Anti-prothrombin antibodies combined with lupus anti-coagulant activity is an essential risk factor for venous thromboembolism in patients with systemic lupus erythematosus.

Anti-prothrombin antibodies (anti-prothrombin) and anti-beta2-glycoprotein I antibodies (anti-beta2-GP I) are the most common and characterized anti-phospholipid antibodies (aPL) detected using specific enzyme-linked immunosorbent assay (ELISA) systems. Recently, lupus anti-coagulant (LA) activity detected by a phospholipid-dependent coagulation assay was reported to be associated with anti-prothrombin and/or anti-beta2-GP I. Here we show that the co-existence of IgG anti-prothrombin and LA activity might be an essential risk factor for venous thromboembolism (VTE) in patients with systemic lupus erythematosus (SLE). We examined not only the levels of antibodies to prothrombin and anti-beta2-GP I (both IgG and IgM isotypes) using an ELISA system, but also LA activity detected using both diluted Russell's viper venom time (dRVVT) and STACLOT LA test in 124 patients with SLE. The SLE patients were divided into four groups according to the results of ELISA and LA assay results for each aPL: group A, ELISA+ and LA+ group B, ELISA+ and LA-; group C, ELISA- and LA+ group D, ELISA- and LA-. Regarding IgG anti-prothrombin, the prevalence of VTE was significantly higher in group A (16/35 cases, 45.7%, P < 0.001, Fisher's exact probability test) than in the other groups (B, 2/30, 6.7%; C, 1/22, 4.5%; D, 1/37, 2.7%). With respect to IgM anti-prothrombin and IgG or IgM anti-beta2-GP I, the prevalence of VTE was higher in both groups A and C than in group D, but no statistical difference in prevalence was found between groups A and C. Multivariate logistic regression analysis of risk factors for VTE confirmed that the co-existence of IgG anti-prothrombin and LA activity was the only significant risk factor for VTE (odds ratio, 19.13; 95% confidence intervals, 4.74-77.18).

Efficient retrovirus-mediated PIG-A gene transfer and stable restoration of GPI-anchored protein expression in cells with the PNH phenotype.

Paroxysmal nocturnal hemoglobinuria (PNH) is a clonal hematopoietic stem cell disorder characterized by complement-mediated hemolysis due to deficiencies of glycosylphosphatidylinositol-anchored proteins (GPI-APs) in subpopulations of blood cells. Acquired mutations in the X-linked phosphatidylinositol glycan-class A (PIG-A) gene appear to be the characteristic and pathogenetic cause of PNH. To develop a gene therapy approach for PNH, a retroviral vector construct, termed MPIN, was made containing the PIG-A complementary DNA along with an internal ribosome entry site and the nerve growth factor receptor (NGFR) as a selectable marker. MPIN transduction led to efficient and stable PIG-A and NGFR gene expression in a PIG-A-deficient B-cell line (JY5), a PIG-A-deficient K562 cell line, an Epstein-Barr virus-transformed B-cell line (TK-14(-)) established from a patient with PNH, as well as peripheral blood (PB) mononuclear cells from a patient with PNH. PIG-A expression in these cell lines stably restored GPI-AP expression. MPIN was transduced into bone marrow mononuclear cells from a patient with PNH, and myeloid/erythroid colonies and erythroid cells were derived. These transduced erythroid cells restored surface expression of GPI-APs and resistance to hemolysis. These results indicate that MPIN is capable of efficient and stable functional restoration of GPI-APs in a variety of PIG-A-deficient hematopoietic cell types. Furthermore, MPIN also transduced into PB CD34(+) cells from a normal donor, indicating that MPIN can transduce primitive human progenitors. These findings set the stage for determining whether MPIN can restore PIG-A function in multipotential stem cells, thereby providing a potential new therapeutic option in PNH.

Association between the prevalence of antibodies to beta(2)-glycoprotein I, prothrombin, protein C, protein S, and annexin V in patients with systemic lupus erythematosus and thrombotic and thrombocytopenic complications.

