Mutational analysis in murine models for myeloma-associated Fanconi's syndrome or cast myeloma nephropathy

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.

Complete primary sequences of two lambda immunoglobulin light chains in myelomas with nonamyloid (Randall-type) light chain deposition disease

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.

Maintenance cyclosporin monotherapy after renal transplantation--clinical predictors of long-term outcome

BACKGROUND

There is considerable debate about whether maintenance cyclosporin (CsA) monotherapy is advisable or not in renal transplantation.

METHODS

Between August 1984 and December 1989, 463 adult patients received a first cadaver graft. Initial immunosuppression was sequential: antilymphocyte or antithymocyte globulins (10-14 days), prednisone and azathioprine were combined and CsA was introduced (6-8 mg/kg/day) when the antilymphocyte or antithymocyte globulins were discontinued. When the graft function was stable and the peak of preformed lymphocytotoxic antibodies was < or = 25% and/or the number of rejection episodes was < or = 1, the steroid therapy was stopped within 1.5-3 months after transplantation, and azathioprine within 3-12 months. Patients with both anti HLA antibodies > 25% and more than one rejection episode were excluded. Cyclosporin doses were adapted for whole-blood trough levels between 100 and 200 ng/ml (monoclonal antibody radioimmunoassay or high-performance liquid chromatography). Cyclosporin monotherapy was attempted in 234 of the 463 patients.

RESULTS

At the end of the investigation in January 1993 (follow-up time > 36 months, mean 60.5 +/- 4.5 months), 135 patients were receiving CsA without steroids or azathioprine. The 99 CsA monotherapy failures were due to rejection episodes in 48 cases, CsA A nephrotoxicity in 26 cases, and other causes in 25 cases, including five deaths and four with poor compliance. Renal function was stable in patients with successful CsA monotherapy: mean creatininaemia was 124 +/- 10 mumol/l at the time of CsA monotherapy inclusion and 129 +/- 10 mumol/l at the end of follow-up (mean time of CsA monotherapy 52 +/- 6 months). The parameters for predicting monotherapy success were age (43.2 versus 37.8. P = 0.0014), timing of trial inclusion > or = 6 months post-transplant (7.9 +/- 3 versus 5.3 +/- 3.1 months, P = 0.04), and excellent and stable renal function at the time of inclusion (124 +/- 10 versus 145 +/- 32 mumol/l, P < 0.001).

CONCLUSIONS

Maintenance CsA monotherapy was effective in 58% of low-immunological-risk first-graft patients and probably did not jeopardize overall results of our first grafts: patient and graft survival were respectively 90 and 73% at 6 years. We propose this policy to avoid long-term complications of glucocorticoid and azathioprine in selected compliant recipients with low immunological risk, follow-up time post-transplantation > 6 months, and stable creatininaemia levels.

Cast nephropathy in mu heavy chain disease

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.

High prevalence and usual persistence of serum monoclonal immunoglobulins evidenced by sensitive methods in renal transplant recipients

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.

[Digital necrosis associated with fenoxazoline poisoning. Apropos of a case and review of the literature]

We report the case of a 53 year-old woman with paroxystic hypertension and digital ischemia. The only triggering factor was chronic intoxication by a nasal vasoconstrictor:fenoxazoline. The worsening of the lesions required amputation of the third phalanx of the 3rd and 5th finger and the pulp of the 4th finger of the left hand. The review of literature exhibits association between fenoxazoline intoxication and paroxystic hypertension, myocardial ischemia or stroke, but association between fenoxazoline intoxication and digital ischemia has never been reported. We emphasize the extreme caution necessary with the prescription and the chronic consumption of this kind of drug.

Renal involvement in Behçet's disease. Case report and review of the literature

A female patient has suffered from Behçet's disease (BD) for 15 years. During one recurrent episode proteinuria and microscopic hematuria were discovered. Renal biopsy revealed focal segmental glomerulopathy with IgA deposits. Renal involvement in BD is uncommon and includes amyloidosis, crescentic glomerulonephritis and IgA nephropathy. BD is a cause of secondary IgA nephropathy. Immunologic features of the two diseases, particularly increased serum IgA, are reviewed.

