DNA sequence analysis proves Hb M-Milwaukee-2 is due to beta-globin gene codon 92 (CAC-->TAC), the presumed mutation of Hb M-Hyde Park and Hb M-Akita.

Among the causes of congenital methemoglobinemia, Hb M-Milwaukee-2 was one of the earliest described, in a patient who also had Hb E trait. The structure of Hb M-Milwaukee-2 has been elusive. DNA sequence analysis, as here reported, proves that this hemoglobin variant is due to the mutation CAC-->TAC at codon 92 of the beta-globin gene, corresponding to the substitution of tyrosine for histidine. This mutation is identical with that presumed to be the cause of Hb M-Hyde Park and Hb M-Akita. In addition, the DNA mutation of Hb E, GAG-->AAG at codon 26, was confirmed in this case.

51Cr release assay of clozapine-induced cytotoxicity: evidence for immunogenic mechanism.

Serum drawn from patients during clozapine-induced agranulocytosis was toxic to human polymorphonuclear leukocytes (PMNs). Toxicity was produced by an immunoglobulin fraction, predominantly of the IgM class. The offending drug was not necessary at this stage to produce cytotoxicity. These effects were observed by inhibiting post-phagocytosis glycolysis, by ejection of trypan blue, or by enhanced release of 51Cr from lysed-labeled PMNs. Direct chemical toxicity, produced by clozapine or its metabolites, was tested by similar procedures. At a concentration of 10(-5) M in a colloidal milieu produced by dilution with AB serum, no cytotoxicity was observed; however, in aqueous medium. N-desmethylclozapine was toxic to PMNs and proliferating lymphocytes. Post-recovery serum appeared to be inert, but cytotoxicity was restored by adding clozapine or N-desmethylclozapine to the sensitive patient's serum. At this stage, cytotoxicity as measured by 51Cr release was abrogated by anti-IgG or anti-IgM. These relationships favor an immunologic mechanism that damages peripheral PMNs. Development of colony-forming units-granulocyte (CFU-G) was similarly inhibited in normal marrow cultures by cytotoxic serum alone, whereas no metabolite had such an effect at the same concentration (10(-5) M).

Agranulocytosis during antibiotic therapy: drug sensitivity or sepsis?

Forty-three patients reviewed from the literature and five cases of agranulocytosis during antibiotic therapy studied by the author are presented. Time required to develop agranulocytosis with antibiotics was < 19 days in comparison to > 40 days required with nonantibiotic drugs. In all, agranulocytosis occurred concomitantly with drug treatment and became normal as treatment was discontinued. Retrospective rechallenge studies suggest that agranulocytosis may be dose related. In all cases PMNs were almost completely deleted and marrows were devoid of granulocyte precursors. In contrast, leukopenia secondary to overwhelming sepsis displayed persisting granulocytes in peripheral blood and marrow. While leukagglutinins were not found in nine cited cases, four serums were toxic to test PMNs as measured by suppression of postphagocytosis respiratory burst. Clindamycin directly suppressed development of CFU-G in one sensitive patient but not in 16 normal controls. The hazard of antibiotics in suppressing granulocytopoiesis is emphasized by these observations.

Cytotoxic activity in serum of patients with clozapine-induced agranulocytosis.

Studies were conducted on serum samples collected from 15 patients during the course of clozapine-induced agranulocytosis. During acute phases of agranulocytosis, serum was cytotoxic to peripheral polymorphonuclear neutrophils (PMNs), as indicated by complement-dependent suppression of postphagocytosis respiratory burst and by increased retention of trypan blue dye by test PMNs. Cytotoxicity was removed by adsorption with allogeneic PMNs, was attenuated by antibody to immunoglobulin M but not by antibody to immunoglobulin G antigen-binding fragment, was not dialyzable, and was partially removed by 2-mercaptoethanol and dialysis. Three patients in a longitudinal study all had perturbed postphagocytosis respiratory burst 20 days before agranulocytosis developed. In all patients cytotoxicity disappeared less than 40 days after treatment when the offending drug was discontinued. Trypan blue dye reactivity was similar when tested. At 20% of culture medium, all serum samples partially suppressed development of colony-forming units of granulocytes and macrophages (CFU-GM) in marrow cultures. At 40% of culture medium, agranulocytosis serum suppressed CFU-GM completely but did not inhibit development of colony-forming units of erythroblasts (CFU-E) or burst-forming units of erythroblasts (BFU-E). Addition of clozapine alone or to agranulocytosis serum neither enhanced nor suppressed toxicity to peripheral PMNs. Neither clozapine nor its toxic metabolic end-products directly produced equivalent cytotoxicity to cellular function or proliferation at 10(-5)mol/L. Serum from patients given clozapine who did not have agranulocytosis and samples from allogeneic normal subjects were not cytotoxic to test PMNs. Cytotoxicity was specific to granulocyte cell lines because development of CFU-GM was inhibited by agranulocytosis serum, whereas CFU-E and BFU-E were not similarly affected. Further studies are in progress to distinguish between immunogenic and non-immunogenic mechanisms.