BACKGROUND: Anti-phospholipid (aPL) antibodies (Abs) frequently found in the plasma of patients with systemic lupus erythematosus (SLE) have been associated with thrombotic complications. Our aim was to clarify the roles in thrombosis of aPL Abs that react with complexes of phospholipids and plasma proteins such as beta(2)-glycoprotein I (beta(2)-GPI), prothrombin, protein C, protein S, and annexin V. METHODS: We determined the prevalence of aPL Abs to various phospholipid-binding plasma proteins in SLE patients with arterial thrombosis (30 cases), venous thrombosis (19 cases), thrombocytopenia (14 cases), fetal loss (14 cases), and patients without complications (91 cases). The aPL Abs were measured by an ELISA system in which human plasma proteins (beta(2)-GPI, prothrombin, protein C, protein S, and annexin V) were immobilized on gamma-irradiated or plain polystyrene plates. RESULTS: All types of aPL Abs were frequently observed in the patients with SLE when gamma-irradiated polystyrene plates were used (51 of 168 cases positive for anti-beta(2)-GPI, 94 of 168 cases positive for anti-prothrombin, 36 of 168 cases positive for anti-protein C, 47 of 168 cases positive for anti-protein S, and 50 of 168 cases positive for anti-annexin V), whereas no Abs to these plasma proteins were detected when plain polystyrene plates were used. Multivariate analysis confirmed that both anti-beta(2)-GPI and anti-prothrombin Abs were significant risk factors for arterial thrombosis [odds ratios (ORs), 8.8 and 14.5, respectively; 95% confidence intervals (CIs), 3.2-25 and 1.8-116, respectively] but not for venous thrombosis. The presence of anti-protein S Abs was a significant risk factor for venous thrombosis (OR, 30.4; CI, 3.3-281) but not for arterial thrombosis. The only significant risk factor for fetal loss was the presence of anti-annexin V Abs (OR, 5.9; CI, 1.4-14.8). CONCLUSIONS: Patients with SLE frequently have some aPL Abs to beta(2)-GPI, prothrombin, protein C, protein S, and annexin V. Thrombotic complications in SLE may depend on the antigenic specificities of these Abs, alone or in combination.

Downregulation of an AIM-1 kinase couples with megakaryocytic polyploidization of human hematopoietic cells.

During the late phase of megakaryopoiesis, megakaryocytes undergo polyploidization, which is characterized by DNA duplication without concomitant cell division. However, it remains unknown by which mechanisms this process occurs. AIM-1 and STK15 belong to the Aurora/increase-in-ploidy (Ipl)1 serine/threonine kinase family and play key roles in mitosis. In a human interleukin-3-dependent cell line, F-36P, the expressions of AIM-1 and STK15 mRNA were specifically observed at G2/M phase of the cell cycle during proliferation. In contrast, the expressions of AIM-1 and STK15 were continuously repressed during megakaryocytic polyploidization of human erythro/megakaryocytic cell lines (F-36P, K562, and CMK) treated with thrombopoietin, activated ras (H-ras(G12V)), or phorbol ester. Furthermore, their expressions were suppressed during thrombopoietin-induced polyploidization of normal human megakaryocytes. Activation of AIM-1 by the induced expression of AIM-1(wild-type) canceled TPA-induced polyploidization of K562 cells significantly, whereas that of STK15 did not. Moreover, suppression of AIM-1 by the induced expression of AIM-1 (K/R, dominant-negative type) led to polyploidization in 25% of K562 cells, whereas STK15(K/R) showed no effect. Also, the induced expression of AIM-1(K/R) in CMK cells provoked polyploidization up to 32N. These results suggested that downregulation of AIM-1 at M phase may be involved in abortive mitosis and polyploid formation of megakaryocytes.

Detection of small populations of CD59-deficient erythrocytes in patients with aplastic anemia or myelodysplastic syndrome and normal individuals.

To detect a small population of blood cells with a deficiency of glycosyl phosphatidylinositol (GPI)-anchored protein, we evaluated the expression of CD59 by flow cytometry on one million erythrocytes, which is about 100 times more than the number of erythrocytes tested by our standard immunoassay. Blood samples from healthy volunteers, patients with aplastic anemia (AA), and patients with myelodysplastic syndrome (MDS), who all showed no detectable GPI deficiency by the standard assay, were investigated. The numbers of CD59-deficient erythrocytes were 5 to 145/10(6) erythrocytes in the healthy volunteers (mean 29.2), and one of the volunteers had an increase in the deficient cells exceeding the mean + 3 SD (141.7), a normal limit. A CD59-deficient population was detected in 6 of the 21 (28.6%) patients with AA and 5 of the 18 (27.8%) patients with MDS. The new assay was performed again in 5 of these 11 patients and the normal individual who had the CD59-deficient populations at 6 and 12 months after the initial study. The number of deficient cells gradually increased in 1 patient with MDS (from 511 to 2892/10(6) erythrocytes), while the numbers of the other 4 patients showed a tendency to decline, although the deficient populations were repeatedly detected on most of the occasions. Changes in the number of the deficient cells were also seen in the healthy volunteer, but they were rather rapid; the numbers changed from 145 to 5661 and then to 18/10(6) erythrocytes within 3 months. The CD59 assay used in this study is easy to perform and enabled us to detect less than 1% GPI-deficient cells.

