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The common leukocyte antigen CD45 plays a central role in T cell activation in coupling the T cell receptor (TCR) to the phosphatidylinositol pathway via interactions with TCR-associated protein tyrosine kinases lck and fyn. We here demonstrate that engagement of CD45 by monoclonal antibodies (mAb) on activated T cells induces tumor necrosis factor (TNF)-alpha as well as TNF-beta, interleukin (IL)-2 and IL-3 gene expression. When human alloreactive T cells are stimulated with mAb 4B2, which recognizes a determinant common to all CD45 isoforms, a vigorous production of TNF-alpha mRNA was detected, which peaked 2 h later. Anti-CD45 mAb cross-linking was required. In contrast, neither mAb 10G10, which recognizes an epitope distinct from the one recognized by mAb 4B2, nor mAb UCHL-1, a CD45RO-specific antibody, induced any significant increase in TNF-alpha transcription. Nuclear run-on transcription assays demonstrated that CD45 cross-linking caused transcriptional activation of the TNF-alpha gene. De novo protein synthesis was not required, since incubation with cycloheximide (CHX) did not block transcriptional activation. CHX in contrast up-regulated TNF-alpha gene expression and increased transcript half-life, an effect that was under control of post-transcriptional mechanisms. Engagement of CD45 by itself did not affect transcript stability. CD45 ligation resulted in TNF-alpha secretion. These results indicate that in addition to its role in TCR/CD3-mediated T cell activation, CD45, in an epitope-specific manner, may act as a primary signaling molecule, leading to the transcriptional regulation and secretion of a major pro-inflammatory cytokine.

Background: Multiple evanescent white dot syndrome (MEWDS) is a benign acquired isolated chorioretinal disorder. Symptoms include photopsia, visual blur and scotomas. Ocular examination reveals multiple white dots at the level of the deep retina. A parainfectious disorder was suggested but the exact mechanism of MEWDS is still unknown. Postulating that MEWDS might be an antigen driven inflammatory reaction, we analyzed HLA subtypes in patients with MEWDS., Patients and Methods: Sixteen patients were diagnosed with MEWDS in Lausanne from 1985 to 1994. Blood was withdrawn in 9/16 patients. HLA-A, -B and -DR were sought., Results: HLA-B51 was detected in 4/9 patients (44.4%). Other HLA subtypes were detected sporadically., Conclusions: The frequency of HLA-B51 haplotype was found to be 3.7 times more elevated than in a normal control caucasian group. This suggests the possibility that MEWDS might be a genetically determined disorder as it is the case for other ocular diseases like Birdshot chorioretinopathy (HLA-A29), Harada's disease (HLA-DRMT3), acute anterior uveitis (HLA-B27) or Behçet's disease (HLA-B51). We have no explanation for the presence of HLA-B51 in both Behçet's disease and MEWDS. The association of HLA-B51 and MEWDS needs confirmation by further testing.

Over a period of 5 years, an isolated light chain (kappa = 9, lambda = 12) was detected in 21 sera by immunofixation electrophoresis. Further analysis with anti-delta- and anti-epsilon-specific antisera identified four delta heavy chains, all associated with a lambda light chain, and no epsilon heavy chains. For evaluation of the role of two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) in the diagnosis of IgD paraproteins, as a possible alternative or complement to immunofixation, IgD paraproteins were retrospectively analyzed by 2D-PAGE. Delta Heavy chains migrated to gel areas clearly distinguishable from other heavy chains alpha, gamma, or mu, and in a wide range of isoelectric points (pI: 5.4-8). In one serum, the monoclonal delta chain had a pI range comparable to that of albumin and was undetectable. However, all four delta chains were easily identified when analyzed from affinity-purified immunoglobulin fractions. These observations showed the following: 1) IgD paraproteins are not rare among apparently isolated monoclonal light chains detected by routine immunofixation, strongly confirming the need for further analysis with anti-delta antisera, before assumption of a light-chain disease. 2) 2D-PAGE analysis of affinity-purified immunoglobulin fractions allowed correct identification of IgD monoclonal gammopathies in all cases. 3) However, although 2D-PAGE analysis is now easy to perform, well standardized, and highly sensitive, this technique remains time-consuming and expensive, and does not appear suitable for routine practice as a first-line diagnostic procedure. 2D-PAGE should find its place as a complement to immunofixation and in the definitive demonstration, in selected ambiguous cases, of the clonal pattern of a suspected gammopathy at immunofixation.

