Changes in axial alignment of the ipsilateral hip and knee after total hip arthroplasty

AIMS

We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA).

PATIENTS AND METHODS

We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively.

RESULTS

The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R(2) : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R(2): 0.193, p < 0.001).

CONCLUSION

Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain.

TAKE HOME MESSAGE

Internal rotation of the hip at rest and lateral patellar tilt increase after THA.

Eight-year preservation of knee function with radiographic healing phenomena after anti-tumor necrosis factor-α therapy for a severely erosive knee in a young patient with rheumatoid arthritis

A 23-year-old woman developed rheumatoid arthritis (RA). The pain in her right knee was aggravated and anti-tumor necrosis factor (TNF)-α therapy was selected at the age of 35. The range of motion and Larsen grade were 5º to 120º and 4, respectively. Infliximab and etanercept therapies were quite effective and the pain of the right knee improved. An X-ray at 1 year showed radiographic healing phenomena that included reappearance of a clear visible cortical plane, partial filling-in of erosions and cysts, and sclerosis of the subchondral bone. An X-ray at the age of 43 showed that the radiographic healing phenomena were still preserved after 7 years. The right knee remained pain-free although the Larsen grade was still 4, and the knee function was preserved for 8 years. In conclusion, anti-TNF-α therapy may preserve knee function with radiographic healing phenomena and prevent total arthroplasty of severely erosive knees in young RA patients.

A long-term follow-up study of cervical lesions in rheumatoid arthritis

To determine the natural history of cervical lesions in rheumatoid arthritis, 161 patients who had been followed for a minimum of 5 years were enrolled in this study. The average follow-up period was 10.2 years (range, 5 to 20 years). The severity of the rheumatoid arthritis was classified into three types based on the multiplicity of peripheral joint rheumatoid involvement: a least erosive subset, a more erosive subset, and a mutilating disease subset. Ninety-two patients (57%) had upper cervical involvement, which progressed in the order of anterior atlantoaxial subluxation, anterior atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Subaxial subluxation was found in 18 patients (11%). In 17 of these 18 patients, upper cervical lesions were also noted. The incidence of cervical involvement in each disease subset was 39% in the least erosive group, 83% in the more erosive group, and 100% in the mutilating disease group. Fifty percent of the patients with cervical involvement had neck pain, and the remaining patients were asymptomatic. Neural involvement occurred in 10 patients. In 7 of these 10 patients, vertical subluxation of the atlas was responsible for the neural deficit. Six patients required surgical intervention because of progressive myelopathy.

Foot deformities in rheumatoid arthritis and relevance of disease severity

OBJECTIVE

To investigate foot deformities in rheumatoid arthritis (RA) in relation to the disease severity.

METHODS

Radiographs of 100 weight bearing feet of 50 patients who had had RA for >10 years (mean 13.5 years) were studied. The patients were classified into 2 study groups according to the severity of disease. We measured hallux valgus angle (HVA), intermetatarsal angle between first and 2nd (M1/2), and intermetatarsal angle between first and 5th (M1/5) on anteroposterior (AP) radiographs, as well as calcaneal pitch (CP) and first metatarsal pitch (MP) on lateral radiographs. The differences in these angles between the 2 groups (Inter-group study) and the correlations among angles within each group (Intra-group study) were examined.

RESULTS

Inter-group study showed significant differences between the 2 groups for all variables. Intra-group study, on the other hand, showed no correlation between variables of the 2 deformities, i.e., splaying of forefoot (M1/2 and M1/5) and flattening of longitudinal arch (CP and MP). Only HVA correlated with the splaying (M1/2 and M1/5) in both study groups.

CONCLUSION

Disease severity is related to the progression of foot deformities in RA, but the flattening and the splaying are not correlated with each other. We believe that foot deformities should be treated properly and early, especially for patients who are expected to have severe disease.

Pathological fracture of a lumbar vertebra caused by rheumatoid arthritis--a case report

We describe a case of rheumatoid arthritis (RA) with collapse of the L3 lumbar vertebra for which surgery was performed. The pathogenesis of lumbar lesions affected by RA is discussed and the literature reviewed.

Cervical lesions related to the systemic progression in rheumatoid arthritis

STUDY DESIGN

Cross-sectional study of cervical involvement in rheumatoid arthritis.

OBJECTIVES

To clarify the correlation between the deterioration of cervical lesions and the systemic progression of rheumatoid arthritis.

SUMMARY OF BACKGROUND DATA

The natural course of cervical lesions varies. To date, no systemic parameter has been clarified to predict the progression.

