The molecular mechanisms of post-adhesive transmigration of T cells.

Leukocyte extravasation is an essential phenomenon in inflammatory responses of the body. However, less is known about the mechanisms of transendothelial migration of leukocytes subsequent to their adhesion to the endothelium. It could be considered that at least three different cellular responses participate in the transmigration of adherent leukocytes: 1) polarization of adherent cells in cell shape, 2) interactions between adherent cells and molecules bound to the endothelial surface to stimulate migration through the junction between adjacent endothelial cells, and 3) co-ordination with endothelial cells to open the junction. Molecules involved in these events are discussed in this review.

Subarachnoid hemorrhage and systemic lupus erythematosus.

The frequency, clinical profile, treatment and outcome of subarachnoid hemorrhage (SAH) in patients with systemic lupus erythematosus (SLE) were assessed retrospectively, based on the case records of SLE of the Jichi Medical School Hospital over a 20 year period. Clinically defined SAH was found in 10 (3.9%) out of 258 SLE patients, which represented a frequency higher than previously assumed. Five patients had active SLE and lacked an apparent cause of SAH, other than SLE. A high mortality rate (5/5), no visible aneurysm on angiogram (3/4), and an onset during intractable SLE or after discontinued or no steroid therapy because of medical noncompliance (4/5) were characteristic of patients with active SLE, and thus an earlier successful suppression of SLE, if possible, might have prevented their SAH. In contrast, in the 5 patients with inactive SLE, 2 out of 3 saccular aneurysms were successfully clipped and small bleeding of one patient without aneurysms remitted spontaneously without the need for additional steroid therapy. When one death, which occurred outside of medical care, was excluded, the survival ratio of the hospitalized SAH patients with inactive SLE was significantly better than that with active SLE (3/4 versus 0/5, P=0.0476). In conclusion, the relatively common occurrence of SAH in SLE patients, and a significantly different clinical impact of SAH in respect to active and inactive SLE, were suggested from the results.

Nucleolin as the earliest target molecule of autoantibodies produced in MRL/lpr lupus-prone mice.

To elucidate the autoantigen against which autoantibodies are produced in the earliest phase of the disease process of systemic lupus erythematosus (SLE), serum samples were collected individually and serially from 10 NZB/NZW F1 and 10 MRL/lpr mice. Using immunoblots with mouse thymoma cell (EL-4) lysates as substrates, all mice were found to generate autoantibody against an either 150-kDa, 110-kDa, 75-kDa, or 55-kDa molecule in as early as 4 weeks. Anti-DNA antibodies occurred almost at the same time or after those against these four molecules. The number of antigens reactive with autoantibodies in immunoblots increased gradually with age. Antibodies against histone molecules were produced after 8 weeks of age. Among the four antigens, the 110-kDa molecule was identified as nucleolin, which is an abundant nucleolar phosphoprotein. Nucleolin binds DNA, RNA, and nucleic acid-binding proteins such as histone H1. Nucleolin is a target of granzyme A of cytotoxic T cells, and autoantibodies against it are found in sera from patients with SLE as well as from those with various viral infections. These results indicate that nucleolin is one of the immunodominant molecules that break down self-tolerance and initiate autoantibody-spreading in a mouse model of SLE.

In vitro and in vivo inhibition of activation induced T cell apoptosis by bucillamine.