Blastic transformation of splenic lymphoma with villous lymphocytes after a well-controlled chronic phase of more than 10 years.

A 30-year-old Japanese man with splenomegaly and lymphocytosis was examined in 1985. Blood analysis revealed that some of the lymphocytes had short-surface villi with polar distribution. The cells showed Ig lambda+, CD5+, CD11c+, CD19+, CD22+, CD23+, CD24+, FMC7+ phenotype. A small M peak was detected in the serum. Splenic lymphoma with villous lymphocytes (SLVL) was diagnosed on the basis of these findings. Remission was induced and was maintained with low-dose chlorambucil for more than 10 years. In 1996, the patient developed splenomegaly and lymphadenopathy with "B" symptoms and a high serum lactase dehydrogenase (LDH) level. Large blastoid cells with prominent nucleoli were observed in the bone marrow; later, a small number appeared in the peripheral blood. The bone marrow cells showed a complex chromosomal abnormality involving del(7)(q32). Southern blot analysis of immunoglobulin gene rearrangements in SLVL cells that had been cryopreserved in 1986 and of bone marrow cells in 1996 showed 2 rearranged bands in each cell sample; 1 band showed identical sizes in the 2 samples, and the other showed different sizes. These findings suggest that the blastoid cells were derived from SLVL cells through transformation. After this transformation, the disease followed a highly aggressive course. Various chemotherapeutic agents had little effect, and the patient died 3 months later.

GATA-1 blocks IL-6-induced macrophage differentiation and apoptosis through the sustained expression of cyclin D1 and bcl-2 in a murine myeloid cell line M1.

Cytokines exert pleiotropic effects on target cells in a manner dependent on the cell type or stage of differentiation. To determine how instinctive cell properties affect biological effects of cytokine, we introduced an erythroid/megakaryocyte lineage-specific transcription factor, GATA-1, into a murine myeloid cell line M1, which is known to undergo macrophage differentiation in response to interleukin 6 (IL-6). Overexpression of GATA-1 changed the phenotype of M1 cells from myeloid to megakaryocytic lineage. Furthermore, GATA-1 blocked both IL-6-induced macrophage differentiation and apoptosis of M1 cells. Although STAT3 is essential for IL-6-induced macrophage differentiation of M1 cells, GATA-1 had little or no effect on tyrosine phosphorylation, DNA binding, and transcriptional activities of STAT3 in Western blot analysis, electropholic mobility shift assay (EMSA), and luciferase assays. During IL-6-induced macrophage differentiation of M1 cells, IL-6 down-regulated cyclin D1 expression and induced p19(INK4D) expression, leading to reduction in cdk4 activities. In contrast, sustained expression of cyclin D1 and a significantly lesser amount of p19(INK4D) induction were observed in IL-6-treated M1 cells overexpressing GATA-1. Furthermore, although bcl-2 expression was severely reduced by IL-6 in M1 cells, it was sustained in GATA-1-introduced M1 cells during the culture with IL-6. Both IL-6-induced macrophage differentiation and apoptosis were significantly abrogated by coexpression of cyclin D1 and bcl-2, whereas overexpressions of cyclin D1 or bcl-2 inhibited only differentiation or apoptosis, respectively. These results suggested that GATA-1 may not only reprogram the lineage phenotype of M1 cells but also disrupt the biologic effects of IL-6 through the sustained expression of cyclin D1 and bcl-2. (Blood. 2000;95:1264-1273)

T-prolymphocytic leukaemia with spontaneous remission.

