patients, all fulfilling strict criteria of "immunologically typical" (i.e. CD5+, CD23+) B-cell chronic lymphocytic leukemia (CLL). Although changes of CD20 antigen density did not correlate with clinical parameters representative of either tumor mass (i.e. clinical stage, histological pattern of bone marrow involvement, absolute peripheral blood lymphocytosis) or disease progression (i.e. lymphocyte doubling time), a trend toward a better life-expectancy was observed in the low CD20 expression group compared with the high CD20 expression group (p = 0.05; relative risk of death, 0.51, 95% confidence interval, 0.24-1.04). Given the correlation between CD20 ABC and mean fluorescence intensity (MFI) of light chain (LC) surface immunoglobulins (Sm Ig) (r = 0.481, p < 0.0001), as well as the impact of MFI of Sm Ig LC on overall survival (p = 0.01; relative risk of death 0.44; 95% confidence interval, 0.10 to 0.76), we tried to verify whether a combination of B-cell markers, evaluated in a quantitative manner, could have additive prognostic properties. To this purpose we gave a value of 1 or 0 to each B-cell marker according to whether it was expressed at a low (i.e. CD20 ABC < 17.9 x 10(3) molecules/cell, MFI of LC Sm Ig < 100) or high (i.e. CD20 ABC > or = 17.9 x 10(3) molecules/cell, MFI of LC Sm Ig > or = 100) level thus allowing patient stratification into two groups with scores of 2 and 0-1, respectively. Survival of patients who scored 2 was significantly longer respectively. Survival of patients who scored 2 was significantly longer than that of patients who scored 0-1 (p = 0.02; relative risk of death, 0.44; 95% confidence interval, 0.22-0.72). However, when quantitative changes of CD20 antigen and LC Sm Ig expression, either alone or in combination, were simultaneously analyzed in a Cox model which included usual clinico-hematological features, only absolute peripheral blood lymphocytosis (p = 0.0001) and Binet clinical stages (p = 0.0001) maintained their prognostic power unmodified. Although variability of CD20 and Sm Ig expression make it possible to appreciate biological heterogeneity of B-cell CLL better, however, they cannot substitute well-established clinico-hematological features in the prognostic assessment of B-CLL patients.

Phenotypic analysis of receptor-ligand pairs on B-cells in B-chronic lymphocytic leukemia

Whole-blood three-color immunofluorescence analysis was used to investigate the role of CD5/CD72 and CD21/CD23 receptor-ligand pair formation on B-chronic lymphocytic leukemia (B-CLL) cells as well as sCD23 and bcl-2 oncoprotein expression in disease progression and activity and total tumor mass in B-cell chronic leukemia (B-CLL) patients. Thirty-four patients with B-CLL and 19 controls were included in the study. The majority of B-cells in B-CLL patients coexpressed CD5 and CD72 as well as the CD23 antigen. Unlike B-cells in B-CLL patients, B-cells in all healthy controls tested had high expression of CD21 antigen. We identified two groups of B-CLL patients according to high (n = 20) or low levels (n = 14) of CD21 expression on CD19+CD23+ B-cells. Only in the patients with high CD21 expression, were sCD23 levels positively correlated with factors known to have prognostic significance in B-CLL (Rai stage and TTM) and could, therefore, be used as a prognostic parameter for these B-CLL patients. Bcl-2 oncoprotein expression did not differ between these patient groups. We presumed that in patients with a lower expression of CD21 antigen, the contribution of the CD21 molecule to homotypic adhesion was lacking. Further studies are necessary to determine the possible association of higher expression of the CD21 antigen with disease progression and the aggressive character of the B-CLL.

Prognostic evaluation of specific cutaneous infiltrates in B-chronic lymphocytic leukemia

