[Analysis of anti-platelet antibodies using flow cytometry]

We analyzed the production of anti-platelet antibodies by alloimmunization in patients with hematological disorders who receive blood transfusions frequently. HLA antibodies were detected by anti-human globulin lymphocyte cytotoxicity test (AHG-LCT), and anti-platelet antibodies by flow cytometry (FCM). Results from FCM correlated well with those of AHG-LCT. The rate of coincidence was 92.1%. Production of alloantibodies in patients was detected in 32.7% in the without filter group, but decreased to 17.1% (p < 0.05) in the filter group. The avidin-biotin assay and concentration of globulin fraction in patient's serum by affi-gel blue column were useful for increasing sensitivity in detecting anti-platelet antibodies. Anti-platelet specific antibodies were detected in 5 patients (5/226; 2.2%) and these antibodies coexisted with HLA antibodies in all patients. The antibody in 3 of these patients were identified as HPA-2b (Siba), and those in the other 2 patients were combined antibodies on platelet identification panel and immunoblotting. It may be possible that high titer serum of anti-platelet specific antibodies could be identified by its fluorescent intensity. Measures against HPA-2b are considered necessary because platelet specific antibodies were produced in 2.2% of patients who received blood transfusions frequently.

A patient with Tn syndrome associated with myelodysplastic syndrome showed abnormal glycophorin B

A Japanese male patient with myelodysplastic syndrome (MDS) was shown to have associated Tn syndrome; the first report of Tn syndrome with MDS. The Tn expression was demonstrated on erythrocytes, granulocytes, monocytes, platelets, and lymphocytes by flow cytometric analysis using a lectin and an antibody. Electrophoresis of erythrocyte membrane proteins revealed slower mobility of glycophorin B from the patient than that from normal individuals, suggesting a glycophorin B molecular abnormality.

[Administration of intravenous immunoglobulins in adult patients with hematologic diseases]

Abnormalities in serum immunoglobulin levels or in antibody production may develop as a result of many different diseases. Antibody deficiency may occur in previously normal persons with haematologic malignancies or who received immunosuppressive agents in treatment of cancer or in anticipation of bone marrow transplantation. Effective regimens may develop in primary immunodeficiencies and secondary immunodeficiencies as well as in idiopathic thrombocytopenic purpura. Some reports and information about the other haematological indications were published in medical literature. However, the consensus conference on IVIG at the National Institutes of Health (Bethesda--May 21, 1990) recommended treatment with IVIG in haematology only for CLL, ITP and after bone marrow transplantation, as a prevention for GVHD. The adverse effects of IVIG therapy are minimal, but they exist. The other important subject is the cost of widespread use of IVIG; therefore the indications must be carefully concerned and documented before therapy is started.

Serological screening, using three different test systems of platelet-transfused patients with hematologic-oncologic disorders

Sera of hematologic-oncologic patients were tested regularly after platelet transfusions in three test systems: lymphocytotoxicity test, platelet adhesion immunofluorescence test, and--only selected sera--in the monoclonal antibody-specific immobilization of platelet antigen test. Of 388 patients 53 (14%) had HLA antibodies 5 of these in combination with platelet-specific alloantibodies. Lymphocyte-restricted (non-HLA) reactions were observed in 20 patients, the majority of which was attributed to lymphocyte-specific auto- or alloantibodies. Sera of 27 patients showed platelet-specific reactions, usually cold-reacting autoantibodies which have no effect in vivo.

[The phenomenon of the enhancement of the formation of lymphocytotoxic alloimmune antibodies during the use of plasmapheresis]

Apheresis was applied in 17 patients with hypoplastic anemia, myelodysplastic syndrome, chronic renal failure and other diseases sensitized to HLA. Apheresis was done for removal of anti-HLA antibodies and prevention of nonhemolytic transfusion reactions. Multiple massive apheresis led to a marked decrease in the antibody level. After the first or second apheresis with removal of 700.0-2000.0 ml of plasma weekly half of the patients showed increasing titres of lymphocytotoxic antibodies.