T-prolymphocytic leukaemia (T-PLL) is a rare dis-order with a poor prognosis. A 69-year-old man was diagnosed as having a small-cell variant of T-PLL according to the French-American-British classification by haematological, immunological and ultrastructural studies, although the cells had a CD7- phenotype and no chromosomal abnormality. He had no symptoms or organomegaly. The number of his lymphocytes, 53.7 x 109/l at the time of diagnosis, gradually decreased without therapy, and he was in complete remission 39 months later. A rearranged band in the T-cell antigen receptor-beta gene, which was detected at the time of diagnosis, decreased or disappeared. This is the first report of a T-PLL case with spontaneous complete remission.

Induction of apoptosis by extracellular ubiquitin in human hematopoietic cells: possible involvement of STAT3 degradation by proteasome pathway in interleukin 6-dependent hematopoietic cells.

The ubiquitin-proteasome pathway is responsible for selective degradation of short-lived cellular proteins and is critical for the regulation of many cellular processes. We previously showed that ubiquitin (Ub) secreted from hairy cell leukemia cells had inhibitory effects on clonogenic growth of normal hematopoietic progenitor cells. In this study, we examined the effects of exogenous Ub on the growth and survival of a series of human hematopoietic cells, including myeloid cell lines (HL-60 and U937), a B-cell line (Daudi), and T-cell lines (KT-3, MT-4, YTC-3, and MOLT-4). Exogenous Ub inhibited the growth of various hematopoietic cell lines tested, especially of KT-3 and HL-60 cells. The growth-suppressive effects of Ub on KT-3 and HL-60 cells were almost completely abrogated by the proteasome inhibitor PSI or MG132, suggesting the involvement of the proteasome pathway in this process. Furthermore, exogenous Ub evoked severe apoptosis of KT-3 and HL-60 cells through the activation of caspase-3. In interleukin-6 (IL-6)-dependent KT-3 cells, STAT3 was found to be conjugated by exogenous biotinylated Ub and to be degraded in a proteasome-dependent manner, whereas expression levels of STAT1, STAT5, or mitogen-activated protein kinase were not affected. Moreover, IL-6-induced the up-regulation of Bcl-2 and c-myc, and JunB was impaired in Ub-treated KT-3 cells, suggesting that the anti-apoptotic and mitogenic effects of IL-6 were disrupted by Ub. These results suggest that extracellular Ub was incorporated into hematopoietic cells and mediated their growth suppression and apoptosis through proteasome-dependent degradation of selective cellular proteins such as STAT3. (Blood. 2000;95:2577-2585)

Borna disease virus infection in two family clusters of patients with chronic fatigue syndrome.

A high rate of Borna disease virus (BDV) infection has been demonstrated in patients with chronic fatigue syndrome (CFS). Herein, we focused on BDV infection in two family clusters of patients with CFS: a father, mother, two sons and one daughter (family #1); and a father, mother, two daughters and one son (family #2). All members, except for the elder son in family #1 and the father and son in family #2, were diagnosed with CFS. The results supported that all the family members with CFS were infected with BDV, as evidenced by the presence of antibodies to viral p40, p24 and/or gp18 and BDV p24 RNA in peripheral blood mononuclear cells. The healthy members, except for the father of family #2 who was positive for antibody to p24, were all negative by both assays. Follow-up studies in family #1 continued to reveal BDV antibodies and BDV RNA, except in the mother, who lost the RNA upon slight recovery from the disease.

Platelet activation induced by combined effects of anticardiolipin and lupus anticoagulant IgG antibodies in patients with systemic lupus erythematosus--possible association with thrombotic and thrombocytopenic complications.

