Easy discrimination of hematogones from lymphoblasts in B-cell progenitor acute lymphoblastic leukemia patients using CD81/CD58 expression ratio.

INTRODUCTION: The discrimination of leukemia lymphoblasts (LB) in diagnosis and follow-up of B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) by multiparameter flow cytometry (MFC) may be difficult due to the presence of hematogones (HG). The aim of this study was to compare lymphoblasts of BCP-ALL and HG for the expression of the most discriminating antigens. METHODS: A total of 82 bone marrow samples (39 BCP-ALL and 43 patients with HG) were analyzed using MFC. Mean fluorescence intensity (MFI) was measured for ten markers commonly used in hematology laboratories: CD45, CD19, CD10, CD34, CD38, CD20, CD22, CD58, CD81, and CD123. Statistical comparison of the MFI between LB and HG was performed. The presence on LB of aberrant expression of myeloid and/or T-cell markers was also investigated. RESULTS: Qualitative pattern expression of antigens showed overexpression on LB of CD58, CD22, CD34, CD10 and underexpression of CD81, CD45, CD38 when compared to HG. Expression of CD123 was positive in 34% of BCP-ALL LB and always absent on HG. Aberrant antigen expression (myeloid and/or T-cell marker) including CD123 was observed in 58% of BCP-ALL patients. The use of a MFI antigen ratio of the most discriminating markers (CD81/CD58) (analysis of variance, P < 0.005) increased the distinction of LB versus HG with a high specificity and sensitivity as demonstrated by the use of ROC curve analysis (AUC of CD81/CD58: 0.995). CONCLUSION: We demonstrate in this study that routine use of the MFI antigen ratio (CD81/CD58) in addition to the MFC evaluation using WHO classical criteria appears to be an efficient approach to discriminate LB from HG.

Role of CD81 and CD58 in minimal residual disease detection in pediatric B lymphoblastic leukemia.

INTRODUCTION: Minimal residual disease (MRD) in B lymphoblastic leukemia has been demonstrated to be a powerful predictor of clinical outcome in numerous studies in both children and adults. In this study, we evaluated 86 pediatric patients with both diagnostic and remission flow cytometry studies and compared expression of CD81, CD58, CD19, CD34, CD20, and CD38 in the detection of MRD. METHODS: We evaluated 86 patients with B lymphoblastic leukemia who had both diagnostic studies and remission studies for the presence of MRD using multicolor flow cytometry. We established our detection limit for identifying abnormal lymphoblasts using serial dilutions. We also compared flow cytometry findings with molecular MRD detection in a subset of patients. RESULTS: We found that we can resolve differences between hematogones and lymphoblasts in 85 of 86 cases using a combination of CD45, CD19, CD34, CD10, CD20, CD38, CD58, and CD81. Our detection limit using flow cytometry is 0.002% for detecting a population of abnormal B lymphoblasts. Comparison with MRD assessment by molecular methods showed a high concordance rate with flow cytometry findings. CONCLUSIONS: Our study highlights importance of using multiple markers to detect MRD in B lymphoblastic leukemia. Our findings indicate that including both CD58 and CD81 markers in addition to CD19, CD34, CD20, CD38, and CD10 are helpful in MRD detection by flow cytometry.

[THE LEVEL OF EXPRESSION OF MOLECULES OF ADHESION ON LYMPHOCYTES DEPENDING ON AMOUNT OF THEIR CYTOPLASM].

