Mira Menon

Reactivity pattern of ‘myeloid monoclonal antibodies’ with emphases on MCS-2

The reactivity pattern of the murine monoclonal antibody (MoAb) MCS-2 was tested on a panel of 724 cases of leukemia-lymphoma. MCS-2 was positive in 178/185 (96%) cases of AML (FAB M1-3), 10/10 cases of AMMol/AMoL (FAB M4/5), 42/45 (93%) cases of CML, 1/1 case of CMoL, 37/38 (97%) cases of CML-myeloid blast crisis, 0/9 cases of CML-lymphoid blast crisis. No positive staining was seen in 238 cases of T-CLL, mycosis fungoides, Sèzary-syndrome, B-CLL, hairy cell leukemia, multiple myeloma and T- and B-lymphoma nor in 32 cases of B-ALL, Burkitt-lymphoma, Null-ALL and immature T-lymphoma. A positive expression was found in 8/110 cases of cALL, 1/6 cases of pre B-ALL and 1/35 cases of T-ALL. Fifteen other MoAbs (MCS-1, OKM1, My-1, Leu-M1, Leu-M3, CA-2-38, MY4, MY7, MY8, MY9, VIM-D2, VIM-D5, Mol, Mo2, 63D3) which are associated with the myelomonocytic cell lineages were tested by indirect immunofluorescence on 60 or more patients (62-149 cases). A wide variability in the frequency of positivity was seen for the panel of cases studied and for the blast cell populations per individual samples: 21-96% of the AML cases (FAB M1-3) and 31-100% of the AMMoL/AMoL cases (FAB M4/5) were positive for the various MoAbs. None of the analysed MoAbs stained only myelocytic or only monocytic leukemias, but a certain degree of preference for the monocytic variants was noted for Leu-M3, CA-2-38, MY4, VIM-D2, Mo2 and 63D3. The detection of MCS-2 on immature ALL blast cells might indicate a coexpression of lymphoid and myeloid markers on very immature cells, or an abnormal gene expression by malignant cells, or the identification of a so far undetected subclass of acute leukemias.

Incidence of TdT Positivity in Cases of Leukemia and Lymphoma

The expression of the enzyme marker terminal deoxynucleotidyl transferase (TdT) was examined by immunofluorescence assay in the cells from 333 cases with various types and subtypes of leukemia or lymphoma. More than 90% of cALL and T-ALL, 70% of Null-ALL and 80% of pre-B-ALL were TdT-positive. One case in the commonly TdT-negative group of B-ALL showed TdT-positive cells. All cases of mature B-cell malignancies (B-CLL, hairy cell leukemia, B-cell lymphoma) have been TdT-negative. In the group of mature T-cell malignancies, T-CLL and mycosis fungoides were negative and 2 out of 6 mature T-cell lymphomas were TdT-positive. 13% of acute myeloid leukemias and 36% of CML in blast crisis expressed TdT. Therefore, these TdT-positive cases of CML in blast crisis also carrying the common ALL-antigen belong to the lymphoid subtype. CML and erythroleukemia were invariably TdT-negative. TdT has become an indispensable indicator of immature lymphoid leukemia cells and is particularly valuable as part of the panel of markers used in leukemia phenotyping.

Heterogeneity of marker expression in B-cell leukemias and its diagnostic significance

Lymphoproliferative disorders of B-cell origin are identified by surface immunoglobulin markers. Clinically, these include several types of leukemias and lymphomas. We have attempted to further characterize B-cell leukemias immunologically using monoclonal antibodies Leu-1 and FMC-7. While cases of classical B-CLL have been shown to react with Leu-1 monoclonal, most other B-cell leukemias often do not react with Leu-1. Our results show that use of an additional monoclonal FMC-7 does not contribute towards diagnostic reliability.

Expression of a monocyte-specific esterase isoenzyme in cases of acute myeloid leukemias.