A 43-year-old patient was admitted for swollen and painful ankles, knees and elbows, palpable purpura of the lower extremities and fever. Splenomegaly had been diagnosed 5 years previously. At clinical workup, spleen and liver size were increased and purplish papular skin lesions were noted above the ankles. Erythrocyte sedimentation rate was 2 mm/h. ASAT and ALAT as well as rheumatoid factor were moderately elevated. Serology was positive for hepatitis C. Differential diagnosis of palpable purpura and complementary diagnostic procedures are discussed.

The authors review aspects of occupational asthma that are important for the practitioner. Insurance problems are dealt with in the light of local regulations. Detailed chapters are devoted to baker's asthma (various aeroallergens), to plastic workers and painters (isocyanates) and to respiratory diseases among farmers. Finally, a list of other occupations in which asthma typically occurs is given. The responsibility of practitioners in charge of young patients about to choose their future profession is underlined.

Allergic granulomatosis and angiitis (Churg-Strauss syndrome) is characterized by a systemic vasculitis in the context of bronchial asthma and eosinophilia. Pathologically, there is a necrotizing vasculitis of small arteries and veins with extravascular granulomas, infiltration of vessels and perivascular tissue with eosinophilia. Pulmonary, peripheral nervous system, cardiovascular and cutaneous manifestations are most frequently encountered. Renal failure and high blood pressure are more rare. These features, within the setting of bronchial asthma and eosinophilia, differentiate Churg-Strauss syndrome from polyarteritis nodosa. Steroid associated to cyclophosphamide have considerably improved the prognosis and risk of relapse.

The transmembrane tyrosine phosphatase CD45 plays an important role in TCR/CD3-mediated signaling. We demonstrate in this study that ligand binding to the CD45 molecule induces homotypic cell adhesion of activated, but not resting, T lymphocytes. mAbs to CD45 (4B2 and 10G10) and to CD45RO (UCHL1), but not to CD45RA (IOL2), caused sustained adhesion of alloreactive T cell lines. In contrast, none of the anti-CD45 mAbs induced aggregation of resting peripheral T cells. CD45-mediated adhesion of activated T cells involved both CD11a/18-dependent as well as CD11a/18-independent mechanisms. mAb 4B2 induced a strictly CD11a/18-dependent adhesion that was completely inhibited by both the protein kinase C (PKC) inhibitor sphingosine and the protein tyrosine kinase (PTK) inhibitors genestein and herbimycin A. In contrast, mAb 10G10, which recognized an epitope on CD45 distinct from the one recognized by mAb 4B2, induced CD11a/18-independent adhesion that was inhibited by sphingosine, but not by genestein or herbimycin A. Biochemical studies revealed direct evidence for activation of protein kinase C and protein tyrosine kinase after engagement of CD45 on activated T cells by mAb 4B2. These results indicate that in addition to its role in TCR/CD3-mediated activation, engagement of CD45 transduces signals that result in enhanced adhesiveness of activated T cells.

The clonality of immunoglobulins (Igs) in cryoprecipitates (n = 41) was studied by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Our series included 24 cryoglobulins characterized by immunofixation electrophoresis (IF), 12 'trace amount' cryoglobulins, defined by a protein content in the precipitate of less than 0.05 mg/ml of serum, and five cryoglobulins of undetermined protein composition by IF. 2-D PAGE analysis showed polyclonal IgG associated either with monoclonal Igs (type II cryoglobulins; n = 14) or with polyclonal IgM (type III cryoglobulins; n = 14). In ten cryoprecipitates (two 'trace amount' cryoglobulins as well as seven of 19 type II and as one of five type III cryoglobulins by IF) polyclonal IgG were associated with a mixture of polyclonal and monoclonal IgM. These cryoglobulins were tentatively named type II-III cryoglobulins. A monoclonal IgM was observed in one cryoprecipitate (type I cryoglobulins). Two cryoglobulins presented unexpected 2-D patterns, characterized by the presence of oligoclonal IgM, with trace amounts of Igs of different isotypes (tentatively named type II-III(variant) cryoglobulins). A peptide of 44 kDa with a pI of 5.45 was observed in all cryoglobulins containing IgM (n = 40). This peptide was also present in purified monoclonal or polyclonal IgM fractions. N-terminal microsequencing (12 amino acid residues) revealed that this IgM-associated peptide was an unknown protein. Our results highlight the role of 2-D PAGE as an aid in the analysis of cryoglobulins.

