Arteriosclerosis obliterans associated with anti-cardiolipin antibody/beta2-glycoprotein I antibodies as a strong risk factor for ischaemic heart disease in patients with systemic lupus erythematosus.

OBJECTIVE: The main objective of this study was to clarify the role of aPLs in the pathogenesis of arteriosclerosis obliterans (ASO), ischaemic heart disease (IHD) and cerebral vascular disorder (CVD) in patients with SLE. METHODS: We evaluated 155 patients with SLE by using objective tests for diagnosing ASO, IHD and CVD and laboratory tests including ELISA for aCL/beta2-glycoprotein I antibodies (aCL/beta2-GPI) and anti-phosphatidylserine/prothrombin antibodies (anti-PS/PT). RESULTS: Twenty-five (16.1%) of the 155 SLE patients were diagnosed with ASO. Both aCL/beta2-GPI and anti-PS/PT levels were significantly higher in SLE patients with ASO (mean +/- S.E., 104.3 +/- 38.8 U/ml for aCL/beta2-GPI, P < 0.01; 72.6 +/- 48.9 U/ml for anti-PS/PT, P < 0.05) than in SLE patients without ASO (22.8 +/- 9.9 U/ml for aCL/beta2-GPI; 18.3 +/- 4.4 U/ml for anti-PS/PT). Multivariate logistic analysis including aCL/beta2-GPI, anti-PS/PT and traditional risk factors (hypercholesterolaemia, hypertension and diabetes mellitus) confirmed that the presence of aCL/beta2-GPI was the most significant risk factor for ASO in SLE patients [odds ratio (OR) 3.45; 95% CI 1.40, 8.56; P < 0.01]. Furthermore, the prevalence of ASO was associated strongly with IHD (OR 11.8; 95% CI 3.45, 40.1; P < 0.0001) but not CVD (OR 1.84; 95% CI 0.65, 5.21; P = 0.25). CONCLUSIONS: The presence of aCL/beta2-GPI contributes to the risk of development of ASO, which may represent an important mechanism for the pathogenesis of IHD in patients with SLE.

Amylase-producing plasmacytoma cell lines, AD3 and FR4, with der(14)t(8;14) and dic(8)t(1;8) established from ascites.

We established two human plasma cell lines, FR4 and AD3, from ascitic fluid in a patient with IgA k plasmacytoma (PC). Aberrant amylase production was found in this patient. Both AD3 and FR4 were free of Epstein-Barr virus, and both produced Ig A k in vitro. They produced amylase of the salivary type in vitro. This was confirmed by the demonstration of amylase mRNA comigrating with salivary gland mRNA. These cell lines commonly had unusual chromosomal abnormalities der(14)t(8;14) and dic(8)t(1;8). AD3 had additional chromosomal abnormalities compared with FR4. This suggests that AD3 is a subline of FR4. The oncogene c-myc is rearranged in most case of Burkitt's lymphoma with t(8;14). However, neither rearrangement nor amplification of the c-myc allele was detected in our PC lines. These lines expressed c-myc of 2.4 kb. There were no structural changes in the amylase genes of AD3 and FR4 detectable with Southern blotting analysis. As these lines were authentic PC lines, they would be useful for the future study of the relationship between the mechanism of oncogenesis and the rare tumor aberration, amylase production.

Association of protein tyrosine phosphorylation with B cell differentiation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA).

We have assessed whether tyrosine protein kinase (TPK) is involved in B cell differentiation. In vitro phosphorylation of an endogenous substrate in B cell leukemias showed that leukemic B cells at different stages of differentiation had specific endogenous substrates in tyrosine phosphorylation as well as distinct TPK activity. To clarify the relationship between TPK and the process of B cell differentiation, we studied protein tyrosine phosphorylation in two kinds of leukemic B cells, which showed distinct responses to TPA (12-O-tetradecanoylphorbol-13-acetate) in B cell differentiation. TPA-treated leukemic B cells from patients with B cell chronic lymphocytic leukemia (B-CLL) differentiated into cytoplasmic immunoglobulin (clg)+ plasmacytoid cells, while TPA-treated leukemic B cells from patients with hairy cell leukemia (HCL) did not differentiate into clg+ cells, but showed a peculiar morphological change, spreading. Untreated B-CLL cells and HCL cells showed similar TPK activities and tyrosine protein phosphorylation. When treated with TPA, enhanced phosphorylation was seen in B-CLL cells, while a clear reduction in phosphorylation was found in HCL cells. However, using 4-hydroxycinnamide derivatives which reduce TPK activity, we found that only the reduction of TPK activity did not lead HCL cells to spreading. These data suggest that protein tyrosine phosphorylation and/or dephosphorylation might be involved in B cell differentiation, but only the change of TPK activity in HCL cells is not sufficient to induce effects.