On the possible mechanisms and predictability of clozapine-induced agranulocytosis.

Studies were conducted on serum removed from 15 patients before, during, and after, clozapine-induced agranulocytosis. Cytotoxic studies were compared with samples taken from patients during treatment with clozapine who did not develop agranulocytosis or treatment controls (TC); additional controls consisted of allogeneic (NC) and autogeneic serum from apparently normal people. The effect of serum on measurable functions of polymorphonuclear neutrophils (PMNs) taken from normal people was tested. Procedures under study included suppression of post-phagocytosis-induced 14CO2-indicated respiratory burst, as well as ejection of trypan blue by test PMNs. PMNs exposed to active agranulocytosis serum plus complement displayed diminished 14CO2 emission during phagocytosis or failed to eject trypan blue. PMNs exposed to serum of TC and NC continued to function normally as regards 14CO2 emission and trypan blue ejection. Five patients studied before the development of agranulocytosis showed suppressed PMN function, which increased to peak value during agranulocytosis and then disappeared within 40 days of recovery. Similar suppression of colony forming units of granulocytes and macrophages (CFU-GM) was found whenever agranulocytosis serum was included in the marrow culture. The cytotoxic material required complement for its full expression, was not dialysable, was neutralised by anti-IgM serum, and was absorbed by test PMNs. Furthermore, solutions of clozapine or 5 of its metabolites offered no similar suppression of PMN function in vitro after incubation in an aqueous medium or with normal serum. These observations favour development of an immunogenic clone in sensitive people during active treatment with clozapine, which eventually leads to precipitous depletion of PMNs and their precursors. The early appearance of this suppressive substance may offer an early warning for development of agranulocytosis.

Drug-induced agranulocytosis. Peripheral destruction of polymorphonuclear leukocytes and their marrow precursors.

Drug-induced agranulocytosis is a highly individualized and unexpected reaction to specific drugs. It may be due to immunogenic or cytotoxic factors. Most instances are produced by a poorly understood immune response to immunogenic drugs. Others are associated with direct suppression of marrow committed stem cells by the direct action of the offending drug or its toxic metabolic end products. The early appearance of polymorphonuclear neutrophil (PMN) antibodies may offer an early warning to sensitized patients. Antibodies, if present, disappear shortly after the drug is discontinued. Agranulocytosis, due to direct action of the drug, is characterized by morphologic aplasia of marrow and is more likely to occur if the affected host has a concomitant defect in marrow cellular proliferation. Accumulation of toxic metabolic end products such as arene oxides may occur if the host is deficient in a microsomal system required to dispose of this material.

Clozapine-induced agranulocytosis: non-cross-reactivity with other psychotropic drugs.

Clozapine, an atypical neuroleptic with unique clinical and preclinical properties, represents a potentially valuable addition to the psychopharmacopeia. Its development and use have been limited by its higher frequency, compared with other pharmacologic treatments, of the potentially fatal side effect of agranulocytosis. This article describes the natural history of five cases of agranulocytosis that occurred in the course of clozapine treatment. The cases were generally uniform as to onset, recovery, and hematologic features. No patient had hematologic reactions to treatment with psychotropic agents before or after clozapine treatment. These findings, along with other work in progress, suggest that clozapine's granulocytoxic effects are produced by a highly specific immune-mediated mechanism.

Reclassification of leukemia among A-bomb survivors in Nagasaki using French-American-British (FAB) classification for acute leukemia.

The concordance rate for diagnoses of atomic bomb-related cases of leukemia in Nagasaki was determined using the French-American-British (FAB) classification for acute leukemias and myelodysplastic syndromes (MDS). Two Radiation Effects Research Foundation (RERF) hematologists and one of the members (JMB) of the FAB cooperative group reviewed independently the peripheral blood and/or bone marrow smears from 193 people with leukemia or a related disorder. There was 85% agreement in the identification of types and subtypes of acute leukemia. There was almost complete agreement for the diagnoses of non-FAB disorders (chronic myeloid leukemia (CML), adult T-cell leukemia (ATL) and others) resulting in overall concordance of 88.2%. The present study suggests that the previously established leukemia types for about a quarter of the cases of acute leukemia and related disorders except CML should be changed. Considerable numbers of cases of ATL and MDS were involved in this series. The frequency of the former disease was not high in the high-dose irradiated group, but that of the latter was considerably high. All subtypes of AML except M3 and M6 were present in the high-dose group. The striking difference in CML incidence between Nagasaki and Hiroshima may continue to be a problem in relation to biological response to radiation exposure.

