Serum immunoglobulins in the nephrotic syndrome. A possible cause of minimal-change nephrotic syndrome

Group B streptococcal cellulitis in a child with steroid-responsive nephrotic syndrome

Although infectious complications of nephrotic syndrome are common, group B Streptococcus is a rare pathogen in these patients. We present a 4-year-old child with nephrotic syndrome who developed group B streptococcal cellulitis and bacteremia, an association not previously discussed in the literature, and review the factors that predispose patients with nephrotic syndrome to infection.

In vitro decrease of glomerular heparan sulfate by lymphocytes from idiopathic nephrotic syndrome patients

BACKGROUND

Lymphocytes are involved in the physiopathologic mechanism of idiopathic nephrotic syndrome (INS). We have recently demonstrated that plasma from patients with INS decreases human glomerular epithelial cell (GEC) glycosaminoglycans (GAGs), particularly heparan sulfates (HS) in vitro. In this study we investigate the effect of peripheral blood lymphocytes (PBL) from INS patients on glomerular cell GAG and HS.

METHODS

Human GECs were cultured with total peripheral blood mononuclear cells (PBMCs), PBL, and monocytes from patients and controls. The amounts of GAG and HS were assessed using a cationic membrane after metabolic labeling.

RESULTS

In coculture with GECs, mononuclear cells from controls decreased total epithelial cell GAG (-30% with PBMC, P < 0.05; -25% with PBL, P < 0.02; -19% with monocytes, P < 0.05). Particularly HSs were decreased (-36% with PBMC, P < 0.05; -27% with PBL, P < 0.02; and -19% with monocytes, P < 0.05). When GECs were in coculture with PBL from INS patients, the decrease in GAG and HS was significantly greater in comparison to control PBL (-10%, P < 0.02; -10%, P < 0.02, respectively, for GAG and HS). Moreover, supernatants of stimulated PBMCs from patients decreased also GAG and HS in comparison with controls (-13%, P < 0.02; -15%, P < 0.02, respectively, for GAG and HS).

CONCLUSION

These data provide direct evidence that PBLs from INS patients are able to decrease GEC HS as previously shown with plasma from patients. This might be instrumental in the onset of albuminuria.

Indirect quantification of lipid peroxidation in steroid responsive nephrotic syndrome

AIMS

To test the hypothesis that oxygen free radicals are mediators of excessive protein permeability in steroid responsive nephrotic syndrome.

DESIGN

Case control study.

PATIENTS

20 children with steroid responsive nephrotic syndrome; controls: 20 children admitted for elective surgery.

SETTING

The paediatric and biochemistry departments of the Maulana Azad Medical College, New Delhi, India.

METHODS

Blood samples were taken twice from children with nephrotic syndrome (on admission and on urinary remission) and once from controls. Biochemical assays were carried out on these blood samples to quantify the indirect markers of free radical injury in the body, namely: vitamin E, reduced glutathione (GSH), glucose-6-phosphate dehydrogenase (G6PD), malonyldialdehyde (MDA), and membrane cholesterol in erythrocytes.

RESULTS

There was some evidence supportive of oxidative injury in the children with nephrotic syndrome in the form of greatly reduced concentrations of antioxidants vitamin E (155.4 microg/100 ml in controls, 86.4 microg/100 ml in patients) and G6PD (364 mU/ml in controls, 205.1 mU/ml in patients). However, concentrations of the oxidation byproduct MDA were raised only in the remission phase of the disease (0.984 nmol/ml in controls, 1.158 nmol/ml in cases), whereas those of GSH were unaltered.

CONCLUSIONS

Changes in the concentrations of MDA, G6PD, and vitamin E are consistent with increased amounts of oxidation in steroid responsive nephrotic syndrome. Further research is needed to explain whether these changes are a cause or consequence of the disease.

Plasma protein abnormalities in nephrotic syndrome: effect on plasma colloid osmotic pressure and viscosity

The concentrations of 25 plasma proteins were measured in 22 patients with membranous nephropathy. For some large proteins, the plasma concentrations were increased; there were also large proteins with low plasma concentrations, but small or medium-sized proteins showed uniformly lower plasma concentration than the controls. Plasma colloid osmotic pressure (π) and viscosity (η) were not interrelated but showed positive and significant correlations with plasma concentrations of small and medium-sized proteins (π) and plasma concentrations of large proteins (η), respectively. Nephrotic plasma is not efficient in maintaining plasma π but highly efficient in maintaining plasma η. High plasma fibrinogen concentrations and low antithrombin III concentrations may predispose to thrombosis, and low IgG concentrations may account for the higher predisposition to bacterial infection. The relative composition of nephrotic plasma is heavily dependent on the size of the different proteins. Plasma π and η are also maintained by the relative preponderance of different plasma proteins.