OBJECTIVE: To investigate the mechanism of autoimmune phenomena, occasionally seen in patients with rheumatoid arthritis treated with bucillamine (BUC) and D-penicillamine (D-Pen), by evaluating their effects on apoptosis of T cells induced by T cell receptor activation or dexamethasone. METHODS: In vitro apoptosis was induced in a T cell hybridoma (SSP3.7) and a B cell line (WEHI 231) by activation of respective receptors or dexamethasone, in the presence or absence of BUC or D-Pen. In vivo apoptosis was induced in BALB/c mice by staphylococcal enterotoxin B (SEB), with or without BUC or D-Pen, and thymocytes were examined for it by FACS. RESULTS: Stimulation with anti-CD3 and dexamethasone induced apoptosis in 72% and 71% of SSP3.7 cells, respectively. However, only 16% of SSP3.7 cells became apoptotic by anti-CD3 when BUC was added to the culture media. By contrast, 80% of SSP3.7 cells became apoptotic when stimulated by dexamethasone, even in the presence of BUC. BUC did not affect apoptosis of WEHI 231 cells induced by anti-IgM. Although SA981 (a metabolite of BUC) inhibited apoptosis of SSP3.7 cells induced by anti-CD3, D-Pen did not. BUC, SA981, or D-Pen did not significantly influence the level of interleukin 2 secretion stimulated by anti-CD3. In contrast, both BUC and D-Pen inhibited apoptosis of Vbeta8+ thymocytes induced in vivo by SEB superantigen. Neither BUC nor D-Pen significantly changed the number of CD4+CD8+ thymocytes in BALB/c mice injected with dexamethasone. CONCLUSION: BUC decreased, while D-Pen did not, the apoptosis of T cells stimulated by anti-CD3 in vitro, although they both inhibited the deletion of immature thymocytes reactive with SEB in vivo. This may explain autoimmune phenomena sometimes seen during the treatment of rheumatic patients with these drugs.

[Three patients with systemic sclerosis complicated by microangiopathic hemolytic anemia and thrombocytopenia].

Clinical profiles and the treatment process of three female patients with systemic sclerosis (cases 1, 2, and 3) complicated by thrombotic microangiopathic hemolytic anemia (TMHA) were described. Thrombocytopenia preceded renal damage and hypertension in cases 1 and 2, although the chronological relationship between these parameters were unknown in case 3. Plasma exchange therapy using fresh frozen plasma was beneficial in cases 1 and 2. Cases land 3 presented with delirium and fluctuating psychosis, respectively. Early detection of thrombocytopenia and insidious hemolysis might be essential for starting effective plasmapheresis treatment in a part of patients with scleroderma kidney who present with thrombotic thrombocytopenic purpura (TTP) like disorder.

Dermatomyositis and cutaneous necrosis: report of five cases.

Abstract We report on five patients with dermatomyositis (DM) and cutaneous necrosis. Patients presented with classic DM skin eruptions, mild myositis, and a high incidence (4/5) of interstitial pneumonia. Cutaneous necrosis developed independently of steroid therapy, with the majority of lesions being cured following several months of sterilization treatment. In addition, one patient with accompanying cancer presented with multiple necrotic lesions. Topical treatment using gentiana violet against local infection was considered to have been essential in accelerating healing.

Probing the substrate specificity of the intracellular brain platelet-activating factor acetylhydrolase.

Platelet-activating factor acetylhydrolases (PAF-AHs) are unique PLA2s which hydrolyze the sn-2 ester linkage in PAF-like phospholipids with a marked preference for very short acyl chains, typically acetyl. The recent solution of the crystal structure of the alpha(1) catalytic subunit of isoform Ib of bovine brain intracellular PAF-AH at 1.7 A resolution paved the way for a detailed examination of the molecular basis of substrate specificity in this enzyme. The crystal structure suggests that the side chains of Thr103, Leu48 and Leu194 are involved in substrate recognition. Three single site mutants (L48A, T103S and L194A) were overexpressed and their structures were solved to 2.3 A resolution or better by X-ray diffraction methods. Enzyme kinetics showed that, compared with wild-type protein, all three mutants have higher relative activity against phospholipids with sn-2 acyl chains longer than an acetyl. However, for each of the mutants we observed an unexpected and substantial reduction in the V(max) of the reaction. These results are consistent with the model in which residues Leu48, Thr103 and Leu194 indeed contribute to substrate specificity and in addition suggest that the integrity of the specificity pocket is critical for the expression of full catalytic function, thus conferring very high substrate selectivity on the enzyme.

Circulating myeloperoxidase and anti-myeloperoxidase antibody in patients with vasculitis.

