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Brain-derived neurotrophic factor (BDNF), a major neuronal growth factor, is also known to exert an antiapoptotic effect in myeloma cells. Whereas BDNF secretion was described in B lymphocytes, the ability of B cells to produce sortilin, its transport protein, was not previously reported. We studied BDNF production and the expression of its receptors, tyrosine protein kinase receptor B and p75 neurotrophin receptor in the human pre-B, mature, and plasmacytic malignant B cell lines under normal and stress culture conditions (serum deprivation, Fas activation, or their combination). BDNF secretion was enhanced by serum deprivation and exerted an antiapoptotic effect, as demonstrated by neutralization experiments with antagonistic Ab. The precursor form, pro-BDNF, also secreted by B cells, decreases under stress conditions in contrast to BDNF production. Stress conditions induced the membranous expression of p75 neurotrophin receptor and tyrosine protein kinase receptor B, maximal in mature B cells, contrasting with the sequestration of both receptors in normal culture. By blocking Ab and small interfering RNA, we evidenced that BDNF production and its survival function are depending on sortilin, a protein regulating neurotrophin transport in neurons, which was not previously described in B cells. Therefore, in mature B cell lines, an autocrine BDNF production is up-regulated by stress culture conditions and exerts a modulation of apoptosis through the sortilin pathway. This could be of importance to elucidate certain drug resistances of malignant B cells. In addition, primary B lymphocytes contained sortilin and produced BDNF after mitogenic activation, which suggests that sortilin and BDNF might be implicated in the survival and activation of normal B cells also.

CD1d-restricted invariant natural killer T (iNK T) cells activated by their experimental ligand alpha-galactosylceramide (alpha-GC) can produce both T helper 1 (Th1) and Th2 cytokines and display regulatory functions. Recent studies identified CD4(+) and CD4(-) CD8(-) double-negative (DN) iNK T cells as the two major components of the human population and suggest that they display a Th2 and a Th1 profile, respectively. We compared the Th2-promoting activity of freshly isolated human CD4(+) and DN iNK T cells in terms of their capacity to induce Ig production by autologous B cells. Secretion of IgG and IgE but not IgM was enhanced by the CD4(+) T cell subset (including iNK T cells) but not by its DN counterpart. iNK T cells were directly responsible for this pro-Th2 effect, as demonstrated by the requirement for both alpha-GC stimulation and CD1d presentation, as well as by its disappearance upon iNK T cell depletion. Interaction with iNK T cells led to progressive accumulation of isotype-switched and activated B cells. Myeloid dendritic cells (DC) completely block the induction of Ig production in co-culture. This dominant inhibitory effect of myeloid DC was concomitant with a specific loss of interleukin (IL)-4 production by CD4(+) iNK T but not by conventional T cells. These data support the conclusion that, conversely to the interferon (IFN)-gamma-producing DN human iNK T cell population, interleukin (IL)-4-producing CD4(+) iNK T cells can activate and help B cells to produce both IgG and IgE through a CD1d-dependent mechanism, in keeping with a functional Th1/Th2 dichotomy between these subsets.

In human African trypanosomiasis, trypanosomes first develop in the blood and lymph (Stage 1), then spread to the central nervous system (CNS) (Stage 2). Disruption of the blood-brain barrier of unknown mechanism occurs in Stage 2 disease. The hypothesis that cerebrospinal fluids (CSF) from African trypanosomiasis patients might contain factor(s) able to induce apoptosis in endothelial cells led us to evaluate this effect by two methods, the TdT-mediated dUTP nick end labelling (TUNEL) method and the measurement of soluble nucleosomes released by apoptotic cells in culture supernatant by ELISA. Apoptosis induction by CSF was also studied with microglial cells, the resident macrophages in the brain, which participate in the blood-brain barrier in the perivascular area. In contrast with control CSF, African trypanosomiasis patients' CSF induced apoptosis in both microglial and endothelial cells. The results obtained with the two methods correlated well, and showed that Stage 2 CSF induced apoptosis at higher levels in microglial cells, whereas the disease stage was not decisive for apoptosis induction in endothelial cells. We measured soluble Fas ligand (sFasL) and anti-Fas antibodies levels, two potent inducers of the Fas signalling pathway leading to apoptosis, in CSF from African trypanosomiasis patients and controls. CSF from African trypanosomiasis patients contained sFasL, and anti-Fas antibodies at higher levels than in controls. Stage 2 CSF contained more sFasL than Stage 1 CSF, and anti-Fas antibodies were detected only in Stage 2 CSF. Caspase-8 inhibitor effect and statistical data suggest that other pro-apoptotic factors may be involved in some CSF-induced apoptosis. Apoptosis induction may participate in the pathogenesis during African trypanosomiasis, and the presence of sFasL and anti-Fas antibodies may provide new tools for diagnosis and prognosis of the disease.