Proteinuria and albumin homeostasis in the nephrotic syndrome: effect of dietary protein intake

Nephrotic syndrome is analyzed in the light of interventions designed to decrease proteinuria and renal injury. The effect of dietary protein intake on urinary protein losses and albumin homeostasis are discussed on the basis of the pathophysiologic mechanisms known to account for changes in renal function of nephrotic patients. In addition, the effect of angiotensin-converting enzyme inhibitors for reduction of proteinuria is discussed in terms of the modulation of glomerular permselectivity and hemodynamics.

The primary glomerulopathies

Disorders of glomerular structure and function are encountered frequently in clinical medicine. Many arise as part of a well-defined multisystem or multi-organ disease process, while in others the clinical and laboratory manifestations are consequent to the sole or predominant involvement of glomeruli. The latter are known as the primary glomerulopathies. These disorders can evoke a variety of clinical syndromes, including acute glomerulonephritis, rapidly progressive glomerulo-nephritis, nephrotic syndrome, "symptomless" hematuria and/or proteinuria, and chronic glomerulonephritis. The identification of underlying morphology, through the application of renal biopsy techniques, can provide useful information for both prognosis and treatment. Pathogenic mechanisms involved in the primary glomerulopathies are varied, but immunologic perturbations underlie many disease entities. This article describes the clinical features, pathology, natural history, and treatment of the main categories of primary glomerulonephritis, with emphasis on recent developments and practical aspects of diagnosis and management.

HLA-DQB1 allele associates with idiopathic nephrotic syndrome in Japanese children

HLA-DQA1 and -DQB1 genes were investigated in 30 Japanese children with idiopathic nephrotic syndrome (INS) using the polymerase chain reaction-restriction fragment length polymorphism method. Compared with control children, there was a significant increase in the HLA-DQA1*0501, DQB1*0301 and DQB1*0601 alleles, whereas the frequency of DQB1*0501 showed a significant decrease in the patients. The increase of DQA1*0501 can be explained as being a result of a linkage disequilibrium with DQB1*0301. The previous result demonstrating a positive association of DRw6 and DRw8 with INS is also assumed to be attributable to a linkage disequilibrium with DQB1*0301 and 0601. A total of 83% of patients compared with 37% of controls possessed DQB1*0301 and/or DQB1*0601 allele (P < 0.001, RR = 8.6). Only these alleles have alanine at residue 13 and tyrosine at residue 26 in the hypervariable region in the Beta 1 domain of DQB1 gene. These findings suggest that the unique amino acid residues in the DQB1 gene may contribute to disease susceptibility in Japanese children with INS.

Serum and urine soluble interleukin-2 receptor in idiopathic nephrotic syndrome

Although a cellular immune pathogenesis is suspected in idiopathic nephrotic syndrome of childhood (INS), there is scant direct evidence of in vivo immune activation. In order to investigate cytokine cascade activation in INS, soluble interleukin-2 receptor (sIL-2R) in plasma and urine was characterized and its levels measured in INS patients during relapse. Immunochemically detectable sIL-2R had a molecular mass of 35-46 kDa in both serum and urine and the molecule appears to be excreted intact; the pI was 5.05. INS patients had elevated serum sIL-2R levels compared with adult normal controls (845 +/- 97 vs. 373 +/- 47 U/ml, P = 0.001) and were significantly higher than previously published age-matched controls. Urinary excretion of sIL-2R was 47.2 +/- 13 U/mg creatinine in patients. Both the sIL-2R excretion rate and the fractional excretion of sIL-2R were positively correlated with the excretion of albumin (P = 0.02 and 0.002, respectively). These increased serum and urine levels occurred whether relapse was or was not associated with an intercurrent illness. We conclude that: (1) despite increased sIL-2R excretion during INS relapse, serum levels are significantly elevated; (2) while the elevated urinary levels could result from enhanced intrarenal production, they more likely reflect the increased serum levels; (3) the elevated sIL-2R levels support an immune pathogenesis in INS.

Altered in vitro lymphocyte response in childhood nephrotic syndrome

The immune system, and disturbed T lymphocyte function in particular, has previously been implicated in the pathogenesis of childhood idiopathic nephrotic syndrome. As this disorder is commonly responsive to steroid therapy, we set out to determine whether in vitro suppression of lymphocyte blastogenic response to the mitogen phytohaemagglutinin (PHA) could predict the clinical situation. Comparing nine nephrotic children with nine healthy controls we were able to show the inhibitory prednisolone dose that suppressed lymphocyte blastogenesis by 50% (ID50) at a known concentration of PHA was significantly greater (P < 0.005) for nephrotic individuals. However, the in vitro assay did not reliably predict the clinical response to prednisolone. This study further implicates altered lymphocyte function in the mechanisms underlying idiopathic nephrotic syndrome.