Immunophenotyping of cytologic specimens by flow cytometry

Immunophenotyping by flow cytometry is well established as an ancillary technique in the diagnosis of hematopoietic neoplasms. However, flow cytometry is rarely performed on cytologic specimens because most cytologist are more comfortable with direct microscopy and believe that there is inadequate cellularity for analysis. Paradoxically, cytologic material is usually cell suspensions making it ideal for flow cytometry. In order to evaluate the usefulness of immunophenotyping cytologic specimens by flow cytometry, we retrospectively reviewed all cytologic specimens submitted to our flow cytometry unit from 1988 to 1991. Thirty-one cerebrospinal fluid specimens were analyzed. There were inadequate cells for analysis in 15 cases. Five showed a monoclonal proliferation; 11 were nondiagnostic. A range (r) of one to six cell surface markers were performed. Thirty-two body cavity fluids were analyzed: 7 peritoneal, 19 pleural, 2 pericardial, and 4 bronchoalveolar lavage. There were cells to analyze in all cases. Seven had a monoclonal proliferation; 25 were nondiagnostic (r = 4-21 markers performed). One hundred eighteen fine needle aspirates (FNA) were reviewed; 58 FNA were radiologically guided, 60 were superficial lesions. There were inadequate cells for analysis in two cases. Sixty-one demonstrated a monoclonal proliferation; 55 were nondiagnostic (r = 1-22 markers performed). We conclude that immunophenotyping by flow cytometry is of limited value for cerebrospinal fluid analysis and that knowledge of previous immunophenotyping studies is essential for correct analysis; analysis of body cavity fluids is easily performed but less often demonstrates a monoclonal proliferation. Immunophenotyping by flow cytometry is a valuable adjunctive technique for FNA and yields adequate cells for analysis.

PG-M1: a new monoclonal antibody directed against a fixative-resistant epitope on the macrophage-restricted form of the CD68 molecule

A new anti-macrophage monoclonal antibody (PG-M1) was produced by immunizing BALB/c mice with fresh spleen cells from a patient with Gaucher's disease. PG-M1 reacts strongly with a fixative-resistant epitope of an intracytoplasmic molecule, selectively expressed by virtually all macrophages of the human body. Although attempts to immunoprecipitate the molecule recognized by PG-M1 have failed so far, the reactivity of the antibody with COS-1 and WOP cells transfected with a human complementary DNA clone encoding for the CD68 antigen suggests that PG-M1 is a new member of the CD68 cluster. However, unlike other CD68 antibodies (KP1, EBM11, etc.), which react with both macrophages and myeloid cells, PG-M1 detects a fixative-resistant epitope on the macrophage-restricted form of the CD68 antigen. In 957 routinely fixed, paraffin-embedded samples, PG-M1 showed a more restricted reactivity with elements of the monocyte/macrophage lineage than the previously described monoclonal antibodies MAC-387 (anti-calgranulins), KP1 (CD68) and Ki-M1P. Among hematological malignancies, PG-M1 only labels acute leukemias of M4 and M5 type and rare examples of malignant histiocytosis/true histiocytic sarcoma. In contrast, acute leukemias of the M1, M2, M3, M6, M7, and L1-L3 types, non-Hodgkin's lymphomas, and Hodgkin and Reed-Sternberg cells of Hodgkin's disease are consistently PG-M1-negative. In the daily diagnostic practice, PG-M1 seems to be particularly valuable for the diagnosis of myelomonocytic or monocytic leukemia and neoplasms of true histiocytic origin in routine paraffin sections.

Coagulation abnormalities and cerebral infarction

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Antibodies to platelet glycoprotein V in polytransfused patients with haematological disease

Polytransfused patients often develop platelet-reactive antibodies (PRAb). These give positive reactions in the platelet immunofluorescence test (PIFT) and may be either lymphocytotoxic (LCTAb) or platelet-specific antibodies (PSAb). The latter may be detected in the PIFT using chloroquine-treated platelets (Chl-PIFT) or by immunoblotting. Serial samples from 106 multiply transfused patients with bone marrow failure were screened by PIFT using a microplate method and flow-cytometric analysis. PSAb activity was confirmed by Chl-PIFT. In 45 (42%) of the patients studied PSAb were detected; 37 (35%) formed LCTAb and 19 (51%) had co-existent PSAb. Sera from 25 of 27 patients with a positive Chl-PIFT, retested by immunoblotting, recognised determinants of Mr 82-160 kD on whole platelets. A large group became sensitised to a component of Mr 105-115 kD reduced (99 kD non-reduced) with similar electrophoretic mobility to GPIIIa using a monoclonal anti-GPIIIa and two human polyclonal anti-HPA-1a sera; some also produced anti-GPIIb. The largest group recognised a determinant of Mr 80-83 kD, probably glycoprotein V (GPV). Three sera were immunoblotted against thrombin-treated platelets and the results confirmed GPV specificity.

