[Endovascular repair of iliocaval arteriovenous fistula complicating lumbar disc surgery]

Vascular complications of lumbar disc surgery are rare. Few cases have been reported. Arteriovenous fistulas are the most common. They are due to anatomical relationships between the last lumbar vertebrae, the corresponding discs, and the iliac vessels; degenerative lesions of the intervertebral discs facilitate instrumental vessel perforation, and operative difficulty. Computed tomography is particularly accurate for making the diagnosis. Treatment strategies consist in surgery or endovascular management. Percutaneous endovascular treatment using a stent-graft is a reasonable option for treating arteriovenous fistula. We describe the case of a 50-year-old patient who developed an iliocaval arteriovenous fistula following lumbar disc hernia surgery. The lesion was excluded by a stent-graft. The postoperative period was uneventful.

Osteoblast-induced osteoclast apoptosis by fas ligand/FAS pathway is required for maintenance of bone mass

The interplay between osteoblasts and osteoclasts has a crucial role in maintaining bone homeostasis. In this study, we reveal that osteoblasts are capable of inducing osteoclast apoptosis by FAS ligand (FASL)/FAS signaling. Conditional knockout of FASL in osteoblasts results in elevated osteoclast numbers and activity, along with reduced bone mass, suggesting that osteoblast-produced FASL is required to maintain physiological bone mass. More interestingly, we show that osteoblasts from ovariectomized (OVX) osteoporotic mice exhibit decreased FASL expression that results from the IFN-γ- and TNF-α-activated NF-κB pathway, leading to reduced osteoclast apoptosis and increased bone resorption. Systemic administration of either IFN-γ or TNF-α ameliorates the osteoporotic phenotype in OVX mice and rescues FASL expression in osteoblasts. In addition, ovariectomy induces more significant bone loss in FASL conditional knockout mice than in control group with increased osteoclast activity in which the levels of RANKL and OPG remain unchanged. Taken together, this study suggests that osteoblast-induced osteoclast apoptosis via FASL/FAS signaling is a previously unrecognized mechanism that has an important role in the maintenance of bone mass in both physiological conditions and OVX osteoporosis.

Assessing the economic impact of Rx-to-OTC switches: systematic review and guidelines for future development

INTRODUCTION

Switching drugs from prescription to non-prescription status (Rx-to-OTC) presents a unique set of challenges and opportunities to policy-makers and the industry in terms of managing health outcomes, pharmaceutical spending, and steering of consumer choices of therapy. Decision-analytic models are used to address uncertainty and produce reasonable estimates of the economic impact of switches for payers. This article presents a critical literature review of existing models which assess the economic impact of Rx-to-OTC switches, and provides guidelines in which future economic evaluations of Rx-to-OTC switches could be improved.

METHODS

A comprehensive search strategy was implemented in Medline and Embase, to retrieve published economic evaluations on Rx-to-OTC switches from 1995-2010. The research digest of the International Society of Pharmacoeconomics and Outcomes Research (ISPOR) was reviewed for potentially relevant abstracts for the past 3 years. Each model used was critically evaluated in terms of structure, relevance of inputs, methodology used, and robustness of results.

RESULTS

Worldwide, the economic impact of Rx-to-OTC switches has only been evaluated in a total of 12 peer-reviewed publications. Ten out of 12 studies were US-based, and two European-based. The models covered various disease categories, including allergy, hypercholesterolemia, gastroenterology, contraception, pulmonology, and virology. Seventy-five per cent of the models predicted cost savings for payers and patients. Limitations of the models mainly included use of strong assumptions and non-inclusion of specific populations due to lack of data. Guidelines were developed to help future model development. They cover structural issues on decision context, health states, and clinical outcomes, and other considerations for model specifications.

CONCLUSIONS

Although reviewed studies lacked quality, this review of economic evidence of Rx-to-OTC switches suggests that switches may produce cost savings to public and private payers. This is especially important in light of the trend towards more switches.

[Epithelioid hemangioendothelioma of bone complicated by femoral fracture]

A 54-year-old man was seen with a fracture of the left femur. Plain radiographs revealed a 40-mm lytic centromedullary lesion. Magnetic resonance T1- and T2-weighted sequences showed high and low signals. After stabilization of the fracture, the tumor was removed followed by reconstruction with a vascularized fibula. The pathological examination demonstrated proliferation of non atypical CD34 and CD31 positive epithelioid cells with few lumens, accompanied by abundant fibrous stroma, sometimes masking tumor cells. Satisfactory motion was achieved with no recurrence at 20 months follow-up. Bone hemangioendothelioma can simulate metastasis and must be distinguished by immunohistochemistry. Prognosis is a subject of debate as the tumor is considered to exhibit intermediate malignancy by some authors while other consider it to be a malignant tumor.

[Lanthanides and microanalysis. Effects of oral administration of two lanthanides: ultrastructural and microanalytical study]

The subcellular localization of cerium and lanthanum in the intestinal mucosa was studied after oral administration of cerium chloride or lanthanum chloride or lanthanum chloride followed 30 minutes after of cerium chloride to young adults Wistar rats. Two methods of observation and microanalysis were used. The transmission electron microscopy revealed the presence of dense electron granulations in the lysosmes of the duodenum enterocyte, when these elements were administrated simultaneously. The ion mass microanalysis permits to detect the presence of La and Ce as bright points outlining the intestinal villi. These points correspond to the lysosomes containing the granulations previously described. These granulations are formed by the cerium and the lanthanum associated to the phosphor and forming probably insoluble salts of Ce/La phosphate.