HLA extended haplotypes in steroid-sensitive nephrotic syndrome of childhood

Idiopathic nephrotic syndrome has been postulated to have an immunopathogenic basis. To determine whether steroid-sensitive nephrotic syndrome is associated with greater than expected frequencies of specific extended haplotypes of the major histocompatibility complex, we studied genetic markers (Class I, II, III HLA alleles and glyoxalase I) in 173 subjects in 42 families of patients with nephrotic syndrome of childhood. The single allele, DQW2, was found in 72% of steroid sensitive patients compared with only 35% of the controls (P = 0.003). In half of 32 steroid sensitive, but not 10 steroid resistant, patients, one or both of two specific extended haplotypes (alleles that segregate together) were identified. The first, [HLA-A1, B8, DR3, DRW52, SCO1], occurred in 11 of 64 haplotypes, or 17%, compared to 5% of controls (P = 0.017). The other, [HLA-B44, DR7, DRW53, FC31], occurred in 10 of 64 haplotypes, 16% compared to 3.8% of controls (P = 0.014). Five patients had both haplotypes. Patients with these specific extended haplotypes had a greater frequency of relapses than did those with other haplotypes. These data provide additional support for the hypothesis that steroid-sensitive nephrotic syndrome has an immunogenetic basis.

Intravenous immunoglobulin in minimal change nephrotic syndrome: a crossover trial

To determine whether intravenous immunoglobulin (IVGG) would be an efficacious adjunct in the treatment of childhood minimal change nephrotic syndrome (MCNS), we enrolled ten patients with frequently relapsing or steroid-dependent MCNS in a double-blind crossover clinical trial. At the time of relapse of the nephrotic syndrome, patients were assigned to treatment with a single outpatient infusion of IVGG (800 mg/kg) or intravenous albumin as a control. The relapse was treated concurrently with standard doses of oral prednisone. At the time of the next relapse, patients who had first received IVGG were treated with albumin, and vice versa. There were no significant differences in the length of remission between the IVGG and albumin treatments. The study had a power of 0.72 to detect a true difference of 45 days between the two therapies. We conclude that in the dose of drug used in this trial, administered at the time of relapse in conjunction with prednisone therapy to children with frequently relapsing or steroid-dependent MCNS, IVGG does not lead to a clinically important extension of the period of remission.

Serum immunoglobulins and IgG subclasses in patients with glomerulonephritis

The serum concentrations of IgG, IgA, IgM and of the four subclasses of IgG were determined by radial immunodiffusion in 103 patients, mean age 42 (range 16-72), with various types of glomerulonephritis. Forty-nine healthy blood donors, mean age 41 years (range 19-65), served as controls. Kidney biopsies were obtained from all the patients for examination by histopathology and by immunofluorescence. The glomerulopathies were classified according to WHO criteria. The serum immunoglobulin patterns were different for the various clinical groups of patients. Patients with Wegener's granulomatosis, rapidly progressive glomerulonephritis and SLE had a significant increase in total IgG and of IgG4 (P less than 0.05-0.001). Patients with minimal change disease had low concentrations of IgG (P less than 0.001) with a significant decrease in IgG1 and IgG2 (P less than 0.001 and 0.01, respectively). Highly significant increases in IgA were noted for patients with IgA nephritis (P less than 0.001) but high levels were also seen in patients with chronic glomerulonephritis. The findings might have diagnostic implications.

Dysfunction of the monocyte-macrophage system in the idiopathic minimal change nephrotic syndrome

We studied the function of phagocytes and the distribution of lymphocyte subpopulations in 23 patients with Idiopathic Minimal Change Nephrotic Syndrome. All the patients were in relapse at the time of the study. The latter was performed before specific therapy was started. Our control group consisted of 26 normal children who were studied while undergoing routine analysis prior to plastic surgery. Polymorphonuclear leukocytes from the patients showed no alterations in their ability to ingest and to kill candidas. On the contrary, peripheral blood monocytes had a normal phagocytic function with a decreased candidacidal activity when compared to normal controls (p less than 0.001). No correlation was found between serum immunoglobulin levels and the monocyte lytic function. The absolute number of B lymphocytes was significantly increased (p less than 0.05), whereas the absolute number of total lymphocytes, T lymphocytes and T4+ and T8+ cell subsets did not differ from those of the age-matched normal controls. Natural killer cells were functionally normal.

The immune system in minimal change nephrotic syndrome

Numerous examples of abnormal immune responsiveness have been described in minimal change nephrotic syndrome (MCNS). The of MCNS with allergy and with certain genetic markers of immune responsiveness, as well as the excellent response of proteinuria to immunomodulatory agents, has suggested a causal relationship between the immunological and renal abnormalities. However, the nature of this relationship is uncertain. Before it can be clarified, the basic mechanism(s) involved in disturbed immunity in patients with MCNS must be better characterized. Studies of humoral and cellular immune function support the hypothesis that immune regulation is abnormal. However, conclusive evidence of participation by a defined immunoregulatory system in the events leading to immune dysfunction has not been obtained. Thus, considerable work remains to be done in determining the nature and cause of abnormal immunity in MCNS prior to investigating its potential role in the pathogenesis of proteinuria.