Flow cytometric analysis of terminal deoxynucleotidyl transferase. A simplified method

The authors evaluated a new cell membrane permeabilization method for the flow cytometric detection of terminal deoxynucleotidyl transferase (TdT). In this method, gradient-separated leukocytes or unseparated blood or bone marrow cells were incubated in a commercially available diethylene glycol-based red blood cell lysing solution, which not only lyses red blood cells, but also permeabilizes leukocyte cell membranes; the light scattering properties of the cells are retained. The validity of the current method was demonstrated by the good concordance of the findings with previously published data as follows: (1) practically identical results were obtained when an established method for cell permeabilization was used in parallel on the same samples; (2) the proportion of TdT-positive cells in normal peripheral blood was negligible; (3) the proportion of TdT-positive cells in normal bone marrow averaged 1%, and a significant portion of TdT-positive cells in normal bone marrow expressed CD10 and CD34; and (4) TdT-positive cell populations were seen with the expected frequencies in various types of leukemia. This method for TdT flow cytometry provides significant advantages over previously used methods and is especially suitable for TdT detection in routine laboratories.

[Immunohistochemical identification of proliferating cell nuclear antigen (PCNA) in hematological disorders]

We used bone marrow smears to examine how immunohistochemical identification of PCNA (proliferating cell nuclear antigens) which markers of proliferation, works for various hematopoietic cells in hematological disorders. Short-term fixation with buffered acetone formalin allowed us not only to observe morphosis properly but also to identify the occurrence of PCNA in erythroblasts, megakaryocytes, plasma cells and blasts. For blasts of leukemia patients, we could distinguish more positive cases from less positive ones regardless of the increase or decrease of cells. A change in PCNA due to the existence of neoplastic cells was also observed. These findings suggest that in the future, analyzing the occurrence of PCNA in hematopoietic cells can provide us with immunohistochemically important information on diagnosis of malignancy and follow up.

Expression of the Tn antigen on erythroid cells from a patient with Tn syndrome

In order to examine expression of the Tn antigen on erythroid cells from a patient with Tn syndrome, we applied a selective two phase liquid culture system for human erythroid progenitors in peripheral blood. The cells were analyzed with flow cytometry employing an anti-Tn antibody and a lectin of Vicia villosa which recognizes only the Tn determinant. In the second phase, the Tn antigen was expressed on the cultured cells from the patient on day 3 and Tn-positive cells reached 62.7% on day 9. On the other hand, Tn-positive cells were not detected in the volunteer's cultured cells. When the patient's cells were co-cultured with the cells from a healthy volunteer, the percentage of Tn-positive cells was much lower than the expected value, suggesting that the normal cells suppressed the expression of Tn antigen on the patient's cells.

Anti-phosphoinositide auto-antibodies in sera of cancer patients: isotypic and immunochemical characterization

High levels of circulating anti-phosphatidylinositol (PtdIns) auto-antibodies (auto-Ab) have been previously found in sera of patients with malignant tumors. Using our ELISA test, a high statistical level of immunological binding directed against PtdIns was found in a large series of sera from patients with proliferative pathologies. In contrast to tumor markers, anti-PtdIns auto-Ab did not vary whatever the histological grades, TMN classification and patient's age. These anti-PtdIns auto-Ab were immunoglobulins (Ig) of G class. Their specificity was evaluated by competition experiments in ELISA and found to be rather high. An increase of these circulating auto-Ab reflected possible disturbances in PtdIns turnover and appearance of endogenous neo-antigen with PtdIns structure.

Clinical applications of phenotypic analysis

The ability to track lymphocyte differentiation and activation via the expression of cell surface marker molecules has had an enormous impact on diagnosis, monitoring and therapy of a wide range of diseases. Here, Katalin Pálóczi highlights studies from Hungary on the clinical applications of such analysis.

Systemic and cutaneous plasmacytosis with multiple skin lesions and polyclonal hypergammaglobulinaemia: significant serum interleukin-6 levels

We report two patients who developed benign plasmacytosis with multiple skin lesions. The cases were characterized by hyperplasia of mature plasma cells, and polyclonal hypergammaglobulinaemia. One patient had hyperplasia of mature plasma cells not only in the skin, but also extensively in lymph nodes and the retroperitoneal areas around the ureters. The other had plasma cell hyperplasia limited to the skin. Extensive investigations failed to reveal any clinical or laboratory evidence suggesting the presence of any underlying disease accompanying the hypergammaglobulinaemia and/or plasma cell proliferation, such as chronic infectious disease, collagen disease or other chronic inflammatory disorder. Clinically and histologically, the first patient showed features compatible with a diagnosis of systemic plasmacytosis and the second with a diagnosis of cutaneous plasmacytosis. Significant serum interleukin-6 (IL-6) levels were detected in both patients, suggesting that IL-6 may be involved in the pathogenesis of these conditions.

