Mutations in the gene for the G-CSF receptor that interrupt signals required for the maturation of myeloid cells are involved in the pathogenesis of severe congenital neutropenia and associated with the progression to acute myeloid leukemia.

No abstract

Myelofibrosis is characterized by reticulin fibrosis of the bone marrow with resulting features of myelophthisis. Besides hematopoietic malignancies and other neoplasms involving the bone marrow, myelofibrosis has been described in association with autoimmune disorders, especially systemic lupus erythematosus. We describe the clinicopathologic features of a primary form of autoimmune myelofibrosis (AIMF) in patients who do not have systemic lupus erythematosus or another well-defined autoimmune syndrome. Absence of marked splenomegaly, peripheral blood cytopenias with mild teardrop poikilocytosis and leukoerythroblastosis, bone marrow lymphoid aggregates, and presence of autoantibodies are some of the salient features of primary AIMF. AIMF should especially be differentiated from chronic idiopathic myelofibrosis, a neoplastic myeloproliferative disease. Primary AIMF appears to have an excellent prognosis, with all patients reported in this series responding to a short course of corticosteroid therapy.

Immunophenotyping has become common in the diagnosis and classification of acute leukemias and is particularly important in the proper identification of cases of minimally differentiated acute myeloid leukemia (AML-MO). To evaluate the immunophenotype of adult AML, 106 cases were studied by cytochemical analysis and by flow cytometry with a panel of 22 antibodies. The results were compared with the French-American-British (FAB) Cooperative Group classification, as well as with available cytogenetic data on each case. CD45, CD33, and CD13 were the most commonly expressed antigens (97.2%, 95.3%, and 94.3%, respectively). Lymphoid-associated antigens were expressed in 48.1% of cases. CD20 was the most commonly expressed lymphoid antigen (17%), although often expressed in only a subpopulation of leukemic cells, followed by CD7 (16%), CD19 (9.8%), CD2 (7.5%), CD3 (6.7%), CD5 (4.8%), and CD10 (2.9%). Some immunophenotypes correlated with FAB type, including increased frequency of CD2 expression in AML-M3; lack of CD4, CDllc, CD36, CD117, and HLA-DR expression in AML-M3; increased frequency of CD20 and CD36 expression and lack of CD34 expression in AML-M5; increased frequency of CD5 expression in AML-M5a; and increased frequency of CD14 expression in AML-M5b, when compared with all other AMLs (P < .05). When compared with AML-

No abstract

In an attempt to determine factors predictive of survival in patients seropositive for human immunodeficiency virus (HIV) with acquired immune deficiency syndrome (AIDS)-related lymphoma, the authors studied 60 such patients, all of whom were treated with curative intent. Eleven patients presented with lymphoma primary to the brain (P-CNS); the remaining 49 had systemic AIDS-related lymphoma. Patients with P-CNS lymphoma had more severe underlying HIV-related disease than did patients with systemic lymphoma as evidenced by a higher incidence of AIDS before the diagnosis of lymphoma (73% versus 37%; P = 0.04), and lower median number of CD-4-positive lymphocytes in peripheral blood at diagnosis of lymphoma (30/dl versus 189/dl; P = 0.005). Median survival of such patients was 2.5 months versus 6.0 months for patients with systemic lymphoma ( P = 0.04). Forty patients with systemic AIDS-related lymphoma have died; three factors were strongly associated with shorter survival: (1) Karnofsky performance status (KPS) of less than 70% (multivariate relative survival risk [RSR] = 3.1); (2) history of AIDS before the diagnosis of lymphoma (multivariate RSR = 3.0 for opportunistic infection plus Kaposi's sarcoma); and (3) bone marrow involvement (RSR = 3.1)). All three factors (KPS of less than 70%, prior AIDS diagnosis, and marrow involvement) were associated with early demise attributed to AIDS, whereas death attributed to lymphoma per se was associated with only two factors (KPS of less than 70% and marrow involvement). In the absence of all three risk factors, a "good prognosis" group of 17 patients was defined, with a median survival of 11.3 months; the median survival of the remaining patients ("poor prognosis") was 4.0 months (P = 0.0002). Attainment of complete response to therapy (CR) was strongly related to prolonged survival in the patients in the good prognosis group (17.8 months in patients with CR versus 5.0 months in those with less than CR); however, such meaningful prolongation of survival was not seen in patients with poor prognosis who attained CR (6.3 months versus 3.4 months). The patients with poor prognosis may be unable to tolerate the insult of multiagent chemotherapy, experiencing low CR rates (25%) and death caused by lymphoma and AIDS. However, patients in either prognostic category who attained CR remained at risk for dying of AIDS while the lymphoma was in remission. Thus, it is apparent that meaningful prolongation of survival in the patient with AIDS-related lymphoma

Indeterminate and interdigitating cell tumors are rare proliferations of immunoregulatory cells that demonstrate morphologic, immunologic, and ultrastructural features similar to their cells of origin. Although an association of lymphoproliferative disease with Langerhans' cell histiocytosis is well described, only sporadic cases of non-Langerhans' dendritic cell proliferations have been published. The authors describe three patients with low grade B-cell lymphoproliferative disease who developed subsequent indeterminate cell or interdigitating cell tumors. When the two cases of indeterminate cell tumor are added to those previously described in the literature, it appears that 4 of 13 cases (31%) are associated with a history of low grade B-cell malignancy. Possible explanations for the relationship between these two disorders are discussed.

No abstract