Major histocompatibility complex antigens in steroid-responsive nephrotic syndrome

An increased frequency of specific major histocompatibility complex (MHC) class I, II and III antigens in children with steroid-responsive nephrotic syndrome (SRNS) has been reported. This frequency distortion, in some cases, is thought to affect the outcome of the disorder. We studied the phenotypic frequency of HLA antigens -A, -B, and -DR, as well as complement proteins Bf and C4 in an unrelated population of 25 SRNS children. Complete MHC haplotypes were also derived for four families in which 8 individuals developed SRNS. HLA-DR8, with a relative risk of 4.8, showed the strongest association with SRNS. Nonetheless, the 95% confidence intervals of this and the relative risks for all other antigens fell below 1.0. No common haplotype was found in SRNS patients in whom complete family studies were available, and disease and inheritance of the MHC were discordant in two of these families. In this study of well-characterized SRNS patients we were unable to discover a clear association between this disorder and the MHC.

A transient monocyte defective function in idiopathic nephrotic syndrome (lipoid nephrosis)

Alterations in phagocytosis have been studied in 25 patients with idiopathic nephrotic syndrome (INS). At the time of investigation all patients had normal renal function.

Decreased antibody-dependent cellular cytotoxicity in minimal change nephrotic syndrome

Secondary IgG response to a tetanus toxoid booster and in vitro measurement of immunoglobulin synthesis, antibody-dependent cellular cytotoxicity (ADCC) and gamma-interferon (IFN-gamma) production were evaluated in 20 healthy controls and in 17 children with minimal change nephrotic syndrome (MCNS), during the acute nephrotic phase and 6 months after remission. Defective responses were observed in all but IFN-gamma production during the acute nephrotic phase; these improved with disease remission. There was a significant correlation between decreases in vitro IgG production and ADCC reaction. These data indicate that defective antibody production is associated with decreased ADCC during the acute nephrotic phase of MCNS.

Long-term prognosis for children with nephrotic syndrome

Follow-up survival and health information were obtained, after a median of 27.5 years, from 132 patients who had been seen originally as children with nephrotic syndrome between 1951 and 1967. Ninety seven patients were alive. Recurring edema or proteinuria, or both, persisted in 15 percent of those still alive. Eight of 11 parous women reported relapses during pregnancy. There was no apparent increase in malignancies, atopic diseases, clinical defects in cell-mediated immunity, or cardiovascular diseases. Twenty two patients (17%) died of renal causes between 3 months and 8 years after the onset of nephrotic syndrome. Steroid resistance was the presenting feature universally predictive of a poor outcome; nine of the 11 such patients died and the other two are now receiving hemodialysis. Hematuria was present initially in 41 percent of the patients who died of renal causes, compared with 14 percent of those still alive. Hypertension was noted on the first examination in 22 percent of those who died of renal causes, compared with 10 percent of those alive.

Escherichia coli cellulitis in children with idiopathic nephrotic syndrome

Although Streptococcus pneumoniae is traditionally considered the preponderant bacterial pathogen in children with nephrotic syndrome, recent data suggest an increase of infections with encapsulated gram-negative organisms. We report two children with idiopathic nephrotic syndrome in relapse who developed spontaneous Escherichia coli cellulitis. The organism was recovered from the cellulitis tissue aspirate of one, and from the blood of the other. Both patients responded to appropriate antibiotic therapy. Initial treatment of sepsis, peritonitis or spontaneous cellulitis in nephrotic patients should include broad spectrum antibiotic coverage pending results of appropriate cultures.

Penicillin resistant pneumococcal peritonitis in nephrotic syndrome

Two infants with nephrotic syndrome who developed penicillin resistant pneumococcal peritonitis while receiving penicillin chemoprophylaxis are reported and the problems associated with prophylaxis against pneumococcal infection discussed. It is suggested that penicillin prophylaxis may be hazardous in an environment in which penicillin resistant pneumococci are prevalent.

Less commonly recognized features of childhood nephrotic syndrome

This article reviews aspects in the clinical presentation of nephrotic syndrome that are not generally considered characteristics of the syndrome's definition. The importance of various general clinical aspects such as hematuria, hypertension, and other laboratory or histologic findings are discussed. The clinical relevance and management of other specific aspects such as lipid alterations, coagulation abnormalities, calcium and vitamin D metabolism, and nutritional complications derived from the nephrotic syndrome also are included in this review.

Steroid-sensitive mechanism of soluble immune response suppressor production in steroid-responsive nephrotic syndrome

Soluble immune response suppressor (SIRS), a lymphokine that suppresses antibody production and delayed type hypersensitivity in vivo, has been detected in urine and serum from certain patients with nephrotic syndrome. In the present paper, the relationship between SIRS production and nephrotic syndrome is further characterized. A striking correlation was found between detection of SIRS and the presence of steroid-responsive nephrotic syndrome (SRNS). A potential mechanism of SIRS production in SRNS patients was identified, in that lymphocytes from patients produced SIRS without requiring activation by exogenous agents, and incubation of normal lymphocytes with serum from patients activated the cells to secrete SIRS in culture. Although SIRS disappears rapidly from urine or serum after initiation of corticosteroid therapy, hydrocortisone (10(-6)-10(-7) M) did not block secretion of SIRS by activated suppressor cells. It did, however, inhibit in vitro activation of lymphocytes to produce SIRS by concanavalin A, interferon, or SRNS patient serum. The association of suppressor cell activation with SRNS and the sensitivity of both to steroids suggest that the pathogeneses of albuminuria and SIRS production are related.