Role of light chain variable region in myeloma with light chain deposition disease: evidence from an experimental model

Light chain deposition disease (LCDD) results from a propensity of some human monoclonal L chains to form tissue deposits. We designed an experimental model for in vivo expression of human kappa L chain sequences in mice and compared a somatically mutated LCDD chain with a closely related control kappa chain, both encoded by the unique V kappa IV gene. Mice secreting the LCDD chain but not those producing the control chain showed deposits with a distribution similar to that observed in patients. These data show that discrete changes in V region sequences can play a major role in tissue deposition of human L chains.

Sequences of V kappa L subgroup light chains in Fanconi's syndrome. Light chain V region gene usage restriction and peculiarities in myeloma-associated Fanconi's syndrome

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.

Sequences of V kappa L subgroup light chains in Fanconi's syndrome. Light chain V region gene usage restriction and peculiarities in myeloma-associated Fanconi's syndrome

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.

Protease resistance and binding of Ig light chains in myeloma-associated tubulopathies

Kidney tubule dysfunction and lesions are frequent complications of myeloma, related to unknown properties of the monoclonal light chain. We have analyzed protease sensitivity and binding properties of urinary light chains from four patients with Fanconi's syndrome, 12 with cast nephropathy, and four control patients without myeloma-associated tubulopathy. All light chains were normal-sized, monomeric and/or dimeric, and none was N-glycosylated. Kinetic studies of light chain digestion by pepsin and the lysosomal enzyme cathepsin B showed the generation of a protease-resistant 12 kDa fragment, corresponding to the V domain of the kappa chain in the four Fanconi's syndrome patients; in two out of four the V domain was also completely resistant to trypsin. Western and dot blots revealed similar patterns of reactivity of light chains from patients with the Fanconi's syndrome towards other light chains. Properties of cast-nephropathy light chains were more heterogeneous but clearly differed from those of Fanconi's syndrome: (i) 9 out of 12 were of the lambda-type; (ii) only four yielded a transient 12 kDa fragment after cathepsin B digestion, but all showed some resistance to proteolysis of the entire molecule or a fragment thereof to at least one protease, at variance with control light chains; (iii) they displayed various patterns of reactivity with other light chains; (iv) 7 out of 12 reacted specifically with Tamm-Horsfall protein (THP) by ELISA, in contrast with those of Fanconi's syndrome. In one patient who presented with cast nephropathy and the Fanconi's syndrome, the light chain exhibited both partial resistance of the V kappa domain to cathepsin B and the highest reactivity with THP.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal involvement in hematological disorders: monoclonal immunoglobulins and nephropathy

The study of monoclonal immunoglobulin-associated nephropathies is useful for analyzing the physicochemical properties of immunoglobulin components responsible for their deposition in the kidney. Notable advances include the first description of truncated heavy-chain deposition disease, characterization of protease resistance and binding properties of immunoglobulin light chains involved in myeloma-associated Fanconi's syndrome and cast nephropathy, and identification of hepatitis C virus as a plausible causative agent of the so-called essential mixed cryoglobulinemias.

Monoclonal immunoglobulin deposition disease: a review of immunoglobulin chain alterations

Monoclonal immunoglobulin deposition disease, a complication of overtly malignant or apparently benign immunoproliferative disorders, is a severe disease featuring tissue deposition of monoclonal light, light and heavy, or heavy chains. A number of converging arguments strongly suggest a direct pathogenetic role of structural abnormalities or peculiarities of variables regions of light and/or heavy chains (associated with deletions in the constant region for the heavy chains). Recent structural data on these abnormal immunoglobulin chains are reviewed.

Monoclonal Ig L chain and L chain V domain fragment crystallization in myeloma-associated Fanconi's syndrome