[Polyarthritic manifestations revealing Stickler syndrome]

Stickler syndrome, also called hereditary arthro-ophthalmopathy is a dominant disorder, with poly-epiphyseal dysplasia resulting in early osteoarthritis. It usually includes bilateral myopia, that changes little during the follow up period, but can lead to retinal detachment. Children with Stickler syndrome can show facial dysmorphism that may improve with age, but severe anomalies may exist such as Pierre Robin sequence. Our case, a woman, 20-year-old, presents chronic polyarthritis which is an unusual feature of this disease. The diagnosis of Stickler's syndrome is based on polyepiphyseal dysplasia in skeletal radiography and bilateral myopia. Otherwise, this patient has no facial dysmorphism.

[Valgus osteotomy in the treatment of pseudoarthrosis of the femoral neck: 41 cases]

PURPOSE OF THE STUDY

Treating hip trauma victims who develop nonunion of the femoral neck remains a challenge in orthopedic surgery. We studied the clinical and radiological outcome after Pauwels osteotomy for valgisation.

MATERIAL AND METHODS

This retrospective series included 41 patients (25 men and 16 women), mean age 44.5 years. Initial treatment was surgical in 21 cases and had been insufficient in 91%. Nonunion (subcapital in 53%, transcervical in 40% and basicervical in 7%) had persisted for 16 months. A tight nonunion was present in 65.9% of the cases and the femoral head appeared normal in 70%. Femoral osteotomy was performed for simple valgisation in 78% of the cases with a mean 31.5 degrees correction (range 15 degrees to 50 degrees ). A nail or screwed plate was used for fixation. Results were analyzed at a mean 76 months post-surgery.

RESULTS

Bone healing was achieved in 98% of the cases. The only failure was related to inappropriate surgical technique. Necrosis was observed in 16 cases. The functional outcome was very good or good in 82% of the patients.

CONCLUSION

Osteotomy for valgisation remains a very good salvage procedure for nonunion of the femoral neck following hip trauma. It can be used for elderly subjects even in the presence of early stage or partial necrosis.

Identification of a polymorphic microsatellite marker in the mouse Fas ligand gene

We describe the characterization of a polymorphic microsatellite marker, located 1.8 kb downstream of exon 4 in the mouse Fas ligand gene. This (GT) repeat sequence allows the identification of four alleles which can very easily be distinguished by simple agarose electrophoresis.

[Primary chemotherapy with the Rosen T10 protocol before conservative surgery in limb primitive osteosarcomas: results about 56 cases]

We report the results of a prospective Tunisian study using primary chemotherapy followed by conservative surgery in primitive limb osteosarcoma. From January 1988 to January 1998, 56 patients affected by limb osteosarcoma entered in a prospective study of neoadjuvant chemotherapy with the T10 protocol before surgery with a conservative intent. Initial work-up include: clinical exam with tumor measurements, chest and limb X-rays, limb CT-scan or MRI, chest CT-scan, bone scintigraphy and hematological and renal biological exams. Patients receive pre- and post-operative chemotherapy according to the T10 modified protocol. Fifty-six patients (33 M/23 F) with a mean age of 19 years (8 to 28) are included. Mean clinical and radiological tumor size is around 14 cm. Main histologic type is classic osteosarcoma (50% of cases) and 10 patients (9%) presented with initial metastasis; 42 patients on 56 receive the whole pre-operative protocol. Treatment is well tolerated excluding 18 episodes of mucositis, 29 of leucopenia (< grade 3), 7 of thrombopenia (< grade 3), 4 of cutaneous toxicity, 2 of pulmonary toxicity and 3 of nausea-vomiting. We observe 36% of good histological responders and 64% of bad responders to primary chemotherapy, 27 patients on 49 operated (53%) have a conservative surgery and 18 (47%) a radical surgery. With a median follow-up of 51 months (8 to 128), 29 patients remain alive free of disease (15/17 GR and 14/30 BR), 2 are alive with disease, 2 died by toxicity, 14 died by progressive disease and 9 are lost to follow-up with evolutive disease. Five year disease-free survival is 55% for the 46 non metastatic patients. In univariate analysis, seric alkaline phosphatase level (p = 0.0014) and histological response to chemotherapy (p = 0.0218) are significant factors for prognosis.

[Use of Ilizarov fixator in the treatment of post-osteomyelitis pseudoarthroses in children]

PURPOSE OF THE STUDY

The aim of this study was to emphasize the importance of the distraction osteogenesis technique in the treatment of post-osteomyelitis nonunion. We report 12 cases.

PATIENTS AND METHODS

Mean patient age was 9.5 years. There were 7 cases of nonunion of the femur and 5 involving the tibia. Nonunion was associated with 5.9 cm shortening in 10 cases, 8.4 cm circumferential bone defect in 1 case, shortening and bone defects in 6 cases, and shortening and joint deformities in 2 cases.