METHODS

One hundred seventy-three patients with rheumatoid arthritis participated in this study. The authors studied the progression of cervical lesions and investigated the relation between the types of cervical subluxation at the end of study and the following four variables: the serum level of C-reactive protein, the number of joints with erosion, carpal height ratio, and disease subset (least erosive subset, more erosive subset, and mutilating disease subset).

RESULTS

Of the 173 patients, 55 already had cervical subluxation before entering the study. During the follow-up period, 44 patients deteriorated radiographically, and 77 (45%) had cervical involvement, including involvement of upper cervical lesions in 65 patients, upper lesions combined with subaxial subluxation in 10, and subaxial subluxation alone in 2. The upper cervical subluxation progressed in the order of anterior atlantoaxial subluxation, atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Deterioration of upper cervical lesion and occurrence of subaxial subluxation were closely correlated with an elevation of serum C-reactive protein level, an increase in the number of joints with erosion, and a decrease in the carpal height ratio. The incidence of cervical involvement and the extent of deterioration were different among the disease subsets.

CONCLUSIONS

The serum level of C-reactive protein, the number of joints with erosion, and the carpal height ratio correlated closely with the extent of the cervical subluxation. The average C-reactive protein values during the follow-up period correlated with progression of the cervical lesions. The classification of rheumatoid disease subset was useful for predicting the terminal feature of the cervical lesions.

[A case of basilar impression treated with mandible splitting transoral approach]

We report a case of basilar impression treated with mandible splitting transoral approach surgery. A 39-year-old man presented a ten-year history of gait disturbance. He had experienced acceleration of his spastic paraparesis for the past few years. Neurological examination on admission demonstrated tetraparesis (MMT4/5), severe hyperreflexia in his arms and legs, severe sensory loss below C2, urinary retention and inability to open his mouth widely. Radiological findings showed the dens and the body of C2 are deeply invaginated to the atlas and the foramen magnum and medulla and upper cervical cord were markedly compressed by this basilar invagination. After carrying out posterior decompression and occipito-cervical fixation, we attempted to remove the invaginated dens and the C2 vertebral body using a conventional transoral approach. But limitation of mouth opening made operative fields narrow. Consequently because of insufficient anterior decompression his neurological deficits could not be alleviated. Employment of mandible splitting procedure brought about a wide operative view so that complete removal of the residual dens and 70% drilling out of the C2 body was made possible. Postoperative complications were negligible. Finally, great alleviation of his deficits was achieved. Mandible splitting procedure is effective for obtaining a wide operative field on the anterior approach to the craniocervical junction.

Bone marrow stromal cells contribute to synovial cell proliferation in rats with collagen induced arthritis

OBJECTIVE

To observe the migration of bone marrow stromal cells into the joint cavity and the contribution of such cells to synovial proliferation in rats with collagen induced arthritis (CIA).

METHODS

After bone marrow stromal cells preliminarily labeled with fluorescent dye or 3H thymidine accumulated in the bone marrow of splenectomized rats by intraperitoneal injection, the migration of labeled stromal cells in rats with CIA was analyzed by liquid scintillation counting, autoradiography, and fluorography.

RESULTS

In splenectomized control rats, labeled bone marrow stromal cells were mostly found in the bone marrow and not in the synovium. Over 2 weeks after immunization, labeled stromal cells were microscopically found migrating directly into the joint cavity through the area between the articular margin and the synovial insertion (the bare zone). Labeled stromal cells were mainly found in the sublining layers of proliferating synovial tissue.

CONCLUSION

At the onset of CIA, bone marrow stromal cells migrated from the bone marrow into the affected joint cavity and seemed to contribute to synovial proliferation.

The MEK kinase activity of the catalytic domain of RAF-1 is regulated independently of Ras binding in T cells

Deletion of the amino-terminal domain of Raf-1, which contains the Ras-binding region, results in the constitutive activation of the liberated Raf-1 catalytic domain in fibroblast cell lines. We demonstrate that the MEK kinase activity of the isolated Raf-1 catalytic domain, Raf-BXB, is not constitutively active, but is regulated in Jurkat T cells. Raf-BXB is activated by engaging the antigen receptor-CD3 complex, or treating cells with phorbol myristate acetate or okadaic acid. Increasing intracellular cAMP inhibits Raf-1 activation stimulated by phorbol myristate acetate, but not the activation of Raf-BXB. Serine 621, but not serine 499, is essential for Raf-BXB MEK kinase activity. Because Raf-BXB does not bind Ras, the data establishes a Ras-independent signal in directly regulating the activity of the Raf-1 catalytic domain.

