High incidence of intact or fragmented immunoglobulin in urine of patients with multiple myeloma.

In this prospective study we determined the incidence of intact/fragmented immunoglobulin and Bence Jones protein in urine immunofixation using Sebia reagents and HydrasysTM 2 apparatus and compared the results to concentrations of serum free light chains (FLC) assessed using Siemens BNTM II nephelometer and the immunoassay Freelite (Binding Site) in 289 patients with multiple myeloma at diagnosis. It was found that in one third of IgG, IgA and IgD myeloma patients, intact/fragmented immunoglobulin can be detected in urine and is connected with impaired renal function and reduced survival. Urine immunofixation detects monoclonal protein (FLC and intact/fragmented immunoglobulin) in 66-79% of IgG and IgA myeloma patients while serum FLC immunoassay detect it in 82-94% of IgG and IgA myeloma patients. However, the latter method is inadequate for detection of intact/fragmented immunoglobulin in urine. Serum FLC immunoassay and urine immunofixation are complementary methods in diagnosing and monitoring monoclonal protein in patients with myeloma.

Immunoglobulins of the human amniotic fluid.

PROBLEM: Except for the description of a secretory immunoglobulin (S-Ig) of a low size, no recent study has investigated the molecular status of antibodies in the human amniotic fluid. METHOD: After separation with a high performance chromatography, we analyzed the different isotypes of amniotic Igs by immunoblotting and ELISA. RESULTS: IgG is found to be the major isotype and to contain mother-derived tetanus antitoxins. IgA is much less abundant, whereas no IgM can be detected. IgA is monomeric, with a low level of secretory IgA and with various amounts of free secretory component (SC). The presence of a low level of SC-containing immunoglobulin of a low size is confirmed during the last trimester of pregnancy. This molecule contains no alpha chain but includes a Fabgamma fragment noncovalently associated with SC. IgG, IgA, and SC are detected in the fetal urine and, therefore, can reach the amniotic fluid by this route. CONCLUSION: In addition to the predominant maternal IgG, the amniotic fluid contains different molecular forms of fetal immunoglobulins. Their function as an immune barrier against infection and against mother-derived autoantibodies is discussed.

Evaluation of patterns of urinary proteins by SDS-PAGE in rats of different ages.

The patterns of urinary proteins in rats of different ages were examined on SDS gradient polyacrylamide gel electrophoresis coupled with silver staining. Proteins were fractionated into at least 26 bands. Densitometric measurements were used to characterize protein excretion patterns. The results showed that proteinuria in newborn, young and adult rats is predominantly tubular, consisting of low molecular-weight species. Conversely, late adults and old rats had a mixed glomerular pattern, with a steadily increasing excretion of albumin, IgG and transferrin, as was the case of other high molecular-weight proteins. Fragments of both immunoglobulins and albumin were found in all urine samples assayed. In 1 month old rats the percentage of Tamm-Hörsfall (T-H) protein was higher (P < 0.01) than in the remaining groups studied. In newborns, relatively high albumin, IgG and transferrin percentages were detected, as well as an alpha 1-acid glycoprotein and carbonic anhydrase excretion (P < 0.05 and P < 0.01 respectively) higher than that observed in the other age groups studied.

Free fragments of gamma chain in the urine. A possible source of confusion with gamma heavy-chain disease.

With currently used microconcentrators, high-resolution electrophoresis, and immunofixation electrophoresis, relatively homogeneous free fragments of gamma chain (FFGC) unaccompanied by light chains, which cannot be found in the serum, may be discovered in the alpha-2 region during routine examination of the urine. The urinary alpha-migrating FFGC is of no apparent clinical significance and should not be confused with the antigenically related FFGCs of gamma heavy-chain disease. In gamma heavy-chain disease, the FFGCs are often demonstrable in the urine, but are always present in the serum and migrate in the beta-gamma region.

Quantification of human urinary free secretory component, secretory and nonsecretory IgA by ELISA.

The specific quantification of human urinary free secretory component (FSC), secretory IgA (SIgA) and total IgA using ELISA has been hampered by mutual interferences of these three molecules. Using affinity chromatographically purified antisera an attempt was therefore made to reduce these interferences without necessitating further assay steps. FSC and total IgA were measured in unprocessed urine by means of anti-FSC and anti-IgA as well as alkaline phosphatase-coupled anti-FSC or anti-IgA antisera. SIgA was determined using anti-IgA as well as alkaline phosphatase-coupled anti-FSC. Nonsecretory urinary IgA was calculated from the measured SIgA and total IgA. The mutual interferences of FSC, SIgA or nonsecretory IgA in the three assay systems were low and not relevant for normal samples. Normal urinary concentrations were: FSC 344 +/- (SD) 208 ng/ml (n = 120), SIgA 1,874 +/- 1,133 ng/ml (n = 123) and nonsecretory IgA, depending on the way of standardization, 712 +/- 699 (n = 56) or 878 +/- 732 ng/ml (n = 51). SIgA excretion increased with age. Lower urinary SIgA as well as total and nonsecretory IgA levels were observed in males as compared to females. No correlation evolved between the hormonal status of women and the excretion of FSC, SIgA or IgA. In IgA-deficient patients virtually no nonsecretory IgA or SIgA was detected in the urine while the FSC concentration was in the normal range.

Immunoglobulin light-chain immunoblots of urine proteins from patients with tubular and Bence-Jones proteinuria.