The lymphocytes are true immunocytes specialized in discerning antigen in organism. Their behavior in blood is regulated by several classes of adhesion proteins, including selectin, integrin, immunoglobulin. In healthy humans there is no data concerning level of expression of adhesion molecules on lymphocytes depending on size of their cytoplasm. The study was carried out to determine level of expression of adhesion molecules of lymphocytes depending on size of their cytoplasm. The flow cytometer was applied to determine in venous blood level of expression of adhesion molecules in 50 individuals (22 males and 28 females) aged from 20 to 60 years and having no chronic pathology in anamnesis. The analysis of lymphocytogram permitted to differentiate lymphocytes according volume of cell considering size of cytoplasm: small lymphocytes- up to 8 mkm; medium - from 8 to 12 mkm; large - more than 12 mkm. In males a tendency was established concerning decreasing of concentration of lymphocytes with expressed molecule of L-selectin. The absence was detected concerning gender differences in level of lymphocytes with receptor LFA-1 and also lymphocytes with molecule ICAM-1. In males concentration of lymphocytes with receptor LFA-3 was higher than in females but only as a tendency. The lower level of expression of molecule PECAM-1 in males was observed. The correlation analysis between level of expresion of adhesion molecules and concentration of lymphocytes differing in size of cytoplasm, demonstrated that at increasing of size of cytoplasm of lymphocytes increases number of statistically reliable correlations. The shedding of molecules of L-selectin in lymphocytes proceeds significantly more active than in monocytes. At that, medium plasma lymphocytes and large granular lymphocytes identified as natural killers are more predisposed to migration. However, lymphocytes entering condition of lympho-proliferation have less ability to adhesion.

Erythroid Adhesion Molecules in Sickle Cell Anaemia Infants: Insights Into Early Pathophysiology.

Sickle cell anaemia (SCA) results from a single mutation in the ß globin gene. It is seldom symptomatic in the first semester of life. We analysed the expression pattern of 9 adhesion molecules on red blood cells, in a cohort of 54 SCA and 17 non-SCA very young infants of comparable age (median 144 days, 81-196). Haemoglobin F (HbF) level was unsurprisingly elevated in SCA infants (41.2% ± 11.2) and 2-4 fold higher than in non-SCA infants, yet SCA infants presented significantly decreased Hb level and increased reticulocytosis. Cytometry analysis evidenced a specific expression profile on reticulocytes of SCA infants, with notably an increased expression of the adhesion molecules Lu/BCAM, ICAM-4 and LFA-3, both in percentage of positive cells and in surface density. No significant difference was found on mature red cells. Our findings demonstrate the very early onset of reticulocyte membrane modifications in SCA asymptomatic infants and allow an insight into the first pathological changes with the release of stress reticulocytes expressing a distinctive profile of adhesion molecules.

[The expression level of adhesion molecules on neutrophils depending at segmentation of their nuclei].

The article deals with results of detection of expression level of adhesion molecules on neutrophils and segmentation of their nuclei. It is established that in conditions of absence of antigen stimulation neutrophils of circulating pool express molecules of L-selectin in 53.34%, LFA-1 molecules in 65.64%, ICAM-1 in 40.51%, LE4-3 in 58.72% and PECAM-1 in 59.74%. The full readiness to realization of phase of sliding, strong adhesion and immediately transmigration itselfis detected in neutrophils with five segments in nucleus.

Membrane compartmentalization in Southeast Asian ovalocytosis red blood cells.

Red blood cells (RBCs) from individuals with Southeast Asian ovalocytosis (SAO) contain a mutant band 3 protein that causes the formation of unique linear oligomers in the RBC membrane. We used single-particle tracking to measure the lateral diffusion of individual glycophorin C (GPC), band 3, and CD58 proteins in membranes of intact SAO RBCs and normal RBCs (nRBCs). GPC, an integral protein that binds with high affinity to the RBC membrane skeleton, showed oscillatory motion within confinement areas that were smaller in SAO RBCs than in nRBCs. The additional confinement in SAO RBCs could be due to membrane stiffening associated with the SAO phenotype. Band 3 in both SAO RBCs and nRBCs also showed confined motion over short times (ms) and distances (nm), and the area of confinement was smaller in SAO RBCs than in nRBCs. These data presumably reflect the constraints imposed by band 3 oligomerization. Similarly, the glycosylphosphatidylinositol-linked protein CD58 showed loosely confined diffusion in nRBCs and a substantially higher degree of confinement in SAO RBCs. Restricted protein mobility could contribute to the altered adherence of parasite-infected RBCs to vascular endothelium that is thought to protect individuals with SAO from severe manifestations of malaria.

The detection of sLFA-3 in plasma of patients with hemorrhagic fever with renal syndrome.