RESULTS

Consolidation was obtained in 11 cases with an average delay of 11.6 months. Infection was eradicated in 75 per cent of the cases. Average residual shortening was 0.4 cm. Joint deformities and axial deviations were corrected at the same time in all cases.

DISCUSSION

The advantages of the Ilizarov technique are well known for the treatment of such deformities and musculoskeletal system disorders subsequent to osteomyelitis: nonunion, infection, shortening, joint deformities and malunion.

[Consequences of tibiotalar arthrodesis on the foot. A retrospective study of 36 cases with 8.5 years of followup]

The authors report the results of a retrospective study of 36 cases of tibiotalar arthrodesis performed in 22 men and 14 women with an average age of 32 years. All patients were reviewed with an average of 8.5 years follow-up. The predominating etiologies were ankle osteoarthritis (15 cases) and neurologic deformities of the foot (13 cases). Arthrodesis was performed using the Meary technique in 60% of cases, using the Charnley technique in 20% and the Crawford-Adams technique or with clamps in the other cases. Fusion was obtained in 97% of cases. Long-term results were assessed using Duquennoy et al.'s scoring system. They were very good or good in 58% of cases, fair in 31% and poor in 11%. The study of distal repercussions of tibiotalar arthrodesis shows progressive deterioration of the subtalar joint in 70% of cases and appearance or increase of degenerative changes in 75% of cases. The final results of the procedure depend on this deterioration; the latter is related with the arthrodesis position. Midtalar joint is a compensation joint showing hypermobility in 40% of cases. Degenerative changes were limited and asymptomatic in 80% of cases. Based on the findings in this study and on the literature, we conclude that the foot should be fixed at 90 degrees or with less than 5 degrees of equinus, with 5 degrees of valgus and 10 to 15 degrees of external rotation.

Structural basis of the gp120 superantigen-binding site on human immunoglobulins

B cell superantigens (SAg) interact with normal human nonimmune Igs (Igs), independently of the light chain isotype, and activate a large proportion of the B cell repertoire. Recently, the major envelope protein of HIV-1, gp120, was found to exhibit SAg-like properties for B cells with potential pathologic consequences for the infected host. This unconventional mode of interaction contrasts with its binding to immunization-induced Abs, which requires the tertiary structure of the heavy and light chain variable regions. In this report, we have examined the structural basis of the interaction between human Igs and gp120. We found that gp120 binding is restricted to Igs from the V(H)3 gene family and that the two V(H) genes 3-23 and 3-30, known to be overutilized during all stages of B cell development, frequently impart gp120 binding. We also provide evidence that the viral gp120 SAg can interact with only a subset of the human V(H)3+ Igs that can convey binding to the prototypic bacterial B cell SAg protein A from Staphylococcus aureus. Finally, we have identified amino acid positions present primarily in the first and third framework regions of the Ig heavy chain variable region, outside the conventional hypervariable loops, which correlate with gp120 binding. In a three-dimensional sequence-homology model, these residues partially overlap with the predicted SAg protein A binding site for V(H)3+ Igs.

Myocyte enhancer factor-related B-MEF2 is developmentally expressed in B cells and regulates the immunoglobulin J chain promoter

Immunoglobulin J chain gene expression is induced by the delivery of a lymphokine signal to antigen-activated B cells in a primary immune response. A major interleukin 2 (IL-2)-responsive region that contains two adjacent control elements (JA and JB) exists within the J chain promoter. Transcription factor PU.1 positively regulates J chain gene expression by binding to one of the control elements (JB) in the J chain promoter. In the present study we have determined that a myocyte enhancer factor 2 (MEF2)-related nuclear factor, named B-MEF2, positively regulates the J chain gene promoter activity via the second control element (JA). An in vitro translated MEF2 family member, MEF2C, was found to bind the JA site with identical properties as endogenously expressed B-MEF2 in B cell lines. Moreover, in vivo experiments showed that a dominant negative mutant of MEF2C blocked B-MEF2 regulation of the J chain promoter. Consistent with its role as positive regulator of J chain gene expression, B-MEF2 levels were enhanced in highly differentiated B cells. In addition, induction of an IL-2-responsive presecretor cell line BCL1 with IL-2 or IL-5 (which up-regulates J chain gene expression) resulted in an increased expression of B-MEF2. We conclude that a MEF2-related transcriptional factor, B-MEF2, acts as a stage-specific positive regulator of J chain gene expression in the B cell lineage.

[A rare diaphyseal bone tumor: degenerative mucoid cyst]

The purpose of the study was to clarify the clinico pathological features of periosteal ganglion. The authors present a case of an unusual diaphyseal bony tumor in a 27 years old man. The diagnosis of diaphyseal periosteal ganglion cyst was made on roentgenographic appearance, presence of mucoid material and histologic evidence of a synovial type cellular lining. The patient was successfully treated with excision. The follow-up examination showed no recurrence one year after surgery. The radiological differential diagnosis were considered and possible pathogenes for a periosteal ganglion was discussed. Periosteal ganglia must be considered as a cause of cortical erosions. This lesion may radiologically mimic other periosteal lesions. Treatment with excision is successful in most cases.