Effects of interferon-alpha on L-BCGF- and TNF-alpha-induced proliferation of hairy cell leukemia in Japan.

Interferon-alpha (IFN-alpha) is very effective in patients with hairy cell leukemia (HCL), although its mechanism of action is still unknown. To investigate this issue, we studied the in vitro response to IFN-alpha of a variant type of HCL, recently reported by us as the Japanese variant. Their clinical response to IFN-alpha (remission rate 35.7% in the multicenter study in Japan) was inferior to that of typical HCL (remission rate 80%; mean of previous reports). We found that both low molecular weight B-cell growth factor (L-BCGF) and tumor necrosis factor-alpha (TNF-alpha) induced the proliferation of HC from patients with the Japanese variant, as well as those with typical HCL. While, in typical HCL, IFN-alpha strongly inhibited the in vitro proliferation of HC induced by L-BCGF and TNF-alpha, the inhibitory effect of IFN-alpha on L-BCGF and TNF-alpha-induced proliferation was low in most Japanese variant patients. These in vitro findings may be related to the extent of clinical efficacy of IFN-alpha in the Japanese variant, obtained in the multicenter study. Since the degree of inhibition was parallel in L-BCGF- and TNF-alpha-induced proliferation in three patients examined simultaneously, it appeared that the antiproliferative effect of IFN-alpha is not specific to individual growth factors. Rather, IFN-alpha might affect fundamental growth mechanisms triggered by these factors.

Phenotypical heterogeneity of CD4+CD8+ double-positive chronic T lymphoid leukemia.

Chronic T lymphoid leukemias are defined as leukemias of post-thymic T cells. The CD4+CD8+ double-positive (DP) phenotype is seen in a few cases. Since DP generally occurs in thymic T cells, whether the DP T leukemia cells represent thymic or peripheral T cells has been a matter of controversy. To address this issue, we studied phenotypical features in eight cases of DP T cell leukemia. Thymic DP T cells and peripheral CD8+ T cells have CD8 of alphabeta subunit, while CD8alphaalpha is induced in CD4+ T cells on activation with IL-4. We found that two patients with DP T large granular lymphocyte leukemia (LGLL) showed dim expression of CD8alphaalpha, identical to the phenotype on IL-4-activated DP-T cells. The leukemic cells of these patients expressed IL-4 mRNA and produced high levels of IL-4. These findings suggest that they may be derived from peripheral CD4+ T cells. Three patients with adult T cell leukemia/lymphoma (ATLL) showed CD8alphaalpha, suggestive of an activated peripheral T cell origin. One case expressed CD8alphaalpha dim and IL-4 mRNA, while the other two cases expressed no IL-4 mRNA and showed CD8alphaalpha bright phenotype, features not found in normal T cell populations. Three patients with T-prolymphocytic leukemia (T-PLL) expressed CD8alphabeta. The DP phenotype is relatively common in T-PLL, and CD4+CD8alphabeta+ is characteristic of thymic T cells. The DP T-PLL cells did not express TdT,CD1 or recombination activating gene-1 (RAG-1), which is down-regulated at the late stage of thymic T cell development. On the basis of these findings, we propose a late thymic origin for DP T-PLL. The phenotype of DP T cells differed for each entity and appeared to correlate with minor normal DP T cell population.

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.

Establishment of a new cell line from a patient with hairy cell leukemia-Japanese variant.

