CD5 links humoral autoimmunity with B-cell chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) does not result from accumulation of CD5⁺ B cells but, presumably, represents an antigen-driven dynamic process. Autoimmune diseases (AIDs) include hemolytic anemia, thrombocytopenic purpura and immune neutropenia. In turn, CLL and B-cell lymphoma develop in the frame of an AID. Such reciprocal interactions suggest that similar B cells are involved in both disorders. Phenotypic features (i.e., several membrane markers) and functional characteristics of CD5⁺ B cells (i.e., Epstein–Barr virus transformation and expression of apoptotic proteins) distinguish CLL and AID CD5⁺ B cells from their normal counterparts. These cells produce often nonpathogenic polyspecific low-affinity autoantibodies, whereas they present the antigen to antiself B or T cells to feature pathogenic monospecific high-affinity autoantibody. The CD5 molecule itself plays a part by translocating phosphatases to the vicinity of the B-cell antigen receptor, thereby precluding transduction from the B-cell receptor. Such might be the link between CLL and AID, both prevented by the CD5 machinery.     

ZAP-70在慢性淋巴细胞白血病/小淋巴细胞淋巴瘤中表达及其与预后的关系

目的 探讨慢性淋巴细胞白血病/小淋巴细胞淋巴瘤(CLL/SLL)病理学特点及ZAP-70蛋白表达的预后意义.方法 采用免疫组织化学EliVision法,回顾性检测ZAP-70在52例CLL/SLL患者淋巴结和骨髓活检组织中的表达特点,并随访患者.结果 (1)病理学特征:12例淋巴结呈现均一性成熟小淋巴细胞增生,6例可见增殖中心.40例骨髓中瘤细胞形态与淋巴结的相似,但未见增殖中心.浸润模式分为结节型(9例)、间质型(3例)、混合型(9例)、弥漫型(19例)4种,比较非弥漫型和弥漫型存活率,二者差异无统计学意义(Fisher精确检验,P=0.199).(2)ZAP-70表达定位在细胞质和细胞核,21例(40.4%)患者ZAP-70阳性,其中因本病或感染等相关因素死亡11例.31例(59.6%)ZAP-70阴性,包括因本病或感染死亡4例.比较二组生存期,阳性组明显较阴性组短(39个月和59个月,x2=6.991,P=0.008).(3)随访51例患者,死亡21例,其中因本病及感染等相关因素死亡15例.结论 CLL/SLL患者ZAP-70阳性表达提示预后不良.     

The diagnostic value of CD1d expression in a large cohort of patients with B-cell chronic lymphoproliferative disorders

Immunophenotyping is indispensable in the differential diagnosis of B-cell chronic lymphoproliferative disorders (B-CLPDs). However, B-CLPDs often show overlapping immunophenotypic profiles and may be diagnostically challenging. CD1d is an HLA class I-like molecule that presents glycolipids to invariant natural killer T cells. Normal mature B cells constitutively express CD1d, but with the exception of some conflicting data, its expression in B-CLPDs is unknown. We demonstrate that in 222 B-CLPD cases, CD1d expression of less than 45% is strongly predictive of CLL (likelihood ratio, 32.3; specificity, 97.4%; sensitivity, 84.1%). In addition, CD1d showed significantly higher staining intensity in splenic marginal zone lymphoma compared with atypical hairy cell leukemia, lymphoplasmacytic lymphoma, and mantle cell lymphoma, thus allowing the discrimination of the former from the latter immunophenotypically overlapping B-CLPDs. It is important to note that in a given patient, CD1d expression on malignant B cells was similar between tissues and remained unaffected by disease stage and treatment status. Our findings strongly argue for the incorporation of CD1d into routine lymphoma panels.     

Adhesion molecule expression in CD5-negative/CD10-negative chronic B-cell leukemias: comparison with non-Hodgkin's lymphomas and CD5-positive B-cell chronic lymphocytic leukemia