To evaluate a role of myeloperoxidase (MPO) and antibody to myeloperoxidase (anti-MPO) in vasculitis, MPO and anti-MPO were determined by enzyme-linked immunosorbent assays in sera from 43 patients with vasculitis, 40 with rheumatoid arthritis, 36 with systemic lupus erythematosus (SLE), 23 with mixed connective tissue disease, 13 with systemic sclerosis, 22 with polymyositis/dermatomyositis, 18 with Sjögren's syndrome, and 30 normal controls. Kidney and lung sections from patients with vasculitis were stained for MPO. Anti-MPO titers were significantly higher (p<0.005) in the patients with vasculitis (mean+/- SD absorbance at 405 nm: 0.53 +/- 0.37) than in any other groups (0.15 +/- 0.04 to approximately 0.21 +/- 0.11). MPO levels in patients with vasculitis were comparable with those in patients with other diseases except SLE. In two patients with vasculitis, anti-MPO decreased sharply with simultaneous increases in MPO 1-2 weeks after they developed pulmonary hemorrhage. Numerous cells positive for MPO infiltrated the Bowman's spaces. These results indicate that MPO may contribute to the pathogenesis of vasculitis and a sudden fall in anti-MPO may predict a poor prognosis in some cases.

Characterization of the 4C8 antigen involved in transendothelial migration of CD26(hi) T cells after tight adhesion to human umbilical vein endothelial cell monolayers.

In extravasation of T cells, little is known about the mechanisms of transendothelial migration subsequent to the T cells' tight adhesion to endothelium. To investigate these mechanisms, we developed a monoclonal antibody (mAb), termed anti-4C8, that blocks transmigration but not adhesion in a culture system in which high CD26-expressing (CD26(hi)) T cells preferentially migrate through human umbilical vein endothelial cell (HUVEC) monolayers cultured on collagen gels. Anti-4C8 reacted with all CD3(+) T cells and monocytes but not neutrophils or HUVECs. The structure defined by this antibody was an 80-kD molecule. The mAb at 1 mug/ml inhibited 80-90% of migration of CD3(+) T cells through unstimulated and interferon gamma-stimulated HUVEC monolayers without interfering with adhesion and cell motility. When added to the cultures after the adhesion, anti-4C8 completely blocked subsequent transmigration of adherent T cells. Phase-contrast and electron microscopy revealed that T cells are arrested at the intercellular junctions of HUVECs in the presence of anti-4C8. Anti-4C8 exhibited agonistic effects on resting T cells without other stimuli under culture conditions in which anti-4C8 can stimulate T cells. First, in the checkerboard assay using collagen gels, the antibody promoted chemokinetic migration of the cells in a dose-dependent manner from 0.1 to 10 mug/ml. The predominant population of T cells that migrated into collagen gels with impregnated anti-4C8 were CD26(hi). Second, solid-phase-immobilized anti-4C8 induced adhesion of T cells to the substrate, often with polarizations in cell shape and large pseudopods rich in filamentous (F-) actin. Third, soluble anti-4C8 augmented F-actin content preferentially in CD26(hi) T cells when added to T cells at a high dose of 10 mug/ml. Finally, both anti-4C8-induced chemokinetic migration and transendothelial migration were inhibited by pretreatment of T cells with pertussis toxin. These findings suggest that stimulation via the 4C8 antigen increases cell motility of CD26(hi) cells with profound cytoskeletal changes through signaling pathways including G proteins. The 4C8 antigen may be involved in preferential transmigration of CD26(hi) cells adherent to HUVECs.

UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6N-acetylglucosaminyltransferase holds a key role on the control of CD15s expression in human pre-B lymphoid cell lines.