Effect of the nephrotic syndrome on the concentration of serum complement components

The concentration of 12 component and four control proteins of the complement system was measured in serum from 43 children with a nephrotic syndrome, which subsequently proved to be steroid-responsive, and from 13 children with focal glomerulosclerosis (FGS) and was compared with values from 197 normal subjects. Of classical pathway complement components, 40% of patients had low C1q levels and 20%, low C2 levels. Mean serum levels of C1s, C4, C1INH, and C4bp were elevated. Of alternative pathway components, factors B and I were low in one third, while levels of C3 and H were commonly elevated. Of the terminal components, only C8 and C9 were low. In five patients with FGS with hypoalbuminemia without edema, all component levels were normal. With the exception of C1q, C1s, and C8, high molecular weight (mol wt) components were in high concentration and low mol wt components in low concentration. The three exceptions may be explained by the subunit structure of C1 and C8. From a practical standpoint, the study indicates that edematous patients with a nephrotic syndrome may have low serum levels of C1q and C2, simulating classical pathway complement activation such as commonly occurs in glomerulonephritis. However, low levels of C4, and possibly C1s, can be used as indicators of classical pathway activation since their levels are not reduced by a nephrotic syndrome.

Decline of vaccine-induced antipneumococcal antibody in children with nephrotic syndrome

Twenty-five children with steroid-responsive idiopathic nephrotic syndrome were studied for persistence of antipneumococcal capsular polysaccharide antibody during relapse of their disease and at 1, 6, and 12 months after vaccination with the 14-valent pneumococcal vaccine. Nonrelapsers (group I) were compared to those who had at least one relapse but whose sera were obtained during remission (group II). Group II had a more rapid decline in total anticapsular antibody per month than group I (5.3% v 2.4%). Analysis by individual anticapsular types showed that differences between groups approached significance only for type 4 (P = .07). Rates of decline of antibody against pneumococcal capsular polysaccharide varied among types. One year after vaccination, 50% of patients had less than 300 ngAbN/mL against types 4, 6A, 7F, 8, and 19F. Sera obtained from seven patients during relapse had geometric mean antibody concentrations less than 300 ngAbN/mL against those same types; two of these types have been reported to cause disease in vaccinated patients with nephrosis. Decline of antibody against pneumococcal capsular polysaccharide following vaccination varies by capsular type. Type-specific analysis should be used when monitoring serum antibody levels in these patients after vaccination.

Splenic hypofunction in the nephrotic syndrome of childhood

The reticuloendothelial system, including the spleen, subserves important immunologic functions. Loss of splenic function results in an increased incidence of severe bacterial infections and is accompanied by thrombocytosis. Several nephrotic children were noted to have remarkably high platelet counts and predisposition to bacterial infection with encapsulated organisms. We, therefore, investigated the splenic function of nine children with primary nephrotic syndrome and measured the phagocytic function of the spleen by sequestration of Technetium-99-labelled heat-treated autologous RBC, administered intravenously. Four children had decreased splenic function. Repeat studies performed in two of these children after remission of the nephrotic syndrome gave normal results. There were six episodes of bacterial infection (3 peritonitis, 1 septic arthritis, 1 cellulitis, and 1 Escherichia coli urinary tract infection) among the four patients with decreased splenic function. There were no episodes of bacterial infection among the five nephrotic children with normal splenic function. Nephrotic patients with decreased splenic function had significantly increased platelet counts (921,000 +/- 196,000; mean +/- SEM) compared to those with normal function (435,000 +/- 46,000; P less than 0.001). Our findings suggest the possibility that some nephrotic children may have decreased splenic function in association with increased susceptibility to bacterial infections.

Remission of idiopathic nephrotic syndrome after treatment with cyclosporin A

Nephrotic syndrome in minimal change lipoid nephrosis and focal segmental glomerulosclerosis may be due to alteration of glomerular anionic sites by a lymphokine. Six adults with nephrotic syndrome who were resistant to treatment with corticosteroids and immunosuppressants were treated with cyclosporin A. In three patients with minimal change lipoid nephrosis who had been nephrotic for 3.5 to 23 years proteinuria resolved within 12 to 42 days. Subsequently, these patients became dependent on cyclosporin A. In three patients with focal segmental glomerulosclerosis who had been nephrotic for four to six years mean (SD) 24 hour urinary protein decreased from 14.7 (8.4) g to 3.6 (0.6) g within 20 to 25 days, serum albumin concentration rose, and oedema subsided. One patient died of myocardial infarction when still in partial remission after 11 weeks' treatment. Two patients remained proteinuric despite continuing treatment with cyclosporin A, but control of sodium balance was easy and serum albumin concentrations remained higher than without cyclosporin A. In all patients renal function improved during treatment. These preliminary results show that cyclosporin A may be effective in the treatment of patients with nephrotic syndrome that resists every other form of treatment and especially in the treatment of those with minimal change lipoid nephrosis. The results are in keeping with a T lymphocyte mediated mechanism of minimal change lipoid nephrosis and focal segmental glomerulosclerosis, but they also suggest that minimal change lipoid nephrosis and focal segmental glomerulosclerosis are separate entities.

