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Background/Aim: Interleukin (IL)-17 is a newly discovered cytokine that is secreted by activated memory CD4+ T cells and modulated the early stage of immune response. To elucidate the pathophysiology of minimal-change nephrotic syndrome (MCNS), we focused on IL-17, which is one of the key factors in regulating an inflammatory response, and thus determined the daily excretion of IL-17 in urine. Methods: For this purpose, excretion levels of IL-17 were measured in the urine of patients with MCNS during relapse and remission using a highly sensitive sandwich enzyme-linked immunosorbent assay. The data obtained were compared with levels of daily urinary excretion of IL-17 in patients with IgA nephropathy (IgAN). A group of healthy subjects served as control. In both experimental groups urine levels of IL-17 excretion were plotted against their daily urinary protein excretion. Results: We demonstrated increased levels of IL-17 excretion in the urine of patients with MCNS and IgAN as compared to the non-nephrotic and healthy controls. In MCNS the daily urinary IL-17 (uIL-17) excretion was increased and returned to baseline with remission of the nephrotic syndrome (NS). We also demonstrated a positive correlation between urinary protein excretion and daily uIL-17 excretion. Conclusion: Taken together, these data indicate that uIL-17 excretion is increased during the NS, suggesting the possibility that daily uIL-17 excretion may reflect the disease activity of NS.

Background/Aim: The processes involved in development of IgA nephropathy (IgAN) are not yet well understood. Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine and is an essential component of immune and inflammatory responses. To examine further the possible role of MIF in IgAN, we measured MIF levels in the urine. The purpose of the present study was to evaluate the involvement of MIF in IgAN. Methods: Urine samples were obtained from 20 IgAN patients. The disease controls included 20 patients with minimal-change nephrotic syndrome (MCNS). A group of healthy subjects served as control. The samples were assayed for MIF protein by a sandwich enzyme-linked immunosorbent assay (ELISA). Results: The MIF levels in the urine of patients with IgAN examined were significantly higher than those of the healthy control subjects. In contrast, the levels of urinary MIF (uMIF) in patients with MCNS did not differ significantly from normal values. In IgAN patients, uMIF significantly correlated with the magnitude of proteinuria, but not with the grade of hematuria. We also investigated the relationship between uMIF levels and pathological features. Among patients with IgAN, uMIF levels were significantly correlated with the grade of glomerular crescent formation and that of mesangial cell proliferation. There was also a significant correlation between uMIF levels and the number of both intraglomerular and interstitial macrophages. Conclusion: Although the underlying mechanisms remain to be determined, these data provide evidence that urinary excretion of MIF is increased in IgAN patients with active renal lesions.

Background/Aim: A lymphokine, the vascular permeability factor (VPF), which increases vascular permeability, has been characterized in minimal-change nephrotic syndrome (MCNS). Transforming growth factor-β (TGF-β) is an immunosuppressive cytokine that inhibits proliferation, cytokine production, and cytotoxic activity of T cells and natural killer cells. We, therefore, investigated the effects of TGF-β1 on the release of VPF by peripheral blood T cells from MCNS patients. The aim of our study was to determine the in vitro immunosuppressive capacity of TGF-β1 in patients with MCNS. Methods: To further test the effect of TGF-β1 on concanavalin A (Con A)-induced VPF release, normal and MCNS T cells were stimulated with 5 µg/ml of Con A in the presence or absence of TGF-β1, and the culture supernatants were tested for the presence of VPF by the method of Lagrue et al. The disease controls included 16 patients with IgA nephropathy. Results: Significantly increased spontaneous and Con A-stimulated secretion of VPF was detected in T-cell cultures of MCNS patients with the nephrotic syndrome as compared with those of normal controls. Addition of TGF-β1 to these cultures inhibited the release of VPF in a dose-dependent manner. The effect of TGF-β1 on the release of VPF was specific, since a reversion was obtained with a neutralizing monoclonal antibody to human TGF-β1. Conclusion: Together, our data demonstrate that TGF-β1 antagonizes the ability of T cells to release VPF, and suggest a role of TGF-β1 in the pathophysiology of VPF in vitro.