The relationship between numerous histologic variables and survival was investigated in 54 consecutive lesions of specific skin infiltrates of B-cell chronic lymphocytic leukemia (B-CLL) from 27 patients (16 males and 11 females, mean age 65 years, range 42-83 years). All patients were followed for up to 204 months or until death. Histopathologically, the infiltrates showed a patchy perivascular (35%), diffuse (31.5%), nodular (31.5%) or bandlike (1.9%) pattern. In 28% of the cases, an admixture of reactive cells within the infiltrate including eosinophils, histiocytes, neutrophils and plasma cells was observed. Cytomorphologically, small B-lymphocytes with condensed chromatin predominated in most infiltrates. However, some biopsies showed a small but significant number of medium- or large-sized neoplastic cells of the B-lymphocyte lineage with variable cytomorphological features. In a multivariate analysis, several histologic parameters within the infiltrates were found to show a significant association with long survival, namely, an infiltrate of moderate density, a nodular pattern, involvement of the lower dermis only, and presence of predominantly small B-lymphocytes (more than 95%) with condensed chromatin. Histologic variables that independently correlated with relatively short survival included an infiltrate of severe intensity, a diffuse pattern, epidermal changes (especially acanthosis and ulceration), medium-sized and large B-lymphocyte (more than 5%), and reactive cells within the infiltrate (neutrophils, eosinophils, and plasma cells). Overall analysis of our results showed two histologic patterns with a significant prognostic impact (p < 0.01; z = 5.4). Pattern I (33 biopsies) correlated with relatively long survival (2-year survival rate; 97%) and consisted of infiltrates showing predominantly small B-lymphocytes (more than 95%) without reactive cells or epidermal changes. Pattern II (21 biopsies) indicated short survival (2-year survival rate; 49%) and included all the rest of the biopsies i.e., infiltrates with medium- and large-sized B-lymphocytes (more than 5%), admixture of reactive cells, and epidermal changes. Results from our study suggest that histologic features in specific skin infiltrates of B-chronic lymphocytic leukemia may be helpful in identifying prognostically different subgroups of patients and planning therapeutic schedules.

Clinical, biological, and immunophenotypical characteristics of B-cell chronic lymphocytic leukemia with trisomy 12 by fluorescence in situ hybridization

The clinical, biological, and immunophenotypical characteristics of B-cell chronic lymphocytic leukemia (B-CLL) patients with trisomy 12 detected by fluorescence in situ hybridization (FISH) using a chromosome 12 alpha-centromeric probe (D12Z3) were analyzed in the present study. From a total of 104 consecutive B-CLL patients, 21 (20%) displayed trisomy 12, the percentage of trisomic cells ranging from 13% to 76%. From the clinico-biological point of view, patients with trisomy 12 were associated with atypical CLL morphology (43% vs 10%, P = 0.04) and BM diffuse pattern (75% vs. 25%, P = 0.02) together with increased WBC counts (141 +/- 220 vs. 58 +/- 67 x 10(9)/L, P = 0.04). In contrast, no association was detected between the presence of trisomy 12 and other disease characteristics such as age, sex, clinical stage, hepatomegaly, lymphadenopathies, haemoglobin levels and platelet counts, and the cell cycle distribution of PB leukocytes in both groups of patients. Trisomy 12 patients had a significantly higher expression of the FMC7 antigen both in percentage (34 +/- 34% vs. 13 +/- 20%, P = 0.02) and absolute numbers (29 +/- 62 vs. 7 +/- 17 x 10(9)/L, P = 0.007). No major differences were found regarding the expression of mouse rosettes, CD19+, and CD19+/CD5+ lymphocytes. Upon analyzing the correlations between the disease characteristics of trisomy 12 cases, significant associations were found between the percentage of trisomic cells and both the WBC count (r = 0.52, P = 0.02) and the PB lymphocyte count (r = 0.60, P = 0.007).(ABSTRACT TRUNCATED AT 250 WORDS)

A scoring system for the classification of CD5-B CLL versus CD5+ B CLL and B PLL

B CLL is a monoclonal proliferation of lymphocytes which express the CD5 antigen (CD5+ CLL). Rare exceptions (less than 10%) are CD5-, as are the majority of B PLL. We have studied the clinical, cytological and immunophenotypic characteristics of a series of 12 CD5-CLL and have established a score which allows the distinction between CD5+ CLL, CD5- CLL and PLL. Among the CD5- CLL, there were significantly more cases with advanced stage (Rai and Binet) and splenomegaly. The cytological study found more mixed CLL according to FAB classification (more prolymphocytes). There were significantly more CD23-, FMC7+, SIg strong positive cases. A score from 0 to 6 was established based on clinical, cytological and immunophenotypic criteria. Typical CD5+ CLL was scored 0, score 6 corresponded to typical PLL. There were significantly more higher scores amongst CD5- CLL. It therefore appears that CD5- CLLs share certain features with B PLL. The use of this scoring system will allow determination of prognosis within these different categories, thus identifying groups which require specific therapy.

Aberrant CD8 antigen expression in a patient with B chronic lymphocytic leukaemia showing unusual disease progression

Co-expression of T cell antigens in B-CLL has been well recognized. The commonest T cell antigen known to be expressed in B-CLL is CD5, and recent reports suggest that CD5 expression is associated with good prognosis. Expression of CD8 antigen, however, is much less common with uncertain prognostic significance. We report a case of B-CLL with aberrant CD8 expression, who had unusual disease progression with a fatal outcome.