[Giant cell tumors of the distal end of the radius treated by resection-arthrodesis]

The distal end of the radius is one of the sites commonly affected by giant-cell tumor of bone; it poses problems of reconstruction after resection of the distal radius. The authors present a retrospective study of 5 giant cells tumors treated by resection-arthrodesis of the wrist. These tumors were seen in 3 men and 2 women. From the radiological point of view, all tumors were extensive and lytic lesions centered in the epiphysis and involving the metaphysis; the wrist joint was respected. From the histological point of view, the tumors were grade I in 3 cases and grade II in 2 cases. With a mean follow up of 8 years, the results were considered good in 3 cases, fair in 1 case and poor in 1 case. A high incidence of bone complications was noted: delayed union (up to 11 months) and fracture of the graft, which occurred in 3 patients.

[Fracture-luxation of the femur head. Apropos of 10 cases]

The authors report 10 segmental fractures of the femoral head associated with a dislocation of the hip. Using PIPKIN's classification, they noted 1 type I, 7 type II and 2 type III fractures. The initial treatment of the hip dislocation was conservative in all cases. Failure of reduction was noted in 6 cases and was complicated by fracture of the femoral neck in 2 cases. The attitude regarding the head fragment was: conservative in 5 cases, the reduction was considered satisfactory in 4 cases and poor in 1 case; surgical in the other 5 cases: screw fixation in 1 case, excision of the fragment in 1 case and prosthetic replacement of the femoral head in 3 cases. After a mean follow-up of 5 years, functional results were satisfactory in the majority of cases. The radiological assessment showed malunion without osteoarthrosis in one case and avascular necrosis of the femoral head in three cases. The authors propose a treatment policy based upon their experience and a review of the literature.

Effect of hepatitis B virus on tumour necrosis factor (TNF alpha) gene expression in human THP-1 monocytic and Namalwa B-cell lines

In response to viruses, monocytes and B cells produce TNF alpha. Therefore, we investigated TNF alpha gene expression and protein secretion in a human monocytic cell line, THP-1, and a Burkitt's lymphoma B-cell line, Namalwa, in response to hepatitis B virus (HBV). Stimulation by phorbol myristate acetate (PMA) (100 ng/ml for 48 h) induced TNF alpha secretion in THP-1 and Namalwa cells (100 to 300 pg/ml). In THP cells, the optimum response (> 2000 pg/ml) was obtained in the presence of a second mitogenic signal such as lipopolysaccharide (LPS) (10 microg/ml for 24 h). In our activation conditions, Northern blot analysis revealed a marked accumulation of TNF alpha mRNA species at 1.7 kb in both cell lines. When PMA- or PMA+LPS-stimulated THP-1 cells were exposed to HBV, TNF alpha protein and mRNA significantly decreased (> 50%). In contrast, HBV exposure of PMA-activated Namalwa cells resulted in strongly increased TNF alpha protein secretion (1 ng/ml). In this case, HBV induced TNF alpha mRNA accumulation that consisted of two types: a regular 1.7 kb and two novel high molecular weight (HMW) species at 3.7 and 4.3 kb. Exposure of stimulated THP-1 and Namalwa cells to HBV resulted in HBs and pre-S1 antigen production in the supernatants. In addition, HMW HBV DNA forms were detected in both cell lines, but with distinct HindIII restriction patterns. These findings indicate that TNF alpha gene expression may be differently regulated by HBV in activated human macrophages and B cells, and thus TNF alpha may be involved in the pathogenesis of HBV.

Identification of the B cell superantigen-binding site of HIV-1 gp120

Previous studies showed that the gp120 envelope protein of HIV-1 is able to crosslink membrane IgM on normal human B cells and to induce their activation in a V(H)3 immunoglobulin gene-family-specific manner. Because this V(H) gene family is the largest in the human repertoire, this superantigen (SAg) property is thought to have deleterious consequences for the host, including a progressive decline of B cells with progression of the HIV-1-induced disease. Here, we have identified the sequence motifs on gp120 involved in SAg binding to normal Igs. We show that this SAg-binding activity is present in gp120s from highly divergent isolates of HIV-1 belonging to clades derived from various geographical origins, and that carbohydrate residues are not essential for its expression. The SAg-binding site is formed by protein sequences from two regions of the gp120 molecule. The core motif is a discontinuous epitope spanning the V4 variable domain and the amino-terminal region flanking the C4 constant domain. The most critical residues appear to be Leu395-Asp397 and Ile425-Gln427. Residues from the C2 constant domain (positions 252-272) also seem to play an accessory role in SAg binding of gp120 to normal human Igs. These findings are important in the design of a successful gp120-based vaccine against HIV-1.

[Intramuscular myxoma. Apropos of two cases]

The authors report two cases of rare localization of intra muscular myxoma: one in the buttock, and the other in the lumbar area. The first case, a 58 years old woman had a four month history of a mass in the buttock. Computed tomography revealed the presence of a solid tumor. Diagnosis was based on histological examination. After surgical treatment no recurrence was observed after fourteen months. The second case was a 54 years old woman who presented a sciatica with back pain and neurological signs. The symptoms didn't response to medical treatment. Computed tomography showed an enlarged and-cystic lumbar lesion extending to the first sacral hole, with bone erosion of L3 and L4 articular apophysis and spinous process. Needle biopsy and surgical excision of the tumor were performed. Total neurological recovery was observed and no recurrence was observed after three years. The authors reminded the characteristics of this rare and benign soft tissue tumor and specified the place of magnetic resonance imaging (MRI) to establish the diagnosis which was still confirmed by histological examination of an open biopsy. Clinical follow-up revealed exceptional recurrence and no metastasis.