Background/Aim: The etiology of minimal-change nephritic syndrome (MCNS) is obscure. It has been speculated that T cells play a role in the pathogenesis of MCNS. Interleukin (IL)-18, a novel immunoregulatory cytokine with potent inferon-γ-inducing activities, may play an important role in T-helper type 1-mediated immune responses. To examine further the possible role of IL-18 in nephrotic syndrome (NS), in the present study we measured IL-18 levels in the urine in different clinical stages of MCNS. The aim of this study was to investigate the involvement of IL-18 in MCNS. Methods: Urine samples were obtained from 20 MCNS patients. The disease controls included 20 patients with IgA nephropathy. The samples were assayed for IL-18 protein by a sandwich enzyme-linked immunosorbent assay. Results: Compared with normal controls, significantly increased urinary levels of IL-18 were detected in MCNS patients with the NS. The urinary IL-18 (uIL-18) levels correlated with the degree of proteinuria in MCNS patients. Moreover, when individual MCNS patients were followed through their clinical illness, uIL-18 levels were increased during the active phase and decreased as the patients went into remission. Conclusions: These results indicate that uIL- 18 is detectable in a subgroup of patients with active NS and correlates to their disease activity in patients with MCNS. Our findings support the notion that IL-18 may play a role in the pathophysiology of NS.

Background/Aim: In a previous study, we reported that interleukin (IL)-12 could upregulate the production of vascular permeability factor (VPF) derived from activated human peripheral blood mononuclear cells. Since IL-18, a novel immunoregulatory cytokine with potent interferon-γ inducing activities, has been shown to be a strong cofactor for T helper type 1 cell development, we tested the hypothesis that IL-18 in combination with IL-12 can act synergistically to modulate the production of VPF. Methods: For this purpose, T cells were isolated from heparinized venous blood, stimulated with concanavalin A, and incubated in the presence of IL-18 or IL-12, and the production of VPF was determined by the method of Lagrue. Results: There was a significant increase in VPF production from concanavalin A-stimulated T cells following incubation with IL-18 or IL-12. More importantly, the combination of the cytokines was found to give a potent synergistic stimulation of VPF by concanavalin A-activated T cells from normal subjects. To determine the specificity of the stimulatory effect, neutralizing anti-IL-18 and anti-IL-12 antibodies were preincubated with IL- 18 and IL-12, respectively, prior to the addition of responder cells. The antibodies completely inhibited the effects of IL-18 and IL-12. Thus, these data show that IL-18 can synergize with IL-12 to selectively increase the production of VPF from T cells. The present study further demonstrates that IL-18 and IL-12 are in fact acting in synergy in patients with minimal-change nephrotic syndrome. Conclusions: Taken together, our results indicate that both IL-18 and IL-12 contribute to the VPF production in vitro and suggest that they play key roles in the complexity of cytokine regulation in the pathophysiology of VPF.

It has been proposed that a vascular permeability factor (VPF) is involved in the pathogenesis of lipoid nephrosis (LN). There is now increasing evidence that interleukin 10 (IL-10) and interleukin 13 (IL-13) have regulatory effects on cytokine production by activated macrophages. These results prompted us to study the effects of recombinant human IL-10 and IL-13 on VPF secretion in LN. In the present study, we demonstrate that the regulatory cytokines IL-10 and IL-13 are potent inhibitors of the VPF activity of activated peripheral blood mononuclear cells. Each cytokine was found to suppress VPF secretion in a dose-dependent fashion. More importantly, the combination of the cytokines was found to give a potent synergistic suppression of VPF by concanavalin A activated peripheral blood mononuclear cells from patients with LN. When both anti-IL-10 and anti-IL-13 antibodies were added together to the peripheral blood mononuclear cells, a further increase of concanavalin A enhanced secretion of VPF occurred. These data establish IL-10 and IL-13 as potent inhibitors of VPF activity and suggest their utility in controlling deleterious VPF-mediated responses such as occur in LN patients with nephrotic syndrome.

In this study we have examined the effects of recombinant human interleukin (IL)-13 on peripheral blood monocytes (PBM) from patients with IgA nephropathy (IgAN). Significantly increased spontaneous and lipopolysaccharide (LPS)-stimulated secretion of tumor necrosis factor-alpha (TNF) and IL-8 was determined in PBM cultures of IgAN patients compared to those of normal controls. In the present study, IL-13 inhibited the spontaneous as well as the LPS-stimulated cytokine secretion of PBM in IgAN. Significant inhibitory effect of IL-13 was observed in cultures of PBM from IgAN patients as well as from normal persons. When both LPS and anti-IL-13 antibody were added together to the PBM, a further increase of LPS-enhanced secretion of cytokines occurred. Taken together, these results indicate that IL-13 down-regulates the secretion of TNF and IL-8 from IgAN PBM.