Hemorrhagic fever with renal syndrome (HFRS) is an acute viral disease characterized by endothelial dysfunction. The cellular immune response, especially the virus-specific CD8+ T lymphocytes, is known to attack vascular endothelial cells (VEC) and to contribute to the diffuse damage and penetrability increasing of VEC. Lymphocyte function associated antigen 3 (LFA-3) is expressed on T lymphocytes and VEC, which is contributed to the activation of T lymphocytes. The expression of LFA-3 on the activated T lymphocytes and VEC is highly increased, which can exfoliate into plasma to increase the level of soluble LFA-3 (sLFA-3) in plasma. So the change of sLFA-3 levels is correlated with the activation of T lymphocytes. In this study we detected the levels of sLFA-3 in plasma of patients with HFRS. We examined the levels of sLFA-3 in plasma samples collected from 53 HFRS patients by double antibody sandwich ELISA. We found variable, but persistently elevated levels of sLFA-3 throughout the various phases and types of the HFRS disease, which suggest that sLFA-3 levels have correlation with disease stages. Moreover, elevated sLFA-3 levels are closely correlated to the severity of HFRS and the degree of kidney damage.

Normal patterns of expression of glycosylphosphatidylinositol-anchored proteins on different subsets of peripheral blood cells: a frame of reference for the diagnosis of paroxysmal nocturnal hemoglobinuria.

BACKGROUND: Evaluation of the expression of glycosylphosphatidylinositol-anchored membrane proteins (GPI-AP) is currently used for the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). In this study, we analyzed the amount of expression of a wide variety of GPI-AP in different subsets of hematopoietic cells present in normal peripheral blood (PB), to establish their normal patterns of expression and provide a frame of reference for the definition of the best combination of GPI-AP and PB cell subsets to be applied in the diagnosis and monitoring of PNH. RESULTS: Our results show variable patterns of expression of different GPI-AP in distinct subsets of normal PB cells. Combined use of CD55 and CD59 represented the most useful dual-marker combination; however, its utility remained suboptimal for several subsets of leukocytes and for platelets. CONCLUSIONS: For some cell subsets such as the neutrophils additional useful markers could be selected from a relatively broad panel (CD16/CD24/CD55/CD59/CD66b/CD157), whereas for other cell subsets the number of useful antigens was either restricted (monocytes: CD14/CD55/CD157; B cells: CD24/CD48/CD52/CD55; CD4+ T cells: CD48/CD52/CD55; eosinophils: CD55/CD59; CD8+ T cells: CD48/CD55) or limited to a single marker (CD48 on CD56low NK cells, CD55 on BDCA3- dendritic cells and CD56high NK cells, and CD59 for red cells), from all antigens analyzed.

Monocyte and neutrophil adhesion molecule expression during acute hyperglycemia and after antioxidant treatment in type 2 diabetes and control patients.

OBJECTIVE: We hypothesized that acute hyperglycemia (an independent cardiovascular risk factor) increases the expression of proatherogenic leukocyte adhesion molecule in type 2 diabetes and controls and that the expression of these adhesion molecules would be antioxidant sensitive. METHODS AND RESULTS: Twenty-three type 2 diabetes patients and 13 control patients underwent two oral glucose tolerance tests 14 days apart and took placebo or 800 IU daily of oral alpha tocopherol between tests. Monocyte and neutrophil expression of adhesion molecules Mac-1, LFA-1 and 3, ICAM-1, and VLA-4 were measured at 0, 120, and 240 minutes by using laser flow cytometry. Baseline adhesion molecule expression did not differ between groups, but there was a rapid, highly significant increase (P<0.0001) in the intensity of monocyte Mac-1 expression after a glucose load in both groups. Alpha-tocopherol supplementation reduced only Mac-1 expression in the diabetes group (P=0.03). CONCLUSIONS: Acute glycemic excursions of any degree cause highly significant, rapid increases in monocyte Mac-1 expression in type 2 diabetes patients and controls. Mac-1 mediates leukocyte vascular infiltration and is prothrombotic. These data suggest a mechanism for the link between glycemic excursions and increased vascular event rates.