The classification of CD5-negative/CD10-negative chronic B-cell leukemias (CD5-/CD10- CBL) can be problematic. Most of these cases may represent leukemic non-Hodgkin's lymphoma (NHL) other than B-cell chronic lymphocytic leukemia (BCLL); nonetheless, some investigators still advocate the term "CD5-negative BCLL." Because adhesion molecule (AdMol) expression patterns reflect the biology of lymphoid neoplasms, we studied a series of 106 B-cell lymphoproliferative disorders, including CD5+ BCLL (n = 56), NHL other than BCLL (n = 35), and CD5-/CD10- CBL (excluding hairy cell leukemia and prolymphocytic leukemia) with no prior history of NHL (n = 15) for expression of components of the very late antigen-4 complex (alpha4/beta1 integrin (CD49d/CD29)), components of the mucosal addressin-cell adhesion molecule receptor (alpha4(CD49d)/beta7 integrin), and L-selectin (CD62L). CD62L expression was significantly greater in CD5+ BCLL than in NHL (P < .001). Conversely, CD29, CD49d, and beta7-integrin expression were significantly greater in NHL than in CD5+ BCLL (P < .001 for each marker). These differences persisted when only blood and bone marrow samples were analyzed, with the exception of differences in CD62L expression, which approached, but did not reach, statistical significance (P = .08). The group of CD5-/CD10- CBL displayed an AdMol profile similar to NHL and was significantly different than CD5+ BCLL in expression of beta7 integrin, CD29, CD49d, and CD62L (P range < .001-.011). In summary, CD5-/CD10- CBL display an AdMol profile resembling NHL and significantly different from CD5+ BCLL, supporting the growing notion that "CD5-negative BCLL" generally represents leukemic NHL rather than a variant of true CD5+ BCLL.     

Usefulness of CD79b expression in the diagnosis of B-cell chronic lymphoproliferative disorders

We evaluated anti-CD79b for its usefulness in the diagnosis of B-cell chronic lymphoproliferative disorders (BCLPDs), particularly chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). We analyzed 100 BCLPDs for CD5, CD19, CD20, CD23, CD79b, and surface immunoglobulin light chain (sIg) expression by 4-color flow cytometry. CD20, CD79b, and sIg expression were quantified. Correlational analysis and univariable and multivariable logistic regression models were used to determine the best combination of antigens for the immunophenotypic classification of CLL vs other BCLPDs. Positive and statistically significant Spearman pairwise correlations between CD20, CD79b, and sIg fluorescence intensity were demonstrated. In the simplest models in which a single variable was considered, cutoff points were chosen that gave misclassification rates for CLL of 16% for CD79b, 19% for sIg, and 18% for CD20. Low-intensity CD79b, CD20, and sIg are associated highly with CLL. A panel containing CD5, CD19, CD23, and sIg allowed correct classification of most cases. Addition of CD20 or CD79b improved diagnostic accuracy; CD79b was slightly better than CD20. CD79b seems to be a useful addition to a standard flow cytometry panel for the evaluation of BCLPDs.     

Chronic lymphocytic leukemia/small lymphocytic lymphoma with trisomy 12 and focal cyclin d1 expression: a potential diagnostic pitfall

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and mantle cell lymphoma usually are distinctly different in regard to clinical presentation, morphology, immunophenotype, and molecular/genetic findings. In spite of this, select cases may show overlapping characteristics and represent a diagnostic challenge. Cyclin D1 immunohistochemical staining is usually envisioned as a definitive method for resolving this differential diagnosis, with positivity supporting a diagnosis of mantle cell lymphoma. We report a case involving a 58-year-old man with a diagnosis of CLL/SLL for several years. A lymph node excision was performed after increased adenopathy was noted in the cervical region. The excised lymph node showed typical morphologic findings of CLL/SLL, including the presence of characteristic proliferation centers. Cyclin D1 staining, using 3 different antibodies, was present in scattered prolymphocytes and paraimmunoblasts, mostly within proliferation centers. Fluorescence in situ hybridization and conventional cytogenetics demonstrated trisomy 12 and an absence of t(11;14) in lymph node tissue. Focal cyclin D1 expression by immunohistochemistry in nodal CLL/SLL is quite unusual and is discussed as a potential diagnostic pitfall.     

Polymorphism in the CD5 gene promoter in B-cell chronic lymphocytic leukemia and mantle cell lymphoma

Despite the low incidence of microsatellite instability (MSI) in lymphoid malignant neoplasms, it has been reported that the CD5 promoter MSI was relatively frequent among B-cell chronic lymphoproliferative disorders. We studied the presence of MSI in the CD5 promoter in 134 cases of B-cell chronic lymphocytic leukemia (B-CLL) and 47 of mantle cell lymphoma (MCL) by comparing the pattern of microsatellite repeats on autologous germline and tumor DNA samples. Microsatellite alterations were not observed in any case. However, the allele distribution of this polymorphism showed a higher frequency of the 18 CA allele (0.585) in MCL cases (P = .026; odds ratio [OR], 1.75; 95% confidence interval [CI], 1.07-2.87) and of the 19 CA allele (0.179) in B-CLL cases (P = .005; OR, 2.26; 95% CI, 1.27-4.01) compared with control cases (0.442 and 0.087, respectively). This suggests that although MSI seems not to be involved in the pathogenesis of these 2 lymphoid malignant neoplasms, the polymorphic CD5 promoter is associated with increased susceptibility to these disorders.     

