Free light chains of immunoglobulins in amyloidosis

Monomeric (M) and dimeric (D) forms of free light chains in serum have been measured by a sensitive radioimmunoassay in eight patients with amyloidosis without monoclonal proteins. Significantly elevated concentrations of D lambda chains were demonstrated in two of four patients with localized amyloidosis. The two patients had a significantly increased D/M ratio of both kappa and lambda chains. One patient had localized amyloidosis and normal concentration of monomeric and dimeric light chains had an abnormal fragment of light chains. A low kappa/lambda ratio was found in patients with localized amyloidosis. Four patients with secondary amyloidosis and renal insufficiency had increased amounts of free light chains. The concentration of light chains and the D/M ratio in this group corresponded to the impairment of renal function.

Polymeric Bence Jones proteins in serum in myeloma patients with renal insufficiency

The polymeric forms of Bence Jones protein (BJ) in serum and the influence on renal function were investigated in 59 patients with multiple myeloma and 2 with Waldenström's macroglobulinemia. Eight of 35 patients with kappa and 26 with lambda type BJ protein had decreased renal function. The investigation showed a considerable variation between patients in serum concentrations of tetrameric (T), dimeric (D) and monomeric (M) forms of BJ protein. A significantly higher fraction of D forms of BJ protein resulting in a high D/M ratio was found in the myeloma patients compared with polyclonal light chains in 10 normal controls. The renal function in multiple myeloma was, however, not correlated to the D/M ratio or to the BJ protein tetramers. This suggests that the nephrotoxicity of BJ proteins is not associated with polymerization of BJ proteins in serum. BJ proteins of aberrant size were found in 3 patients with rapidly decreasing renal function. Histological investigation in 2 of these patients revealed nodular glomerulosclerosis.

Nonsecretory myeloma associated with nodular glomerulosclerosis

A patient with nonsecretory multiple myeloma in associated with nodular glomerulosclerosis is reported. The clinical course was characterized by rapidly progressing renal insufficiency terminating in uremia within three months. Histological investigation of the kidney revealed extensive nodular formations in the mesangial areas consisting of basement membrane-like material, in places with content of fibrils. Immunofluorescence demonstrated deposition of kappa chains. Amyloid was not present. Routine methods for investigation of serum and urine showed severe hypogammaglobulinemia without M-components. Using a sensitive radioimmunoassay for free light chains, an abnormal non-dissociable kappa chain polymer with a molecular weight of 55 000 was found in serum and urine. The findings support the hypothesis that mesangial accumulation of paraproteins induce an increased synthesis of basement membrane material leading to formation of the nodules. Abnormal polymerization of kappa chains might provoke the formation of the glomerular nodules.

Serum concentrations of immunoglobulins and free light chains before and after vascular events in essential hypertension

Serum concentrations of immunoglobulins (Ig) and free light chains (LC) of Ig have been determined at regular intervals during five years in patients with essential hypertension and correlated to development of vascular complications. In 6 cardiac event patients serum IgG increased by 11.9% (p less than 0.05) and LC by 19.8% (p less than 0.05). IgG levels correlated positively with LC levels (r = 0.59, p less than 0.001) and changes in IgG correlated positively with changes in LC (r = 0.46, p less than 0.01). The post-event increments in IgG persisted up to 21 months. No significant changes in serum concentrations of IgA, IgM, albumin and creatinine were found. In 10 cerebral event patients and in matched groups of 15 uncomplicated hypertensive patients, no significant changes in the above parameters could be demonstrated. It is concluded that heart tissue damage in essential hypertension induces a long-lasting stimulation of B-lymphocytes, and it is suggested that the high Ig levels found in as yet uncomplicated hypertensive patients may reflect an ongoing damage of the vascular bed.

Patterns of proteinuria and circulating immune complexes in febrile patients

Circulating immune complexes (CIC) were detected in 8 of 15 patients with fever due to non-renal infections. Elevated urinary albuMin and beta-2-microglobulin excretion rates were found during the febrile period compared to the levels two days after normalization of the temperature. No relationship could be demonstrated between CIC and the excretion rates of albumin and beta-2-microglobulin or the albumin/beta-2-microglobulin ratio. Thus we have not been able to confirm the hypothesis that the glomerular type of proteinuria is caused by immune complexes.