Immunological profile in children with minimal change nephrotic syndrome

Peripheral blood from patients with active stage of minimal change nephrotic syndrome (MCNS) was examined for concanavalin A (ConA)-inducible suppressor T cell activity, proliferative response to phytohemagglutinin (PHA) and in the autologous (AMLR) and allogeneic (MLR) mixed lymphocyte reaction, proportions of T cells with receptors for IgM (Tu) or IgG (T gamma) and the levels of serum immunoglobulin M, G and A. Six of 9 patients with MCNS studies showed deficiency of ConA-induced suppressor cell activity. In the AMLR, only one of 9 patients with MCNS demonstrated depressed proliferative response (p less than 0.05). In the allogeneic MLR, T cells from 5 of 9 patients with MCNS demonstrated poor proliferative response when stimulated with normal control non-T cells. Five of 9 patients with MCNS had depressed proliferative response to PHA. The proportion of total T cells, Tu cells and T gamma cells in the patient group were comparable to healthy control group. Serum IgG was significantly decreased in 7 of 11 patients. This study demonstrates multiple immunological abnormalities in patients with MCNS that might play a role in its pathogenesis.

Pathogenesis and treatment of immune-mediated renal disease

There is now convincing evidence to suggest that most forms of glomerulonephritis and tubulointerstitial nephropathy involve the immune system in the destructive process. Such involvement can be mediated by a humoral immune response, a cell-mediated immune response, or a coordinated response of both limbs of the immune system derived from complementary T- and B-cell interactions.

Identification of the lymphokine soluble immune response suppressor in urine of nephrotic children

Patients with minimal change nephrotic syndrome (MCNS) frequently have suppressed in vivo and in vitro immune responsiveness of uncertain etiology. Because increased suppressor cell activity has been associated with this disease, urines from MCNS patients were screened for activity of the lymphokine soluble immune response suppressor (SIRS), a product of concanavalin A- or interferon-activated suppressor T cells. Urines from untreated MCNS patients suppressed polyclonal plaque-forming cell responses of cultured splenocytes. This suppressive activity was identified as human SIRS by the following functional and physical criteria: molecular weight estimated by gel filtration; kinetics of suppression; inhibition of suppression by catalase, levamisole, and 2-mercaptoethanol; abrogation of activity by acid or protease treatment; elution pattern on high performance liquid chromatography; and cross-reactivity with monoclonal antimurine SIRS antibodies. Suppressive activity disappeared from urine after initiation of treatment but before remission of symptoms. Urines were tested from 11 patients with MCNS, all of whom excreted SIRS. In addition, two nephrotic patients with acute glomerulonephritis and three nephrotic patients with membranoproliferative disease excreted SIRS, but other nephrotics and all nonnephrotic patients did not. These results indicate that excretion of SIRS occurs in certain cases of nephrotic syndrome and that the presence of SIRS in the urine is not accounted for solely by the presence of proteinuria or nephrosis. Serum from four nephrotic patients also contained SIRS, whereas neither serum nor urine from six normal subjects contained SIRS activity. The systemic presence of SIRS in these four patients, and the identification of SIRS in urines from a larger group of patients, suggest a possible role for SIRS in the suppressed immune responses often found in nephrotic syndrome.

Juvenile rheumatoid arthritis and milk allergy

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Decreased serum transferrin concentration in children with the nephrotic syndrome: effect on lymphocyte proliferation and correlation with serum immunoglobulin levels

Recent evidence suggests that transferrin has immunoregulatory functions. In the nephrotic syndrome, excessive urinary losses can produce hypotransferrinemia. Whether low serum transferrin concentration in children with the nephrotic syndrome is related to their decreased immunoglobulin concentrations and to the decreased in vitro response of lymphocytes to a mitogen was studied. Twenty patients, 2 to 15 years of age, were studied. Fifteen patients had the nephrotic syndrome and 5 had other renal disorders. Of 13 patients with nephrotic syndrome in relapse, serum transferrin and gamma-globulin concentrations were decreased in 10 and 11 patients, respectively. Transferrin levels correlated with the concentrations of total protein (r = 0.87, P less than 0.001), albumin (r = 0.91, P less than 0.001), and gamma-globulin (r = 0.78, P less than 0.001). Urinary electrophoretic analyses suggested that hypogammaglobulinemia was not explained simply by urinary losses. In order to determine whether decreased serum transferrin concentrations might limit immunoglobulin synthesis, the effect of hypotransferrinemic sera on lymphocyte proliferation in vitro was tested. At low concentrations of serum, tritiated thymidine uptake was directly proportional to the serum transferrin concentration (r = 0.86, P less than 0.001 at 0.02% serum concentration). Addition of transferrin completely restored the ability of patients' sera to support lymphocyte proliferation. These results suggest that hypotransferrinemia might influence in vivo lymphocyte function and immunity in the nephrotic syndrome.