The expression of the apoptosis inducer Fas (CD95/APO-1) surface receptor by human foetal neurons was investigated in vitro and ex vivo. Immunofluorescence studies of brain and spinal cord cells in primary cultures and of cryosections obtained from 9- and 10-week-old human foetuses, respectively, showed that all Fas-expressing cells were motoneurons (5.3 and 4.2% of the neurons in brain or spinal cord cultures, respectively) on the basis of morphology, reactivity with the monoclonal antibody SMI-32, a mostly motoneuronal marker and acetylcholine esterase expression. Fas was undetectable on the other cell types in culture. The ability of Fas to induce apoptosis of cultured cells from both tissues was determined by using the terminal transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) method combined with the same double-staining procedure. Under basal culture conditions, about 9% of cells, all glial fibrillary acidic protein-expressing astrocytes, were apoptotic. After a 48-h incubation with Fas ligand, mean 28.5% of brain motoneurons and 29.4% of spinal motoneurons underwent apoptosis, with an inhibition by Z-IETD-FMK, a caspase-8 inhibitor. Hence, Fas appears to be functional through a caspase-8-dependent pathway in a subpopulation of human foetal motoneurons.

Background: The clinical relevance of distinguishing two types of glomerulonephritis (GN) with non-amyloid organized immunoglobulin (Ig) deposits-fibrillary GN (FGN) and immunotactoid (microtubular) GN (IT/MTGN)-on the basis of ultrastructural organization, is debated., Methods: Twenty-three patients with organized glomerular Ig deposits were classified into two groups based on the fibrillar or microtubular ultrastructural appearance of the deposits. Kidney biopsy samples were studied by immunofluorescence microscopy, using anti-light chain conjugates (all cases) and anti-IgG subclass conjugates (13 patients). In each group, we studied clinicopathological features, associated monoclonal gammapathy (detected by immunoelectrophoresis and/or immunoblot) or B-cell lymphoproliferative disease, effects of chemotherapy and long-term renal outcome., Results: In 14 IT/MTGN and 9 FGN patients, clinical symptoms [hypertension, nephrotic syndrome (NS) and hematuria] and the mean diameters of the substructures were similar. In 13 IT/MTGN patients, glomerular (IgG1, 2 or 3) deposits were monotypic (kappa, 7 cases; lambda, 6 cases). Glomerular deposits were associated with a monoclonal Ig of the same isotype in eight patients, detected in the serum (5 cases), and/or in the cytoplasm of lymphocytes (4 cases), and with lymphoproliferative disease in seven patients. The ultrastructural features of monoclonal Ig inclusions in lymphocytes were similar to those of glomerular microtubular deposits. In contrast, none of the FGN patients presented lymphoplasmocytic proliferation or paraproteinemia. Glomerular Ig deposits were polyclonal in eight cases and contained IgG4 in all three cases studied. Although patient and renal survival did not differ significantly between the two groups, chemotherapy led to remission of NS in ten IT/MTGN patients, with parallel improvement in hematological parameters., Conclusions: The identification of ultrastructural patterns in these nephropathies is important. GN with organized microtubular monoclonal deposits (GOMMID) probably accounts for a large proportion of immunotactoid (microtubular) GN cases.

More than 35 years ago, study of an unknown immunoglobulin (Ig) in the serum from a myeloma patient led to the discovery of IgD. Subsequently, the finding that it also exists as a membrane-bound Ig stimulated a large number of studies during the 70s. Then, the interest on IgD shrank, largely because of the lack of known function of secretory IgD (secIgD) and of a stagnating knowledge of the functions of surface IgD. In the recent years, very significant advances followed the tremendous accumulation of data on the physiology of the B cell receptor, of which IgD is the major component, on the role of secIgD in normal and diseased individuals. This review, which is focused on human IgD but integrates data in the mouse and other species when needed, summarizes present data on the structure, synthesis and functions of both membrane and secIgD, IgD receptors and the involvement of IgD in various diseases, especially the hyperIgD syndrome.

Sera from 26% of patients with sporadic amyotrophic lateral sclerosis (ALS) induced in vitro apoptosis of a human neuroblastoma cell line, as detected by two methods, and most contained anti-Fas autoantibodies. In contrast, Alzheimer sera (studied as controls) very rarely induced apoptosis and did not contain detectable anti-Fas antibodies. Soluble Fas-ligand levels in ALS sera were not different from those in normal sera, except for slightly higher levels in a single case. In mixed cultures of rat embryonic brain and spinal cord cells, ALS sera (and agonistic anti-Fas monoclonal antibodies and soluble Fas-ligand) induced the apoptosis of a subpopulation of neurons. These neurons were motoneurons on the basis of staining with the monoclonal antibody SMI 32 and Fas expression was restricted to these SMI 32-positive neurons. These data are compatible with the hypothesis of the participation of an autoimmune mechanism possibly related to anti-Fas autoantibodies in certain ALS patients.