In this paper, we summarize our five-year observation of two-dimensional polyacrylamide gel electrophoretic (2-D PAGE) analysis of immunoglobulin (Ig) light (L) chain patterns on serum/plasma and/or purified human Ig, and compare this technique with agarose electrophoresis and/or immunofixation examination. Polyclonal Ig L chains were seen as large "fuzzy" areas with several zones of high density. The majority (71%) of the monoclonal Ig L chains of monoclonal gammopathy detected by conventional electrophoresis appeared as a single large and well-defined spot on 2-D PAGE analysis, with the remaining appearing as multiple spots. The presence of oligoclonal Ig, reflected by multiple spots in 2-D PAGE, and several bands in immunofixation, was observed in 5 of 26 patients after allogeneic bone marrow transplantation and in 5 patients with tumors. In the majority (77%) of hypergammaglobulinemia, L chains appeared as a wide spread of small and well-defined spots in 2-D PAGE analysis. This pattern suggested oligoclonal Ig-secreting B cell clone expansion, and corresponding abnormalities were not detected with immunofixation. 2-D PAGE analysis also detected oligoclonal Ig expansions whereas conventional electrophoretic examination was normal in 10 additional patients after bone marrow transplantation, and in 6 of 10 immunocompetent patients with acute severe infections. Analysis of the Ig L chain pattern of a severe combined immune-deficient mouse populated with human peripheral blood leukocytes confirmed the skewed human Ig production in the model. In summary, 2-D PAGE appears to be a sensitive tool for the analysis of Ig diversity in various clinical situations.

An IgG3 monoclonal antibody, 6-19, derived from unmanipulated MRL/MpJ-lpr/lpr mice, exhibiting cryoglobulin and anti-IgG2a rheumatoid factor activities, induces skin leukocytoclastic vasculitis and glomerulonephritis when injected into normal mice. To determine the role of the gamma 3 heavy chain constant region in the generation of cryoglobulins and associated tissue lesions, we have established an IgG1 class switch variant, clone SS2F8, from the 6-19 hybridoma by sequential sublining. Here we report that the SS2F8 monoclonal antibody, which loses the cryoglobulin activity but retains the rheumatoid factor activity, fails to generate skin and glomerular lesions. The lack of pathogenicity of the IgG1 SS2F8 switch variant is not due to mutations in variable regions, since nucleotide sequence analysis shows no differences between both clones. In addition, we have observed that the IgG1 SS2F8 switch variant exhibits < 10% of the rheumatoid factor activity, as compared with the IgG3 6-19 monoclonal antibody, suggesting that the self-associating property of the gamma 3 isotype promotes antibody-binding activity. The present study indicates that the cryoglobulin activity associated with the gamma 3 isotype is critically involved in the pathogenicity of 6-19 anti-IgG2a rheumatoid factor monoclonal antibody and highlights the pathogenic relevance of autoantibodies of the IgG3 subclass in murine systemic lupus erythematosus.