Free light chains of immunoglobulins in serum from patients with rheumatoid arthritis, sarcoidosis, chronic infections and pulmonary cancer

Free light chains of immunoglobulins were measured in serum from 181 patients with rheumatoid arthritis (RA), sarcoidosis, pulmonary tuberculosis, pulmonary cancer and chronic bronchitis, i.e. patients with long-term stimulation of the immune system. Increased concentrations of light chains were found in patients with active sarcoidosis, and the light chain level appeared to be a marker of disease activity in sarcoidosis. The mean (+/- S.D.) concentration of kappa plus lambda chains in active sarcoidosis of more than two years' duration was 38.3 +/- 13.7 mg/l, that is twice the concentration of 19.4 +/- 5.5 mg/l found in normals. Some patients with seropositive RA also had increased serum values. The light chain concentrations in seropositive RA were correlated to the severity of the disease measured by clinical staging and laboratory tests. A modest increase in light chains was observed in one patient with tuberculosis, and in two patients each with chronic bronchitis and pulmonary cancer.

Characteristics of the Danish families with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is caused by autosomal dominantly inherited mutations in the MEN1 gene. Here, we report 25 MEN1 mutations - of which 12 are novel - found in 36 Danish families with MEN1 or variant MEN1 disease. Furthermore, one FIHP family was found to have an earlier reported mutation. The mutations were predominantly found in exons 9 and 10 encoding the C-terminal part of menin. Seven of the mutations were missense mutations, changing conserved residues. Furthermore screening of 93 out of 153 consecutive patients with primary hyperparathyroidism (pHPT) identified five mutation carriers. Two of these belonged to known MEN1 families, whereas the only MEN1-related disease in the other three was pHPT. Screening of 96 consecutive patients with fore-/midgut endocrine tumours revealed five mutation carries out of 28 patients with sporadic gastrinomas, whereas no mutations were found in 68 patients with other fore-/midgut endocrine tumours. Moreover, screening of 60 consecutive patients with primary prolactinoma did not identify any mutation carriers. Our data indicate that MEN1 mutation screening is efficient in patients with familial MEN1. Screening should also be offered to patients with pHPT or gastrinomas after thorough investigation into the family history. In contrast, sporadic carcinoid tumours or primary prolactinomas are rarely associated with germ-line MEN1 mutations.

Improvement of upper airway obstruction after 131I-treatment of multinodular nontoxic goiter evaluated by flow volume loop curves

Symptoms of tracheal-esophageal compression are often related to a large nontoxic goiter. The aim of the present study was to evaluate to what degree upper airway obstruction, as measured by flow volume loops, FIF50% and FEF50%/FIF50% (Forced Expiratory Flow at 50% of the vital capacity/ Forced Inspiratory Flow at 50% of the vital capacity) exists in nontoxic multinodular goiter, and whether changes occur after 131I-treatment. Thirteen patients with large multinodular nontoxic goiters were evaluated by estimation of FIF50%, FEF50%/FIF50% ratio and a graphic plot of the flow volume loop curve before and three, six and 12 months after treatment with 131I. FIF50% increased over 12 months from median 1.79 l/sec (range 1.46-3.02) to 2.84 l/sec (1.13-5.69) (p = 0.01). A progressive increase was seen over time (p = 0.001, trend analysis). The FEF50%/FIF50% ratio decreased from in 1.45 (0.32-2.26) to 1.03 (0.43-2.13) 12 months after treatment (p < 0.001). A progressive decrease was seen over time (p = 0.001, trend analysis). By visual evaluation 11 had a flow volume loop curve typical for an upper airway obstruction and in 9 patients the FEF50%/FIF50% ratio was > 1.2. In conclusion we found that upper airway obstruction is present in patients with multinodular nontoxic goiter, and seems to be reduced after 131I-treatment. Flow volume loop curves and measurement of FEF50% and FIF50% are important estimates for upper airway obstruction in these patients.

Dietary protein restriction and the progression of chronic renal insufficiency: a review of the literature

It is well known that dietary protein restriction can delay the appearance of uraemic symptoms and give symptomatic relief in patients with chronic renal failure. During the last decade, several investigators have argued that protein restriction instituted at an early phase in renal disease may influence the rate of progression of renal failure favourably. Animal experiments have given strong evidence that, in the case of nephron loss, high dietary protein promotes further loss of renal function. Many studies have been conducted to investigate the possible favourable effect of a protein-restricted diet in patients with renal disease. However, the scientific proof that long-term protein restriction delays the progression of chronic renal insufficiency in man is still missing.