The prevalence of serum anti-phospholipid antibodies (aPL) was evaluated in multiple sclerosis (MS) patients to search for a possible association with a distinct form of the disease. Anti-cardiolipin antibodies (Ab) (aCL) and anti-beta 2 glycoprotein I Ab (abeta2GPI) were measured together with antinuclear Ab (ANA), anti-double-stranded DNA Ab (anti-ds DNA) and anti-myelin Ab in 89 patients. Twenty-nine (32.6%) patients had serum aPL, 19xaCL (15 of the IgG and four of the IgM isotype), 14 abeta2GPI (two IgG and 12 IgM) (four of these patients had both Ab). Prevalence of aCL correlated with that of ANA, which were positive in 52 patients (P=0. 005) and with anti-myelin Ab detected in two patients (P=0.046) but not with that of anti-ds DNA (mostly of the IgM class) detected in 28% of case by ELISA. No correlation could be found between aPL and age, sex, duration of the disease from diagnosis, category of MS, clinical course, clinical symptoms, serum IgM levels nor atypical lesions by magnetic resonance imaging. Hence, aCL and abeta2GPI are neither rare in MS nor associated with a specific clinical form of the disease and they cannot be a diagnosis exclusion criteria., (Copyright 2000 Academic Press.)

Pathogenic mechanisms of the demyelinating encephalopathy featuring the nervous phase of human African trypanosomiasis (HAT) are largely unknown. They might include autoimmune disorders. A variety of autoantibodies is detected during the disease and we have previously evidenced anti-galactocerebroside (GalC) antibodies in the serum and cerebrospinal fluid (CSF) from patients in the nervous stage (stage II) of HAT. We now show that anti-GalC antibodies recognize an antigen located on the parasite membrane and common to different strains of trypanosomes. By using affinity chromatography with a rabbit anti-GalC antiserum, a 52-kD proteolipid was isolated from the membrane of Trypanosoma brucei (T. b.) brucei AnTat 1.9, AnTat 1. 1E, and T. b. rhodesiense Etat 1.2/R and Etat 1.2/S. Antibodies directed against this antigen were found in the CSF from patients with nervous stage HAT. These CSF also contained anti-GalC antibodies and adsorption with the proteolipid decreased anti-GalC reactivity. Immunization of mice with this antigen induced the production of antibodies which cross-reacted with GalC but no protection from experimental infection with T. b. brucei. These data support the hypothesis that anti-GalC antibodies detected in the CSF from HAT patients might be induced by molecular mimicry with a parasite antigen.

In stage II human african trypanosomiasis (HAT), which is characterized by central nervous system (CNS) involvement, neurones and oligodendrocytes might be targets of dysimmune processes. Nitric oxide (NO) production by peripheral macrophages is documented in HAT. We studied the production of NO by murine astrocytes and microglia cocultured with Trypanosoma brucei (T. b.) brucei AnTat 1.9. Purified astrocytes or microglia from mouse brains were cocultured with T. b. brucei, and in some instances with interferon (IFN)-gamma, which is known to be released during the disease and also to be a growth factor for trypanosomes. Inducible NO synthase (iNOS) expression was studied by indirect immunofluorescence and reverse transcriptase-polymerase chain reaction. NO production was determined by measuring nitrite generation in culture. Detection of iNOS in astrocytes and microglia in the presence of T. b. brucei, was closely associated with nitrite production and was strongly enhanced by the addition of IFN-gamma to the culture medium. The stimulation of iNOS activity required parasite-cell contact and likely occurred at the transcriptional level. This study demonstrates the induction of iNOS in CNS-related macrophage cells in the presence of trypanosomes and its potentiation by IFN-gamma.

We have designed an in vivo model in which murine hybridoma cell clones producing human Ig light chains (LC) are administered to mice. Depending on which monoclonal LC is expressed, this model mimics either cast myeloma nephropathy or the pathological condition defined as myeloma-associated Fanconi's syndrome (FS) with LC crystallization. Morphological alterations of the kidney cells are thus obtained in mice. All studied LC are closely related human monoclonal VkappaI proteins, which differ by a limited number of substitutions within the variable region. In the case of an FS monoclonal LC, we show that limited changes introduced through site-directed mutagenesis in the variable domain may suppress formation of intracellular crystals within tubular cells. We also show that multiple peculiarities of the variable region are simultaneously needed to allow LC crystallization; this property thus likely results from a unique LC tridimensional conformation imposed by concomitant somatic mutations of a specific germinally encoded framework.