Expression mechanism of CD15s (sialyl-Lex, sLex) antigen has been investigated using human B lymphoid cell lines. sLexstructures were not expressed in mature B lymphoids but highly expressed in pre-B leukemia and pre-B lymphoma cell lines. The expression site was mainly on the O -linked oligosaccharide chains and E-selectin mediated-cell adhesion capability of sLex-positive cells were significantly suppressed by benzyl-alpha-GalNAc treatment. Subsequently, the bases of the sLexexpression control mechanism were examined at the levels of enzymatic activities and transcripts of glycosyltransferases. (1) The activities of alpha1-->3fucosyltransferase, alpha2-->3sialyltransferase, beta1-->4Gal-transferase, and elongation beta1-->3GlcNAc-transferase, did not correlate with sLexexpression levels. (2) The transcripts of Fuc-TVII were not parallel with sLexexpression, and those of ST3Gal IV and beta1-->4Gal-transferase were constitutively detected in all cell lines tested. (3) There was no detectable enzyme activity for core 3 and 4 backbone structure synthesis in human B cell lines. (4) By contrast, the enzyme activities and transcripts of UDP-GlcNAc:Galbeta1-->3GalNAc (GlcNAc to GalNAc) beta1-->6 N -acetylglucosaminyltransferase (Core2GnT) had significant correlation with the cell surface expression of sLexantigen. (5) Moreover, Western blot analysis revealed the presence of a major approximately 150 kDa glycoprotein that carries O -linked oligosaccharides recognized by anti-sLexmonoclonal antibody in sLex-positive pre-B leukemia cell lines. This correlation of Core2GnT with CD15s expression suggests that Core2GnT is a regulator of the cell surface expression of sLexin human pre-B lymphoid cells.

Acute acalculous cholecystitis in systemic lupus erythematosus: a case report and review of the literature.

A 27-year-old woman with systemic lupus erythematosus (SLE) was found to have acute acalculous cholecystitis. At the time of admission, the patient was not under corticosteroid or immunosuppressive therapy. Computed tomography (CT) and ultrasonography revealed findings in the gall bladder consistent with acute acalculous cholecystitis. Her abdominal pain completely disappeared following corticosteroid therapy, with dramatic improvement in the images of CT and ultrasonography. Six similar cases of SLE complicated with acute acalculous cholecystitis have been reported in the literature and they were all treated surgically by cholecystectomy or cholecystostomy. This is the first case report in which acute acalculous cholecystitis accompanying SLE was treated successfully by corticosteroid without surgical intervention.

A close temporal relationship of liver disease to antiribosomal P0 protein antibodies and central nervous system disease in patients with systemic lupus erythematosus.

OBJECTIVE: To determine whether there is a close temporal relationship of liver disease to serum IgG and/or IgM antiribosomal P0 protein antibodies (anti-P0) and central nervous system (CNS) lupus in patients with systemic lupus erythematosus (SLE). METHODS: The study included 70 patients with active SLE. Of these, 30 had IgG and/or IgM anti-P0 and 14 had CNS lupus other than psychiatric disease (nonpsychiatric CNS lupus). Of these 14 patients, 11 had anti-P0. Laboratory manifestations of liver disease were retrospectively analyzed. RESULTS: Liver disease not attributed to any cause other than SLE (SLE liver disease) was present in 8 of the 11 patients with anti-P0 with nonpsychiatric CNS lupus (72.7%), in none of the 19 patients with anti-P0 without nonpsychiatric CNS lupus (0%), and in one of the 40 patients without anti-P0 (2.5%). The prevalence of SLE liver disease was significantly greater in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups (p < 0.0001). Mean levels of liver enzymes (lactate dehydrogenase, glutamic oxaloacetic transaminase, glutamate pyruvate transaminase, gammaglutamyl transpeptidase) were significantly higher in patients with anti-P0 with nonpsychiatric CNS lupus than in the other 2 groups. Serial studies in 3 patients showed that the appearance of anti-P0 and liver dysfunction slightly preceded the onset of nonpsychiatric CNS lupus. CONCLUSION: Anti-P0 may be related to the pathogenesis of CNS lupus and SLE liver disease found simultaneously in SLE. The appearance of anti-P0 and liver dysfunction may predict onset of CNS lupus.

Human monocyte-endothelial cell interaction induces platelet-derived growth factor expression.