Urine protein excretion after Hymenoptera sting

The urinary excretion of albumin was measured on 7 consecutive days after a bee or wasp sting in 20 healthy persons, using a semiquantitative immunochemical chromatographic procedure (Micral stick). The mean albumin excretion was 11.1 +/- 15.0 (SD) mg/l. This was not significantly different from the findings in a control group of 17 volunteers with no history of bee or wasp sting (mean 8.7 +/- 17.4 mg/l). Pathologic albumin excretion (50-100 mg/l) was found in three of the sting group, with mean 37.2 +/- 23.7 mg/l. After 2 more months the urinary albumin excretion had normalized in two of the three, with mean 19.3 +/- 16.0 mg/l. Nephrotic syndrome did not occur. Reactions to the sting corresponded to 1-4 on the Müller scale, but were not correlated to albumin excretion.

Thyroid volume and morphology and urinary iodine excretion in a Danish municipality

In order to throw light upon the eventual need for iodine supplementation in Denmark, four age groups of women (15, 30, 45 and 60 years) from the Holbaek municipality were invited for a clinical and ultrasound study of thyroid volume, structure and function. Of the 570 women invited, 391 accepted and were divided into the following groups: group I: 15 years, N = 113; group II: 30 years, N = 100; group III: 45 years, N = 98; group IV: 60 years, N = 80. The results were as follows the thyroid gland was palpable in 39% and visible in 16% of the entire group; 19% had a family history of thyroid disorders and 7.6% had a previous thyroid disorder. Thyroid volumes (median (range)) as measured by ultrasound were 12 ml (4-29 ml), 18 ml (5-47 ml), 18 ml (7-64 ml) and 18 ml (9-51 ml) in groups I-IV, respectively. The calculated 24-h iodine excretion was 65 micrograms (19-365 micrograms), 88 micrograms (15-274 micrograms), 97 micrograms (40-737 micrograms) and 83 micrograms (50-999 micrograms) in groups I-IV, respectively. An abnormal echo structure was present in 3, 10, 21 and 30%, respectively. Defining a goitre as a thyroid volume above 28 ml indicated a goitre prevalence of 17% in females aged 30-60 years in the Holbaek area of Denmark. Among the 60-year-old women, 3% had a clinically significant goitre (WHO grade III). Thyroid volume did not correlate with iodine excretion. The benefit of iodine supplementation is discussed.

No microalbuminuria or other adverse effects of long-standing hyperfiltration in humans with one kidney

Hypertrophy and hyperfiltration are characteristic features of single kidneys and kidneys of patients with insulin-dependent diabetes mellitus (IDDM). In both cases the hyperfiltration has been suggested to be involved in the pathogenesis of renal functional deterioration. We studied the effect of long-standing hyperfiltration on kidney function in 29 subjects with one kidney, three of whom were insulin-dependent diabetics. Four groups were studied: (1) uninephrectomized less than 10 years since uninephrectomy (UN) (n = 7; age, 30 +/- 6 years); (2) uninephrectomized greater than or equal to 10 years since UN (19 +/- 11 years, 10 to 52); n = 14; age, 38 +/- 15 years; (3) congenital unilateral renal agenesis (n = 5, age, 39 +/- 16 years); and (4) IDDM patients with one kidney (n = 3; age, 28 to 52 years; diabetes duration, 8 to 31 years; years with one kidney, 18 to 30). Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured by the constant infusion technique, kidney volume (KV) by ultrasonic scanning, and urinary albumin excretion rate (UAE) by radioimmunoassay. In all subjects GFR, RPF, and KV were within the normal range, representing a single kidney hyperfiltration of approximately 70% and hypertrophy of approximately 100%. Only one of the subjects with renal agenesis had an elevated UAE (117 micrograms/min); the remainder had a normal UAE, ie, less than 10 micrograms/min, and the diabetics were below the risk level of 20 micrograms/min. Serum creatinine was normal and BP was slightly elevated in only three subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect on renal haemodynamics, glomerular filtration rate and albumin excretion of high oral protein load

The effect on glomerular filtration rate (GFR), renal plasma flow (RPF) and excretion of albumin and beta-2-microglobulin in the urine after a high oral protein or amino acid load was investigated in young healthy males. After both test meals an increase in GFR of 10%, and in RPF of about 9-18%, was seen. The filtration fraction and albumin excretion rates were unchanged. The increase in GFR was significant from 20 to 60 min after intake of meat and remained elevated for more than 2 h. After the meat meal, a decrease in renal vascular resistance and an increase in S-creatinine, S-phosphate, S-carbamide and beta-2-microglobulin excretion rates was seen, but not after the amino acid load. During the experiments a gradual decrease in S-protein was noted. We conclude that the increase in RPF and GFR caused by intake of protein or amino acids in short-term experiments is not associated with impaired permselective properties of the glomerular membrane expressed in the albumin excretion rate.