[Tuberculosis of the trochanter. Apropos of 17 cases]

This paper presents a short study of 17 cases of tuberculosis of the greater trochanter seen during a period of 19 years at the National Orthopaedic Institute in Tunis. The onset of the infection is slow with patients presenting at a mean of 7 years after initial symptoms. The diagnosis is confirmed by biopsy and culture of the organism. Management is based on treatment with antituberculous drugs, although surgical excision of the lesion is sometimes required. Successful resolution of the symptoms is usually achieved unless the hip joint becomes involved. Our patients showed good results at a mean follow up of 5 1/2 years.

Osteoid osteoma of the acetabulum

Osteoid osteoma of the acetabulum can be expected to cause nonspecific symptoms of hip inflammation. In a sixteen year old girl, investigation by routine radiographs and a bone scan suggested a focus of inflammation with a nidus and sclerosis of the acetabulum and overgrowth of the head and neck of the femur. Removal of the lesion by an anterior approach with dislocation of the hip gave excellent results when seen after three years with a normal gait and normal hip motion.

[A case of bladder pheochromocytoma]

Phaeochromocytoma is an endocrine neuroectodermal tumour usually located in the adrenal gland, but occasionally arising in other organs. The authors report a case of a vesical phaeochromocytoma presenting with haematuria. Radiological and endoscopic investigations revealed a right laterovesical submucosal tumour. Partial cystectomy was performed. The normality of the postoperative endocrine survey suggested disappearance of the tumour and absence of any other sites.

IL-4 inhibits the expression of high affinity IL-2 receptors on monoclonal human B cells

In the presence of anti-mu antibodies (anti-microAb), monoclonal B lymphocytes from patients suffering from B type chronic lymphocytic leukemia (B-CLL) can respond to IL-2. In contrast to the effect it exerts on normal B cells, IL-4 does not promote DNA synthesis by B-CLL lymphocytes. Rather this interleukin inhibits the response to IL-2 in all patients' cells that responded to this interleukin. We thus examined whether IL-4 would modulate the number and/or the affinity of IL-2 receptors. A 3-day activation of cells by anti-microAb induced a few hundred high affinity IL-2 receptors (HA-IL-2R) on B-CLL cell surface, as determined by Scatchard analysis. Treatment of cells with IL-4 caused a marked decrease in the number of HA-IL-2R without interfering with the binding ability of IL-2. In contrast with this profound suppressive effect, IL-4 did not down-regulate the expression of each chain, alpha and beta (p55 and p75, respectively), of the HA-IL-2R heterodimer. In fact, the expression of alpha and beta induced by anti-microAb was enhanced by IL-4. Altogether, IL-4 exerts a critical influence on the function and the configuration of HA-IL-2R without inhibiting the expression of two subunits, alpha and beta.

IL-4 inhibits the expression of high affinity IL-2 receptors on monoclonal human B cells

In the presence of anti-mu antibodies (anti-microAb), monoclonal B lymphocytes from patients suffering from B type chronic lymphocytic leukemia (B-CLL) can respond to IL-2. In contrast to the effect it exerts on normal B cells, IL-4 does not promote DNA synthesis by B-CLL lymphocytes. Rather this interleukin inhibits the response to IL-2 in all patients' cells that responded to this interleukin. We thus examined whether IL-4 would modulate the number and/or the affinity of IL-2 receptors. A 3-day activation of cells by anti-microAb induced a few hundred high affinity IL-2 receptors (HA-IL-2R) on B-CLL cell surface, as determined by Scatchard analysis. Treatment of cells with IL-4 caused a marked decrease in the number of HA-IL-2R without interfering with the binding ability of IL-2. In contrast with this profound suppressive effect, IL-4 did not down-regulate the expression of each chain, alpha and beta (p55 and p75, respectively), of the HA-IL-2R heterodimer. In fact, the expression of alpha and beta induced by anti-microAb was enhanced by IL-4. Altogether, IL-4 exerts a critical influence on the function and the configuration of HA-IL-2R without inhibiting the expression of two subunits, alpha and beta.