The glomerular tip lesion: a previously undescribed type of segmental glomerular abnormality

We describe a distinctive and previously undescribed abnormality of the kidney. It consists of a combination of changes in the glomerulus and in the proximal convoluted tubule. The glomerular abnormality consists of a well-localized collection of intracapillary foam cells and marked vacuolation of the adjacent glomerular epithelial cells. The abnormality is always situated in the same position in the glomerular tuft namely adjacent to the origin of the proximal convoluted tubule, with adhesion to Bowman's capsule. The rest of the tuft appears normal by light microscopy but shows foot-process fusion by electron microscopy. The abnormality of the proximal convoluted tubular cells invariably affects the first part of the tubule adjacent to the glomerulus but in some cases involves the tubules more extensively in the cortex. Study of a series of 100 2-micron serial sections from one case indicated that probably every glomerulus had a lesion at the origin of the tubule. A study of 185 renal biopsies nearly all with segmental lesions revealed biopsies from 20 patients with this distinctive abnormality. There were 14 males, age 20-57, median 44 years, and six females age 19-65, median 22 years, all presenting with proteinuria, nearly all with the nephrotic syndrome. All except four were treated with steroids and in all those treated the proteinuria improved. Only one patient not treated with steroids had progressive renal impairment. Four patients died, none from renal failure. This lesion, the glomerular tip lesion, as we have called it, seems to be a well-defined and specific pathological entity. It has some similarities to minimal change nephropathy but there are clear and important differences. Previously it may have been included in series of cases of 'focal glomerulosclerosis' but that term is imprecise and is generally taken to have an unfavourable clinical course. For these reasons it is inappropriate to use 'focal glomerulosclerosis' as a name for the glomerular tip lesion.

A lymphocytotoxic factor(s) in plasma of patients with minimal change nephrotic syndrome: partial characterization

The incidence, relationship to clinical disease, and physical characteristics of a plasma cytotoxic factor(s) were studied in steroid-responsive minimal change nephrotic syndrome (MCNS) and other renal diseases. Plasma activity was found in 76% of 67 children with MCNS and in 67% of 9 children with focal segmental sclerosis (FSS). Of 31 normal adults and children and 7 adults with membranous glomerulonephritis, only 1 individual had toxic plasma. In MCNS, degree of plasma activity was not related to clinical disease, prednisone dosage, or serum levels of IgG or alpha-2-macroglobulin. The active factor(s) was found more frequently in plasma than in serum, was heat stable and nondialyzable by selected filtration, and was approximately 100,000 to 300,000 molecular weight. By DEAE column chromatography, activity coincided with fractions containing IgA and IgM but not IgG. While the nature of the plasma factor(s) has not been identified, these data indicate that MCNS plasma may adversely affect lymphocyte viability by a slow process of cytotoxicity requiring 24 or more hr, and that such plasma activity occurs frequently in children with MCNS and also with the more severe FSS.

Serum hemolytic factor D values in children with steroid-responsive idiopathic nephrotic syndrome

Serum hemolytic factor D activity, an important component of the ACP, was measured in patients with SR-INS. The mean serum factor D hemolytic activity of patients with SR-INS in relapse was significantly reduced compared to the mean of the control group. Twenty-one of 27 SR-INS patients in relapse (78%) had reduced serum factor D activity. In contrast, the mean serum factor D hemolytic activity of SR-INS patients in remission was not significantly different from that in the control group. Factor D hemolytic activity was also reduced in other types of renal disease with the nephrotic syndrome. Serum factor D values were highly correlated with the serum albumin concentration. Although hemolytic factor D activity could not be detected in the urine, the low molecular weight and the significant correlation with serum albumin concentration suggest that urinary loss is responsible for the low serum levels of factor D. Deficient serum values of factor D may contribute to the increased susceptibility of SR-INS patients in relapse to bacterial infections with organisms which activate the ACP.

Steroid-responsive nephrotic syndrome and allergy: immunological studies

Immunological studies were performed on 84 children with steroid-sensitive nephrotic syndrome as part of an investigation of the relationship between steroid-responsive nephrotic syndrome and allergy. Serum total IgE levels tended to be raised, particularly in children who had frequent relapses of nephrotic syndrome. Ten children had extremely high levels (greater than 1500 IU/ml) and several of them had neither a history of atopy nor any other identifiable cause. 25% of the children had at least one positive test for specific IgE antibody. IgE was not detected by immunofluorescence in renal biopsy tissue from 25 children, regardless of whether the child was in remission or relapse at the time of biopsy. Serum IgG and IgA levels were depressed particularly at the time of a relapse. Serum IgM tended to be raised and to remain so, even in children who had been in remission for more than a year. No clinically useful relationship was found between the frequency of HLA antigens and the occurrence or course of the syndrome, whether or not accompanied by atopy. Clinical and immunological features of atopy are more common in children with idiopathic nephrotic syndrome. This may be a causal or non-causal association. Pollen sensitivity is a rare cause of nephrotic syndrome; careful search for provocative agents may show other causes.