Titin and ryanodine receptor epitopes are expressed in cortical thymoma along with costimulatory molecules.

Cortical-type thymomas are associated with myasthenia gravis (MG) in 50% of the cases. MG is caused by antibodies against the acetylcholine receptors (AChR), but additional non-AChR muscle autoantibodies such as those against titin and ryanodine receptor (RyR) are found in up to 95% of MG patients with thymoma. To elucidate the induction of non-AChR autoantibodies in thymoma-associated MG, we studied cortical-type thymomas from seven thymoma MG patients, and sera from six of them. All six had titin antibodies, and four had RyR antibodies. Titin and RyR epitopes were co-expressed along with LFA3 and B7 (BB1) costimulatory molecules on thymoma antigen-presenting cells (APC) in all thymomas. In normal thymus, the staining by anti-titin, anti-RyR, anti-LFA3, and anti-BB1 antibodies was weak and occurred exclusively in the medulla and perivascularly. Our results indicate a primary autosensitization against titin and RyR antigens inside the thymoma. In MG-associated thymoma, the mechanisms involved in the initial autosensitization against titin and RyR are probably similar to those implicated in the autosensitization against AChR. In all cases, there is an overexpression of muscle-like epitopes and costimulatory molecules indicating that the T-cell autoimmunization is actively promoted by the pathogenic microenvironment inside the thymoma.

n-3 polyunsaturated fatty acid supplementation, monocyte adhesion molecule expression and pro-inflammatory mediators in Type 2 diabetes mellitus.

AIMS: To examine the effect of n-3 polyunsaturated fatty acid supplements on the monocyte surface expression of adhesion molecules involved in proatherogenic monocyte-endothelial interactions, and on pro-inflammatory mediators in Type 2 diabetes mellitus. METHODS: Twenty-nine subjects with Type 2 diabetes and 21 controls without diabetes were studied. Monocyte expression of leucocyte function-associated antigens 1 and 3, intercellular adhesion molecule-1, and the major histocompatibility complex class II molecule HLA-DR were measured using a laser flow cytometric method. Supplementation with 2.08 g n-3 fatty acids for 21 days was undertaken and measurements repeated. Plasma soluble adhesion molecule concentrations, plasminogen activator inhibitor-1 activity and antigen and pro-inflammatory mediators (cysteinyl leukotriene and monocyte leukotriene B4) were also measured. RESULTS: Groups did not differ in monocyte expression of adhesion molecules or HLA-DR, or in leukotriene production although plasma soluble adhesion molecule concentrations were higher in the diabetes groups (P<0.05). n-3 fatty acid supplementation influenced neither the expression of these molecules nor plasma soluble adhesion molecule concentrations or leukotriene production. CONCLUSIONS: This study does not support increased monocyte adhesion molecule expression or abnormal monocyte production of pro-inflammatory mediators as mechanisms for increased atherogenic risk in Type 2 diabetes. Cardioprotective actions of n-3 fatty acids may not be mediated through these mechanisms.

Localized adhesion molecule expression and circulating LFA-3 levels in adult and early onset forms of periodontitis.

Because of their importance in mediating cellular interactions in chronic inflammatory diseases, this study has examined the expression of a number of adhesion molecules in adult (n=11), generalized early onset (n=5) and localized early onset (n=2) forms of periodontitis. In comparison with immunostaining profiles of cryostat sections of healthy gingival tissue (n=7), the beta 1 integrins VLA-1, VLA-2 and VLA-4 were found to be up-regulated in periodontitis, with VLA-6 being markedly elevated. Although only small differences were observed in ICAM-1 and LFA-3 expression in the gingival epithelium, there was particularly notable up-regulation of these adhesion molecules within the inflammatory infiltrates of the diseased tissues. However, there were no statistically significant differences between the serum levels of a soluble form of LFA-3 in periodontitis patients (n=47) compared with healthy control subjects (n=40), although the generalized early onset and adult periodontitis groups exhibited wider ranges of circulating LFA-3. These findings show that there is localized modulation of adhesion molecule expression in the chronic inflammatory periodontal diseases studied, but that the levels of LFA-3 in the circulation nevertheless remain unaffected.