Monoclonal free L chains secreted in immunoproliferative disorders are frequently involved in renal complications, including a specific proximal tubule impairment, the Fanconi's syndrome, which is generally featured by intracellular crystallization of L chain-related material. In a patient with myeloma-associated Fanconi's syndrome, hexagonal crystals (most surrounded by smooth membranes) were found in kidney proximal tubular cells and bone marrow plasma cells and phagocytes. The sequence of the patient's monoclonal kappa-chain was deduced from that of identical kappa-cDNA clones from the tumoral plasma cells. Small protein-enriched gel filtration fractions from urine yielded crystals morphologically similar and with the same 60 A periodicity on electron micrographs as those found in the cells. N-terminal sequencing and mass spectrometry studies showed that the crystals contained a 107-amino acid fragment (with a C-terminal lysine) corresponding to the V domain together with a low proportion of the entire kappa-chain. In vitro trypsin and pepsin treatment of the native entire kappa-chain yielded a homogeneous V domain fragment which, contrary to other monoclonal kappa-chains, was completely resistant to further proteolytic attack. The patient's kappa-chain also displayed an unusual self-reactivity, as demonstrated by a Western blot technique. The peculiar proneness of the V domain to resist proteolysis and to form crystals might prevent the normal cell catabolism of the L chain and lead to crystallization and renal impairment.

Monoclonal Ig L chain and L chain V domain fragment crystallization in myeloma-associated Fanconi's syndrome

Monoclonal free L chains secreted in immunoproliferative disorders are frequently involved in renal complications, including a specific proximal tubule impairment, the Fanconi's syndrome, which is generally featured by intracellular crystallization of L chain-related material. In a patient with myeloma-associated Fanconi's syndrome, hexagonal crystals (most surrounded by smooth membranes) were found in kidney proximal tubular cells and bone marrow plasma cells and phagocytes. The sequence of the patient's monoclonal kappa-chain was deduced from that of identical kappa-cDNA clones from the tumoral plasma cells. Small protein-enriched gel filtration fractions from urine yielded crystals morphologically similar and with the same 60 A periodicity on electron micrographs as those found in the cells. N-terminal sequencing and mass spectrometry studies showed that the crystals contained a 107-amino acid fragment (with a C-terminal lysine) corresponding to the V domain together with a low proportion of the entire kappa-chain. In vitro trypsin and pepsin treatment of the native entire kappa-chain yielded a homogeneous V domain fragment which, contrary to other monoclonal kappa-chains, was completely resistant to further proteolytic attack. The patient's kappa-chain also displayed an unusual self-reactivity, as demonstrated by a Western blot technique. The peculiar proneness of the V domain to resist proteolysis and to form crystals might prevent the normal cell catabolism of the L chain and lead to crystallization and renal impairment.

NZB/NZW F1 mouse nephritis and immune response are not changed by treatment with a 15-lipoxygenase derivative

15-HETE is an arachidonic acid derivative issued from the 15 lipoxygenase pathway. This fatty acid possesses immunomodulatory capabilities since it was reported that it generates CD8 + suppressor T-cells either in vitro or ex vivo. The aim of the present report was to study if the suppressive capabilities of 15-HETE were able to influence the onset of the NZB/NZW Fl auto-immune disease. For that purpose we produced 15-HETE and injected the eicosanoid twice a week to NZB/WFI mice for 40 weeks. During the 15-HETE treatment of the animals it was observed an augmentation of the proliferative response of lectin-stimulated splenocytes (at weeks 20 and 30) then the thymidine uptake decreased (at week 40). In fact we observed that among 15-HETE treated mice the evolution of the nephropathy was not changed, the 'glomerular activity score' remained the same for the treated animals compared to controls. On the contrary antinuclear antibodies occurred earlier even if in some experiments the generation of CD8 + cells was demonstrated.

Complementary DNA sequence of human amyloidogenic immunoglobulin light-chain precursors

The primary structure of three amyloid precursor light chains was deduced from the sequence of complementary DNA (cDNA) from bone marrow cells from patients affected with classical lambda (patient Air) or kappa (patient Arn) amyloidosis and from a patient (Aub) in whom lambda amyloid deposits were unusual by their perimembranous location in the kidney glomerulus. All three RNAs were of normal size, as estimated by Northern blotting, and encoded normal-sized light chains. The deduced light-chain sequence from patient Arn was related to the V kappa 1 subgroup, and included ten residues that had not been previously reported at these positions, only one of which (Leu-21) was located in a beta-sheet (4-2). The unusual presence of Asn-70 determined a potential N-glycosylation site. The sequence of the light chain from patient Air belonged to the V lambda 1 subgroup, and included three unusually located amino acid residues, one of which had already been reported in an amyloidogenic lambda-chain. The sequence of the light chain from patient Aub was related to the V lambda 3 subgroup, and contained five amino acid residues that had not previously been described at the corresponding positions; two of them (His-36 and Ser-77) were located in beta-sheets (3-1 and 4-3 respectively). This sequence was also peculiar because of the presence of numerous acidic residues in the complementarity-determining regions. Such unusual primary structures might be responsible for the amyloidogenic properties of these light-chain precursors.