OBJECTIVE: The purpose of this study was to investigate whether the synthesis of platelet-derived growth factor (PDGF), a major mitogen and chemoattractant for vascular smooth muscle cells, was induced by the direct cell-to-cell interaction between human monocytes and umbilical vein endothelial cells (ECs). METHODS: PDGF protein and mRNA expression were determined by cellular ELISA, immunohistochemical and Northern blot analyses. RESULTS: Coculture of monocytes and ECs secreted a large amount of PDGF into the supernatant, whereas culture of ECs or monocytes alone induced low levels of PDGF production. In Northern blot analysis, substantial amounts of PDGF-A and -B mRNA were induced by coculture of monocytes with ECs. Immunohistochemistry revealed that PDGF-B chain protein was detectable in both ECs and monocytes. PDGF production by ECs induced by conditioned medium of the coculture was significantly inhibited by Abs against interleukin-1 beta (IL-1 beta) and tumor necrosis factor- alpha (TNF alpha). CONCLUSIONS: These results indicate that the direct cell-to-cell interaction between human monocytes and ECs induces PDGF synthesis in both types of cells, suggesting that PDGF produced locally by monocyte-EC adhesive interaction plays an important role in the pathogenesis of atherosclerosis by promoting the migration and accumulation of vascular smooth muscle cells.

Detection of large macrophage colony forming cells in the peripheral blood of patients with rheumatoid arthritis.

OBJECTIVE: To test for the presence of colony forming cells, that form large macrophage colonies (> 2.5 mm in diameter, > 10,000 cells), in the peripheral blood of patients with rheumatoid arthritis (RA) and to determine its association with the clinical and laboratory features of RA. METHODS: Peripheral blood mononuclear cells (PBMC) from 96 patients with RA and 20 healthy controls were assayed for in vitro colony formation. In addition, PBMC from 38 patients with other rheumatic diseases including systemic lupus erythematosus (SLE), progressive systemic sclerosis (SSc), and polymyositis/dermatomyositis (PM/DM); 23 patients with infectious inflammatory diseases were also assayed. RESULTS: Large macrophage colony forming cells were detected in the peripheral blood of 19% of patients with RA (18/96), but not in that of healthy controls. In addition, these cells were detected in the peripheral blood of 11 of the 38 patients with other rheumatic disease (7/13 SSc and 4/11 PM/DM), but not in the 23 patients with infectious diseases. In the patients with RA, interstitial lung disease was significantly more frequently observed among patients in whom colony forming cells were found than among those in whom they were not found (p < 0.001). CONCLUSION: Based on the size of the colonies they formed, the macrophage colony forming cells detected in patients with RA probably corresponded to primitive hematopoietic progenitor cells, defined as high proliferative potential colony forming cells (HPP-CFC). Our observations provide preliminary evidence of the appearance of HPP-CFC in the circulation during inflammation of RA, and during that in other rheumatic diseases such as SSc and PM/DM, and of the association of HPP-CFC with interstitial lung disease in patients with RA.

Association of interleukin 6 release from endothelial cells and pulmonary hypertension in SLE.

OBJECTIVE: To investigate how sera from 37 patients with systemic lupus erythematosus (SLE) stimulate interleukin (IL) 6 release from IL-1beta pretreated endothelial cells and compare these effects to those of sera from 16 normal controls. METHODS: Endothelial cells pretreated 18 h with IL-1beta (5 U/ml) were incubated 2 h with sera diluted 10-fold with phosphate buffered saline (PBS). IL-6 concentrations in endothelial culture supernatants collected after incubation were measured by ELISA. RESULTS: Compared with PBS, sera from controls and 24 patients with SLE suppressed IL-6 release from IL-1beta pretreated cells. However, sera from 13 patients with SLE augmented IL-6 release. Of note, sera from 5 patients with pulmonary hypertension induced the highest level of IL-6 release. IgG from control sera suppressed IL-6 release, whereas F(ab')2 did not. Both IgG and F(ab')2 from the sera of patients with SLE with pulmonary hypertension augmented IL-6 release from IL-1beta pretreated cells. CONCLUSION: IgG antiendothelial cell antibodies from patients with SLE may be associated with the pathogenesis of SLE and pulmonary hypertension.