Serum levels of leukocyte functional antigen-3 in pregnancy and preeclampsia.

BACKGROUND: Adhesion molecules have been demonstrated to be involved in placental growth and development in normal pregnancy. Experimental evidence indicates that adhesion molecules are key factors of endothelial activation in preeclampsia. The aim of our study was to evaluate serum levels of the adhesion molecule Leukocyte Functional Antigen (LFA)-3 in healthy, non pregnant, female controls, healthy pregnant women, and preeclamptic women. METHODS: In our study we included 45 healthy, non pregnant, female controls, 45 healthy pregnant women, and 45 preeclamptic women. An enzyme-linked immunosorbent assay was used to determine serum levels of LFA-3. Results were correlated to clinical data. RESULTS: The median LFA-3 serum level in healthy, non pregnant, female controls was 0.2 (range 0 to 8.6) ng/mL. LFA-3 serum levels in healthy pregnant women were 4.8 (range 0 to 18) ng/mL and were significantly elevated compared to healthy, non pregnant, female controls (Mann-Whitney U-test, p=0.004). A cut-off level of 4.8 ng/mL was selected according to the 75th quantile of serum levels measured in the panel of healthy, non pregnant, female controls. In preeclamptic women, whose pregnancies had to be terminated due to exacerbation of preeclamptic symptoms, LFA-3 serum levels above the cut-off level were seen in 14/27 (52%) cases. In contrast, preeclamptic women, who went into spontaneous labor showed elevated LFA-3 serum levels in 17/18 (95%) cases (chi-square test, p=0.002). LFA-3 serum levels revealed a statistically significant influence on the odds of termination of pregnancy due to exacerbation of preeclamptic symptoms (unconditional logistic regression, p=0.02) with an odds ratio of 0.1 (95% CI, 0.006 to 0.7) by every doubling of LFA-3 values. CONCLUSIONS: Our results suggest that LFA-3 expression is upregulated in healthy pregnant women compared to healthy, non pregnant, female controls. Failure of LFA-3 upregulation in preeclampsia is associated with an increased risk for termination of pregnancy due to exacerbation of preeclamptic symptoms.

Immunohistochemical and serological comparison of idiopathic and hepatitis C virus-associated forms of oral lichen planus.

The oral form of the inflammatory disease lichen planus occurs spontaneously due to unknown aetiological factors. However, it has recently been observed to occur with increased frequency in patients infected with the hepatitis C virus. Because of the prominent role of adhesion molecules in immune cell interactions, we have compared the expression of these antigens in the hepatitis C virus-associated and idiopathic forms of the disease. The results show similar patterns of expression of very late activation antigen-4, lymphocyte function-associated antigen-3 and intercellular adhesion molecule-1, but relatively elevated levels of these antigens in oral lichen planus patients with no hepatitis C virus infection. In addition to differences in Langerhans cell distribution, serum levels of "soluble" intercellular adhesion molecule-1 as well as immunoglobulin G were significantly increased in the hepatitis C virus-associated group. These findings show that there are some differences in the lesional and systemic immune reactivities of the two types of oral lichen planus which may be related to possibly distinct pathogenic mechanisms.

Investigation of the survival of paroxysmal nocturnal hemoglobinuria red cells through the immunophenotyping of reticulocytes.

BACKGROUND: Complement-mediated lysis of red cells (RBCs) is a classic feature of paroxysmal nocturnal hemoglobinuria (PNH) that is traditionally studied with a combination of radiolabeling of RBCs and in vitro hemolysis tests. Phenotyping of reticulocytes was used as an alternative method for the evaluation of the relative life span of normal RBCs (PNH I) and RBCs that were partially (PNH II) or completely (PNH III) deficient in CD59. STUDY DESIGN AND METHODS: Murine monoclonal antibodies CD55, CD58, and CD59 and thiazole orange were used to phenotype reticulocytes by two-color flow cytometry in nine PNH patients. RBC survival could be calculated from the ratio of CD59- or CD59low mature RBCs to CD59- or CD59low reticulocytes obtained from these patients who had not received a transfusion. RESULTS: The life span of PNH III RBCs varied from about 17 to 60 days. PNH II reticulocytes were found in the four patients with PNH II RBCs. The life span of PNH II RBCs varied with their residual expression of CD59, and cells with 15 to 20 percent of the normal amount of CD59 were protected against in vivo hemolysis. CONCLUSION: Phenotyping of reticulocytes is a convenient and reliable tool for evaluating the relative survival of normal and PNH RBCs. PNH II and PNH III reticulocytes are phenotypically distinct, and some PNH II RBCs may be sensitive to complement-mediated lysis in vitro, but normally they are complement-resistant in vivo.