Antiphospholipid antibodies (aPL) are well known to be associated with arterial and venous thrombosis. In a series of 180 patients with systemic lupus erythematosus (SLE), the prevalence of arterial thrombosis was obviously higher in the patients who had both anticardiolipin antibodies (aCL) and lupus anticoagulant (LA) (17/35, 48.6%, p<0.05) (Table 1) than in the other patients bearing aCL or LA alone or neither of them (2/145, 1.4%). Since a substantial fraction of the former group of patients with arterial thrombosis also had thrombocytopenia (12/17, 70.6%), there was a possibility that aCL and LA might have enhanced platelet activation and aggregation. To test this possibility, we studied the in vitro effects of aCL and LA on the enhancement of platelet activation by flow cytometric analysis using anti-CD62P and anti-CD41 monoclonal antibodies directed against platelet activation-dependent granule-external membrane (PADGEM) protein and platelet glycoprotein IIb (GPIIb), respectively. Platelet activation defined by the surface expression of CD62P was not induced by aCL+ x LA+ plasma only, but was significantly augmented by aCL+ x LA+ plasma in combination with adenosine diphosphate (ADP) at a low concentration that had only a modest effect on platelet activation. In contrast, aCL+ x LA-, aCL- x LA+ and aCL- x LA- plasma samples were incapable of enhancing platelet activation in the presence or absence of ADP stimulation. In addition to plasma samples, the purified IgG from aCL+ x LA+ plasma (aCL+ x LA+-IgG) also yielded apparent enhancement of platelet activation induced by ADP. Furthermore, platelet activation was generated by the mixture of aCL+ x LA--IgG and aCL- x LA+-IgG fractions prepared from individual patients, but not by each fraction alone. These results suggest that aCL and LA may cooperate to promote platelet activation, and may be involved, at least partially, in the pathogenesis of arterial thrombosis and thrombocytopenia in patients with SLE.

CD59-deficient blood cells and PIG-A gene abnormalities in Japanese patients with aplastic anaemia.

Patients with aplastic anaemia (AA) frequently develop paroxysmal nocturnal haemoglobinuria (PNH) as a late complication. We investigated the frequency of the development of PNH features including a glycosyl phosphatidylinositol (GPI) anchoring defect in 73 Japanese patients with AA. A deficient expression of CD59 was found on erythrocytes and/or granulocytes in 21/73 (28.8%) of the patients. A Ham/sugar water test was positive in 13/21 patients. We also examined mutations of the PIG-A gene in 11 patients with CD59 deficiency. A heteroduplex analysis detected PIG-A gene abnormality in 10/11 patients tested. Nucleotide sequencing was performed in six patients and identified eight mutations including three mutations in one patient. The mutations of the PIG-A gene were all different and included two single-base insertions, one single-base deletion, two two-base deletions, and one each of eight-base insertion and nine- and ten-base deletions. All mutations but one caused frameshifts. Our findings indicate that a high proportion of Japanese patients with severe AA have a GPI-anchoring defect and that the PIG-A gene is mutated in the AA patients who had a GPI deficiency. We found no significant difference in the pattern of the PIG-A gene mutation between the AA patients with a GPI deficiency and those with de novo PNH.

Assessment of alkaline phosphatase on the surface membrane of neutrophils by immunofluorescence.

Expression of alkaline phosphatase (ALP) on the surface membrane of neutrophils (mNAP) was studied by immunofluorescence using an anti-ALP monoclonal antibody. Fluorescent intensity distribution of mNAP was analyzed using FACS (fluorescence-activated cell sorter). The mean fluorescent intensity (MFI) of the mNAP in this assay was well correlated with the neutrophil ALP (NAP) score demonstrated cytochemically (r = 0.832). mNAP levels in various hematological disorders were evaluated by % mNAP+ cells and MFI. The levels in aplastic anemia and polycythemia vera were significantly higher, and in chronic myelocytic leukemia and paroxysmal nocturnal hemoglobinuria (PNH), the levels were significantly lower compared with the levels in healthy volunteers. Two-color immunofluorescence with anti-ALP and anti-CD16 showed that the PNH clone was essentially negative for mNAP, whereas residual normal neutrophils (CD16+) had levels slightly higher than those in normal individuals. Highly reproducible results were obtained in the blood samples which were stored at 4 degrees C for at least 24 hr without any treatment prior to immunofluorescent staining. No degradation of fluorescent intensity was seen 4 days after staining and fixation. The mNAP assay is simple, without subjective evaluation for quantification, and is useful for differential diagnosis of hematological disorders.

Natural killer cell-derived large granular lymphocyte lymphoma of lung developed in a patient with hypersensitivity to mosquito bites and reactivated Epstein-Barr virus infection.