Repeated measurements of serum immunoglobulin-free light chains in early sarcoidosis

Serum immunoglobulin free light chains (LC) are frequently increased in chronic active sarcoidosis but rarely in disease of less than 2 years duration. LC were re-measured in 19 sarcoidosis patients who were previously examined during early disease. At first examination LC were elevated in only 4 patients; all of them had achieved normal values at second LC measurement, at an average of 28 months later, in parallel with remission or inactive sarcoidosis in most cases. Elevated LC appeared eventually in 2 patients with clinical evidence of active sarcoidosis, but not in other patients with a similar clinical course. The frequent elevation of LC in chronic active sarcoidosis is, in most cases, dependent on a year-long stimulation of the immune system, longer than has been present in this series.

Free light chains of immunoglobulins in serum from patients with leukaemias and multiple myeloma

The serum concentration of free kappa and lambda light chains of immunoglobulins were measured in 114 patients with myelo- and lymphoproliferative disorders including multiple myeloma. Increased concentrations of a single light chain type, suggesting monoclonal origin, were found with high frequency in B-cell diseases only. Thus 6 out of 9 patients with chronic lymphatic leukaemia and 24 of 28 patients with multiple myeloma had increased concentrations of a single chain type. The highest values reported in chronic lymphatic leukaemia were approximately 10 and in multiple myeloma 1000 times normal mean. Cytostatic treatment of chronic lymphatic leukaemia was followed by a decrease in the light chain levels. The levels were, however, not correlated to the number of circulating lymphocytes, the lymphatic infiltration of tissue or clinical activity. Increased concentrations of both chain types, suggesting a polyclonal origin, were found in both of 2 patients with acute monocytic leukaemia, 6 of 7 with acute myelomonocytic leukaemia, 2 of 23 with acute myeloid leukaemia and 1 of 7 with acute lymphoblastic leukaemia. The highest levels of light chains in these groups were 5 times normal mean. All patients with myeloproliferative disorders revealed normal values of both light chain types.

Tubular proteinuria following jejuno-ileal bypass surgery

By means of immunonephelometry, determinations of a number of high molecular weight (HMW) and low molecular weight (LMW) proteins in urine and serum were undertaken in 42 consecutive patients, who had been subjected to jejuno-ileal bypass surgery for treatment of massive obesity two to six years before the study. Five patients demonstrated a distinct LWM proteinuira, ie excessive excretion of free-light lamdba and kappa chains of immunoglobulin and beta-2-microglobulin. The creatinine clearance was normal in four of these five patients. This LMW-proteinuria group differed from the remaining 37 patients in several respects. First, they had lost weight more effectively (P less than 0.01); secondly, they exhibited secondary hyperparathyroidism (P less than 0.05), increased levels of alkaline phosphatase and low serum concentrations of bicarbonate (P less than 0.001). It is suggested that LMW proteinuria may be a manifestation of secondary hyperparathyroidism.

Light chain polymerism in normal individuals in patients with severe proteinuria and in normals with inhibited tubular protein reabsorption by lysine

The polymeric forms of free kappa and lambda light chains were estimated in serum and urine from twelve normal individuals, from seven patients with nephrotic syndrome associated with normal GFR, and from eleven normal persons after inhibition of renal tubular protein reabsorption by lysine. The investigation showed that the serum concentrations of the monomeric and dimeric forms of light chains were similar in the three groups. The urinary excretion was increased in patients with nephrotic syndrome, the mean excretion of kappa chains being 9.2 mg/24 h and of lambda 6.6 mg/24 h compared with normal excretion of 2.2 mg/24 h for kappa and 1.0 mg/24 h for lambda. After inhibition of tubular protein reabsorption, the urinary light chains excretion increased to 101.3 mg/24 h for kappa and 40.0 mg/24 h for lambda chains, i.e. approximately 40 times normal level. The relative concentrations in the urine of the monomeric and dimeric forms of the two chain types were varied widely in the three groups investigated, particularly for lambda monomers where a low excretion rate and clearance value was found during inhibition of the protein reabsorption. The reason for the variations were found to be differences in polymerization and consequently differences in glomerular filtration. Evidence for a preferential reabsorption of any of the chain types or polymers was not seen.