High-resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used to analyze serum samples and purified immunoglobulins (Ig) obtained from "normal" individuals and from patients diagnosed with monoclonal gammopathies (MG) (n = 47; 5 IgA, 15 IgM, 15 IgG, 4 biclonal IgG, 1 IgD, 7 Bence Jones proteins). Polyclonal and monoclonal heavy (H) chains were located at different restricted gel positions according to their isotype. Monoclonal H chains appeared as sets of spots characterized by charge (pI) and size (M(r)) microheterogeneity. Most of the monoclonal gamma chains were not seen on the gels (12/15). Supplementary polypeptides of 45-48 kDa were detected in serum samples containing monoclonal IgM, but were not seen in MG of other isotypes. However, these polypeptides were not specifically associated with monoclonal IgM because they were also found on protein maps of purified polyclonal IgM. Polyclonal light (L) chains appeared as cloudy bands containing several zones of higher density, whereas monoclonal L chains were usually resolved as single sharp spots. In 6 samples, monoclonal L chains were not seen, and in 9 samples, they appeared as two or more spots, characterized by different pI and/or M(r). In one sample obtained from a patient with a biclonal gammopathy, the L chains were resolved as 4 different spots. Our results confirm that 2-D PAGE is an excellent tool to study Ig. Analysis of the L chain region of the gels was particularly informative. Several monoclonal L chains exhibited heterogeneous two-dimensional spot patterns, suggesting that "subtile" clonal mutations of B-cell lineage and/or posttranslational modifications were involved in their production.

The reduction of the bronchial inflammatory reaction, in itself a triggering event for bronchospasm, is one of the main targets for treatment in bronchial asthma. An early engagement of anti-inflammatory agents is, therefore, as necessary for long-term treatment as the reduction of irritating or antigenic environmental factors. Assessment of therapeutic efficacy necessitates a regular and long-lasting surveillance of the patient. It can be provided by peak-flow measurement, performed by the patient himself. Finally, the close cooperation by patient and physician as well as the elaboration of a training program teaching the patient pathophysiology, symptoms and therapeutic possibilities are decisive for therapeutic success, i.e. the best possible restitution of pulmonary function.

Engagement of MHC class II (Ia) molecules on B cells induces tyrosine phosphorylation, phosphoinositide turnover, elevation of intracellular calcium concentrations, and a rise in cAMP levels. However, a role for these biochemical signals in mediating functional responses induced by Ia ligands remains largely undefined. In this study, we utilized the induction of B cell adhesion by Ia ligands to demonstrate a role for signals transduced via Ia molecules in the generation of a functional response. Ia ligands that induced B cell aggregation induced tyrosine phosphorylation, whereas Ia ligands that did not induce B cell aggregation failed to induce any detectable tyrosine phosphorylation. Ia-induced B cell aggregation and tyrosine phosphorylation were inhibited by genistein and by herbimycin A, inhibitors of tyrosine kinases (PTK). Sphingosine and calphostin C, inhibitors of protein kinase C (PKC), also inhibited Ia-induced adhesion whereas HA1004, an inhibitor of cyclic nucleotide-dependent kinases, did not. Ia ligands induced both LFA-1-dependent and LFA-1-independent B cell adhesion. These two pathways of cell adhesion differed in their requirement for activation signals. PKC activation was sufficient for LFA-1-dependent adhesion, whereas LFA-1-independent adhesion required independent phosphorylation events mediated by PKC and by PTK. These results provide functional relevance for biochemical signals transduced via Ia molecules by demonstrating that Ia-induced B cell adhesion is mediated by the activation of PKC and by one or more PTK.

We examined the role of MHC class II molecules in transducing signals to activated human T cells. Cross-linking of MHC class II molecules synergized with submitogenic amounts of anti-CD3 mAb in causing proliferation and secretion of the cytokines IL-2, IL-3, IFN-gamma, and TNF-alpha by MHC class II-alloreactive T cell lines. Signaling via MHC class II molecules in T cells resulted in activation of tyrosine kinases, in generation of inositol phosphates, and in Ca2+ mobilization that was abrogated by the tyrosine kinase inhibitor herbimycin A. Thus, like signaling via TCR/CD3, signaling via MHC class II molecules involved tyrosine kinase-dependent activation of phospholipase C, resulting in phosphoinositol turnover and Ca2+ flux. However the signaling pathways coupled to MHC class II molecules and to TCR/CD3 differed, because engagement of the transmembrane phosphatase CD45 inhibited Ca2+ fluxes triggered via TCR/CD3 but not Ca2+ fluxes triggered via MHC class II molecules.

