Differential cytokine and Toll-like receptor expression in leukemia.

Toll-like receptors (TLRs) and cytokines function in immune regulation and thus may be dysregulated in disease. In this study, 25 leukemia cases and 10 normal controls were analyzed by flow cytometry for differential cytokine and TLR expression. The percentages of CD3+ cells producing TNF-alpha, IL-2, IL-3, IL-4, IL-6, IL-10, IL-12, and IFN-gamma were determined. Statistically significant differences between lymphocytic leukemia cases and normals were observed for all cytokines except IL-12. Differences in expression of all cytokines other than IL-6 and IFN-gamma proved to be statistically significant between myeloid leukemic and normal cases. IFN-gamma and IL-3 dual staining was observed to be most prominent in leukemic samples. Additionally, the staining intensities of TLR3, TLR4, TLR8, and TLR9 in regard to CD3+ cells were evaluated and compared among the three groups. The increased staining intensity of TLR9 in leukemic cases compared to levels in normal controls was statistically significant. No differences of statistical significance were observed between the two leukemic groups for cytokine or TLR expression. These results warrant further study of the mechanism and potential therapeutic value targeting these leukemic patterns.

Zap-70 and CD38 as predictors of IgVH mutation in CLL.

Zeta-chain (TCR)-associated protein kinase 70 kDa (Zap-70) and CD38 expression may be of prognostic significance in chronic lymphocytic leukemia (CLL). Previous studies indicate that Zap-70 and CD38 are usually positive in cases of CLL with unmutated immunoglobulin variable region genes (IgVH) and may be used to predict IgVH mutation status and prognosis. Usually cases of CLL positive for Zap-70 or CD38 indicate a worse prognosis. In the present investigation, 47 cases of CLL were evaluated for CD38 expression, and 17 cases were evaluated for both Zap-70 and CD38 expression. Of the 47 cases, 19 (40.4%) positively expressed CD38. Of the 17 cases evaluated for Zap-70, 11 (64.7%) were positive for Zap-70, while only 6 (35.3%) were positive for CD38 expression; the remaining cases were negative for CD38. The results of this study show that Zap-70 expression may be a better indicator of the mutational status of IgVH and prognosis of CLL than CD38 expression. In addition, CD38 negativity does not necessarily indicate that IgVH mutation has occurred. These data point to the need for a more extensive study to evaluate the significance of Zap-70 and CD38 expression as indicators of IgVH mutation status and prognosis of CLL patients.

Aberrant expression of T-cell markers in acute myeloid leukemia.

According to WHO, several T-cell immunophenotypic markers may be aberrantly expressed in acute myeloid leukemia (AML). TdT may be expressed in greater than one-third of cases, and CD2 and CD7 may be expressed frequently at low intensity; however, the T-cell lineage specific antigen CD3 is usually absent. In this investigation, 30 cases of AML were evaluated for CD2, CD3, CD5, CD7, CD8 and TdT expression, and mean fluorescence intensities (MFI). Of the 3 (10%) cases positive for CD3 and CD8, 1 was bright (MFI>501), and 2 cases were moderate. TdT was moderately expressed in 4 (13.3%) cases with MFI values between 301 and 500. CD2 and CD5 were positive in 5 (16.7%) cases. While CD2 was moderate in all 5 cases, CD5 was bright in 3, moderate in 1 and dim in 1. Of the 15 (50%) cases positive for CD7, 9 were bright, 5 were moderate, and 1 was dim with a MFI value between 201 and 300. These data indicate that CD2 and CD7 may be frequently expressed at greater intensities than WHO specified. These results point to the need for a more extensive study to evaluate the potential prognostic significance of aberrant T-cell marker expression in AML.

Diminished CD10, CD13, and CD15 expression in a differentiated granulocyte population in CML.

Flow cytometric analysis of cluster of differentiation (CD) markers of myeloid cells has been used in conjunction with cell morphology to diagnose chronic myelogenous leukemia (CML). In the present study, 16 cases of CML were studied for levels of expression of myeloid markers CD15, CD13, CD33, and CALLA, i.e., CD10 which is also expressed on mature granulocytes. In 11 (68.8%) of 16 cases, a differentiated granulocyte population was detected that showed decreased expression of both CD10 and CD13. CD10 was found to be negative in 1 (6.3%) case and showed decreased expression in 10 (62.5%) of the cases. CD13 showed decreased expression in 11 (68.8%) of the 16 cases. Of the 15 cases analyzed for CD15, 2 (13.3%) were negative and 6 (40%) showed decreased expression. Of the 11 cases which showed simultaneous diminished expression of CD10 and CD13, 8 (72.7%) also showed decreased expression of CD15. Of the antigens studied, CD33 was the only one to be consistently expressed at normal levels, i.e., 13 (81.3%) cases demonstrated normal expression. Therefore, these results point to frequently decreased expression levels of CD10, CD13, and CD15 and rarely decreased expression levels of CD33 in association with CML.

