Essential thrombocythemia with the Philadelphia chromosome and BCR-ABL gene rearrangement. An entity distinct from chronic myeloid leukemia and Philadelphia chromosome-negative essential thrombocythemia.

A 64-year-old woman presented with a platelet count of 3,225 x 10(9)/L. Bone marrow morphology showed massive megakaryocytic hyperplasia; cytogenetic studies showed the presence of the Philadelphia chromosome (Ph). The presence of a rearrangement involving the major breakpoint cluster region (mbcr) on chromosome 22 was confirmed by Southern blotting techniques. A diagnosis of Ph positive essential thrombocythemia (ET) was made. Such cases constitute less than 5% of patients with ET and it has been proposed that they be considered examples of chronic myelogenous leukemia (CML) because of a shared propensity to progress to blast crisis. An argument is presented for retaining Ph positive ET as an entity separate from Ph negative ET and Ph positive CML.

Splenic hypofunction in systemic lupus erythematosus: response to pneumococcal vaccine.

A woman who presented with splenic hypofunction as a complication of systemic lupus erythematosus is described. Pneumococcal vaccine was given. Her antibody response was measured and the responses of other cases are discussed.

Haptoglobin helps diagnose the HELLP syndrome.

In a case of the HELLP syndrome, anemia was absent, and bilirubin and lactic dehydrogenase levels were normal. In combination with minimal microangiopathic changes in red cell morphology, a decrease in serum haptoglobin was useful to corroborate the presence of intravascular hemolysis.

Malignant granular lymphoproliferation after Epstein-Barr virus infection: partial immunologic reconstitution with interleukin-2.

This report describes a patient who developed a malignant proliferation of granular lymphocytes following Epstein-Barr virus (EBV) infection. For many months, his illness resembled prolonged infectious mononucleosis with persistent fatigue, fever, leukocytosis, and serologic evidence of recent primary EBV infection. After approximately 1 year, however, he developed progressive granular lymphocytosis and extensive lymphocytic infiltration of the bone marrow and liver. Tests for EBV DNA in pre- and postmortem tissue samples using a sensitive DNA hybridization technique were negative. Southern blot analysis of DNA prepared from blood mononuclear cells demonstrated clonal T-cell antigen receptor gene rearrangement. Despite increased numbers of circulating lymphocytes with the morphology and surface phenotype of normal donor natural killer (NK) cells, the patient's NK activity was consistently depressed in a standard in vitro assay. However, in vitro incubation with interleukin-2 (IL-2), but not with alpha- or gamma-interferon, increased the NK activity of the patient's lymphocytes. Intravenous recombinant IL-2 treatment transiently increased the patient's blood NK activity and was associated with seroconversion to EBV nuclear antigens but failed to affect the progression of his disease. Our findings indicate that clonal granular lymphocytic proliferation may develop after EBV infection and confirm the utility of DNA hybridization analysis in distinguishing monoclonal from benign immunoreactive lymphoproliferation. Furthermore, our results suggest that certain functionally inert neoplastic granular lymphocytes acquire NK activity when exposed to IL-2.

The B cell IgM Fc receptor: further evidence for the B cell origin of "null" chronic lymphocytic leukemia.

Fifty-three cases of chronic lymphocytic leukemia (CLL) were studied for the presence of the B cell IgM Fc receptor (Fc microR) using an aggregated IgM reagent. Restricted surface immunoglobulin, using conventional immunofluorescent techniques and FACS analysis, was detected in 43 cases (81%). The cells in the remaining ten cases (19%) expressed negligible surface immunoglobulin (slg-) and did not form E rosettes (E-), but this "null" subset clearly expressed the B cell Fc microR. The coincident membrane expression of the B1 antigen and the la-like antigen, as well as serial studies showing surface membrane light chain acquisition (in one patient), provided additional evidence for the B cell origin of this slg-E- subset. This subgroup of CLL appears to correspond phenotypically to a normal counterpart at a stage of B cell differentiation between the pre-B cell and the slgM+ early B cell. The B cell Fc microR appears to be a consistent and potentially useful marker for sl gE ("null") CLL.

Acquired immunodeficiency syndrome with progressive multifocal leukoencephalopathy and monoclonal B-cell proliferation.

A 34-year-old man who used intravenous drugs developed the acquired immunodeficiency syndrome with lymphadenopathy, Mycobacterium tuberculosis pneumonia, and progressive multifocal leukoencephalopathy. Early biopsy specimens of the lymph node showed hyperplasia without evidence of lymphoma. Later, immunologic analysis of peripheral blood lymphocytes showed inversion of the helper/suppressor T-lymphocyte ratio and persistent monoclonal B-cell proliferation without clinically overt lymphoma. The clinical course of this patient suggests that abnormal immune responses seen in the setting of the acquired immunodeficiency syndrome may evolve into lymphoproliferative disorders detectable by peripheral blood lymphocyte analysis.