Phenotypic characteristics of bone marrow cells in patients with rheumatoid arthritis

OBJECTIVE

Our previous study showed the presence of abnormal myeloid lineage cells in the epiphyseal bone marrow adjacent to joints affected with severe rheumatoid arthritis (RA). Now, we investigated whether there were any changes of other marrow cell populations related to RA, and whether there were any pathologically characteristic changes in the iliac bone marrow, which is one of the major systemic hematopoietic organs.

METHODS

2-Color flow cytometry was carried out to analyze the phenotypes of mononuclear cells (MNC) fractions in bone marrow aspirates and venous blood from 56 patients with RA and 7 non-RA controls.

RESULTS

The absolute number of MNC in the iliac bone marrow was increased by 3-fold in the RA patients compared with the non-RA controls. In contrast, no significant increase of MNC was observed in the tibial epiphyseal bone marrow or peripheral blood. The ratio of each MNC fraction in the iliac bone marrow did not differ significantly between the RA patients and the non-RA controls. In lymphocyte subsets, the percentage of HLA-DR+CD8+ cells to all CD8 cells in the iliac bone marrow increased significantly in the RA patients compared with the non-RA controls. Abnormal myeloid cells (MX-GA+MY4+ cells), specific to severe RA, were found to be more concentrated in the iliac bone marrow than in the tibial epiphyseal bone marrow.

CONCLUSION

Characteristic pathologic changes of the iliac bone marrow suggest an important role of systemic bone marrow in the progression of RA.

Therapeutic effect of intradermal injections with difucosyl lactosamine (dimeric Lex) on patients with rheumatoid arthritis

As reported by us, a new myeloid cell population with an oncofetal membrane marker, dimeric Lex (di-Lex; III3FucV3 FucnLc6), was found in the epiphyseal bone marrow adjacent to the involved joints of patients with severe rheumatoid arthritis (RA). Patients with RA received intradermal (id) injections of di-Lex incorporated in liposome or of high molecular weight glycoprotein, or tumor associated carbohydrate antigen (TCA), containing the same carbohydrate epitope as di-Lex. The epiphyseal myeloid cells were reduced or sometimes eliminated during id injection. In random trials of id injection, observation under clinical and laboratory conditions showed improvement in 63% (17/27) of the patients treated for 6 months with appropriate doses of di-Lex (III3FucnLc4), and in 72% (31/43) of those treated with an identical protocol for TCA. However, id injection with monomeric Lex had no effect.

Raf-1 is required for T cell IL2 production

Engagement of the T cell receptor/CD3 complex activates the serine/threonine kinase, Raf-1, but the physiologic consequences of its activation have not been determined. The effects of Raf-1 on interleukin 2 (IL2) production in T cells were examined using activated and inhibitory forms of Raf-1. A truncated active form of Raf-1 was expressed constitutively from the metallothionein promoter in a malignant T cell line, Jurkat. Treatment of the cells with zinc and cadmium greatly increased active Raf-1 expression. This increase in Raf-1 expression allowed antibodies to CD3 and to CD28 to stimulate IL2 production in the absence of phorbol myristate acetate (PMA) and enhanced IL2 production stimulated by these antibodies in the presence of PMA. The action of active Raf-1 was to increase IL2 gene transcription as it enhanced transcription of a reporter gene linked to IL2 promoter. Finally, the dominant negative form of Raf-1 inhibited transcription directed by the IL2 promoter that was induced by the mitogen phytohemagglutinin (PHA) and PMA. We conclude that Raf-1 activity is necessary for IL2 gene transcription and secretion. These data indicate a role for Raf-1 in the immune response.

Regulation and properties of extracellular signal-regulated protein kinases 1 and 2 in vitro

Extracellular signal-regulated protein kinases (ERK) 1 and 2 and mutants of each were expressed in bacteria with a hexahistidine tag and purified using nickel-chelate chromatography. Basal activity of wild type ERK2 was approximately 2 nmol/min/mg. Self-catalyzed phosphorylation occurred in vitro on the major physiological site of tyrosine phosphorylation in an intramolecular reaction. Rabbit muscle ERK activator activated ERK2 500-1000-fold up to a specific activity (approximately 2 mumol/min/mg) approximating that of ERK1 purified from stimulated cells (Boulton, T.G., Gregory, J.S., and Cobb, M.H. (1991) Biochemistry 30, 278-286). ERK1 could also be activated by the ERK activator to the same extent. Mutants lacking the major site of tyrosine phosphorylation were autophosphorylated at a greatly reduced rate and were no longer highly activated by the ERK kinase. Mutants lacking the major site of threonine phosphorylation were autophosphorylated at the same or an enhanced rate, but the kinase activity of these mutants depended on the residue used to replace the threonine. Replacement by glutamate rendered the kinase capable of being activated by ERK activator, while replacement by alanine did not. Thus, the carboxyl group of glutamate can provide at least some of the features introduced by phosphothreonine in activated ERKs.