Immunoglobulin excretion by patients with monoclonal gammopathies and tubular proteinuria has been analysed by agarose gel isoelectricfocussing of untreated urine and immunoblotting. About three-quarters of the Bence-Jones proteins detected occurred as multiple bands on isoelectricfocussing; in about half of these cases the multiple forms were due to polymerisation or fragmentation of the light chains. In specimens with tubular proteinuria, a characteristic light chain pattern of three broad bands covering the pI ranges 7.1-7.3, 7.8-8.0 and 8.3-8.5 was found. This pattern also occurred in 53% of specimens with Bence-Jones proteinuria and was identical to that found in concentrated normal urine. Intact monoclonal immunoglobulin usually appeared as three or more evenly spaced bands of similar intensity whereas polyclonal intact immunoglobulins produced diffuse staining from pI 5.0-8.5. A scheme for the qualitative analysis of urinary immunoglobulin excretion using this technique has been developed.

The use of thiosulfate to increase polymerization of IgM subunits.

Sodium thiosulfate was used to enhance in vivo the polymerization of myeloma IgM, deficient in disulfide cross-links. The therapy sharply decreased the amount of low molecular weight IgM fractions, while increasing the serum content of molecules of higher molecular weight. The degree of disulfide cross-linking in IgM increased under the influence of thiosulfate. The rate of secretion into the serum and urine of some membrane-related glycopeptides and species rich in sialic acid was reduced. Also, the discharge of L chains to the urine was lowered during the thiosulfate trial. All these changes were attributed to enhancement of disulfide-interchanging enzyme activity by thiosulfate.

Specificity of SLE serum antibody for single-stranded and double-stranded DNA configuration.

The solid phase immunoassay for the measurement of serum antibody to double and single-stranded DNA is described. The technique allows a more accurate definition of the antibody specificity of SLE sera as defined by inhibition techniques. The clinical usefulness of immunologic assays in the management of patients with SLE is described, including measurement of urine light chain protein concentration. A core discussion is provided to illustrate how such a panel of tests is used in management.

The clinical spectrum of light chain myeloma. A study of 35 patients with special reference to the occurrence of amyloidosis.

During a 40 month interval, 35 patients were seen with a plasma cell dyscrasia in which the only detectable monoclonal immunoglobulin abnormality consisted of excess production of either type kappa or type lambda light chains (Bence Jones protein). This group constituted 17.3 per cent of the total number of patients with plasma cell dyscrasias and 25.7 per cent of the patients with myeloma identified during the same period. Variable initial clinical presentation, the absence of a typical monoclonal serum spike and the unreliability of commonly used urine protein tests made recognition of the disorder difficult in many patients. Sulfosalicylic acid and p-toluene sulfonic acid proved valuable in screening for ueine protein. Definition of "proteinuria" by quantitative, electrophoretic and immunochemical studies was essential for diagnosis. Bence Jones proteinemia was present in 80 per cent of the patients; panhypogammaglobulinemia and lytic bone lesions were demonstrable in more than 60 per cent. Although no specific morphologic abnormality of marrow plasma cells was evident by light microscopy, the absence of rouleau on peripheral blood smear was a helpful diagnostic clue. Although patients with lambda light chains presented with more Bence Jones proteinuria, this did not correlate with the severity of initial renal functional impairment or with survival when compared to patients with kappa light chains. No other clinical or laboratory observation differentiated the groups with kappa light chains from those with lambda light chains. Amyloid was identified in seven patients. Their course was dominated by the features of primary systemic amyloidosis instead of the usual findings of classic myeloma. Patients with amyloidosis had lower initial serum albumin levels, fewer lytic bone lesions and reduced survival compared to patients without amyloidosis.

Extramedullary plasmacytoma of stomach.

A single case of gastric plasmacytoma showing unusual clinical and pathological features is described. The patient had gluten sensitive enteropathy, and showed increased circulating IgA levels prior to gastrectomy. Progression of the disease was associated with both K and L light chain proteinuria, hypoalbuminaemia, and vasopressin resistant polyuria. Pathological investigation revealed the coexistence of IgA secreting soft tissue plasmacytoma, with IgG secreting myeloma. The significance of these findings is discussed.

Combination therapy for myelomatosis.

Twenty-eight patients with multiple myeloma have been treated with a quadruple chemotherapeutic regimen consisting of 1, 3 bis (2-chloroethyl)-1-nitrosourea (BCNU), cyclophosphamide, melphalan, and prednisolone. Nineteen new patients and nine who had escaped from previous single-agent therapy were included in the study. The results to date, on eight criteria of response, seem to be superior to those obtained from previous chemotherapeutic regimens. The study has been in progress for 18 months and only three patients have died. Only one who had not received previous therapy died, and she had complicating hyperparathyroidism, which almost certainly contributed to her death.

Urinary excretion of fibrinogen-related materials, complement, and immunoglobulins in proliferative glomerulonephritis and after renal transplantation.

Using a radial immunodiffusion technique we measured the urinary concentration of material related to complement (C3), IgM, and IgG along with fibrin-fibrinogen degradation products and heterophile (sheep) haemagglutinins in 15 patients with proliferative glomerulonephritis and in 10 patients after renal transplantation. There was a significant correlation between all variables measured, and serial studies showed that with the exception of IgG-related materials potentially useful information could be obtained on the detection of rejection and the response to treatment in both conditions. The significance of these observations is discussed.