CD39 activity correlates with stage and inhibits platelet reactivity in chronic lymphocytic leukemia

Background  

Chronic lymphocytic leukemia (CLL) is characterized by accumulation of mature appearing lymphocytes and is rarely complicated by thrombosis. One possible explanation for the paucity of thrombotic events in these patients may be the presence of the ecto-nucleotidase CD39/NTDPase-1 on the surface of the malignant cells in CLL. CD39 is the major promoter of platelet inhibition in vivo via its metabolism of ADP to AMP. We hypothesize that if CD39 is observed on CLL cells, then patients with CLL may be relatively protected against platelet aggregation and recruitment and that CD39 may have other effects on CLL, including modulation of the disease, via its metabolism of ATP.     

B-cell chronic lymphocytic leukemia: correlation of clinical stages with angiogenic cytokine expression.

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by the accumulation of non-cycling B cells in lymphatic and extralymphatic tissues. Earlier studies had validated that angiogenesis was increased in B-CLL. Increased serum concentrations of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) connote a poor prognosis in early-stage B-CLL. Early progression is also related to transforming growth factor-beta (TGF-beta), which inhibits B-cell proliferation and immunoglobulin production. The authors investigated the expression of CD34, VEGF, bFGF, and TGF-beta and their receptors in different stages of B-CLL by analyzing bone marrow samples from 23 patients (11 with Rai stages 0-II; 12 with stages III or IV). TGF-beta2 was expressed more strongly in stages 0 to II than in stages III or IV (P=0.03). There was no significant difference in the intensity of CD34, TGF-beta1, VEGF, and bFGF and their receptors between stages 0 to II and stages III or IV. Staining showed bFGF expression to be stronger than VEGF expression (P=0.001). Results did not confirm an association between the intensity of angiogenesis and B-CLL stage. The expression of TGF-beta2 was stronger in early-stage disease and may help slow disease progression.     

Characteristic CD103 and CD123 expression pattern defines hairy cell leukemia: usefulness of CD123 and CD103 in the diagnosis of mature B-cell lymphoproliferative disorders

By using flow cytometry, we studied CD103 and CD123 expression by the malignant cells in 300 B-cell lymphoproliferative disorder (BC-LPD) cases, including 114 hairy cell leukemia (HCL), 20 HCL variant (HCLv), 9 splenic marginal zone lymphoma (SMZL; in 5, only CD103 was evaluated), 133 chronic lymphocytic leukemia (CLL), 3 follicular lymphoma (FL), and 21 mantle cell lymphoma (MCL). All HCLs expressed uniform CD103 and bright CD123. Among the 20 HCLv cases, 20 (100%) were CD103+ and 8 (40%) were CD123+ (partial or dim). CD103 was negative in all MCL, FL, CLL, and SMZL cases. CD123 was positive in 1 (25%) of 4 SMZL, 3.8% of CLL (5/133), 7 (33%) of 21 MCL, and 1 (33%) of 3 FL cases. CD103 is specific for HCL and HCLv. CD123 expression is more widespread in BC-LPDs but is useful in conjunction with CD25 to differentiate HCLv from HCL. These findings support the usefulness of CD123 and CD103 to aid in the differential diagnosis of BC-LPDs.     

Challenge in diagnosis of CD56+ lymphoproliferative disorders: two cases of CD56+CD33+ lymphoma/leukemia

Two cases of CD56+CD33+ leukemia/lymphoma are reported. The patient in case 1 presented with skin rash, diffuse lymphadenopathy, and hepatosplenomegaly. Blasts with monocytoid and lymphoid features were present in the peripheral blood. The tumor cells expressed HLA-DR, CD4, CD33, CD38, and CD56. Cytogenetic analysis revealed del(2)(p13),del(9)(q22),add(6)(q25),add(12)(p12),-13,-18, and -20. The clinicopathologic features were similar to those of blastic natural killer cell leukemia/lymphoma or type 2 dentritic cell leukemia. The patient in case 2 presented with generalized weakness and skin erythema not responding to antibiotics. Circulating blasts with monocytoid features were seen in the peripheral blood. The tumor cells expressed CD7, CD13, CD33, CD38, and CD56, and cytogenetic analysis revealed -5,add(7)(p22),-8, del(10)(p11.2),-12,der(13; 14)(p10;p10),+14,-16,-18,-19, and del(20)(q13.1). The clinicopathologic features were consistent with a myeloid/ natural killer cell precursor acute leukemia. Both disorders are aggressive hematopoietic malignancies that have similar clinical presentation and morphology but differ in immunophenotype and cytogenetic features.     