The effect of recombinant human interleukin-10 (IL-10) on the in vitro cytokine secretion of peripheral blood monocytes (PBM) was evaluated in patients with IgA nephropathy (IgAN). Significantly increased spontaneous and lipopolysaccharide (LPS)-stimulated secretion of tumor necrosis factor-alpha and interleukin-8 was determined in PBM cultures of IgAN patients compared to those of normal controls. In the present study IL-10 inhibited the spontaneous as well as the LPS-stimulated cytokine secretion of PBM in IgAN. A significant inhibitory effect of IL-10 was observed in cultures of PBM from IgAN patients as well as from normal controls. When both LPS and anti-IL-10 antibody were added together to the PBM, a further increase in LPS-enhanced secretion of cytokines occurred. This study provides some novel information showing the inhibitory effects of IL-10 on cytokine secretion by PBM derived from IgAN patients.

The ability of immune complexes (IC) derived from rat renal tubular epithelial (RTE) antigen to trigger the production of interleukin-1 (IL-1) was investigated. When cultured rat mesangial cells (MC) were activated by the IC, substantial amounts of IL-1 could be detected in the culture supernatants as measured by the mouse thymocyte assay. To avoid the effect of prostaglandins on the IL-1 assay, we cultured the MC with addition of indomethacin and assayed IL-1 activity in the culture supernatants. This cyclooxygenase inhibitor augmented IC-induced IL-1 production. These biological activities were neutralized by a specific antibody to IL-1. These findings suggest that IC may participate in local inflammatory responses in the kidney partly due to their capacity to induce the synthesis of MC IL-1.

We have investigated the effect of recombinant tumor necrosis factor (r-TNF) on the release of interleukin-1 (IL-1) in glomerular cultures from rats with an accelerated autologous form of nephrotoxic serum nephritis (NTSN). Freshly isolated glomeruli from the NTSN rats were incubated for 24 h in the presence of r-TNF. When the glomeruli were activated by r-TNF substantial amounts of IL-1 could be detected in the supernatants as measured by the mouse thymocyte assay. The r-TNF-induced IL-1 activity was significantly higher in rats with NTSN than those in normal controls and the other control group, consisting of preimmunized rats (rabbit IgG), then given normal rabbit globulin instead of NTS. To avoid the effect of prostaglandins on the IL-1 assay, we cultured the glomeruli with addition of indomethacin and assayed IL-1 activity in the culture supernatants. This cyclooxygenase inhibitor augmented r-TNF-induced IL-1 production. Our data suggest that r-TNF can serve as a potent stimulator of IL-1 synthesis in glomerular cultures from rats with NTSN.

The characteristic function of interleukin (IL)-15 appears to be its ability to mimic the stimulatory action of IL-2 on lymphocytes by utilizing part of the IL-2 receptor complex. To gain insight into the immunoregulatory properties of this cytokine in patients with minimal-change nephrotic syndrome (MCNS), we analyzed effects of IL-15 on vascular permeability factor (VPF) release in vitro. Peripheral blood mononuclear cells (PBMC) were isolated from 16 patients with MCNS, 16 patients with IgA nephropathy (IgAN) and 16 healthy controls. Cells were stimulated with concanavalin A (Con A) and the VPF was assessed using the method of Lagrue with minor modifications. PBMC secreted significantly increased amounts of VPF under stimulation with Con A in patients with MCNS and IgAN patients with the nephrotic syndrome as compared with normal controls. Here we have demonstrated, for the first time, that addition of IL-15 to PBMC obtained from nephrotic patients as well as from normal controls increased Con A-induced release of VPF by 250%. This stimulatory effect was found highly significant and was dose-dependent. The effect of IL-15 on the secretion of VPF was specific, since a complete reversion was obtained with a neutralizing antibody to human IL-15. Our findings reveal that IL-15 has the potential to function as an immunoregulatory molecule of PBMC VPF release. In addition, IL-15 had similar effects to IL-2 in terms of its capacity to upregulate VPF release. Taken together, our data emphasize a positive regulatory role for IL-15 in inducing the release of VPF when present at optimal levels. Therefore, IL-15 antagonists may provide a basis for immune intervention in the pathophysiology of VPF.