Contrasting antigenic maturation patterns in M0-M2 versus M3 acute myeloid leukemias.

Acute myelogenous leukemia (AML) is divided into 8 FAB subgroups based on differentiation and maturation properties of the neoplastic cells. Acute promyelocytic leukemia (APL), or M3 AML, is associated with disseminated intravascular coagulation (DIC). Flow cytometric immunophenotyping differentiates among the AML subtypes. Key markers in this classification include the myeloid antigens CD13 and CD33 and the hematopoietic precursor markers CD34 and HLA-DR. The present study analyzes and compares differences in the expression of these markers in 27 M0-M2 cases and 8 M3 cases. The M0-M2 cases generally expressed all four antigens. CD13 and CD33 were positively expressed in 23 (85.2%) and 21 (77.8%) of the 27 cases, respectively. CD34 and HLA-DR were present in 25 (92.6%) and 26 (96.3%) of the 27 cases, respectively. Analysis of the M3 cases revealed a different immunophenotype as CD13 and CD33 were each positive in all 8 (100%) M3 AML cases while CD34 and HLA-DR were negative in 6 (75%) and 8 (100%) of the 8 M3 cases, respectively. In contrast to expression of the early markers CD34 and HLA-DR in the M0-M2 group, these were negative in the M3 cases which were characterized by heterogeneous CD13 and generally homogeneous and bright CD33 expression.

The immunophenotype of pre-TALL/LBL revisited.

Flow cytometric analysis of cluster of differentiation (CD) markers in abnormal lymphocyte populations is crucial in the diagnosis of precursor T cell acute lymphoblastic leukemia (T-ALL)/lymphoblastic lymphoma (LBL). The World Health Organization (WHO) suggested immunophenotype for pre-T ALL/LBL typically includes the expression of TdT, cCD3, and CD7, while CD2, CD3, CD4, CD5, CD8, and CD10 are variably expressed. The myeloid antigens CD13 and CD33 are usually positive, whereas CD117 and cCD79a are infrequently expressed. Furthermore, there is frequent dual expression of CD4 and CD8. In the present investigation, 19 cases of pre-TALL/LBL were analyzed for selected CD marker expression. Fifteen of 19 cases studied were evaluated for TdT, cCD3, and cCD79a expression. Eleven (73.3%) positively expressed TdT, 15 (100%) positively expressed cCD3, and 9 (60%) positively expressed cCD79a. Of the 17 cases analyzed for CD7, CD5, and CD10 expression, CD7 and CD5 were positive in all 17 (100%) cases, whereas CD10 was positive in 8 (47.1%) cases. Of the 18 cases evaluated for CD2, CD3, CD4, CD8, and dual expression of CD4 and CD8, CD2 was expressed in 14 (77.8%), while CD3 was expressed in 7 (38.9%) cases. CD4 was positive in 11 (61.1%), and CD8 was expressed in 9 (50%). Dual expression of CD4 and CD8 occurred in only 4 (22.2%) of the cases. Of the 16 analyzed for CD13, CD33, and CD117, only 1 case (6.3%) expressed CD13, while 2 (12.5%) cases expressed CD33 and CD117. Thus, these data point to the need for a more extensive study to reevaluate the current WHO defined immunophenotype used in the diagnosis of pre-TALL/LBL.

Antigenic transformation in plasma cell dyscrasia.

The WHO immunophenotype for plasma cell myeloma is deletion of CD19 and CD20, usual expression of CD38, CD138, and CD56, and occasional expression of CD10. Of the 39 cases of plasma cell dyscrasia in our study, the mean fluorescence intensities (MFI) of CD38, CD138, CD56, and CD19 were quantified in 30 cases. CD19 was absent in 38 of the cases (97.4%), whereas CD138 and CD38 were expressed in all 39 cases (100%). Most cases expressed CD38 and CD138 brightly with MFI values greater than 501, whereas all other marker expression was moderate with MFI greater than 301. Whereas CD38/CD56 dual expression was observed in 25 cases (64.1%), 14 failed to express CD56 (35.9%). CD56 expression was bright in 16 cases (53.3%), moderate in 2 cases (6.7%), and negative in the remaining 12 cases (40%) with MFI values of 200 or less. CD117 expression was positive in 9 of 24 cases (37.5%). In 32 of 39 cases, 27 were negative for CD20 (84.4%) and 28 were negative for CD10 (87.5%). Our results point to the value of quantitative fluorescence intensity in the flow cytometric evaluation of CD molecular expression or deletion in the diagnosis of hematopathologic disorders, such as plasma cell dyscrasia.