We here demonstrate that ligand binding to MHC class I molecules induces homotypic cell adhesion of lymphocytes and monocytes. mAb to beta 2-microglobulin caused sustained, largely LFA-1-independent adhesion whereas mAb to the MHC class I alpha H chain caused transient LFA-1-dependent adhesion. Both the protein kinase C inhibitor sphingosine and the tyrosine kinase inhibitor genistein abrogated MHC class I-mediated cellular adhesion. These results indicate that MHC class I molecules transduce signals that induce cell adhesion and suggest that interaction between MHC class I-restricted T cells and APC may result in reciprocal enhanced adhesiveness of these cells.

We observe that PBMC from most adults (16 of 18 subjects tested) show a small but significant in vitro proliferative response to a 30-amino acid-long peptide (peptide 2, amino acids 34-63) derived from toxic shock syndrome toxin. By contrast, PBMC from newborn blood and thymocytes do not proliferate to this peptide, and furthermore, peptide 2 did not displace the binding of radiolabeled TSST-1 to MHC class II positive cells, nor did it induce IL-1 beta mRNA in monocytes, indicating that this peptide does not behave as a superantigen. Proliferation of PBMC to peptide 2 could be blocked by anti-HLA-DR, but not by anti-HLA-DP or DQ mAb, suggesting that HLA-DR molecules are the restriction elements for the recognition of this peptide by T cells. This premise was further confirmed by demonstrating that mouse L cells transfected with human HLA-DR, but not HLA-DP or DQ molecules, supported the proliferation of purified T cells to peptide 2. Studies with subjects of known HLA-DR types showed that all types tested are capable of responding to this peptide, PBMC from adults exposed to mycobacterial Ag showed significantly better proliferative response to peptide 2 than unexposed adults. Studies with truncations of this peptide suggest that a "core" region of eight amino acids that is conserved between low m.w. heat shock proteins and peptide 2 may be critical to T cell recognition of this peptide. The universal presentation of peptide 2 by HLA-DR molecules may contribute to the widespread natural immunity observed against toxic shock syndrome toxin.

We investigated whether staphylococcal exotoxins (SEs), in addition to their capacity to induce T-cell activation restricted by the T-cell receptor (TCR) beta-chain variable region, can deliver an activation signal to human T-cell clones through major histocompatibility complex (MHC) class II molecules. Eleven human T-cell clones (9 alpha beta TCR and 2 gamma delta TCR clones) of different antigenic specificities were tested for their capacity to proliferate in response to toxic shock syndrome toxin 1 (TSST-1) and two SEs, SEA and SEB. In the absence of accessory cells, only 4 alpha beta TCR clones were stimulated to proliferate, each by a single SE, and to mobilize intracellular free Ca2+ in response to that SE, events indicative of TCR engagement and, presumably, recognition restricted by the beta-chain variable region. In the presence of accessory cells, each of the 11 T-cell clones was stimulated to proliferate by any one of the three SEs tested. This apparently TCR-unrestricted SE-mediated polyclonal proliferation of T-cell clones occurred in the absence of an increase in intracellular free Ca2+ and was not dependent on the presence of MHC class II expression on accessory cells. In contrast, SE-mediated polyclonal proliferation did not occur in 3 alpha beta TCR clones derived from an MHC class II-deficient patient. Furthermore, all of the three SEs induced the proliferation of 4 natural-killer-cell clones, suggesting that expression of TCR/CD3 complex is not essential for SE-mediated polyclonal proliferation of activated lymphocytes. These results indicate that MHC class II molecules transduce activation signals to human T- and natural-killer-cell clones.

A mouse mAb, TS 43, which recognized the human CD5 molecule, was found to induce the proliferation of human peripheral blood T cells. TS 43 mAb precipitated from 125I-radiolabeled T cells a 67-kDa band, which comigrated with the 67-kDa band precipitated by the anti-CD5 mAb OKT1. Preclearing of cell lysates with OKT1 mAb abolished the capacity of TS 43 mAb to precipitate radiolabeled material from T cell lysates. Furthermore, a mouse T cell hybridoma transfected with human CD5 was stained by TS 43 mAb. T cell proliferation mediated by TS 43 mAb was monocyte dependent, and was accompanied by IL-2R expression and by IL-2 synthesis. T cell activation by TS 43 mAb involved a rise in intracellular calcium level (CA2+)i and was dependent on the expression of the TCR/CD3 complex because no rise in (Ca2+)i was observed in a TCR-beta-deficient Jurkat T cell mutant. This study indicates that CD5 should be added to the list of surface molecules that can signal T cells to proliferate.