Nephrotic syndrome associated with T-cell lymphoma

Glomerulopathies associated with non-Hodgkin's malignant lymphomas have been observed rarely. Previous reports have never determined the cell type of the lymphoproliferative disorder. This report documents a case of nephrotic syndrome in a patient with T-cell derived non-Hodgkin's lymphoma. The neoplastic cell was studied in terms of cell-surface markers, cytochemical staining, and ultrastructural morphology. Nephrotic syndrome occurred shortly after the apparent onset of the lymphoma. The kidney biopsy specimen was examined by light, fluorescence, and electron microscopy. Histologic findings were consistent with the diagnosis of mild focal and segmental glomerulosclerosis. Such an association, reported here for the first time, may support the hypothesis of a pathogenetic link between acquired T-cell abnormalities and glomerular diseases with minimal histologic injury.

Acute leukemia after cytotoxic treatment for nonmalignant disease in childhood. A case report and review of the literature

The case history of an 11-year-old boy is reported. The child developed the nephrotic syndrome at the age of 17 months. He was treated with prednisolone, cyclophosphamide, cytosine-arabinoside and chlorambucil for the following three and a half years. Three and a half years after cessation of any medical treatment he developed anemia, thrombocytopenia and a diagnosis of acute lymphocytic leukemia (ALL) was made. Subsequently he responded to the West Berlin Protocol. Reviewing the literature, another eight cases of acute leukemia after cytotoxic treatment for nonmalignant disease in childhood have been reported. Most often the myeloblastic form of acute leukemia was diagnosed. Even though the pathogenic mechanism of acute leukemia after cytotoxic treatment is not known, the possibility must be considered that the incidence of this malignant disease is increased after cytotoxic treatment for nonmalignant diseases.

Heterophile antibodies in the serum of children with nephrotic syndrome

Serum of children with the nephrotic syndrome contained high titers of a (19S) IgM antibody against sheep, horse, guinea pig, rat, and rabbit red blood cells but not against cow red blood cells. There was high correlation between high titers of antisheep antibodies and active nephrotic syndrome in the children with minimal change nephrotic syndrome. The antibody differed from the Paul-Bunnell antibody found in patients with infectious mononucleosis and from the anti-Forssman, Hangautziu-Deicher antibody found in patients with horse serum sickness. Rabbit red blood cells completely absorbed the antibody, but horse or guinea pig red blood cells removed only the anti-Forssman activity.

Serum concentrations of immunoglobulins E and G and alpha 2-macroglobulin in childhood renal disease

Serum concentrations of IgE, IgG, and alpha 2-macroglobulin (alpha 2-M) were determined in 67 children with renal disease and in appropriate controls. IgE concentrations were significantly elevated in patients with renal disease and proteinuria, including those with minimal change nephrotic syndrome (MCNS). IgG concentrations were lower and alpha 2-M concentrations higher in patients with proteinuria than in patients without proteinuria. In 16 patients with nephrotic syndrome who had a decrease in proteinuria with therapy, there was a concomitant decrease in mean serum IgE level. All nine with MCNS had a decrease in serum IgE following therapy whereas eight of the nine had a concomitant increase in serum IgG. The findings suggest the possibility that IgE may play an etiologic role in the proteinuria of childhood nephrotic syndrome, and that both elevated serum IgE and proteinuria may represent unusual responses to antigens that are seldom identified. Elevations of IgE secondary to lowered IgG or to entirely nonspecific alterations in IgE metabolism in proteinuric renal disease are other possibilities. Further studies to elucidate the role of IgE in renal disease, including the nature of the altered metabolism of this immunoglobulin, are warranted.

HlA antigens and steroid responsive nephrotic syndrome of childhood

Fifty-four unrelated children with steroid responsive nephrotic syndrome of childhood were studied for 24 alleles at the HLA--A and B loci. A significantly increased incidence of HLA--B8 (Pc less than 0.01) was observed compared to controls. No association between response to cyclophosphamide therapy and HLA antigens was seen.

Thymoma and the nephrotic syndrome: a report of a case

A 48-year-old male presented with the nephrotic syndrome 3 years after resection and irradiation of a thymoma. Renal biopsy revealed membranous glomerulonephritis by electron microscopy. IgA, IgG, and C3 deposition were present in the glomerular basement membrane by immunofluorescence. There was no evidence of other autoimmune diseases or causes of the membranous glomerulonephritis. He has continued to have proteinuria and edema 1 year later.