IgD is a minor component of serum Ig and the control of IgD secretion is virtually unknown. We measured concentrations of IgD (and IgE and IgM as controls) in culture supernatants of peripheral blood mononuclear cells (PBMC) from 60 normal donors as well as mononuclear cells from 10 tonsils following culture in the absence or presence of CD40 mAb and cytokines. Low levels of IgD were measured in cultures of PBMC, either unstimulated or stimulated by anti-CD40 antibodies. IL-4 and IL-10 significantly increased IgD production by CD40 mAb-stimulated cells in the majority of normal subjects studied, whereas in a limited number of individuals, spontaneous IgD production was either low or high, but with no increase upon stimulation. Spontaneous IgD production by tonsil-derived mononuclear cells was higher than by PBMC and increased after CD40 stimulation and even more in the presence of IL-10, but not IL-4. IL-2 and IFN-gamma exerted a dose-dependent inhibition on spontaneous as well as CD40- and cytokine-induced IgD production by PBMC, but not by tonsil mononuclear cells. Activation by IL-4 of CD40-stimulated purified B cells from tonsil and PBMC, and by IL-10 of tonsil B cells increased IgD production, whereas IL-2 and IFN-gamma had no detectable inhibitory effect. This suggests that accessory cells indirectly regulate IgD synthesis. IgD production induced in PBMC by IL-4 or IL-10 appeared to result from an active synthesis, and correlated with an increase in the number of IgD-containing plasma cells as demonstrated by immunofluorescence and increased expression of secreted IgD transcripts. These findings suggest that IgD production by normal peripheral blood human B cells is regulated positively by T(h)2 cytokines and negatively by T(h)1 cytokines.

A 33-year-old man presented an acute motor demyelinating neuropathy following Campylobacter jejuni enteritis. The patient was improved with an IgIV treatment. Clinical features and course time were compatible with the diagnosis of a Guillain-Barré syndrome. The electrophysiologic studies were in favor of multifocal motor neuropathy with conduction blocks. We discuss the nosologic group of this neuropathy.

The occurrence of abnormally low serum immunoglobulin (Ig) levels is well-known in B chronic lymphocytic leukemia (CLL), but published data on IgG subclass levels are virtually absent. We measured serum IgG subclass levels in 52 B CLL outpatients, most in stage A and untreated, using an indirect immunoenzymatic assay with monoclonal antibodies. Mean levels of all Ig isotypes were lower than in normal controls in the whole group of patients, except for IgG2 in those studied at diagnosis. Levels of IgG1, IgG2, IgA, and IgM were lower in patients with a long disease duration than in those studied earlier. IgG subclass deficiencies occurred in 54% of cases and the most frequently affected isotype was IgG1. Every possible combination of IgG subclass and Ig class deficiencies from the selective deficiency of a single subclass to a combined deficiency of all isotypes was observed. This marked heterogeneity argues against the occurrence of isolated defects of one of the cytokines involved in Ig switching as a cause of hypoimmunoglobulinemia in CLL., (Copyright 1999 Academic Press.)

Interleukin 10 (IL-10) has been described as a cytokine inhibitory factor downregulating IL-2 secretion and inducing T cell anergy. The data reported in this study show that preincubation of resting T cells from the human CD4+ clone SP-B21 (and clone TA-23.6) with IL-10 strongly enhances their capacity to further produce IL-2, interferon gamma (IFN-gamma), IL-4 and tumour necrosis factor alpha (TNF-alpha) after subsequent activation. In contrast, when IL-10 was added during the activation step, the previously reported specific inhibition of IL-2 synthesis was observed. Flow cytometric analysis of intracellular IL-2- and IL-4-producing cells revealed that preincubation with IL-10 increased the number of cytokine-producing cells, but did not affect their individual ability to produce these cytokines. We further show that IL-10 plays a dose-dependent role of viability maintenance factor. This effect relates to a direct anti-apoptotic effect of IL-10, which is likely independent of the expression of bcl-2, bcl-x and fas. Such paradoxal properties of IL-10 on T cells should be considered when aiming at using IL-10 as an immunosuppressive molecule in the treatment of diseases.

Objective: To search for a relationship between serum anti-beta2 glycoprotein I (anti-beta2GPI) antibodies and the occurrence of ischaemic complications in giant cell arteritis (GCA), since the latter do not correlate with anti-cardiolipin antibodies (ACL), which are frequently observed in GCA., Methods: IgG and IgM anti-beta2GPI antibodies and ACL were measured by enzyme-linked immunosorbent assays in sera, collected before treatment, from 45 unselected patients with biopsy-proven GCA, including 15 patients with ischaemic events., Results: IgG and IgM anti-beta2GPI antibodies were not detected in any of the patients, contrasting with the presence of ACL in 51%, of them, without correlation with ischaemia., Conclusion: Anti-beta2GPI antibodies are not detectable in GCA, contrasting with the occurrence of ACL, and ischaemic complications are apparently unrelated to the most frequent anti-phospholipid antibodies.