Primary structure of a monoclonal kappa chain in myeloma with light chain deposition disease

Previous data suggest that structural abnormalities of immunoglobulin light chains may be responsible for non-amyloid light chain deposition disease (LCDD). We report on the complete primary sequence deduced from complementary (c)DNA analysis of a normal-sized kappa chain in a case of myeloma-associated LCDD. The patient's urine contained a kappa type Bence-Jones protein made of monomers and dimers of an unglycosylated kappa chain. The bone marrow myeloma cells contained intracellular kappa and gamma chains by immunofluorescence. Biosynthesis experiments showed the production of normal-sized gamma chains and of kappa chains with the same apparent molecular mass (Mr) in SDS gels as the urinary kappa chain (26,000-27,000). These kappa chains were secreted as assembled IgG molecules and as a large excess of free monomers and dimers. The complete sequence of two identical cDNA clones derived from a normal-sized kappa messenger RNA indicated that this kappa chain belonged to the rare V kappa IV subgroup. The kappa mRNA had an overall normal structure made up of the V kappa IV sequence rearranged to J kappa 1 and followed by a normal constant exon of the Km(3) allotype. The variable region differed from the V kappa IV-J kappa 1 germline sequence by 17 amino acid substitutions. The peculiar sequence of the variable region of this kappa chain of a rare subgroup might relate to its tissue deposition.

[Glomerulopathies in monoclonal dysglobulinemias]

Glomerular lesions in monoclonal gammapathies include AL amyloidosis, light chain and monoclonal immunoglobulin deposit disease (LCDD), cryoglobulinemias, Waldenström's macroglobulinaemia and a new entity, atypical membranous glomerulonephritis with organised monoclonal IgG deposits. Present data on deposited material of immunoglobulin origin and immunoglobulin synthesis in amyloidosis and LCDD are reviewed.

Structure of a monoclonal kappa chain of the V kappa IV subgroup in the kidney and plasma cells in light chain deposition disease

That structural abnormalities may be responsible for nonamyloid immunoglobulin (Ig) light chain deposition disease (LCDD) is suggested by previous results of Ig biosynthesis studies, but this hypothesis was not documented at the molecular level. We report on the first complete primary sequence deduced from cDNA analysis of a kappa light chain responsible for LCDD associated with an apparently nonsecretory myeloma. Bone marrow myeloma cells contained intracellular kappa chains and no heavy chains by immunofluorescence. Kidney biopsy showed typical nonamyloid PAS-positive kappa chain deposits. SDS-PAGE analysis of material extracted from a kidney biopsy specimen and of Ig produced by the myeloma cells revealed kappa chains of abnormally high apparent molecular mass (30,000). Comparison of the NH2-terminal aminoacid sequence of the kappa chain deposited in the kidney and of the complete sequence of several identical kappa cDNA clones from bone marrow cells showed the identity of the tissue deposited and plasma cell kappa chain. The kappa mRNA had an overall normal structure and corresponded to the V kappa IV gene rearranged to J kappa 1 and followed by a normal constant exon of the Km(3) allotype. The variable sequence differed from the V kappa IV germline gene by nine point mutations, including an Asp----Asn substitution at position +70 resulting in a potential N-glycosylation site. In vitro biosynthesis experiments and treatment with N-glycosidase provided evidence for the intracellular glycosylation of the monoclonal kappa chain. The peculiar sequence and the glycosylation of a kappa chain of the rare V kappa IV subgroup might be responsible for structural abnormalities leading to tissue deposition.