An evaluation of two methods for detection of circulating immune complexes in patients with rheumatoid arthritis

Immune complexes were detected by Clq-binding activity (Clq-BA) in 58% of 107 patients with seropositive rheumatoid arthritis (RA), and in 24% of 31 patients with seronegative arthritis. The difference is significant. Immune complexes were detected by the anticomplementarity test (AC) in approximately half of the patients without significant inter-group differences. No correlation was observed between the two methods. In 35 randomly selected patients with seropositive RA, a significant correlation was observed between Clq-BA and the functional class and the latex titre for rheumatoid factor. In patients with seronegative RA, the Clq-BA was significantly correlated to the number of joints with impaired mobility. The AC test was correlated to the erythrocyte sedimentation rate and the concentration of hemoglobin and gammaglobulin in patients with seropositive RA. As regards the clinical activity of disease, erythrocyte sedimentation rate and hemoglobin seem better parameters than the Clq-BA and AC tests.

Free light chains in serum during short course immunosuppression after corneal transplantation

The effect of low doses of prednisone on the serum concentration oflight chains, IgG, IgA and IgM in nineteen corneal transplanted patients was investigated. Prednisone in doses of 30 mg daily for 6 days had an instantaneous effect on the concentration of light chains resulting in a mean decrease of 16.5% in relationship to the pre-treatment values. Decrease in the prednisone dose to 15 mg daily was followed by normalization of the light chain concentration. The effect of prednisone on the IgG concentration was less pronounced and more delayed. A mean decrease for IgG of 9.0% of the pre-treatment values was found. Minimum IgG concentration was found 3 weeks later than the minimum for light chains. Differences in the metabolization rate of light chains and IgG is suggested as an explanation for this. The concentration of IgA and IgM was unchanged during treatment. Correlation between corneal rejection and changes in the level of light chains or IgG was not found.

Urinary excretion of albumin beta2-microglobulin and free light chains during lithium treatment

Albumin, beta2-microglobulin and free light chains were determined in urine in nine manic-depressive patients before and at intervals during three months of lithium treatment (longitudinal study). The same determinations were carried out in twenty-seven manic-depressive patients who had been treated with lithium for 3 months to 20 years and also in a control group (transversal study). There were no statistically significant changes in urinary excretions of albumin, beta2-microglobulin and free light chains during the longitudinal study. In one patient albumin excretion gradually increased during the study and remained elevated on reexamination 1 year later. No significant differences were found between the lithium treated patients and control subjects in the transversal study in either albumin, beta2-microglobulin or free light chain excretion. It is not clear whether the increased and sustained albumin excretion in one of the patients was due to lithium or was conincidental. The study shows that in most patients lithium treatment does not affect renal protein excretion.

Circulating immune complexes in syphilitic nephropathy. A case report

A case of transient nephrotic syndrome caused by secondary syphilis is described. A renal biopsy was performed revealing subepithelial hump-like electron-dense deposits and fusion of epithelial foot-processes. Complement C1q-binding-activity and anticomplementarity were demonstrated in the blood, indicating the presence of circulating immune complexes. This strongly suggests that circulating immune complexes are significant in the immunopathogenesis of syphilitic nephropathy.

Normal values for free light chains in serum different age groups

The concentration of free light chains from the immunoglobulins was measured in twelve paired sera from mothers and newborns and from 149 sera from normal individuals in various age groups. Variations in concentration during life are correlated to the variations in the concentration of 'regular' immunoglobulins. A concentration of light chains in cord blood of 35% of mean normal adult level (MNA) together with a rapid passage of light chains across the placenta is interpreted as indicating catabolization of maternal light chains in the fetus. This is further supported by the finding of a lower concentration of light chains in maternal serum than in normal adult serum. The investigation shows that the concentration of light chains falls rapidly from 35 to 24% of MNA during the first few days of life. From the first week of life the concentration of light chains increases and low normal adult values are attained by one year of age. Except for difference in concentration, the elution pattern for light chains from Sephadex G-100 columns was similar for normal, adult and cord blood. The relationship between kappa and lambda chains--the K/L ratio--is 1.2 for normal and maternal serum and 1.0 for cord serum.