MRL-lpr/lpr mice spontaneously develop a lupus-like syndrome characterized by immunopathological manifestations such as necrotizing vascular lesions of ear tips and severe glomerulonephritis. Similar skin vascular and glomerular lesions associated with cryoglobulinemia can be induced in normal mice by injection of a monoclonal antibody (mAb)--6-19 (gamma 3 heavy chain and kappa light chain), exhibiting both cryoglobulin and anti-IgG2a rheumatoid factor (RF) activities--derived from the MRL-lpr/lpr autoimmune mouse. To determine the role of RF and/or IgG3 Fc fragment-associated cryoglobulin activities in 6-19 mAb-induced tissue lesions, a 6-19-J558L hybrid mAb (gamma 3 heavy chain and lambda 1 light chain) was produced by fusion between the 6-19 hybridoma and the J558L myeloma. Here we report that the 6-19-J558L hybrid mAb, which loses the RF activity but retains the cryoglobulin activity, fails to induce skin vascular lesions. However, it is still able to provoke glomerular lesions identical to those caused by the 6-19 mAb. Further, we have observed that the depletion of the corresponding autoantigen, IgG2a, in mice by treatment with anti-IgM antisera from birth also prevents the development of skin but not glomerular lesions. Our results indicate that both RF and cryoglobulin activities of the 6-19 mAb are required for the development of skin vasculitis, but its cryoglobulin activity alone is sufficient to cause glomerular lesions. In addition, cDNA cloning and sequencing of the 6-19 mAb has revealed that the 6-19 kappa light chain variable region amino acid sequence is encoded in a germ-line configuration, suggesting that immunoglobulin variable region germ-line genes could contribute to the generation of pathogenic autoantibodies.

Factor D is an essential enzyme for activation of complement by the alternative pathway (AP). It has been difficult to obtain mouse monoclonal antibodies (Mabs) which block the function of factor D. We have developed a strategy to obtain such Mabs using a double screening procedure of the initial clones. We selected the clone whose supernatant had the lowest level of anti-factor D Ab by ELISA and abolished factor D haemolytic activity. Addition of this Mab to human serum was shown to abolish conversion of C3 by cobra venom factor, haemolysis of rabbit erythrocytes, and activation of C3 and C5 by cuprophane dialysis membranes.

Over a 3-year period 22 episodes of peritonitis were observed among 20 patients treated for end-stage renal failure by CAPD. This represents an overall incidence of 1 episode every 9.5 patient-months (1/14.2 months in 1981, 1/11.3 months in 1982). Eight patients out of 20 never developed peritonitis, and 6 had one episode only. Cocci + were the most frequent culture finding. Two episodes of mycotic peritonitis and 1 sterile peritonitis were observed. Antibiotic treatment was generally successful within 24 h. The incidence of peritonitis was higher among diabetic (1/7 months) than among non-diabetic patients (1/12.6 months). Patient selection, the bag connection technique and the experience accumulated by the dialysis team appear to be the principal factors in lowering the incidence of this complication.