Circulating ICAM-1 (sCD54) and LFA-3 (sCD58) in chronic hepatitis B--a longitudinal study in patients treated with interferon-alpha.

The intercellular adhesion molecule 1 (ICAM-1, CD54) and the lymphocyte associated antigen 3 (LFA-3, CD58) have been found in soluble form (sCD54 and sCD58) in human sera. Data concerning their role in chronic liver disease and their usefulness in disease monitoring are contradictory. We addressed the question whether elevated sCD54/sCD58 correlated either with disease activity or with decreased elimination secondary to reduced liver function in chronic hepatitis B. We studied 31 patients with chronic hepatitis B undergoing interferon alpha therapy in a longitudinal fashion. Serum concentrations of sCD54 and sCD58 were measured at four weeks interval by specific Sandwich ELISA during a follow-up period of ten months. The maximal difference in concentration of each biochemical parameter, e.g., delta AST, delta gGt, delta bilirubin, was determined for each patient during the whole follow-up period. These differences were correlated with the variation in sCD54 (delta sCD54) and sCD58 (delta sCD58) at the respective time points. Using this method, we were able to eliminate interindividual differences in serum concentrations for sCD54 and sCD58 and to avoid bias due to preselection of patients. We found that delta sCD54 correlated with delta AST (p = 0.001) and delta ALT (p = 0.002), whereas there was no such correlation for delta sCD58. Interferon therapy did not affect sCD54 or sCD58 levels. Neither hepatitis B viremia nor the immune response to hepatitis B during the time of seroconversion to anti-HBe did significantly increase sCD54 or sCD58 levels. However, delta sCD54 was associated with delta gamma GT (p = 0.005) and delta sCD58 correlated with delta bilirubin (p = 0.037); a negative correlation was found for delta sCD54 with delta cholinesterase (p = 0.007). Our findings imply that sCD54 and sCD58 may be associated with a decrease in liver function that accompanies hepatic disease activity. sCD54 and sCD58 did not prove useful to monitor disease activity or response to interferon therapy in chronic hepatitis B. From our data we conclude, that decreased elimination of soluble adhesion molecules sCD54 and sCD58 in advanced liver disease may be responsible for increased serum concentrations detected.

Detection of a soluble form of the human adhesion receptor lymphocyte function-associated antigen-3 (LFA-3) in patients with chronic liver disease.