Clinical presentation and natural history of patients with essential thrombocythemia and the Philadelphia chromosome.

Six women presented with the clinical picture of essential thrombocythemia (ET) without the anemia, marked splenomegaly, and extreme leukocytosis characteristic of chronic myelogenous leukemia (CML). All had the Philadelphia chromosome on karyotype analysis of the bone marrow. Peripheral basophilia was present in four cases, providing a clinical clue that the Philadelphia chromosome might be present. Marrow biopsy showed granulocytic hyperplasia and either small megakaryocytes or sheets of megakaryocytes with marked atypia, findings that are more typical of CML than ET. The clinical importance of finding the Philadelphia chromosome in patients who seem to have ET is in assessing prognosis. ET generally follows a chronic, indolent course. However, five of these six patients who had the Philadelphia chromosome underwent clinical transition to the accelerated phase of CML or blastic leukemia in 4-7 years.

Increased prevalence of polycythemia vera in parents of patients on polycythemia vera study group protocols.

An investigation of relatives of 652 patients entered on studies of the Polycythemia Vera Study Group yielded five documented cases of the disease among the parents of patients. When compared with expected values based on the Connecticut Tumor Registry and other population studies a significant increase was found in the lifetime incidence of polycythemia vera in parents of these patients.

Hodgkin's disease with leptomeningeal involvement. Report of a case with long survival.

A 30-year-old white man with Stage IV B Hodgkin's disease, mixed cellularity type, developed leptomeningeal involvement shortly after relapsing on nitrogen mustard, Oncovin (vincristine), procarbazine, and prednisone (MOPP), and while receiving Adriamycin (doxorubicin), bleomycin, Velban (vinblastine), and dacarbazine (ABVD). Whole brain irradiation and intrathecal methotrexate were successfully incorporated into his treatment program. The patient has now been in complete remission for more than 40 months. A review of this rare complication of Hodgkin's disease is presented.

Neurologic manifestations of essential thrombocythemia.

Essential thrombocythemia is a clonal myeloproliferative disorder, characterized predominantly by a markedly elevated platelet count without known cause. We report a case that was recognized during investigation of a transient ischemic attack, and review the neurologic findings in 33 patients with unequivocal essential thrombocythemia under prospective study by the Polycythemia Vera Study Group. Twenty-one patients had neurologic manifestations at some point during their course, including headache (13 patients), paresthesiae (10), posterior cerebral circulatory ischemia (9), anterior cerebral circulatory ischemia (6), visual disturbances (6) and epileptic seizures (2). All patients with neurologic symptoms responded satisfactorily to treatment, although continuous or repeated treatment was often required. Therapeutic recommendations include plateletpheresis for major thrombo-hemorrhagic phenomena, or megakaryocyte suppression with radioactive phosphorus, alkylating agents (such as melphalan), or hydroxyurea; minor symptoms may respond to platelet antiaggregating agents.

Chronic granulocytic leukemia following radiation therapy for Hodgkin's disease.

A 33-year-old white man was treated with irradiation for Hodgkin's disease involving the mediastinum; four years later he developed typical Philadelphia chromosome-positive chronic granulocytic leukemia. The patient has been treated with chronic low-dose busulfan to maintain peripheral blood counts in the normal range and he continues to remain well 27 years after the initial diagnosis of Hodgkin's disease and 23 years following the onset of leukemia.

Leukemia-associated antigens in leukemic transformation of polycythemia vera.

Studies were made to test immune reactivity between anti-leukemic cell sera and nonadherent peripheral blood cells from patients with leukemic and nonleukemic P. vera. Cells from seven patients with leukemic P. vera had complement-dependent cytotoxicity test results showing more than 80% cell killing. In comparison, leukocytes from 37 nonleukemic and nonpolycythemic subjects, with and without blood disorders, failed to show significant cytotoxicity. Cells from 20 patients with nonleukemic P. vera and 10 patients with myelofibrosis, thrombocythemia, and "spent" P. vera also failed to react. Three nonleukemic P. vera patients showed a positive reaction that became progressively stronger; they developed leukemia at a later date. The association of positive reactivity before leukemia is overt, to later development of acute leukemia calls attention to the possible use of immunologic technology as a means of early diagnosis of leukemia.