We herein report on the first two primary sequences (BOU and RAC) of monoclonal light chains of the lambda type responsible for nonamyloid lambda light chain deposition disease. Both patients were affected with severe forms of myeloma complicated with renal failure. The pathological presentation typically featured Congo red-negative deposits along tubular basement membranes but differed somewhat from the typical "Randall-type" kappa light chain deposition disease: they lacked the prominent glomerulosclerosis pattern often featuring nonamyloid kappa deposits and were associated with cylinders or myeloma casts. Both protein sequences were deduced from those of the corresponding complementary DNAs in the bone marrow plasma cells. For each chain, products of three independent amplifications by polymerase chain reaction were sequenced and found to be identical. BOU and RAC lambda mRNAs had a normal overall structure consisting of Vlambda2 segments rearranged to Jlambda2Clambda2 but displayed a number of unusual features within their primary sequences. These substitutions are likely responsible for changes in light chain conformation that promote their aggregation and deposition along renal tubule basement membranes.

Anti-neurofilament (NF) autoantibodies were searched for by enzyme-linked immunosorbent assays (ELISA) in the serum from 85 sporadic amyotrophic lateral sclerosis (ALS) patients, 98 healthy controls and 79 patients with unrelated immunological diseases (Guillain-Barré syndrome, myasthenia gravis and multiple sclerosis). ELISA cutoff value was determined as mean control levels +2 SD and it corresponded to a specificity of 94%. Such high level antibodies were detected in 24.7% of ALS patients contrasting with 12.6% of neurological controls (P<0.05) and only 6.1% of healthy subjects (P<5.10[-4]). In ALS, anti-NF antibodies were significantly associated with a slow evolution, as measured by the mean time spent in the initial functional states. They did not relate with age, sex and clinical form. The predominant isotype of the anti-NF antibodies was IgM lambda by ELISA. In contrast to negative sera, indirect immunohistochemical studies demonstrated that most sera positive for anti-NF antibodies reacted with axons with predominant isotypes restricted to IgM lambda. By using Western blotting, small amounts of serum monoclonal IgM were found with a high frequency in anti-NF antibody-positive patients. These results suggest the possible involvement of anti-NF antibodies in an autoimmune process in a subgroup of ALS patients.

We report on two cases of central nervous system (CNS) relapse after high-dose chemotherapy and autologous stem cell transplantation. A 55-year-old man received two courses of vincristin, doxorubicin and dexamethasone (VAD) as an induction treatment for stage IIIB IgG kappa multiple myeloma. Bone marrow stem cell collection was performed after a high-dose melphalan (HDM) course (140 mg/m2). Autologous bone marrow transplantation (ABMT) was performed with this cryo-preserved unpurged bone marrow sample after a second HDM course. Three months after ABMT, the patient presented with signs of central nervous involvement with plasma cells and monoclonal IgG kappa in the cerebral fluid. The patient died despite systemic and intrathecal chemotherapy. A 50-year-old man was initially treated with 3 courses of VAD for a stage IIIA IgD lambda multiple myeloma. Blood stem cell were collected after a course of high-dose etoposide and cyclophosphamide. ABMT was performed after total body irradiation (TBI) and HDM. Three months later, he presented with right leg palsy and a lumbar puncture showed numerous plasma cells and the presence of the IgG lambda. The patient died of neurological complications three months later. Extramedullary occurred prior to medullary relapse in the two cases, suggesting the presence of an extramedullary clone of plasma cells with a high degree of chemo-resistance. Although high-dose chemotherapy appears promising, this therapeutic approach could allow the occurrence of presently unobserved complications. Wether CNS prophylaxis is indicated in this context, as recommended in leukemia, remains an open question.

Light chain deposition disease is a severe complication of certain immunoproliferative disorders, due to the secretion of a monoclonal light chain which precipitates close to basement membranes of several tissues. A kappa isotype restriction and an unusual frequency of a variable region subgroup (VkappaIV) suggest that precise structural features govern the propensity of pathogenic light chains to precipitate in extracellular spaces. We studied primary structures of light chains from six patients with light chain deposition disease in comparison with light chains from other pathological conditions. Sequence alignment revealed the presence of certain amino acids only in light chain deposition disease, in particular non-polar replacing hydrophilic residues. To determine the role of these residues, structures of the variable domain from four kappa chains belonging to VkappaI and VkappaIV subgroups responsible for deposition disease were modeled using known immunoglobulins as templates. The most evident structural features shared by all pathogenic light chains were hydrophobic residues exposed to the solvent in complementarity determining regions 1 or 3. In contrast to immunoglobulin light chain-related amyloidosis, where deposition of organized material might be due to electrostatic interactions between light chain dimers, hydrophobic interactions could enhance amorphous precipitation in non-amyloid light chain deposition disease.