A cell line, JHC-2, was established from the peripheral blood of a patient with hairy cell leukemia (HCL)-Japanese variant. The JHC-2 cells have cytologic features similar to those of the original tumor cells. They displayed hairy cytoplasmic projections by phase contrast and scanning electron microscopy. The tartrate-resistant acid phosphatase reaction was weakly positive. The immunophenotype of the JHC-2 cells was CD5-, CD10-, CD11c+/-, CD19+, CD21+, CD23+, CD24-, CD25+/-, CD38- and FMC-7+. The expression of surface immunoglobulin (IgG, kappa) and the configuration of Ig gene rearrangements in the JHC-2 cells were identical to those in the original leukemic cells, and the JHC-2 cells displayed trisomy 9 on cytogenetic examination. Southern blot analysis for the Epstein-Barr virus (EBV) genome showed that the JHC-2 cells contained the EBV genome, although the freshly isolated leukemic cells did not. These results indicate that the JHC-2 cell line is an EBV spontaneously transformed B cell line originating from HCL cells.

A HTLV-I carrier who showed various symptoms and antibodies of autoimmune diseases.

We report a 37-year-old female HTLV-I carrier with complicating primary biliary cirrhosis (PBC) and mixed connective tissue disease (MCTD). Serum anti-HTLV-I antibody titer was x256. Flower cells (4.5%) were found in the peripheral blood. Southern blot analysis showed no clonal integration in peripheral blood lymphocyte (PBL) DNA. Polymerase chain reaction showed the HTLV-I genome in PBL DNA. As cholestatic liver dysfunction and serum titer of anti-mitochondrial antibody were found, a clinical diagnosis of PBC was made. This patient later developed MCTD. These diseases responded well to prednisone. The pathogenetic relationship of HTLV-I infection with various autoimmune diseases is discussed.

[Association between antiphospholipid antibodies and arterial or venous thrombosis/thrombocytopenia].

The relationship between thrombotic or thrombocytopenic complications and the existence of anticardiolipin antibodies (aCL) and/or lupus anticoagulant (LA) was studied in 146 patients with systemic lupus erythematosus (SLE). The prevalence of arterial thrombosis was obviously higher in patients who had both aCL and LA than in patients with either aCL or LA alone or in those with neither. Since a substantial fraction of the former group of patients with arterial thrombosis also had thrombocytopenia, there is a possibility that aCL and LA might enhance platelet activation and aggregation. To test this hypothesis, 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). The IgG fraction purified from aCL+.LA+ plasma apparently enhanced platelet activation induced by adenosine diphosphate (ADP) at a low concentration, but IgG fractions from aCL+.LA- or aCL-.LA+ plasma did not cause enhancement of platelet activation. 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 in patients with SLE.

[Large granular lymphocyte leukemia].

Large granular lymphocyte leukemia (LGLL) is defined as clonal proliferation of LGLs in peripheral blood. The following studies were conducted to address some issues in chronic LGLL. (1) Chronic LGLL is characterized by the indolent course, and the diagnosis of leukemia is difficult in such patients as those without distinct organomegaly and/or any evidence of monoclonality. We performed immunohistological studies in a patient with persistent NK lymphocytosis. No organomegaly had been seen in the patient during a three-year-observation, who died from cerebrovascular accident. The autopsy findings revealed multi-organ infiltration including spleen, liver, bone marrow, lymph nodes and lung. These findings suggest that the cells of chronic LGLL have infiltrative capacity characteristic of malignant cells. (2) Lymphocytosis in chronic LGLL is usually stable for a long period. We found that both T- and NK-LGLL cells strongly expressed CD95, an apoptosis related protein. Anit-CD95 did not induce apoptosis, but suppressed proliferation induced by IL-2 or anti-CD3. These results suggest that CD95-CD95 ligand system is involved in the slow cell growth characteristic of chronic LGLL. (3) CD4+CD8+ double positive (DP) cases are rarely seen in LGLL, and the physiologic counterpart of the leukemic cells has not been determined yet. We found that the DP-LGLL had alpha alpha type in the CD8 subunit and did not express RAG-1, these findings being characteristic of peripheral T cells. We also found that they expressed IL-4 mRNA and secreted IL-4 on activation. These results strongly suggest that DP-T-LGLL represents an expansion of a rare subset of peripheral DP-T cells, possibly derived from IL-4 activated CD4 single positive T cells.