[Prevalence of hepatitis C virus in poly-transfused patients with hematologic and oncologic diseases]

Patients with hematological and oncological diseases often require intensive, supportive hematotherapy due to the underlying disease or chemo-/radiotherapy. As a consequence, they had an increased transfusion-associated risk of hepatitis C virus infections (non-A, non-B-posttransfusion hepatitis) until 1989-1990, when specific and sensitive HCV antibody tests became available. This is confirmed by our study of 'first' and 'second' generation (1.0 and 2.0) anti-HCV EIAs against structural and non-structural (NS) antigen-determinants. Ten of 101 patients (10.9%) were anti-HCV positive in 2.0 tests. HCV antibodies were detected more often by 2.0 EIAs and the new HCV-immunoblot (4-RIBA), than by 1.0 EIAs. In this respect, the patients' serological HCV profile differs from that of healthy blood donors, which display a prevalence of NS-antibodies.

[Antigenic composition of serum proteins of the Inv system in normal conditions and in patients with hematologic diseases among the Armenian population]

Inv (1) antigen distribution was studied in 568 normal subjects and in 354 hematological patients in the Armenian population. Inv (1) antigen was detected in 16.7% of the normal Armenians studied. The incidence rate of Inv (1) factor does not depend on the distribution of phenotypes of ABO system, rhesus factor (D), and the sex of the subjects investigated. Inv (1) antigen incidence rate in patients with acute leukemia, chronic lymphocytic leukemia, iron deficiency anemia, lymphogranulomatosis, idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia was similar to that in the control, and only patients with chronic myeloid leukemia had significantly decreased levels of Inv (1) antigen: 6.8% as compared to 16.7% in the population.

[Therapeutic evaluation of imipenem/cilastatin sodium for bacterial infections in patients with hematological diseases]

1. To evaluate the efficacy and tolerance of imipenem/cilastatin sodium (IPM/CS) in severe infections associated with hematopoietic disorders, IPM/CS was administered to a total of 105 patients. 2. Out of 96 patients evaluable for efficacy, clinical responses were excellent in 23 patients, good in 30, fair in 15, poor in 19 and unknown in 9, and the overall response rate was 60.9%. 3. The most common underlying hematopoietic disease was acute non-lymphocytic leukemia and the most common infections were sepsis and suspected sepsis. 4. Daily dose, severity of infection and neutrophil count had effects on the clinical response. 5. The overall eradication rate of bacteria was 83.7%. 6. Side effects were observed in 10 patients (9.5%) and abnormal laboratory test results in 12 (11.4%). From the above findings, we have concluded that IPM/CS is very useful for the treatment of severe infections in compromised patients with hematopoietic diseases.

A study of cell proliferation in formalin-fixed, wax-embedded bone marrow trephine biopsies using the monoclonal antibody PC10, reactive with proliferating cell nuclear antigen (PCNA)

We have investigated proliferation in bone marrow trephine biopsies from 32 patients with normal or abnormal haemopoiesis, using the monoclonal antibody PC10, which detects proliferating cell nuclear antigen (PCNA), together with immunohistochemical markers of haemopoietic cell lineage. PCNA immunostaining revealed the pattern of proliferation within individual haemopoietic lineages in normal marrow. Two unexpected observations were made: of erythroid cells, only pro-erythroblasts and occasional early normoblasts reacted, and positivity of megakaryocytes was unrelated to nuclear lobulation or CD61 expression. The pathological cases represented conditions in which haemopoiesis is increased (reactive hyperplasia, chronic granulocytic leukaemia, myeloproliferative and myelodysplastic syndromes, megaloblastic anaemia). Increases in the number, and disturbances of the spatial organization, of PCNA-expressing cells were present to a variable extent in all cases. Sheets of PCNA-positive megaloblastoid erythrocytes were frequently found in myelodysplastic and myeloproliferative tissue, associated with marked disturbances in the spatial organization of all haemopoietic lineages. Cases of megaloblastic anaemia due to vitamin B12/folate deficiency also demonstrated greatly increased erythroid PCNA expression, with positivity in some giant metamyelocytes. In addition to reflecting increased proliferation, elevated PCNA expression in some bone marrow pathologies may be due to altered kinetics of the protein induced by disturbances in growth factor production.