Morphological effects of sodium fusidate (fusidin) on pancreatic islet cells: an electron microscopic study

Fusidic acid has been shown to prevent the lymphocyte co-stimulatory activities of cytokines and seems--in preliminary trials--clinically effective as an immunoregulatory drug e.g. in insulin-dependent diabetes mellitus. A toxic effect of fusidic acid may however be suspected since a previous study showed a significant dilatation of rough endoplasmic reticulum in cultured pancreatic islet cells from normal rats. In this study we examined the ultrastructural effects of the sodium salt of fusidic acid (fusidin) on cultured rat islet cells (treatment period 3-5 days), and of islet cells from rats receiving fusidin for 6 days. Electron microscopically, fusidin treatment in vitro (3 to 30 micrograms/ml) showed a significant dilatation of the rough endoplasmic reticulum of islet cells. No dose dependent changes were found. In the in vivo model no changes were demonstrated in concentrations of fusidin up to 9.64 micrograms/ml of homogenated pancreatic tissue. It is concluded that treatment with fusidin gives no detectable ultrastructural changes in vivo.

Chronic fatigue syndrome--a controlled cross sectional study

OBJECTIVE

To look for signs of immunodeficiencies and/or longstanding infections underlying chronic fatigue syndrome (CFS).

METHODS

Twenty-one patients fulfilling the Centers for Disease Control criteria for CFS were compared to 21 age and sex matched controls. A number of viral antibodies as well as the following tests evaluating the immune system were studied: autoantibody profile, cell surface markers on isolated blood mononuclear cells, cytokine production, lymphocyte proliferative responses, natural killer cell activity and quantitation of immunoglobulin secreting cells.

RESULTS

Production in vitro of the predominantly T cell derived cytokines interleukin 2 and interferon gamma was significantly higher in patients with CFS compared to the control group. Furthermore, the serum concentrations of IgA and IgE were lower in patients with CFS; however, this difference was caused by a larger number with values of IgA and IgE above the upper limit of the normal range among the controls than among the patients with CFS. All other variables were similar in the 2 groups.

CONCLUSION

A pathogenically significant imbalance of the immune system in patients with CFS cannot be excluded. However, evidence of a causal link between abnormal immunity and CFS was not obtained.

Stimulation of the B9 hybridoma cell line by soluble interleukin-6 receptors

Interleukin-6 (IL-6) exerts its effects by binding to specific receptors on the cell surface. The IL-6 receptor consists of at least two components, a ligand binding 80 kDa low-affinity component (IL-6R) and a signal-transducing non-ligand binding 130 kDa component (gp130). The presence of soluble forms of these components has been described in both conditioned media and biological fluids. The soluble (s) IL-6R has been shown to enhance the IL-6 sensitivity of several both murine and human IL-6 sensitive cell types. A sensitive and commonly used method for measuring biological IL-6 activity is based on the IL-6 dependent proliferation of the murine hybridoma cell line B9. In this paper, we demonstrate that recombinant (r) human (h) sIL-6R enhances the sensitivity of B9 cells in a dose-dependent manner. The rhsIL-6R enhanced the binding of 125I-rhIL-6 to B9 cells. The rhsIL-6R induced stimulation of B9 proliferation was maximal at 100 ng/ml, even without addition of rhIL-6 and in the presence of anti-hIL-6 antibodies. This may be due to endogenous IL-6 production by the B9 cells, low levels of IL-6 in the fetal calf serum used, or perhaps an IL-6 independent effect by the rhsIL-6R. In conclusion, this and other reports point to the necessity of confirming measured biological activities through the use of neutralizing specific antibodies or parallel measurements in immunochemical assays.

Effects of 1,25-dihydroxyvitamin D3 and the analogues MC903 and KH1060 on interleukin-1 beta-induced inhibition of rat pancreatic islet beta-cell function in vitro

The cytokine interleukin-1 beta (IL-1 beta) has been proposed to be involved in pancreatic beta-cell destruction during the development of autoimmune insulin-dependent diabetes mellitus. It has been demonstrated that 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) inhibits T-lymphocyte and monocyte functions in vitro, probably through an effect on cytokine actions, and that in vivo treatment with vitamin D can prevent pancreatic insulitis in diabetes-prone NOD mice. In this study isolated rat pancreatic islets were exposed to human IL-1 beta (25 U/ml) in the absence or presence of 1,25-(OH)2D3 or the analogues MC903 and KH1060 for 48-72 h in tissue culture, whereupon medium insulin accumulation, islet DNA and insulin contents, glucose-stimulated insulin secretion and glucose oxidation rates were assessed. All three vitamin D derivatives counteracted the suppressive effect of IL-1 beta on medium insulin accumulation, 1,25-(OH)2D3 being active at concentrations down to 0.1 nM, i.e., 1-2 orders of magnitude more efficacious than the analogues. However, only KH1060 opposed the suppressive effect of IL-1 beta on islet glucose-stimulated insulin secretion and glucose oxidation rate despite the fact that KH1060 itself reduced the islet DNA and insulin content by approximately 10% and 30%, respectively. The protective effect observed against IL-1 beta-induced beta-cell dysfunction might be related to a beneficial action of vitamin D3 on the mitochondrial calcium metabolism of the beta-cells.