[Multiple myeloma and adhesion molecules].

The physiological role of fibronectin (FN) on the human plasma cells were examined using three PC cell lines, FR4ds, OPM1 and OPM1ds. FR4ds was reactive with anti-VLA-alpha 4 and anti-alpha 5. In contrast, OPM1 and OPM1ds were not reactive with anti-VLA-alpha 5. FN induced spreading in FR4ds and OPM1ds. Albumin blocked these spreadings. FR4ds with mature plasma cell phenotype of alpha 4+ and alpha 5+ was more sensitive for FN than OPM1 and OPM1ds with immature phenotype of alpha 4+ and alpha 5-. Spreading cells proliferated more than floating cells. All these cell lines showed chemotaxis toward FN. alpha 5+ FR4ds was more sensitive for FN than OPM1 and OPM1ds with alpha 5- phenotype. These new abilities of PC of spreading and chemotaxis we found are summarized to be an affinity to organs. It is likely that alpha 4+ and alpha 5- PC with low affinity to organs are stored in peripheral blood as a result. We examined the chemotaxtic activity of myeloma cells in bone marrow and these in pleural effusions in a patient with multiple myeloma. These cells in pleural effusions showed more chemotaxic activity than these in bone marrow. FN induced growth, production of Ig, and motility of PC, which resulted in the augmentation of humoral immunity.

Different membrane anchors of Fc gamma RIII (CD16) on K/NK-lymphocytes and neutrophils. Protein- vs lipid-anchor.

Fc gamma RIII (CD16), the type three receptor for the Fc portion of IgG, is expressed on neutrophils, killer (K)/NK lymphocytes and macrophages. K/NK lymphocyte Fc gamma RIII, which plays a role in antibody-dependent cellular cytotoxicity, is an efficient signal transducing molecule, whereas neutrophil Fc gamma RIII, which plays a role in immune-complex clearance, seems less efficient in signal transduction. Neutrophil Fc gamma RIII has been reported to be a glycan-phosphatidylinositol-anchored membrane protein. Our studies suggest that K/NK lymphocyte Fc gamma RIII is protein-anchored rather than glycan-phosphatidylinositol-anchored. That is, K/NK lymphocyte Fc gamma RIII was resistant to phosphatidylinositol-specific phospholipase C and surface expression of Fc gamma RIII was not affected on K/NK lymphocytes from patients with paroxysmal nocturnal hemoglobinuria, a disorder of hemopoietic stem cells resulting in deficient expression of glycan-phosphatidylinositol-anchored proteins. Different membrane anchoring mechanisms of the Fc gamma RIII may account for different consequences of the ligand binding to two cell types.

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).

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.

Hairy cells from hairy cell leukemia patients presenting with pronounced polyclonal hypergammaglobulinemia secrete a factor enhancing IgG synthesis.

We studied the immunological function of hairy cells from hairy cell leukemia (HCL) patients presenting with pronounced polyclonal hypergammaglobulinemia (PPH). Hairy cell conditioned medium (HCCM) obtained from HCL patients with PPH augmented IgG production by normal peripheral blood mononuclear cells in a dose-dependent fashion, while HCCM from patients without PPH had no effect on IgG production. HCCM from the patients with PPH failed to enhance IgG synthesis by T cell-depleted mononuclear cells. Separation of T and B cells by a 0.4-microns membrane as well as monoclonal antibodies to HLA-DR and CD3 molecules prevented HCCM-dependent IgG synthesis. No B cell growth factor activity, interleukin-1, or interleukin-6 was detected in the HCCM. On examination by fractionation of the HCCM, IgG-inducing activity was detected in the fractions of 5000 to 8000 Da. These results indicate that hairy cells from HCL patients with PPH secrete a factor inducing IgG synthesis, and that the induction of IgG synthesis by the factor requires T-B cell interactions involving T cell receptor/CD3 complex and MHC class II antigens. This factor may play an important role in the development of PPH.

Monocytes appearing repeatedly after chemotherapies had an identical rearrangement pattern of immunoglobulin with leukemic blasts in a patient with CD13+ acute lymphoblastic leukemia.