Regulatory effects of IL-4 on human B-cell response to IL-2

Interleukin-4 (IL-4) counteracts a number of the direct effects of interleukin-2 (IL-2) on B-cells. We here summarize and extend our results, obtained in two different experimental systems, on the antagonism between these two major interleukins. IL-4 inhibits the effect of IL-2 on the proliferation as well as the differentiation of B-type chronic lymphocytic leukemia (B-CLL) cells. When B-CLL cells are activated by anti-mu Ab in the presence of IL-4, this latter enhances the expression of the p55 as well as the p70/75 chain of the IL-2 receptor. In contrast IL-4 profoundly suppresses the number of high affinity binding sites for IL-2 on in vitro activated B-CLL cells. Such a discrepancy between the suppression of IL-2 binding sites and the enhancement of each component of the heterodimeric IL-2 receptor, is as far as we know, yet undescribed. The interaction of IL-4 with its own receptors might influence the state of p55-p70/75 complex association or act on a third subunit of the IL-2 receptor. When used alone, IL-4 enhances the expression of other activation molecules by B-CLL cells: CD23, DR antigen. Similarly IL-4 can concomitantly enhance the specific response of normal B-cells while suppressing the action of IL-2. When normal human B-cells are specifically stimulated by an insolubilized antigen, IL-4 alone induces an expansion of the number of specific antigen-binding cells. In contrast IL-4 profoundly suppresses the generation of antigen-induced IL-2-dependent specific IgM antibody forming cells.(ABSTRACT TRUNCATED AT 250 WORDS)

B8.7 antigen expression on B-CLL cells and its relationship to the LMW-BCGF responsiveness

In this work, we studied the expression of B8.7 antigen on B lymphocytes from patients suffering from B type chronic lymphocytic leukemia (B-CLL) as well as on non Hodgkin lymphoma cells (NHL). B8.7 is an activation marker, which has been reported to be associated with the capacity of activated B cells to respond to LMW-BCGF. B lymphocytes of 11 out of 22 patients tested were B8.7 positive. With the exception of one case, LMW-BCGF is able to induce DNA synthesis by these cells in the absence of costimulation by anti-mu antibodies (anti-mu Ab). The LMW-BCGF dependent proliferation of these malignant cells is inhibited by the anti-B8.7 monoclonal antibody (anti-B8.7 MoAb), in the same line as that of normal B cells. These results obtained with monoclonal B cells confirm that the B8.7 molecule is involved in the signalling pathway of the LMW-BCGF.

Vertebral hydatidosis and paraplegia

We report the management of two children and 11 adults with paraplegia secondary to vertebral hydatidosis. Destruction of pedicles, posterior vertebral elements and discs as well as the vertebral bodies was common and all six patients with thoracic disease had involvement of adjacent ribs. The 13 patients had a total of 42 major surgical procedures; two patients died from postoperative complications and four from complications of the disease and paraplegia. All eight patients initially treated by laminectomy or anterior decompression alone relapsed within two years and seven required further surgery. Circumferential decompression and grafting gave the best results, six of nine patients being in remission an average of three years and six months later. The prognosis for such patients is poor; remission is the aim, rather than cure. Anthelminthic drugs may improve the prognosis, but radical surgery is likely to remain the keystone of treatment in the foreseeable future.

Interleukin (IL) 4 counteracts the helper effect of IL2 on antigen-activated human B cells

We tested the effect of interleukin (IL) 4 on the specific IgM antibody response induced by trinitrophenylated-polyacrylamide beads (TNP-PAA) in cultures of human B cells. T cell help was provided by exogeneous IL2. IL4 profoundly suppressed the response to optimal concentrations (50 U/ml) of IL2, with a 50% inhibitory concentration of 6 U/ml. This was due neither to a shift in the kinetics nor to a switch to an IgG response. The production of anti-TNP antibody (as measured by an enzyme-linked immunosorbent assay in the culture supernatant) was inhibited to the same extent as the generation of plaque-forming cells. The effect of IL4 was completely abolished by a neutralizing antibody toward IL4. Kinetic studies showed that IL4 had to be present during the first 48 h of culture to fully inhibit the response. The sequential stimulation of B cells by antigen and by IL2 showed that IL4 does not negatively interfere with signaling through membrane Ig but counteracts the effect of IL2 on antigen-activated B cells.

Induction of differentiation in human leukemic B cells by interleukin 2 alone: differential effect on the expression of mu and J chain genes

The effects of interleukin 2 (IL2) on the proliferation and differentiation of B cells were analyzed separately using cells from two patients suffering from B-type chronic lymphocytic leukemia. The monoclonal B cells from these patients exhibited an opposite pattern of responsiveness upon in vitro culture with IL2 in the absence of other stimuli. In the first patient, IL2 alone was able to induce DNA synthesis and no Ig production. In the second patient, although no DNA synthesis was detected, B lymphocytes synthesized IgM upon stimulation with IL2 alone. Analysis of mRNA levels was performed on the cells of this latter patient after culture without or with IL2. In the presence of IL2 we observed a strong enhancement of C mu gene expression associated with an increase of the ratio between the secreted form and the membrane-bound form of mu mRNA. In contrast IL2 induced only a marginal enhancement of J chain mRNA. Thus, terminal B cell differentiation of selected monoclonal B cells can be obtained in the absence of DNA synthesis and IL2 alone can mediate this process. Moreover, IL2 can act at selective steps of the molecular events associated with IgM production. These results document the multiple effects of a given IL on the events leading to antibody production and strongly suggest that they can be conditioned by the maturation stage of a given responding cell.