Measurement of serum IgG subclass levels in 3005 patients disclosed abnormally low IgG1 levels with normal levels of the other IgG subclasses and of IgM and IgA in 119 patients, predominantly adults. Not all patients were hypogammaglobulinemic due to nonrare increases of other isotypes, mostly IgM. A familial context of immunodeficiency was frequent, more often combined than selective IgG1 deficiency. A familial association with IgG2 deficiency was found also and IgG1 replaced IgG2 deficiency in 3 cases (and succeeded to or preceded more complex IgG defects in 3 cases, whereas IgG1 deficiency was consistently found at examinations repeated in the absence of therapy in 10 additional cases). Most but not all (83.2%) patients suffered infections, generally moderate, similar to those observed in other selective IgG subclass deficiencies (IgGSD), with predominantly sinorespiratory infections. Other clinical manifestations such as atopy, congenital cardiopathy, and autoimmune diseases were already known in IgGSD but the incidence of asthma was strikingly high (one-fifth of the cases).

The occurrence of kidney diseases was very rarely reported in heavy chain diseases (HCD). At variance with gamma and alpha HCD in which there is no free light chain secretion, about two-thirds of mu HCD patients have urinary Bence Jones (BJ) proteins. We report on a 66 year-old man affected with typical mu HCD who developed renal failure after a 3-year follow-up. He had presented with chronic lymphocytic leukemia with bone marrow vacuolated plasma cells, serum mu HCD protein and serum and urine BJ protein. After an apparent hematological remission following fludarabine therapy, anemia and blood hyperlymphocytosis recurred together with microscopic hematuria, proteinuria and increased creatininemia. Kidney biopsy showed numerous tubular eosinophilic casts which stained for kappa chain determinants by immunofluorescence and an interstitial infiltration by lymphocytes and plasma cells. The hematological and renal condition improved after reinitiation of chemotherapy. This appears to be the first documented report of a light chain-dependent visceral complication in HCD.

Background: The occurrence of serum monoclonal immunoglobulins in kidney transplant recipients is well known but their significance and predictive value for the occurrence of lymphoma are a matter of debate. We therefore conducted a study of monoclonal immunoglobulins by a sensitive method during the long-term follow up of grafted patients., Methods: Monoclonal immunoglobulins were characterized by high-resolution electrophoresis, conventional immunoelectrophoretic analysis, and a sensitive Western blotting procedure in the serum from 84 renal transplant recipients prior to grafting and subsequently, with a 1-8-year follow-up and excluding the patients who developed posttransplant lymphoma., Results: Low abundance monoclonal immunoglobulins were detectable prior to transplantation in 56 cases (66.6%) and after graft in 72 cases (85.5%) (and in 1 case (1.2%) and 18 cases (21.4%) of cases respectively, by immunoelectrophoresis). These abnormalities were often multiple in individual sera. Monoclonal components detected by immunoblotting were transient in 23.8% of patients only (whereas those evidenced by immunoelectrophoresis usually became undetectable by this method) and their pattern was remarkably stable in the majority of cases. The frequency of post-transplant monoclonal immunoglobulins was higher in patients of more than 50 years of age than in younger patients. The appearance of monoclonal components after grafting and their transient character correlated with CMV infections. No correlation was found with various other parameters. The isotypic distribution of monoclonal immunoglobulins with an IgM, IgG3, and IgG1 predominance and an abnormally low kappa/lambda ratio was the same as that observed in various immunodeficiency states. The monoclonal immunoglobulin pattern in three further patients who developed post-transplant lymphoma was unremarkable., Conclusion: Monoclonal immunoglobulins hence are not discriminant for lymphoma and their characterization does not appear to be necessary in the evaluation of followed up grafted patients, at least for a prediction of post-transplant lymphoma.

IL-6, soluble IL-6 receptor (sIL-6R) and soluble gp130 (sgp130) levels were measured in sera and pleural effusions from 42 patients with metastatic carcinoma, non-Hodgkin's lymphoma, tuberculosis, cardiac failure and miscellaneous diseases. Pleural IL-6 levels measured by ELISA were very high in all patient groups (mean 34.8 +/- 15.3 ng/ml) without significant difference according to diseases. IL-6 was shown to be biologically active in a proliferative assay. Serum IL-6 levels were low (0.049 +/- 0.014 ng/ml) and did not correlate with pleural fluid levels. Pleural IL-6 levels correlated with the number of polymorphonuclear cells in pleural fluid (P < 0.03). Pleural sIL-6R levels (76 +/- 8 ng/ml) were always lower than serum levels (196 +/- 12 ng/ml; P < 0.0001) but correlated with them (P < 0.01). Pleural sIL-6R and albumin levels correlated (P < 0.01), suggesting a transudation of sIL-6R from the serum. Pleural sgp130 levels (10.9 +/- 1.0 ng/ml) were lower than serum levels (24.6 +/- 2.8 ng/ml; P < 0.002). After gel filtration of pleural fluid, the bulk of IL-6 (> 90%) was recovered in a 15,000-30,000 fraction, corresponding to the expected mol. wt of free IL-6. These results suggest a production and a sequestration of IL-6 in the pleural cavity in all studied conditions.