Characterization of anti-HLA class II monoclonal antibody LGII-612.14 reacting with formalin fixed tissues

mAb LGII-612.14 derived from a BALB/c mouse immunized with interferon-gamma (IFN-gamma) treated cultured human B lymphoid cells LG-2 has been shown with serological and immunochemical assays to recognize a monomorphic determinant expressed on the beta chain of HLA-DR, -DQ and -DP antigens. The linear nature of the determinant, which is likely to be formed by residues 19-25, is indicated by the reactivity of mAb LGII-612.14 with HLA-DR, -DQ and -DP beta chains purified by electrophoresis in presence of SDS. An unusual characteristic of mAb LGII-612.14 is its reactivity with fixed tissue sections. The intensity of staining is affected by the incubation temperature, the incubation time and the fixative used. Maximal intensity of staining of formalin fixed, paraffin embedded tissue sections required an incubation time of 16 h. The intensity of staining of paraffin embedded tissues initially fixed with Bouin's solution, formalin or ethanol was similar to that of frozen tissue sections and stronger than that of tissues fixed with B5 solution. No staining was detected of paraffin embedded tissues fixed with glutaraldehyde or Zenker's solution. Comparison of the staining patterns with mAb LGII-612.14 of frozen and fixed tissue sections showed that the latter substrates provide a superior detail of tissue architecture and cellular morphology without significant loss of sensitivity. Furthermore, comparison of the characteristics of mAb LGII-612.14 with the few previously published anti-HLA class II mAb reacting with fixed tissues indicates that mAb LGII-612.14 stains formalin fixed, paraffin embedded tissues, while mAb 910D7 and TAL-1B5 stain tissues fixed with less commonly used fixatives. Furthermore, mAb LGII-612.14 is likely to yield more sensitive staining results than anti-HLA-DR, -DQ and -DP mAb KUL/05. The present results indicate that mAb LGII-612.14 represents a useful probe to apply immunohistochemical techniques to the analysis of the distribution of HLA class II antigens in fixed tissues. This will greatly facilitate the use of readily available collections of fixed tissue specimens in retrospective studies to assess the clinical significance of changes in HLA class II antigen expression which occur in various disease states.

Chronic lymphocytic leukemia with low lymphocyte count

BACKGROUND

A peripheral blood absolute lymphocyte count (ALC) of greater than 5 x 10(9)/l is considered the required minimum for diagnosis of chronic lymphocytic leukemia (CLL). Cases with low ALC (CLL-LLC), less than 5 x 10(9)/l, have not been included in the current staging systems, and would not be suspected of having CLL, or investigated for the disease, especially in the absence of clinical manifestations. On the other hand, the diagnostic value of the differential lymphocyte counts have not been emphasized.

METHODS

Cell suspensions from peripheral blood of previously untreated cases of CLL-LLC (n = 12) and typical CLL (n = 189) were analyzed for immunologic evaluation of surface immunoglobulin (SIg), mouse erythrocyte rosettes, CD5, CD19, CD20, CD22, and CD2, as well as cytochemical evaluation of tartrate-resistant acid phosphatase (TRAP). The results in CLL-LLC were compared statistically with typical CLL.

RESULTS

The ages of the 12 patients with CLL-LLC ranged from 47 to 84 years. The absolute lymphocyte counts ranged from 1.5 x 10(9)/l to 4.9 x 10(9)/l, and the percentage of lymphocytes in the differential leukocyte counts ranged from 52% to 93%. None of the patients had signs and symptoms of CLL or other conditions that may cause reactive lymphocytosis. CLL-LLC demonstrated similar characteristics to typical CLL, i.e., weak expression of monoclonal SIg, mouse rosette formation, positive CD5, high CD19 and CD20, negative CD22 and TRAP. No statistical differences existed between the immunologic markers or between SIg isotype distribution in the two groups.

CONCLUSIONS

Cases of CLL-LLC constituted 6% of B-CLL and would have been missed if immunologic investigation was not carried out because of the absence of absolute lymphocytosis and clinical manifestations of CLL. Persistent relative lymphocytosis of > or = 50% of the differential leukocyte count in older individuals (older than 50 years of age), is an indication for further investigation of CLL by immunophenotyping of peripheral blood lymphocytes and examination of bone marrow.