Previously we have demonstrated that eight out of nine IgG3 monoclonal antibodies (mAb) obtained from autoimmune MRL-lpr/lpr mice were able to self-associate and to precipitate in the cold (Gyotoku et al., J. Immunol. 1987. 138:3785). To determine whether the cryoprecipitation of IgG3 mAb is enhanced or inhibited in the presence of specific ligand, we have established eight IgG3 mAb reactive with 2,4-dinitrophenol (DNP) hapten: four mAb were obtained from fusion of spleen cells of C57BL/6 mice immunized with 2,4,6-trinitrophenylated keyhole limpet hemocyanin, three from 129/Sv and one from BALB/c immunized with DNP-lipopolysaccharide. Five of them induced cryoglobulins composed exclusively of the IgG3 mAb. The binding of negatively charged monomeric DNP-amino acid conjugates completely inhibited the cryoprecipitation of all the five cryoprecipitating anti-DNP IgG3 mAb, while the incubation with positively charged or neutral DNP-amino acid conjugates had variable effects: increase, inhibition or no change of the cryoprecipitation. In addition, positively charged DNP-amino acid conjugates were able to induce the cryoprecipitation of one of the non-cryoprecipitating anti-DNP IgG3 mAb. Our data showed that (a) IgG3 mAb derived from non-autoimmune strains of mice, similar to IgG3 mAb derived from an autoimmune MRL-lpr/lpr strain, possessed the unique property to self-associate and were able to form cryoglobulins in most cases; (b) although the Fc-Fc interactions of IgG3 mAb play a decisive role in IgG3 cold solubility, IgG3 cryoprecipitation was markedly influenced after interacting with their specific ligand, depending on the charge of the hapten-amino acid conjugate. This suggested that even minor interferences with the electrostatic equilibrium of the IgG3 by the binding of charged hapten molecules induced dramatic changes in the solubility of the IgG3 mAb at low temperature.

We studied the clinical significance of S. milleri isolated in our hospital in 68 patients during a 18-month period. In 51 patients (median age: 43 years, no underlying diseases in 29 patients), the isolates were associated with significant infections. They were beta-hemolytic in 32 cases and non-hemolytic in 19. The primary infection sites were the head and neck area (21 cases), the lungs (5 cases of pneumonia), the gastrointestinal tract (12 cases), the urogenital tract (3 cases), the soft tissues (6 cases), and the heart (2 endocarditis). Two septicemias were of unknown origin. Head and neck infections and pneumonia were most often associated with beta-hemolytic strains, and bacteremia, gastrointestinal and urogenital tract infections with alpha-hemolytic strains. S. milleri was found in pure culture in 24 cases. Polymicrobial associated flora (27 cases) was more frequent in the abdominal infections (87%) than in supra-diaphragmatic infections (42%). Severe complications were observed in 12 head and neck infections (57%) (cerebral abscesses 3, lethal mediastinitis 2, osteitis 1, meningitis 1, other suppurative lesions 5). When abscesses were present (27 cases), surgery was required in all cases. Despite the high frequency and severity of local complications, the clinical outcome was usually favorable. However, deaths directly related to S. milleri infections occurred in 2 cases of mediastinitis complicating the course of apparently harmless primary infections. Owing to the possible occurrence of life-threatening complications, S. milleri infections require early identification, treatment and surgery when indicated.

Two out of five murine IgG3 anti-trinitrophenyl (TNP) monoclonal antibodies (mAb) obtained either by immunization with TNP-keyhole limpet hemocyanin (KLH) (CB1, CB5, CB6 and 4H10) or with dinitrophenyl-lipopolysaccharide (9A6), exhibited anti-IgG rheumatoid factor (RF) activity (CB6 and 4H10). The anti-IgG activity of these two anti-TNP RF was specifically inhibited by murine IgG as well as by the hapten TNP. In order to identify the structural basis for the anti-IgG activity, the nucleotide sequences encoding the VH and VL regions were determined. By comparing the V regions of the non-RF and RF anti-TNP mAb, it was found that one anti-TNP RF antibody, CB6, shares virtually identical VL and VH regions with two anti-TNP antibodies, CB1 and CB5, but markedly differs from these in the D region. Furthermore, the light chain framework region 2 (FR2) and FR3 of non-RF mAb, CB1, CB5 and 9A6, have amino acid sequences almost identical to those claimed for anti-IgG1 RF activity (Shlomchik et al., J. Exp. Med. 1986. 164: 407). Our findings suggest, at least in the case of CB6 mAb, the involvement of CDR, but not light chain FR residues, in IgG binding.