We recently encountered a patient with acute lymphoblastic leukemia (ALL) who showed temporal monocytosis of an unusually high cell count (5,000-30,000 monocytoid cells/microliter) five times after treatment with different chemotherapies. The leukemic cells expressed B-cell-associated antigens, CD19 and CD10, E-rosette receptor, CD2 and monocyte/myeloid antigen, CD13 simultaneously. They were peroxidase-negative. One week after the initiation of conventional chemotherapy for ALL, the leukemic blasts had disappeared. Alternatively, monocytoid cells appeared along with the recovery from nadir status. They showed several features of monocytes; they were weakly dot-positive for nonspecific esterase, reactive with CD14 and CD13 and Fc gamma-receptor-positive. Furthermore, they migrated into a fungally infected joint space. Features incompatible with normal monocytes were the absence of peroxidase reactivity, the expression of B-cell-associated antigens, CD19 and CD10 and E-rosette receptor, CD2. Southern blot hybridization analysis revealed an unexpected result that HindIII digested DNA from both leukemic blasts and monocytoid cells had the same rearranged band of IgH. Thus, an identical clonality of monocytoid cells, temporally appearing after chemotherapies and leukemic lymphoblasts, was determined in this patient with CD13+ ALL.

Risk of arterial thrombosis in patients with anticardiolipin antibodies and lupus anticoagulant.

The relationship between arterial or venous thrombosis and the levels of anticardiolipin antibodies (aCL) and/or existence of lupus anticoagulant (LA) was studied. The 141 patients with systemic lupus erythematosus (SLE) were divided into four groups: aCL single positive (25 cases), LA single positive (11 cases), aCL and LA double positive (25 cases), aCL and LA double negative (80 cases). The prevalence of thrombosis was higher in aCL and LA double positive patients (21/25 cases, 84.0%, P <0.01) than that in aCL single positive patients (4/25 cases, 16.0%), LA single positive patients (1/11 cases, 9.1%) and double negative patients (3/80 cases, 3.8%). Furthermore, in these double positive patients, all patients (10/10 cases) with a high positive level of aCL (> 10 units/ml) had arterial thrombosis, whereas only 2/15 patients (13.3%) with a low positive level of aCL (3-10 units/ml) were affected. Venous thrombosis was frequently found in the low positive group (9/15 cases, 60.0%). On the contrary, none of 105 LA negative patients had arterial thrombosis and only seven (6.7%) had venous thrombosis. These findings indicate that a high aCL activity combined with a LA positive result might be a risk factor for arterial thrombosis.

High prevalence of thrombocytopenia in SLE patients with a high level of anticardiolipin antibodies combined with lupus anticoagulant.

The relationship between thrombocytopenia and the level of anticardiolipin antibodies (aCL) and/or the existence of lupus anticoagulant (LA) ware studied in 146 patients with systemic lupus erythematosus (SLE). These patients were divided into six groups: A, those LA positive with a high level of aCL (>10 U/ml) (10 cases); B, those LA positive with a low level of aCL (3-10 U/ml) (15 cases); C, those LA positive but aCL negative (<3 U/ml) (12 cases); D, LA negatives with a high level of aCL (12 cases); E, LA negatives with a low level of aCL (16 cases); and F, aCL and LA double negatives (81 cases). The prevalence of thrombocytopenia (platelet count < or = 100 x 10(9)L) was by far the highest in group A (9/10 cases, 90.0%, P < 0.005, Fisher's exact probability test) as compared with group B (4/15 cases, 26.7%), group C (4/12 cases, 33.3%), group D (1/12 cases, 8.3%), group E (4/16 cases, 25.5%), and group F (9/81 cases, 11.1%). When the relationship between moderate thrombocytopenia and arterial or venous thrombosis was studied in these patients with SLE, thrombocytopenia was detected in 10 (83.3%, P < 0.005, Fisher's exact probability test) of 12 patients with arterial thrombosis; however, it was present in only 4 (23.5%) of 17 patients with venous thrombosis and in 14 (12.3%) of 114 patients without thrombosis. These findings suggest that a high aCL activity combined with LA positively reflects a high risk for both thrombocytopenia and arterial thrombosis.