Extracellular signal-regulated kinases in T cells: characterization of human ERK1 and ERK2 cDNAs

Extracellular signal-regulated kinases 1 and 2 are growth factor-sensitive serine/threonine kinases. cDNAs for both human kinases were isolated and sequenced. The nucleic acid and deduced protein sequences of human extracellular signal-regulated kinase 1 were 88% and 96% identical, respectively, to the homologous rat sequences. The nucleic acid and deduced protein sequences of human extracellular signal-regulated kinase 2 were 90% and 98% identical, respectively, to the corresponding rat sequences. A human extracellular signal-regulated kinase 2 specific probe was used to demonstrate that the mRNA for this kinase was present in T cells and did not change with activation. The deduced protein sequences of both human kinases were greater than 95% identical to two Xenopus kinase sequences, indicating that these enzymes are highly conserved across species.

Bone marrow changes in adjuvant-induced and collagen-induced arthritis. Interleukin-1 and interleukin-6 activity and abnormal myelopoiesis

OBJECTIVE

To investigate the role of bone marrow in arthritis.

METHODS

Bone marrow changes over time were investigated in rats with adjuvant-induced and collagen-induced arthritis, using bioassay techniques and histologic analysis.

RESULTS

In both animal models, bone marrow interleukin-1 and interleukin-6 activity began to rise before the onset of arthritis and increased in relation to the progression of arthritis. Enhanced myelopoiesis in the bone marrow was noted in conjunction with the increased cytokine activity.

CONCLUSION

Bone marrow changes such as those demonstrated in this study may be common to various models of induced arthritis and may have an important role in the pathogenesis of this disease.

Effect of early synovectomy on the course of rheumatoid arthritis

Ninety-one patients with rheumatoid arthritis were retrospectively assigned to 3 subsets according to the number of joints with erosion (NJE). The subsets were least erosive (LES); more erosive (MES); most erosive involving multilating disease (MUD). In the early stages of disease the subsets were distinct (p less than 0.001) regarding mean values of annual reduction of carpal height (delta CHR) and serum Clq levels. Patient assessment (radiographic and clinical) continued to deteriorate in the MES and MUD subsets over the 1-5 year interval after synovectomy. Apparent stabilization of knee disease in the LES subset may be a feature of this subset rather than a result of synovectomy. Although synovectomy may offer short term symptomatic relief, we found no evidence that it retards the bony destruction or the disease process.

Facs analysis of myeloid differentiation stages in epiphyseal bone marrow, adjacent to joints affected with rheumatoid arthritis

To analyze the differentiation stages of myeloids statistically, we adopted a two-color FACS system and used appropriate monoclonal antibodies belonging to CD15, CD16 and CD11b. By using HL60 treated with DMSO or human bone marrow MNCs from patients with rheumatoid arthritis, it was proved that with this system, myeloids could be clearly separated according to differentiation stages. Furthermore, the number of myeloids at certain stages of differentiation in the epiphyseal bone marrow of patients with RA or OA was measured. Nine of 15 samples from RA patients showed immature and relatively mature myeloids, while none of the 8 OA samples did. When the proportions of myeloids in epiphyseal bone marrow MNCs were compared with the clinical features, disease subsets in RA and the degree of synovitis, seemed to be important factors for abnormal myelopoiesis.

Elevated activity of myeloid growth factor in bone marrow adjacent to joints affected by rheumatoid arthritis

Myeloid growth activity of rheumatoid arthritis (RA) and normal serum was measured with a newly developed simple method. Abnormally high titers of this activity were found in the bone marrow blood serum adjacent to joints with RA where abnormal myelopoiesis had been found. Maximal activity for myeloid growth was found at a molecular weight of 70 kDa in gel filtration of serum, different from the size of any known factors involved with myelopoiesis.