Serum IgG1 levels are selectively increased in patients with chronic hepatitis C virus (HCV) infection. In 15 patients who received interferon (IFN)-alpha therapy, serum levels of immunoglobulin classes and IgG subclasses were measured during treatment and after it was discontinued. In spite of important individual variations, mean IgG, IgG1, IgA and IgM levels decreased during therapy and tended to return to pre-treatment levels afterwards, with no detectable correlation with clinical and biological parameters. These results suggest an effect of IFN-alpha on in vivo immunoglobulin production, in HCV carriers.

Lymphocytes and monocytes express various levels of membrane-bound CD23, the low affinity receptor for IgE (Fc epsilon RII), and in some cases release it as a soluble form. Soluble CD23 (sCD23) has been implicated in the regulation of many immunological functions of T and B lymphocytes, macrophages and myeloid cells in humans. To study serum sCD23 levels in inflammatory conditions, we selected a systemic disease sensitive to corticotherapy, the giant cell arteritis, which is characterized by an inflammation of the temporal artery. Serum sCD23 levels, as measured by a radioimmunoassay, were increased in these patients, and returned to normal values within the 24 h following initiation of corticotherapy. The data suggest that the increase in sCD23 levels in giant cell arteritis results from an overproduction.

51 monoclonal antibodies (McAb) with putative specificity for human IgA, the IgA subclasses, Am allotypes or secretory component (SC) were evaluated for immunoreactivity and specificity by nine laboratories employing immunodiffusion, agglutination, immunohistological assays, immunoblotting and direct binding and competitive inhibition enzyme immunoassays. McAbs specific for IgA PAN (n = 24), IgA1 (n = 7), IgA2 (n = 3), IgA2m(2) (n = 2), non-IgA2m(2) (n = 4) and SC or secretory IgA (n = 5) were identified that were immunoreactive and specific in the assays employed. The McAbs identified as IgA- or SC-reactive were shown to be non-reactive to human IgG, IgM, IgD, IgE, kappa and lambda by direct binding and competitive inhibition immunoassays. Interestingly, no McAbs with restricted specificity for IgA2m(1) were identified. Some McAbs displayed higher affinity and/or better performance in one or several of the assay groups. The IgA- and SC-specific McAbs identified in this international collaborative study have potential as immunochemical reference reagents to identify and quantitate monomeric and polymeric IgA in human serum and secretions.

Proliferative response of human peripheral blood mononuclear cells (PBMC) stimulated by new lectins purified from seeds of differents Artocarpus species from Vietnam (A. asperulus, A. heterophyllus, A. masticata, A. melinoxylus, A. parva and A. petelotii) was studied and compared to those of the lectin jacalin purified from jackfruit (A. heterophyllus) seeds collected in the island La Réunion. All lectins stimulated human PBMC to proliferate, with a variable efficiency of the mitogenic activity. Phenotypic analysis of cells recovered after 7 day-cultures showed that these lectins mostly stimulated CD4+ T lymphocytes. These results suggest that these lectins from different Artocarpus species are similar in terms of their mitogenic activity although their structural features are not identical.

Serum monoclonal IgM lambda from a patient with axonal neuropathy reacted with axonal, nuclear, cytoplasmic and cell surface components by immunofluorescence. Experiments performed with Fab fragments of the monoclonal IgM proved that this reactivity was clearly due to actual antibody activity. Further study by Western blotting and ELISA showed that the IgM lambda reacted with the 200 kDa neurofilament protein, H1 and H2b histones and L14, L24 and L7 ribosomal proteins. This reactivity was abolished after adsorption either on purified 200 kDa neurofilament protein or on ribosomal proteins, demonstrating that these reactive proteins share a common epitope which possibly reflects sequence similarities. Sequence homology pointed to the involvement of the peptide AKSPEKAK in the epitope, and this was confirmed by dot blot analysis and adsorption experiments with this peptide. In addition, monoclonal IgM showed low level polyreactivity.