The carboxylic esterase (E.C. 3.1.1.1) isoenzymes from cases of acute myeloid leukemias were separated by analytical isoelectric focusing on horizontal thin-layer gels. One isoenzyme consisting of one or two components (bands) could be completely and selectively inhibited by addition of 40 mM sodium fluoride (NaF) to the staining bath. The 105 cases were classified into the groups M1-M6 according to the FAB proposals. The NaF-sensitive isoenzyme was not detected in cases of FAB groups M1/2 (acute myeloblastic leukemia without or with maturation), group M3 (acute promyelocytic leukemia) or group M6 (erythroleukemia). Thirty-one out of 33 cases in the FAB group M4 (acute myelomonocytic leukemia) and 9/9 cases in FAB group M5 (acute monocytic leukemia) expressed the NaF-sensitive isoenzyme. The NaF-sensitive isoenzyme was found at different staining intensities; all M5 cases showed the isoenzyme at strong or very strong intensity, whereas most of the M4 cases displayed the isoenzyme at weak, medium or strong staining intensity. The data presented are further evidence that the presence of the NaF-sensitive esterase isoenzyme indicates monocytic involvement or differentiation in cases of myeloid leukemias. The easy and fast to perform method of isoelectric focusing can be used to distinguish the monocytic variants among the acute myeloid leukemias and can supplement the morphological analysis of these cases.

Expression of FMC7 antigen and tartrate-resistant acid phosphatase isoenzyme in cases of B-lymphoproliferative diseases.

A panel of different B-cell malignancies representing various stages of B-cell differentiation were analyzed for the expression of an antigen labeled by the monoclonal antibody FMC7 and of tartrate-resistant acid phosphatase (TracP) activity. The FMC7 antigen and TracP were not found on early immature pre B-cell proliferations, appeared at early and intermediate B-cell stages, reached their peak of expression in terms of both incidence of positivity and staining intensity at the late B cell stage (as represented by hairy cell leukemia) and were lost at the B-cell/plasma cell transition. Although detected at similar stages of B-cell differentiation, FMC7 and TracP appear to be independently expressed and were not related to a particular Ig class. The simultaneous detection of FMC7 and TracP represents a distinguishing parameter for the identification of hairy cell leukemia.

Search for Blocking Factors in Sera of Patients with Prostatic Cancer

Sera from patients with carcinoma of the prostate were screened for the presence of blocking factors by measuring the inhibition of phytohemagglutinin-induced blastogenesis of normal lymphocytes. The blastogenic index obtained in cancer sera is not significantly different from that obtained in sera of patients with benign prostatic hypertrophy (control group). Determination of alpha-2-globulins in the cancer sera by cellulose acetate electrophoresis revealed slightly elevated levels in patients with metastatic disease but it did not correlate with the inhibitory blocking activity of the serum.

Cell-mediated Immune Competence in Patients with Prostatic Carcinoma

The immune competence of 65 patients with prostatic cancer was evaluated by 2 in vivo and 2 in vitro tests to study the contribution of host factors to the progress of the disease. Patients with benign prostatic hypertrophy served as controls. Our results indicate that the delayed skin hypersensitivity response to common microbial recall antigens (streptokinase/streptodornase, purified protein derivative, dermatophytin 0 and dermatophytin) is unaltered in advanced stages of malignancy. The ability to be sensitized by dinitrochlorobenzene declines significantly in patients with metastatic disease. Blastogenic response of peripheral blood lymphocytes to phytohemagglutinin stimulation is not depressed in late stages of malignancy, although in the circulating T cells per cent and absolute values are somewhat lower in patients with metastases. Herein we show that immune competence (measured by the 4 tests) of patients with prostatic carcinoma does not decrease markedly even in the late stages of the disease. Primary sensitization to dinitrochlorobenzene is the only test showing a decline in responsiveness related to the tumor stage.

Study on Human T Leukemia-Lymphoma Cell Lines by the Second International Workshop Monoclonal Antibodies of the T Cell Protocol

The First International Workshop and Conference on Human Leukocyte Differentiation Antigens was held in November, 1982 in Paris, France; this conference provided means and emphasized the need for a worldwide collaboration in the study of human leukocyte antigens (1). Among numerous impacts of the Workshop, uses of murine monoclonal hybridoma antibodies (mAbs) and of leukemia-lymphoma cell lines as consistent cells were amply recognized (1,2). Limitations and difficulties associated with the use of both mAbs and leukemia-lymphoma cell lines have already been documented (3). Large numbers of growth factor-independent human leukemia-lymphoma cell lines of diverse cell lineages have continued to play significant roles in the research of leukocyte differentiation antigens (4). During the First Workshop 165 coded mAbs were tested on 30 leukemia-lymphoma cell lines (10 T, 10 B, and 10 myelomonocytic or non-T/non-B cell lines) (5).