The vascular permeability factor (VPF) is a lymphokine that has been shown to play a role in lipoid nephrosis (LN). Prior studies have shown that interleukin (IL) 12 promotes T helper type 1 differentiation and enhances production of T helper type 1 cytokines such as gamma interferon and IL-2. We, therefore, investigated the effects of recombinant human IL-12 on the release of VPF by peripheral blood mononuclear cells (PBMC) from LN patients. The VPF activity was measured according to the method of Ovary, with minor modifications. The goal of the present study was to examine the importance of IL-12 in concanavalin A induced VPF release in vitro. The levels of VPF were measured in a group of healthy subjects, LN patients with or without the nephrotic syndrome, and patients suffering from IgA nephropathy. There was a significantly increased concanavalin A induced release of VPF in LN and IgA nephropathy patients with nephrotic syndrome as compared with normal controls. Recombinant human IL-12 was found to enhance VPF release in a dose-dependent manner. Neutralization of endogenously produced IL-12 by anti-IL-12 antibody resulted in a decreased release of VPF by LN PBMC. These data indicate that endogenously produced IL-12 functions as a costimulatory molecule in vitro. Our data show that IL-12 can upregulate the release of VPF derived from LN PBMC. Thus IL-12 might be a potent adjuvant for inducing VPF. Therefore, IL-12 antagonists may interfere with newly initiated and ongoing VPF release associated with nephrotic syndrome.

The effect of recombinant human interleukin 10 (IL-10) on the in vitro secretion of vascular permeability factor (VPF) of peripheral blood mononuclear cells (PBMC) was evaluated in patients with lipoid nephrosis (LN). Significantly increased spontaneous and concanavalin A (ConA) stimulated secretion of VPF was detected in PBMC cultures of LN patients with the nephrotic syndrome as compared with those of normal controls. In the present study, IL-10 inhibited the ConA-stimulated VPF secretion of PBMC in LN. A significant inhibitory effect of IL-10 was observed in cultures of PBMC from LN and IgA nephropathy patients as well as from normal persons. When both ConA and anti-IL-10 antibody were added together to the PBMC, a further increase in ConA-stimulated secretion of VPF occurred. These data suggest that IL-10 is a powerful inhibitor of the secretion of VPF in LN patients.

A 29-year-old Japanese male with a 19-year history of subcutaneous eosinophilic lymphoid granuloma (Kimura's disease) was referred to the Nephrology Service of the Nihon University Hospital for evaluation of edema and massive proteinuria. The renal biopsy disclosed minimal glomerular lesions. In this paper a case of nephrotic syndrome associated with eosinophilic lymphoid granuloma is reported.

Cell-mediated immunity (CMI) was evaluated in 26 patients with lipoid nephrosis (LN), 50 patients suffering from chronic diffuse proliferative glomerulonephritis (CGN) without renal sufficiency and 24 healthy controls. The following parameters were measured: delayed hypersensitivity skin test responses to purified protein derivative (PPD) and candida, circulating lymphocytes. T lymphocytes and T lymphocytes with receptors for the Fc portion of IgG (T gamma cells) or IgM (Tmu cells). Patients with LN in relapse had less mean induration of skin reactivity and a smaller proportion reacting to both antigens as compared with the control subjects. In contrast, the intensity of skin reactivity and the frequency of negative reactions in patients with LN in remission and CGN were similar to those of the control subjects. It was also found that the LN patients in relapse had a significant T lymphocytopenia as well as a significant decrease in absolute numbers of Tmu and T gamma cells, whereas the patients with LN in remission and CGN did not differ significantly from the control population. Thus, the majority of patients with LN in relapse demonstrated an impaired response in a CMI assay system. The disturbed CMI may be secondary to hypoproteinemia and other nutritional factors induced by the nephrotic syndrome.