[Repair of rabbit articular surfaces with allografts of chondrocytes embedded in collagen gels]

In an attempt to restore articular cartilage, allogeneic articular chondrocytes embedded in collagen gels were transplanted onto full-thickness defects in rabbit articular cartilage. Within 24 weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesizing type II collagen. These chondrocytes were autoradiographically proven to be originated from the originally transplanted chondrocytes. As histologically assessed, success rate was about 80%, a marked improvement over the results (40% success rate) in previous studies reporting chondrocyte transplantation without collagen gels. On the other hand, the defects without chondrocyte transplantation healed with fibrocartilaginous tissue more than 24 weeks after treatment. Immunological enhancement induced by transplanted allogeneic chondrocytes or collagen was not significant for eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogeneic transplantation of isolated chondrocytes embedded in collagen gels appears to be one of the most promising methods for the restoration of articular cartilage.

Repair of rabbit articular surfaces with allograft chondrocytes embedded in collagen gel

In an attempt to repair articular cartilage, allograft articular chondrocytes embedded in collagen gel, were transplanted into full-thickness defects in rabbit articular cartilage. Twenty-four weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesising Type II collagen. These chondrocytes were autoradiographically proven to have originated from the transplanted grafts. Assessed histologically the success rate was about 80%, a marked improvement over the results reported in previous studies on chondrocyte transplantation without collagen gel. By contrast, the defects without chondrocyte transplantation healed with fibrocartilage. Immunological enhancement induced by transplanted allogenic chondrocytes or collagen was not significant at eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogenic transplantation of isolated chondrocytes embedded in collagen gel appears to be one of the most promising methods for the restoration of articular cartilage.

The presence of a myeloid cell population showing strong reactivity with monoclonal antibody directed to difucosyl type 2 chain in epiphyseal bone marrow adjacent to joints affected with rheumatoid arthritis (RA) and its absence in the corresponding normal and non-RA bone marrow

The presence of a specific type of cell, highly expressing difucosyl type 2 chain (dimeric Lex; FH-4 antigen), was found in the epiphyseal bone marrow cells of affected joints from patients with active severe rheumatoid arthritis (RA). The antigen was defined by monoclonal antibody FH-4 which was previously found to be directed to the oncofetal marker. The FH-4(+) cell population was identified as myeloid cell lineage with usual morphology specifically found in bone marrow of patients with severe RA, but is virtually absent in the same cell fraction of patients with osteoarthritis, infectious arthritis, and from normal adult subjects.

A B cell-specific differentiation antigen, CD23, is a receptor for IgE (Fc epsilon R) on lymphocytes

Two independent L cell transformants expressing human lymphocyte Fc epsilon R were established by using cellular DNA from RPMI 8866 cells. The surface expression of the receptor was confirmed on the basis of the binding of a panel of anti-Fc epsilon R antibodies and its ability to bind IgE. Anti-CD23 antibodies strongly stained the transformants, indicating possible identity or antigenic relationship between Fc epsilon R and CD23. This interesting observation warrants additional clarification as to the role of CD23 and Fc epsilon R in B cell differentiation.

A B cell-specific differentiation antigen, CD23, is a receptor for IgE (Fc epsilon R) on lymphocytes

Two independent L cell transformants expressing human lymphocyte Fc epsilon R were established by using cellular DNA from RPMI 8866 cells. The surface expression of the receptor was confirmed on the basis of the binding of a panel of anti-Fc epsilon R antibodies and its ability to bind IgE. Anti-CD23 antibodies strongly stained the transformants, indicating possible identity or antigenic relationship between Fc epsilon R and CD23. This interesting observation warrants additional clarification as to the role of CD23 and Fc epsilon R in B cell differentiation.

Molecular structure of human lymphocyte receptor for immunoglobulin E

We have isolated and sequenced a cDNA clone encoding the human lymphocyte receptor for IgE (Fc epsilon R). The deduced protein sequence reveals that Fc epsilon R consists of 321 amino acids, without any signal sequence, and is oriented with its N-terminus on the cytoplasmic side and its C-terminus on the outside of the cell. This molecule shows striking sequence homology with chicken asialoglycoprotein receptor (hepatic lectin), suggesting a possible role for Fc epsilon R in endocytosis. Fc epsilon R mRNA is expressed in B cells, B cell lines, and macrophage cell lines. It is not expressed in T cells or T cell lines, with the exception of an HTLV-transformed T cell line. mRNAs expressed in a macrophage line and in the latter T cell line differ in size from mRNA expressed in B cells. Human BSF-1 (or IL-4) induces the expression of Fc epsilon R mRNA in B cells, but not in T cells.