Reduced expression of CD20 antigen as a characteristic marker for chronic lymphocytic leukemia

The surface antigens expressed by the cells of chronic lymphocytic leukemia (CLL) are well known. Most CLL are monoclonal B-cell lymphoproliferative disorders characterized by the coexpression of B-cell antigens and CD5, an antigen present predominantly on T cells. Very little attention, however, has been paid to the quantitative characteristics of the expression of B-cell antigens in CLL. In this study, we used flow cytometry to analyze the expression of CD20, a well-known B-cell-associated antigen, in lymphocytes from 42 cases of CLL and its tissue counterpart, small lymphocytic lymphoma (SLL), and compared the results with results obtained from the analysis of 21 follicular lymphomas, 20 hyperplastic reactive nodes, and 26 samples of normal peripheral blood. The intensity of CD20 expression in the CLL/SLL cells was significantly lower than that of B cells in the other categories. This antigen expression abnormality does not appear to be a universal phenomenon in CLL/SLL, since CD19, another pan-B antigen, was expressed in CLL/SLL at levels higher than those in follicular lymphomas and comparable to those in reactive lymph nodes. These results indicate that the low CD20 expression can be used as a marker for CLL/SLL. The few cases exhibiting intense CD20 expression may represent a biologically different disease. CLL/SLL cells faintly expressing CD20 also show concomitant low CD5 expression in a manner not observed in normal CD5-expressing B cells.

Immunophenotypic subclassification of chronic lymphocytic leukaemia (CLL)

To determine the significance of the immunophenotypic heterogeneity of B-cell chronic lymphocytic leukaemia (CLL), surface immunoglobulins (SIgs), mouse rosette assays (MR), and a panel of monoclonal antibodies for B cells, T cells and myeloid cells were performed on peripheral blood samples from 61 newly diagnosed cases. Four groups were observed: group I (SIg+, MR+, CD19/20+, CD5+, T antigen (Ag)-; 27 cases); group II (SIg+, MR+, CD19/20+, CD5+, T Ag+; 17 cases); group III (SIg+, MR+ CD19/20+, CD5-, T AG-; 12 cases); and group IV (SIg-, MR+, CD19/20+, Cd5+, T Ag-; 5 cases). Groups were compared according to French-American-British Cooperative Group subtypes, clinical and laboratory features, Rai staging, and survival. Typical CLL morphology (greater than 90% small lymphocytes) was present in 20/20 (100%) of group I cases and 23/27 (85%) group II, III and IV cases (P = 0.09). Expression of a myeloid antigen was seen in 5/27 group I cases (18%) and 1/16 group II cases (6%), but was not predictive of survival (P = 0.36). The CD5- group III had a lower haemoglobin level (P less than 0.0001), higher Rai stage (P less than 0.002), and poorer survival at 5 years (P less than 0.02) than the other groups. We conclude that at least four distinct immunophenotypic subgroups of B-cell CLL can be determined. Expression of myeloid or T-cell antigens does not appear to predict for patient survival; however, lack of CD5 antigen may be associated with more advanced stage of disease and poor patient survival.

Reticulin fibre content of bone marrow infiltrates of malignant non-Hodgkin's lymphomas (B-cell type, low malignancy)--a morphometric evaluation before and after therapy

A morphometric study was performed on bone marrow infiltrates of non-Hodgkin's lymphomas (B-cell type, low malignancy) to evaluate the content of argyrophilic (reticulin) fibres in the various subtypes before and after therapy. In congruence with the corresponding lymph node lesions, subtypes consisted of lymphocytic lymphoma--chronic lymphocytic leukaemia (CLL, n = 39), centroblastic-centrocytic lymphoma (CB-CC, n = 35), lymphoplasmacytoid immunocytoma (LPI, n = 22) and finally hairy cell leukaemia (HCL, n = 21). In comparison with control specimens, morphometric measurements on trephine biopsies (initial staging procedure) disclosed a borderline or minimal increase in reticulin in CLL and moderate fibrosis in CB-CC and LPI, whereas HCL had the greatest increase in fibres. The marrow surrounding focal or patchy lymphoma infiltrates of CLL and CB-CC displayed no relevant changes in fibre density with respect to the control samples. Following chemotherapy, repeated trephine biopsies (restaging procedure) were obtainable from 38 patients. There was no significant decrease in the fibre content of CLL, CB-CC and LPI infiltrates. In HCL an incomplete reduction was recorded after interferon treatment. So-called benign lymphoid lesions may be distinguished from focal-patchy infiltrates of CB-CC and LPI not only by showing a central localization, but also by the absence of significant amounts of reticulin. However, considering the density of the reticulin fibres, a clear-cut discrimination of these lymphoid aggregates from an early nodal-central growth pattern of CLL is not feasible in many cases.