Suppressor cell activity (SCA) was analyzed in 8 patients with focal glomerular sclerosis (FGS) and 11 patients with chronic proliferative glomerulonephritis (CGN). We have assessed the ability of peripheral blood lymphocytes (PBL) stimulated by concanavalin A (Con A) to inhibit the proliferative response of normal allogeneic lymphocytes by both Con A and phytohemagglutinin (PHA). It was found that the FGS patients with nephrotic syndrome (NS) had significantly increased levels of suppression index when compared to the values obtained with normal controls. In contrast, the mean suppression values in the PBL from FGS patients in remission and CGN patients with or without NS, whether the mitogen used was Con A or PHA, were similar to those of the control subjects. Thus, the majority of FGS patients with NS demonstrated an alteration in Con A-induced SCA. The possible significance of these phenomena in the pathophysiology of FGS is discussed.

Peripheral blood mononuclear cells (PBMC) from patients with minimal-change nephrotic syndrome (MCNS) were tested for their ability to produce a factor which increases the urinary protein excretion levels of rats. It was shown that enhanced proteinuria can be produced in 8-hour urine specimens from rats by the injection of concentrated supernatants of cultured concanavalin-A-stimulated PBMC of patients with MCNS, but not from other nephrotics or normal subjects. The increase in urinary protein excretion was associated with a significant alteration of glomerular epithelial cells similar to that seen in MCNS. These results suggest that in MCNS, PBMC release a factor, which we termed a glomerular permeability factor (GPF), causing changes in glomerular permeability with resulting proteinuria.

Cell-mediated immunity (CMI) was evaluated in 8 patients with focal glomerular sclerosis (FGS), 50 patients suffering from chronic mesangial proliferative glomerulonephritis without renal insufficiency and 24 healthy controls. The following parameters were measured: delayed skin reactivity to purified protein derivative, circulating lymphocytes, lymphocyte cell-surface markers (neuraminidase-treated sheep erythrocyte and erythrocyte-antibody-complement rosettes) and functional markers (mitogenic responses to concanavalin A and phytohemagglutinin). The FGS patients with nephrotic syndrome (NS) had a significant depression in CMI, characterized by decreased responses of the lymphocytes to both concanavalin A and phytohemagglutinin, impaired delayed hypersensitivity to purified protein derivative and a decreased proportion of T lymphocytes as compared with normal subjects. In contrast, the levels of all CMI parameters studied in FGS patients in remission and in patients with chronic glomerulonephritis with or without NS did not differ from normal subjects. Thus, the majority of FGS patients with NS demonstrated an impaired response in a CMI assay system. The possible significance of these phenomena in the pathophysiology of FGS is discussed.

Cell-mediated immunity (CMI) was evaluated in 76 patients with renal disease by summation of delayed cutaneous hypersensitivity (DHS) responses to 4 test antigens, purified protein derivative (PPD), Candida, mumps and keyhole limpet hemocyanin (KLH). Patients with lipoid nephrosis (LN) in the nephrotic stage had less mean induration of skin reactivity and a smaller proportion reacting to the former 3 antigens as compared with normal controls or LN patients without the nephrotic syndrome (NS). In contrast, the intensity of skin reactivity and the frequency of negative reactions in LN patients in remission and chronic mesangial proliferative glomerulonephritis (CGN) were similar to those of the control subjects. Immune response to KLH was also impaired in LN patients with the NS as measured by skin testing. The data indicate an impaired DHS in LN and suggest that the impairment relates to the clinical stage of disease.

Leukocyte adherence inhibition (LAI) test was examined in 35 patients with renal diseases and 14 normal controls, using collagenase-treated glomerular basement membrane, glycosidase-treated glomerular basement membrane and renal tubular epithelium as antigens. Although the control group showed strikingly similar mean LAI indices for all antigens tested, the whole group of patients with renal diseases showed a wide scatter of values. Two categories of patients had significantly increased LAI indices (p less than 0.01) when their mean values were compared with those of normal controls: (1) rapidly progressive glomerulonephritis (RPGN) and (2) lupus nephritis (SLE). In the serial studies of the RPGN and SLE cases, there were no significant changes in the pattern of LAI and they continued to give positive and very comparable results when re-examined at intervals of 1-6 months. Out of the 30 patients who were able to be evaluated with the three antigens, 15 cases exhibited positive LAI response to two or more antigens simultaneously. These in vitro findings suggest that there is an abnormal cellular response to certain antigen or widespread LAI reactivity to a variety of renal antigens in certain forms of human glomerulonephritis.