Comparative analysis of flow cytometric techniques in assessment of ZAP-70 expression in relation to IgVH mutational status in chronic lymphocytic leukemia

We compared 1 subjective and 5 objective flow cytometric methods to evaluate zeta-associated protein (ZAP-70) expression in relation to immunoglobulin heavy-chain variable-region (IgVH) gene mutational status in 154 samples from 125 patients with chronic lymphocytic leukemia (CLL). ZAP-70 expression determined by all methods used correlated with IgVH gene mutational status, but none of them demonstrated high concordance rates. Of the objective methods, ZAP-70 staining determined as a ratio of molecules of equivalent soluble fluorochrome intensity in CLL cells to that in normal B cells (ZAP-70+ staining in IgVH germline cases, 59%; ZAP-70- in IgVH mutated cases, 75%) or T cells (ZAP-70+ in IgVH germline cases, 66%; ZAP-70- in IgVH mutated cases, 57%) provides the best combination for assigning ZAP-70+ status to IgVH germline and ZAP-70- status to IgVH mutated cases. The subjective method based on ZAP-70 expression in natural killer/T cells gave a similar result, but reproducibility between laboratories may be difficult. Further studies on ZAP-70 expression in relation to clinical parameters may address whether ZAP-70 is an independent prognostic marker for CLL.     

Factors affecting bryostatin 1-enhanced 2-CdA cytotoxicity in resistant B-cell chronic lymphocytic leukemia

Pre-treatment with bryostatin 1 (bryo) has been shown to potentiate the efficacy of (2-chloro-2-deoxyadenosine, cladribine, 2-CdA) in B-cell chronic lymphocytic leukemia (B-CLL) by increasing the ratio of deoxycytidine kinase (dCK) to 5'-nucleotidase (5'-NT) activity. The bryo-induced increase in dCK/5'-NT activity alone has not been a conclusive indication of final clinical outcome. Therefore, we used an ex vivo assay to investigate factors which may affect the bryo-induced enhancement of 2-CdA efficacy in B-CLL patient-derived samples. Bryo-induced increase in dCK/5'-NT was inversely associated with Rai stage CLL (r=-0.86). Increased dCK/5'-NT activity was not correlated with increased efficacy (cell death) or percentage of cellular [8-3H]-2-CdA converted to [8-3H]-2-CdATP ex vivo. Bryo pre-treatment increased the cellular uptake of [8-3H]-2-CdA and incorporation of [8-3H]-2-CdA metabolites into the DNA fraction. Cell death from 2-CdA was inversely correlated with bryo-induced activity of the DNA repair enzyme, DNA-PKcs, (r=-0.77). Thus, the ability of B-CLL to repair damaged DNA may be a more important predictor of the response to bryo/2-CdA and eventual clinical outcome than dCK/5'-NT activity. Additional CLL patients under bryo-2-CdA therapy are needed to verify these important observations.     

Surface and cytoplasmic immunoglobulin expression in B-cell chronic lymphocytic leukemia (CLL)

Flow cytometric analysis of abnormal lymphocyte populations in chronic lymphocytic leukemia (CLL) has been widely reported to show weak expression of surface immunoglobulin (sIg). The international scoring system to help discriminate between CLL and other B-cell lymphoproliferative disorders lists this as the first of 5 criteria worth 1 point each. In the present study, 30 cases of CLL were studied for surface and cytoplasmic Ig expression. 23 of these 30 (76.7%) cases were positive for sIg. Of these 23, 14 cases (60.9%) showed moderate to bright sIg expression. All of these 23 cases were positive for CD5 and CD23; all were negative for CD10 and only 6 (26.1%) were positive for FMC7. 27 of 30 (90.0%) cases expressed cytoplasmic immunoglobulin (cIg) compared to 5% reported by others. This shows that cytoplasmic Ig occurs in a much greater percentage of cases than reported previously. 23 of 30 (76.7%) cases showed positivity for both surface and cytoplasmic Ig, with 15 showing kappa light chain restriction and 8 showing lambda light chain restriction. Six expressed cytoplasmic Ig only, with 4 showing kappa light chain restriction and 2 showing lambda light chain restriction. One case expressed neither cytoplasmic nor surface Ig. CD38 positivity portends a worse prognosis. Of the 29 cases tested for CD38, 13 (44.8%) were positive. Of these 13 cases, 12 were in the surface Ig/cytoplasmic Ig+ group and 1 in the cytoplasmic Ig+ group only. Also, of the 23 cases tested for CD22 expression, 16 (69.6%) were positive. These data question the use of both "weak" surface Ig expression and lack of CD22 expression as valid scoring criteria for CLL.