BACKGROUND/AIMS: Multiple immune functions, such as cytotoxic reactions, B cell differentiation, and monocyte activation, are mediated via the adhesion receptor/ligand pairs CD2/lymphocyte function-associated antigen(LFA)-3 and LFA-1/ intercellular adhesion molecule(ICAM)-1. Since soluble forms of LFA-3 (sLFA-3) and ICAM-1 (sICAM-1) can interfere with these functions, we asked whether increased levels of sLFA-3 can be found in patients with different forms of chronic liver disease and/or hepatocellular carcinoma. METHODS: sLFA-3 was measured in sera from 84 patients with chronic liver disease (39 with chronic viral liver disease, 30 with autoimmune liver disease, 12 with alcoholic cirrhosis, 3 with other causes of cirrhosis), 24 patients with hepatocellular carcinoma (15 with and 9 without cirrhosis), and 61 normal controls. From 36 of the patients with liver cirrhosis, arterial and hepatic venous serum samples were simultaneously obtained and tested for sLFA-3 and sICAM-1. RESULTS: In comparison to controls, sLFA-3 levels were elevated in patients with liver cirrhosis due to autoimmune liver disease (p < 0.0001) and viral liver disease (p = 0.001), but not in patients with alcoholic cirrhosis. Increased sLFA-3 levels were also found in patients with hepatocellular carcinoma and liver cirrhosis. However, sLFA-3 was not significantly elevated in sera from patients with autoimmune liver disease, viral liver disease, and hepatocellular carcinoma without concomitant liver cirrhosis. No difference was found between arterial and hepatic venous serum levels of sLFA-3 and sICAM-1. sLFA-3 levels correlated positively with aspartate transaminase, alkaline phosphatase, bilirubin, sICAM-1, and inversely with albumin and cholinesterase. CONCLUSIONS: Taken together, sLFA-3 serum concentrations of patients with liver cirrhosis due to autoimmune liver disease or viral liver disease and of patients with hepatocellular carcinoma and cirrhosis are significantly increased compared to controls. Elevated sLFA-3 and sICAM-1 levels might reflect the generalized inflammation in cirrhosis and by interference with cell-cell interactions sICAM-1 and sLFA-3 may limit the extent of inflammation.

Reduced serum levels of a soluble form of the human adhesion receptor CD58 (LFA-3) in patients with inflammatory bowel disease.

The activation of monocytes, neutrophils, and B cells by T-lymphocytes appears to play a pivotal role in the pathophysiology of inflammatory bowel disease. The pan T cell marker CD2 and its ligand CD58 mediate these immune function. We asked whether serum levels of a soluble form of CD58 is altered in patients with inflammatory bowel disease. Soluble CD58 was measured in sera from 41 patients with Crohn's disease, 19 patients with ulcerative colitis, and 24 normal controls. Soluble CD58 levels were significantly decreased in sera from patients with ulcerative colitis and even more with Crohn's disease when compared to controls (p = 0.025 and p < 0.0001, respectively). Reduction of soluble CD58 serum levels correlated significantly with various humoral (e.g. erythrocyte sedimentation rate: r = -0.48, p = 0.0002) and clinical parameters of disease activity (e.g. CDAI: r = -0.44, p = 0.005). In conclusion, serum levels of soluble CD58 are reduced in patients with inflammatory bowel disease. Since soluble CD58 can block the CD2/CD58 interaction further studies have to show whether the reduction of soluble CD58 in patients with inflammatory bowel disease contributes to T cell adhesiveness in the mucosa.

Short course single agent therapy with an LFA-3-IgG1 fusion protein prolongs primate cardiac allograft survival.

The interaction of T cell costimulatory molecules with their ligands is required for optimal T cell activation. Interference with such interactions can induce antigen unresponsiveness and delay xeno- and allograft rejection. We have previously shown that LFA3TIP, a soluble human lymphocyte function-associated antigen (LFA)-3 construct, binds CD2 and inhibits responses of human T cells in vitro. This study reports the first use of a human fusion protein, LFA3TIP, to significantly prolong primate cardiac allograft survival. Based on our observations that LFA3TIP inhibits baboon allogeneic mixed lymphocyte reactions, we gave baboon recipients of heterotopic cardiac allografts injections of LFA3TIP, 3 mg/kg i.v., for 12 consecutive days, starting 2 days before transplantation. This regimen delayed graft rejection from an average of 10.6 +/- 2.3 days for human IgG-treated controls (n = 5) to an average of 18.0 +/- 5.3 days for LFA3TIP-injected animals (n = 7; P < or = 0.01). Grafts from LFA3TIP-treated animals showed markedly diminished coronary endothelialitis as compared with control animals. LFA3TIP reached peak serum levels of approximately 100 micrograms/ml after 7-9 injections and persisted in the 10-micrograms/ml range for 1 to 2 weeks after the final injection. Despite these blood levels, circulating antibodies to LFA3TIP were not detected in the serum. No renal or hepatic toxicity was noted. The possible mechanism by which LFA3TIP acts to inhibit graft rejection is discussed; success in prolonging graft survival when LFA3TIP is used as a single-agent therapy suggests great potential for this novel therapeutic agent.