Retinal and choroidal ischemic syndrome, digestive tract and renal small vessel hyalinosis, intracerebral calcifications and phenotypic abnormalities: a new family syndrome

A new family syndrome is described that affected three of seven siblings and another patient who had been abandoned at birth but came from the same area of France. All four patients were young women with a very peculiar phenotype, poikiloderma and greying of the hair, and idiopathic non-arteriosclerotic cerebral calcifications. Pathological studies demonstrated small-vessel hyalinosis due to basal membrane thickening, mainly in the digestive tract, kidneys and calcified areas of the brain. The clinical and biological expressions of these vascular changes varied. Peripheral retinal ischemic syndrome and chorioretinal scars were found in the ocular fundi of three patients. Malabsorption and protein-losing enteropathy was the main problem in all four, and was the cause of one patient's death. A subarachnoid hemorrhage due to a right sylvian aneurysm also occurred in two of the three sisters and was lethal for one. Nephropathy with renal failure and systemic hypertension is the major problem of the two surviving patients.

[Anti-cytoplasmic antibodies of neutrophil granulocytes in systemic vasculitis]

Autoantibodies to the cytoplasmic components of neutrophil polymorphonuclear granulocytes (ACPA) were searched for by indirect immunofluorescence on ethanol-fixed smears from normal white blood cells in 248 sera from patients with Wegener's granulomatosis, Kawasaki disease and various other vasculitides, connective tissue diseases, nephropathies and infiltrative pulmonary diseases. Apart from a weak positivity in a few Kawasaki disease sera, ACPA were found in Wegener's granulomatosis (and micropolyarteritis) only, with a correlation between ACPA titers and disease activity. These results confirm the value of ACPA in the diagnosis and evaluation of activity of Wegener's granulomatosis.

Nephrotic syndrome associated with chronic lymphocytic leukemia: an immunological and pathological study

Three patients with B chronic lymphocytic leukemia and the nephrotic syndrome had atypical membranous glomerulonephritis or lobular membranoproliferative glomerulonephritis with subepithelial and subendothelial deposits containing IgG1 kappa, IgG1 lambda or IgM and IgG by immunofluorescence, respectively. A monoclonal cryoglobulin was intermittently found in the serum in one case. In two patients, kidney deposits were made of organized microtubular structures. Intracytoplasmic immunoglobulin inclusions in the two patients' lymphocytes showed a very similar electron microscopic pattern. The immunologic phenotype of leukemic lymphocytes was analogous in the three cases (with expression of CD2) and suggestive of a late maturation step. A complete remission of the nephrotic syndrome was observed after therapy with chlorambucil (and prednisone). These observations suggest a direct role of monoclonal immunoglobulins in kidney disease.

Diffuse small intestinal lymphoid infiltration in nonimmunodeficient adults from Western Europe

In two white adults born, raised, and living in central France and presenting with long-lasting malabsorption, massive and diffuse lymphoid infiltrate of the lamina propria associated with crypt scarcity was found along the whole small bowel. It was mostly composed of mature lymphocytes, focally mixed with plasma cells and reactive germinal centers. There was no evidence of celiac disease, systemic or intestinal immune deficiency or alpha-chain disease, overt lymphoid malignancy, or stagnant-loop syndrome. By immunofluorescence the infiltrate was constituted in 1 case of polyclonal B cells and, in the other, of a large majority of T11, T8, T10, and class II-positive T cells associated with a population of monotypic B cells. A gluten-free diet and parenteral nutrition proved ineffective. A dramatic and protracted clinical response was observed in both patients after the onset of oral tetracycline therapy, and still persists after 8 and 5.5 yr, respectively, together with morphologically unchanged small bowel infiltrate. These cases may be the equivalents, in people from Western developed countries, of the predominantly lymphocytic variety of the immunoproliferative small intestinal disease described in people from developing countries.

[Detection of anti-double stranded DNA antibodies of IgG, IgA and IgM classes by ELISA. Comparison with the Farr test and indirect immunofluorescence]

Anti-double stranded DNA antibodies were measured by an immunoglobulin class-specific immunoenzymatic assay (ELISA), in 450 sera from 265 patients as well as by indirect immunofluorescence using Crithidia luciliae as a substrate and, for 124 sera, by the Farr test. ELISA proved specific and reproducible and it yielded results that were well correlated with the Farr assay, with a slightly higher sensitivity of ELISA. Correlation with immunofluorescence was not as good because of the lower sensitivity of the latter method. ELISA enables the levels and isotypes of anti-DNA antibodies to be determined. Both appear to be critical parameters for a clinical interpretation of results, especially with respect to the diagnosis of systemic lupus erythematosus.