Fc epsilon receptor, a specific differentiation marker transiently expressed on mature B cells before isotype switching

The expression of Fc epsilon R on human lymphocytes was studied with the anti-Fc epsilon R mAbs. Fc epsilon R was expressed on most mu+,delta+ circulating B cells, whereas T cells did not express Fc epsilon R even in patients with hyper-IgE syndrome. B cells with gamma, alpha, or epsilon phenotype did not express Fc epsilon R, moreover its expression could not be induced, suggesting that the Fc epsilon R expression was correlated with isotype switching. mu+delta+ B cells in bone marrow did not express Fc epsilon R, but PHA-sup (supernatant from PHA-stimulated cell cultures) could induce its expression, and the addition of IgE augmented this induction. Recombinant IL-2, IL-1, IFN-gamma or -beta, or purified B cell differentiation factor (BSF-2 B cell-stimulatory factor 2) could not induce Fc epsilon R expression in bone marrow B cells. IFN-gamma inhibited the Fc epsilon R expression induced by PHA-sup, suggesting that the human counterpart of BSF-1 may be responsible for Fc epsilon R expression in bone marrow B cells. B cells from patients with common variable immunodeficiency and ataxia telangiectasia did not express Fc epsilon R, but PHA-sup could induce its expression, indicating that circulating B cells of these patients are at a differentiation stage similar to B cells in bone marrow. The study showed that Fc epsilon R is a B cell-specific differentiation marker, the expression of which is restricted to a defined stage of B cell differentiation.

Monoclonal anti-Fc epsilon receptor antibodies with different specificities and studies on the expression of Fc epsilon receptors on human B and T cells

Three monoclonal antibodies, 1-7 (gamma 2b), 3-5 (gamma 1), and 8-30 (mu), specific to Fc epsilon receptors (Fc epsilon R) on human B cells were established. The two monoclonals (1-7 and 8-30) could inhibit the binding of IgE to Fc epsilon R in rosette formation assays, as well as FACS analysis, and were shown to recognize the same epitope of Fc epsilon R. The other monoclonal antibody (3-5) recognized the same molecule but a different epitope, and marginally inhibited the IgE binding. The molecules on RPMI 8866 cells recognized by these monoclonal antibodies had Mr of 46,000 and 25,000 to 30,000 daltons as determined by immunoprecipitation and SDS-PAGE analysis. By employing these monoclonal antibodies, the expression of Fc epsilon R on circulating lymphocytes was studied. Approximately 50% of B cells from normal, nonatopic individuals were found to express Fc epsilon R, and a remarkable increase in the expression of Fc epsilon R was observed in B cells of atopic patients. The expression of Fc epsilon R was not detected in T cells from atopic patients (including hyper IgE syndrome) as well as normal individuals. Incubation of B cells with PHA-conditioned medium plus IgE augmented the expression of Fc epsilon R in the Fc epsilon R+ B cell population but not in Fc epsilon R- population. PHA-conditioned medium plus IgE did not induce Fc epsilon R expression on T cells.

Monoclonal anti-Fc epsilon receptor antibodies with different specificities and studies on the expression of Fc epsilon receptors on human B and T cells

Three monoclonal antibodies, 1-7 (gamma 2b), 3-5 (gamma 1), and 8-30 (mu), specific to Fc epsilon receptors (Fc epsilon R) on human B cells were established. The two monoclonals (1-7 and 8-30) could inhibit the binding of IgE to Fc epsilon R in rosette formation assays, as well as FACS analysis, and were shown to recognize the same epitope of Fc epsilon R. The other monoclonal antibody (3-5) recognized the same molecule but a different epitope, and marginally inhibited the IgE binding. The molecules on RPMI 8866 cells recognized by these monoclonal antibodies had Mr of 46,000 and 25,000 to 30,000 daltons as determined by immunoprecipitation and SDS-PAGE analysis. By employing these monoclonal antibodies, the expression of Fc epsilon R on circulating lymphocytes was studied. Approximately 50% of B cells from normal, nonatopic individuals were found to express Fc epsilon R, and a remarkable increase in the expression of Fc epsilon R was observed in B cells of atopic patients. The expression of Fc epsilon R was not detected in T cells from atopic patients (including hyper IgE syndrome) as well as normal individuals. Incubation of B cells with PHA-conditioned medium plus IgE augmented the expression of Fc epsilon R in the Fc epsilon R+ B cell population but not in Fc epsilon R- population. PHA-conditioned medium plus IgE did not induce Fc epsilon R expression on T cells.