Certain monoclonal Ig light chains (LC) are responsible for marked disturbances of proximal tubule cell functions (Fanconi's syndrome, FS). In patients with FS, intracellular crystal-like inclusions containing LC determinants are commonly found in plasma cells, macrophages, and renal tubular cells. In an attempt at understanding the pathogenesis of myeloma-associated FS, we recently determined the first complete primary sequence of a kappa-LC (CHEB) responsible for the disease. We now report on the primary structure of three other kappa-LC of the V kappa l variability subgroup associated with FS (TRE, TRO, and DEL). After PCR amplification, cDNA encoding these LC were sequenced. CHEB, TRE, and TRO LC genes were found to be highly homologous to the same germline gene O2/O12. These patients had numerous intracellular crystals, whereas the fourth patient, DEL, had no detectable crystals. The LC from the latter patient was homologous to another germline gene, O8/O18. Comparison of these LC sequences to previously reported LC of the V kappa l subgroup allowed identification of a number of unusual amino acid substitutions in the V region that had rarely or never been previously described at the corresponding positions. Some of these unusual substitutions affect highly conserved amino acids located either in an external loop (residue 30) or in inner (residues 48 and 55) and outer (positions 63 and 72) beta-sheets that may be important for the structure and binding properties of the kappa-chains. These and several other substitutions, some of them shared with amyloidogenic kappa-LC, could induce conformational alterations and represent a determinant pathogenic factor.

The molecular status of Abs in the vaginal fluid is reconsidered as a basis for immunization strategies for women' vaccination against HIV. Analysis of separated immunoglobulins (Igs) shows a large proportion of uncleaved IgG, whereas the low amount of IgA includes SIgA, monomers and fragments. SIgM is at a very low level, while free SC molecules are abundant. In addition to the already documented local synthesis, vaginal IgG contains serum-derived tetanus antitoxins. The IgG could reach the lumen by diffusion, and/or be transported by an Fc receptor-associated mechanism as suggested by the subclass imbalance in favour of the IgG1 isotype. VAginal SIgA contains very low levels of antibodies o the cell-well carbohydrates from a dental caries-associated streptococcus confirming the participation of the secretory immune system. IN addition, the low percentage of IgA2 suggests tha a proportion of vaginal SIgA can also derive from actively transported serum polymers. In agreement with our previous studies showing induction of vaginal tetanus antitoxins by intramuscular immunization, these results are in favour of classical, parenteral vaccinations to induce protection of the human vagina.

The Gal beta(1-3)GalNAc-binding lectin jacalin is known to specifically induce the proliferation of human CD4+ T lymphocytes in the presence of autologous monocytes and to interact with the CD4 molecule and block HIV-1 infection of CD4+ cells. We further show that jacalin-induced proliferation is characterized by an unusual pattern of T cell activation and cytokine production by human peripheral blood mononuclear cells (PBMC). A cognate interaction between T cells and monocytes was critical for jacalin-induced proliferation, and human recombinant interleukin (IL)-1 and IL-6 did not replace the co-stimulatory activity of monocytes. Blocking studies using monoclonal antibodies (mAb) point out the possible importance of two molecular pathways of interaction, the CD2/LFA-3 and LFA-1/ICAM-1 pathways. One out of two anti-CD4 mAb abolished jacalin responsiveness. Jacalin induced interferon-gamma and high IL-6 secretion, mostly by monocytes, and no detectable IL-2 synthesis or secretion by PBMC. In contrast, jacalin-stimulated Jurkat T cells secreted IL-2. CD3- Jurkat cell variants failed to secrete IL-2, suggesting the involvement of the T cell receptor/CD3 complex pathway in jacalin signaling. IL-2 secretion by CD4- Jurkat variant cells was delayed and lowered. In addition to CD4, jacalin interacts with the CD5 molecule. Jacalin-CD4 interaction and the proliferation of PBMC, as well as IL-2 secretion by Jurkat cells were inhibited by specific jacalin-competitive sugars.

The sequences of two immunoglobulin gamma 1 heavy chains involved in the formation of non-amyloid tissue deposits were determined in two patients (RIC and THR) affected with plasma cell monoclonal proliferation and heavy-chain-deposition disease. The proliferating plasma cells of patients RIC and THR synthesized truncated gamma 1 chains of 45 kDa and 24 kDa, respectively, carrying internal deletions of the first constant (CH1) domain (RIC) or of the CH1, hinge and CH2 domains(THR). The shortened gamma chains were associated with lambda light chains in the monoclonal IgG component present in the serum from both patients but not in tissue deposits which lacked any detectable light chains. Bone marrow plasma cells from RIC contained short gamma 1 heavy-chain transcripts in which a VDJ exon related to the VH2 subgroup was directly joined to the hinge exon; plasma cells from THR contained short gamma 1 transcripts with a VDJ exon related to the VH3 subgroup joined to the CH3 exon. In both cases, the truncated transcripts carried precise deletions of complete exons and used regular splice sites at the variable/constant junction, consistent with the hypothesis that they originated from abnormal splicing of primary transcripts from the productively rearranged heavy-chain genes. Striking abnormalities of the variable regions were found, especially in framework regions, including replacement of an invariant tryptophan residue in protein from THR, hydrophobic residues most likely exposed to the solvent and inversion of charged amino acids probably exposed on the surface of the molecule.