A 17-year-old female developed natural killer (NK) cell-derived large granular lymphocyte (LGL) lymphoma of the lung. She had a past history of hypersensitivity to mosquito bites (HMB). After an eight-year chronic, active Epstein-Barr virus (EBV) infection, she developed multiple lung lesions and pleural effusion. In the effusion, 60% of the cells were LGL. They were CD2+, 3-, 16+, 56+, 57+, 45RO+/RA + weak, and possessed strong NK activity. No rearrangement of T-cell-receptor genes was detected. From all these results, a diagnosis of NK-LGL lymphoma of the lung was made. EB virus DNA was detected in cells infiltrating the pleural effusion. The clonality of the LGLs was determined by Southern blot hybridization with the terminal repeat sequence of EB virus as a probe, and by chromosomal abnormalities. The patient died from respiratory failure. Necropsy of the lung revealed diffuse lymphoma composed of polymorphic cells with typical angiocentric lesions. Reportedly, lymphomas of NK lineage show predominantly extranodal involvement, and primary lung lesions are rare. In the pleural effusion of the present case, abnormally high levels of soluble Fas ligand, interleukin-10 and interferon gamma were detected. This hypercytokinemia, reflecting the microenvironment of lymphoma cells, may play a role in the progression of the lymphoma and organ injury in the lung.

Low levels of serum acylcarnitine in chronic fatigue syndrome and chronic hepatitis type C, but not seen in other diseases.

Recently, we found a serum acylcarnitine (ACR) deficiency in Japanese patients with chronic fatigue syndrome (CFS). To clarify whether this ACR abnormality is a characteristic of CFS or not, we also studied the levels of serum carnitine in Swedish subjects. Both serum ACR and free carnitine (FCR) levels in normal healthy subjects were quite different between Japanese (n=131) and Swedish people (n=46) (p<0.001). However, it is confirmed that Swedish patients with CFS (n=57) also had serum ACR deficiency (p<0.001). When we studied the levels of serum ACR and FCR in Japanese patients with various kinds of diseases (CFS, hematological malignancies, chronic pancreatitis, hypertension, diabetes mellitus, chronic hepatitis type C, psychiatric diseases), a significant decrease in the levels of serum ACR was only found in patients with CFS and chronic hepatitis type C (p<0.001). Therefore, we concluded that ACR deficiency in serum might be a characteristic abnormality in only certain types of diseases.

Dehydroepiandrosterone sulfate deficiency in chronic fatigue syndrome.

The chronic fatigue syndrome (CFS) is a condition of unknown etiology, characterized by a persistent debilitating fatigue, the muscle-related symptoms and the neuropsychiatric symptoms. Recently, it has been reported that the patients with CFS might have impaired activation of the hypothalamic-pituitary-adrenal axis, and suggested that a part of the patho-genesis of CFS might be associated with abnormalities of the endocrine system. Herein, we show that the majority of Japanese patients with CFS had a serum dehydroepiandrosterone sulfate (DHEA-S) deficiency. Serum DHEA-S is one of the most abundantly produced hormones which is secreted from the adrenal glands, and its physiological function is thought to be a precursor of sex steroids. DHEA-S has recently been shown to have physiological properties, such as neurosteroids, which are associated with such psychophysiological phenomena as memory, stress, anxiety, sleep and depression. Therefore, the deficiency of DHEA-S might be related to the neuropsychiatric symptoms in patients with CFS.

[Polyclonal B-cell lymphocytosis with clinical and hematological features resembling hairy cell leukemia].

A 49-year-old man was admitted to our hospital for investigation of splenomegaly and lymphocytosis. He had no significant past history and was not a smoker. Physical examination revealed massive splenomegaly and no palpable superficial lymph nodes. Hematological examination showed a hemoglobin concentration of 10.5g/dl, a platelet count of 9.8 x 10(4)/microliter, and a leukocyte count of 21.2 x 10(3)/microliter with 70% abnormal lymphocytes. In May-Giemsa stained blood films, the abnormal lymphocytes had round nuclei, abundant, pale cytoplasm, and slightly serrated edges. Phase-contrast microscopic and scanning electron microscopic examinations revealed many long surface villi. Tartrate-resistant acid phosphatase activity in these cells was negative. The abnormal lymphocytes had a CD5-, CD10-, CD11a+, CD11c+, CD19+, CD20+, CD22+ phenotype. These features were similar to those described for a variant form of hairy cell leukemia (HCL-Japanese variant). However, studies of Ig gene rearrangement and expression of sIg revealed a polyclonal proliferation of B cells. On the basis of these findings, this case was diagnosed as hairy B-cell lymphoproliferative disorder, a recently described condition characterized by polyclonal B-cell lymphocytosis and features resembling HCL-Japanese variant. Serological assays for antibodies against Epstein-Barr virus suggested a past infection. Splenectomy alleviated the anemia and thrombocytopenia, but not the lymphocytosis.