Interleukin 4 counteracts the interleukin 2-induced proliferation of monoclonal B cells

B cells from patients suffering from B-type chronic lymphocytic leukemia (B-CLL) are susceptible to the effects of several interleukins. Using the cells from 12 different patients we show that IL-4 does not synergize with anti-mu antibody for the enhancement of DNA synthesis. Moreover IL-4 profoundly (90%) suppresses the response to IL-2 in the 10 patient responders to this interleukin. This suppression occurs whether IL-2 is used alone, in costimulation with anti-mu antibody, or in synergy with IFN-gamma. In no instance did IL-4 induce terminal differentiation. This negative effect of IL-4 can take place in monoclonal B-CLL cells where IL-4 enhances the expression of CD23. IL-4 does not interfere with the upregulation of CD25 by IL-2. Thus, IL-4 may display inhibitory effects on the proliferative response of selected B cell populations. The antagonism between IL-4 and IL-2 has important implications for the potential use of cytokines in the management of B-CLL patients.

Positive effects of interferon-alpha on B cell-type chronic lymphocytic leukemia proliferative response

We studied the effect of recombinant interferon-alpha (IFN-alpha) on the proliferative response of normal human B cells and of lymphocytes from 10 patients with B cell-type chronic lymphocytic leukemia. We show that IFN-alpha, which has no effect on B cell proliferation when used alone, can synergize with anti-mu antibody and can support DNA synthesis by anti-mu activated B cells. This was observed with normal B cells and in 4 of 10 patients with B cell-type chronic lymphocytic leukemia. These four patients were all responders to B cell growth factor (BCGF), whereas the responsiveness to IFN-alpha was not correlated with that of IL-2. The positive functional relationship between IFN-alpha and BCGF in these patients is emphasized by the synergistic effect of these two factors in two of these patients, and the lack of inhibition of BCGF response by even supraoptimal concentrations of IFN-alpha. Among the subgroup of patients unable to respond to IFN-alpha, a synergy between IFN-alpha and IL-2 could be observed.

Positive effects of interferon-alpha on B cell-type chronic lymphocytic leukemia proliferative response

We studied the effect of recombinant interferon-alpha (IFN-alpha) on the proliferative response of normal human B cells and of lymphocytes from 10 patients with B cell-type chronic lymphocytic leukemia. We show that IFN-alpha, which has no effect on B cell proliferation when used alone, can synergize with anti-mu antibody and can support DNA synthesis by anti-mu activated B cells. This was observed with normal B cells and in 4 of 10 patients with B cell-type chronic lymphocytic leukemia. These four patients were all responders to B cell growth factor (BCGF), whereas the responsiveness to IFN-alpha was not correlated with that of IL-2. The positive functional relationship between IFN-alpha and BCGF in these patients is emphasized by the synergistic effect of these two factors in two of these patients, and the lack of inhibition of BCGF response by even supraoptimal concentrations of IFN-alpha. Among the subgroup of patients unable to respond to IFN-alpha, a synergy between IFN-alpha and IL-2 could be observed.

Functional heterogeneity of B-CLL lymphocytes: dissociated responsiveness to growth factors and distinct requirements for a first activation signal

We studied the effects of B cell directed growth factors on B lymphocytes from 11 patients with chronic lymphocytic leukemia (B-CLL). B-CLL lymphocytes were costimulated with anti-mu antibody (Ab) and with three growth factor preparations: recombinant IL2, B cell growth factor (BCGF) (20 kiloDalton (kD) BCGF) and a high molecular weight BCGF (50 kD BCGF). IL2 was the more active factor (in six of 11 patients). The effect of IL2 was dependent on a costimulation with anti-mu Ab or occurred independently of anti-mu Ab, according to the patients. This pattern of reactivity did not correlate with the presence or absence of the IL2 receptor (IL2-R) molecule on fresh B-CLL lymphocytes. Five patients responded to the 20 kD BCGF. Although four of them were also strong responders to IL2, one strongly responded to the 20 kD BCGF and did not respond to IL2. Only one patient responded to the 50 kD BCGF. When an anti-IL2-R Ab was introduced into the culture, only the responsiveness to IL2 was abolished: thus both 20 kD and 50 kD BCGFs activate B-CLL lymphocytes independently of the IL2-R. These results show that several B cell directed growth factors can act independently to support the proliferation of B-CLL lymphocytes.

Synergistic effect of recombinant IL 2 and interferon-gamma on the proliferation of human monoclonal lymphocytes

We studied the effect of interferon-gamma (IFN-gamma) on the proliferation of lymphocytes from 10 B-type chronic lymphocytic leukemia (B-CLL) patients. In no instance did IFN-gamma induce a proliferative response whether used alone or in combination with anti-mu antibody (Ab). This was observed regardless of the responsiveness of a given patient's cells to interleukin 2 (IL 2) and to B cell growth factor (BCGF). In contrast IFN-gamma strongly and reproducibly synergized with IL 2 (but not with BCGF) to support B-CLL proliferation in five of the 10 patients. The effect of IFN-gamma was dose related and could be inhibited by an anti-IFN-gamma monoclonal Ab. A monoclonal Ab toward the IL 2 receptor molecule was also inhibitory. Preincubation with IFN-gamma potentiated the responsiveness of B-CLL to IL 2 in secondary cultures, showing that IFN-gamma exerts its effect before that of IL 2.