The 31 Swiss dialysis units treating adult patients with end-stage renal failure have been surveyed. At the end of 1982, 1849 patients, i.e. 284.5/10(6) population were treated, 821 (44.4%) by center hemodialysis, 205 (11.1%) at home, 115 by self-care hemodialysis, 190 (10.2%) by CAPD and 518 (28.0%) by renal transplantation. Centers located in French-speaking Switzerland treat more patients by center hemodialysis (131.4 vs 119.7/10(6) in the German-speaking area), at home (36 vs 29.4/10(6] and by self-care hemodialysis (47 vs 9.4/10(6], while the centers located in the German-speaking area treat more patients by CAPD (33 vs 18.7/10(6] and renal transplantation (92.3 vs 44.6/10(6]. The nursing staff varies among the centers from 1.6 to 10.2 patients/nurse and is in inverse ratio to the number of patients treated per center. It is concluded that 1. in Switzerland, 284.5 patients per million population are treated for ESRF, representing one of the world's highest ratios, 2. within the same country, wide geographical differences are apparent in the choice and application of the various ESRF treatment modalities, 3. the setting-up of numerous new dialysis units seems to lead to the preferential development of center hemodialysis and to a high nursing staff requirement. Other treatment approaches are recommended.

Out of 100 patients undergoing chronic hemodialysis in Lausanne (Switzerland), 12 developed a carpal tunnel syndrome (i.e. 8 men and 4 women, from 34 to 76 years old). Out of 66 patients with an arteriovenous fistula for less than 4 years, it is interesting to note that only 3 carpal tunnel syndrome were observed; whereas, out of 34 hemodialysis patients being dialyzed more than 4 years, 9 of them showed that syndrome. The symptomatology of the carpal tunnel syndrome is described by the authors. It has always been confirmed by EMG. On 10 patients, the symptoms were so acute that they needed a decompression of the median nerve. Five cases were bilateral. The operation is performed under axillary block, without tourniquet. The results were very satisfactory. Paresthesias disappeared after a few hours or a few days following the operation. No relationship could be established between CTS and the type of nephropathy, severity of polyneuropathy, Ca and P metabolism, vascular access complications, efficacity of dialysis, fluid overload or medical treatment. The authors are investigating the etiology of the carpal tunnel syndrome, ship hypothesize particularly concerning the direct or remote relation between the carpal tunnel syndrome and the arteriovenous fistula.

Among 100 patients treated by chronic hemodialysis, 12 developed a carpal tunnel syndrome (CTS). After surgery, improvement was dramatic with regression of pain and paresthesiae within a few hours. Recovery of motor and sensory deficits was longer (2-3 weeks). No relationship could be established between CTS and the type of nephropathy, severity of polyneuritis, Ca and PO4 metabolism, the presence of vascular access and efficacy of dialysis. The bilaterality of the lesions in 7 patients suggests general pathogenic mechanisms superimposed to the presence of the vascular access. While only 3 out of 65 patients treated for less than 4 years complained about CTS, 9 out of 35 treated for more than 4 years were symptomatic.

A pituitary tumor was diagnosed in a prepubertal 13-yr-old girl, who had elevated plasma LH (58 mIU/ml) and PRL (93 ng/ml) levels; decreased GH, ACTH, and FSH secretion; and diabetes insipidus. After surgery, plasma LH and PRL declined, but not to normal levels. Conventional external radiotherapy to the pituitary was immediately followed by a decrease in LH to prepubertal values (0.7 mIU/ml), while PRL levels became normal only after a long course of bromocriptine therapy. The pituitary tumor was composed of two distinct cell types: small polygonal cells, which were PRL positive by immunohistochemistry, and clusters of pleomorphic large frequently mitotic polynucleated cells, which were LH positive, some of them also being positive for the alpha-subunit or beta LH but not for beta FSH. Four years after surgery and radiotherapy, the patient deteriorated neurologically. Computed tomographic scan showed widespread frontal and periventricular tumor, which had the histological features of a poorly differentiated carcinoma. No PRL, LH, or alpha- or beta-subunits were detectable on immunocytochemistry. While the PRL-positive cells of the pituitary tumor displayed the histological and clinical features of PRL adenomas, the morphological characteristics of LH cells and the sharp decline of plasma LH levels after radiotherapy were suggestive of malignant transformation. In this context, the later brain tumor could have been the result of subependymal spread of the pituitary tumor after it lost its hormone-secreting capacity.