Synergistic effect of recombinant IL 2 and interferon-gamma on the proliferation of human monoclonal lymphocytes

We studied the effect of interferon-gamma (IFN-gamma) on the proliferation of lymphocytes from 10 B-type chronic lymphocytic leukemia (B-CLL) patients. In no instance did IFN-gamma induce a proliferative response whether used alone or in combination with anti-mu antibody (Ab). This was observed regardless of the responsiveness of a given patient's cells to interleukin 2 (IL 2) and to B cell growth factor (BCGF). In contrast IFN-gamma strongly and reproducibly synergized with IL 2 (but not with BCGF) to support B-CLL proliferation in five of the 10 patients. The effect of IFN-gamma was dose related and could be inhibited by an anti-IFN-gamma monoclonal Ab. A monoclonal Ab toward the IL 2 receptor molecule was also inhibitory. Preincubation with IFN-gamma potentiated the responsiveness of B-CLL to IL 2 in secondary cultures, showing that IFN-gamma exerts its effect before that of IL 2.

B cell differentiation and interleukin 2 (IL2): corticosteroids interact with monocytes to enhance the effect of IL2

Upon in vitro activation by Staphylococcus aureus Cowan I strain (SAC) human peripheral blood B cells produce only marginal amounts of Ig when cultured in the presence of interleukin 2 (IL2; 10 U/ml). This response is only moderately increased by the addition of monocytes or of IL1. In the presence of dexamethasone (DM; 10(-7)-10(-8) M) microgram amounts of both IgM and IgG are produced in co-cultures of B cells and monocytes. This response is not modified by inhibitors of cyclooxygenase and is specifically inhibited by a monoclonal antibody interfering with the binding of IL2 to its receptor. This enhancing effect of DM is not observed in the absence of monocytes even if IL1 is added to the cultures. Moreover, monocytes pretreated with DM stimulate the response of B cells cultures in the absence of DM. Enhancement of Ig production by DM and monocytes could be demonstrated with B cells obtained from a patient suffering from a hyperlymphocytic form of B cell type chronic lymphocytic leukemia, and in this case only IgM was produced. Importantly, DM fully inhibited the IL2-dependent proliferation of these monoclonal B cells. Thus, physiological concentrations of DM can modulate monocytic function to enhance the differentiative effect of IL2.

A T chronic lymphocytic leukemia with large granular lymphocytes. Phenotype and functions of leukemic cells under in vitro treatment by differentiation inducers

We reported the morphologic, phenotypic and functional characteristics of leukemic cells with natural killer (NK) properties in a case of T chronic lymphocytic leukemia with large granular lymphocytes. These cells were cytologically and cytochemically characterized as phosphatase acid positive large granular lymphocytes (LGL), and presented parallel tubular arrays at the ultra structural level. They displayed a CD2, CD3, CD8, CD11, Leu 7, and Leu 11 positive phenotype while they lacked B cell markers including surface immunoglobulins. In addition, they expressed human leukocyte antigens (HLA) Class I, but no Class II antigens. These phenotypic studies were also performed after cells were cultured in vitro with 12-0-tetradecanoyl phorbol 13-acetate, gamma interferon, 5-azacytidine, sodium butyrate, phytohemagglutinin, and interleukin 2 (IL2). The cell surface markers underwent several significant changes. Among them we noted a higher percentage of labeled cells with anti-CD6 and CD7 monoclonal antibodies (moAbs), and a positivity with an anti-CD19 (B4) moAb. The leukemic LGL spontaneously developed a NK activity on K 562 tumor cells, which was not affected under the various T and B cells growth factors because they became more sensitive to IL2; but they were also stimulated by a 50-kilodalton (KD) B cell growth factor (BCGF) factor devoid of any T cell proliferation activity. Together these results gave a better characterization of azurophilic granules containing T chronic lymphocytic leukemia, and enabled the documentation of the differentiation of LGL with NK activity.

Different human B cell subsets respond to interleukin 2 and to a high molecular weight B cell growth factor (BCGF)

After activation by anti-mu antibody human B cells acquire the ability to proliferate in the presence of recombinant interleukin 2 (IL 2), a 20-kDa mol. mass B cell growth factor (BCGF) and a high mol. mass BCGF (50-kDa BCGF). An anti-IL 2 receptor (IL 2R) monoclonal antibody inhibits the IL 2-dependent proliferation without affecting that induced by BCGF. B cells expressing the IL 2R after anti-mu antibody activation (IL 2R+ cells) were separated from those not expressing IL 2R (IL 2R- cells). IL 2 stimulated the proliferation of only IL 2R+ cells whereas the 20-kDa BCGF acted on both IL 2R+ and IL 2R- cells. Importantly, the 50-kDa BCGF supported the proliferation of IL 2R- cells whereas it was inactive on IL 2R+ cells. Thus, the B cell subset responding to the 50-kDa BCGF after anti-mu antibody activation is distinct from that responding to IL 2.

Quantitative evidence against inactivation of self-reactive B-cell clones

The frequencies of murine B-cell precursors developing into clones secreting antibodies which bind to autologous (mouse) or heterologous (rabbit or human) forms of the same protein antigen (myosin and albumin) were determined in an attempt to directly test the hypothesis of higher decay rates of B lymphocytes exposed to self-antigens. The results exclude, on a quantitative basis, any form of inactivation or deletion of such cells.