Cytokines suppress human islet function irrespective of their effects on nitric oxide generation

Cytokines have been proposed as inducers of beta-cell damage in human insulin-dependent diabetes mellitus via the generation of nitric oxide (NO). This concept is mostly based on data obtained in rodent pancreatic islets using heterologous cytokine preparations. The present study examined whether exposure of human pancreatic islets to different cytokines induces NO and impairs beta-cell function. Islets from 30 human pancreata were exposed for 6-144 h to the following human recombinant cytokines, alone or in combination: IFN-gamma (1,000 U/ml), TNF-alpha (1,000 U/ml), IL-6 (25 U/ml), and IL-1 beta (50 U/ml). After 48 h, none of the cytokines alone increased islet nitrite production, but IFN-gamma induced a 20% decrease in glucose-induced insulin release. Combinations of cytokines, notably IL-1 beta plus IFN-gamma plus TNF-alpha, induced increased expression of inducible NO synthase mRNA after 6 h and resulted in a fivefold increase in medium nitrite accumulation after 48 h. These cytokines did not impair glucose metabolism or insulin release in response to 16.7 mM glucose, but there was an 80% decrease in islet insulin content. An exposure of 144 h to IL-1 beta plus IFN-gamma plus TNF-alpha increased NO production and decreased both glucose-induced insulin release and insulin content. Inhibitors of NO generation, aminoguanidine or NG-nitro-L-arginine, blocked this cytokine-induced NO generation, but did not prevent the suppressive effect of IL-1 beta plus IFN-gamma plus TNF-alpha on insulin release and content. In conclusion, isolated human islets are more resistant to the suppressive effects of cytokines and NO than isolated rodent islets. Moreover, the present study suggests that NO is not the major mediator of cytokine effects on human islets.

Increased plasma levels of soluble IL-2R are associated with severe Plasmodium falciparum malaria

Plasma samples from children with mild and severe Plasmodium falciparum malaria and from children with unrelated diseases were collected to investigate whether the clinical outcome of infection was associated with plasma factors which reflected the activity of different cells of the immune system. Children with severe P. falciparum malaria had significantly higher plasma levels of soluble IL-2R than children with mild malaria. Plasma levels of IL-2R and levels of parasitaemia were significantly correlated. Neither parasitaemia nor plasma levels of tumour necrosis factor-alpha (TNF-alpha), IL-6, lymphotoxin (LT), interferon-gamma (IFN-gamma), IL-4, soluble IL-4R or soluble CD8 differed significantly between the two groups of children with malaria. High plasma levels of soluble CD8 were associated with failure of lymphocytes to produce IFN-gamma in vitro following stimulation with P. falciparum antigen. We conclude that soluble IL-2R is a useful marker of disease severity independently of the association with levels of parasitaemia, and that functional regulation of different lymphocyte subsets occurs during acute malaria episodes.

Sex- and age-dependency of IgG auto-antibodies against IL-1 alpha in healthy humans

Naturally occurring anti-interleukin (IL)-1 alpha IgG antibodies (Ab-IL-1 alpha) were measured in sera of 466 healthy Danish blood donors. Ab-IL-1 alpha bound IL-1 alpha with exceptionally high affinity (Kd: 10(-11) M) and neutralized both cell-associated and extracellular IL-1 alpha but not IL-1 beta or IL-1 receptor antagonist. More than 80% of the saturable binding of rIL-1 alpha to serum was to Ab-IL-1 alpha, suggesting that these antibodies are the quantitatively most important IL-1 alpha-binding components in serum. Judged by second antibody precipitation assay, the prevalence of Ab-IL-1 alpha varied between 30% and 75% and correlated positively with age (P = 0.037). The binding capacity of serum also increased with age. Although men were more frequently positive than women (P < 0.001), there were no sex- or age-dependent alterations in the average affinities of the antibodies. Free IL-1 alpha-like molecules were generally not detected in these sera. However, acid treatment showed that 25% of Ab-IL-1 alpha-positive sera contained low amounts of IL-1 alpha-Ab-IL-1 alpha immune complexes. IgG4 represented the main IgG isotype, whereas IgG3 Ab-IL-1 alpha were undetectable. The relative amounts of IgG4 Ab-IL-1 alpha increased while IgG2-and IgG1 Ab-IL-1 alpha decreased in elderly individuals. The presence in normal individuals and the lack of affinity maturation with age suggest that Ab-IL-1 alpha may be regulatory natural auto-antibodies perhaps coded by germline genes.

Reduction of spontaneous autoimmune diabetes in diabetes-prone BB rats with the novel immunosuppressant fusidic acid. Effect on T-cell proliferation and production of interferon-gamma

Diabetes-prone (DP) BB rats spontaneously develop a hyperglycaemic condition which closely resembles human insulin-dependent diabetes mellitus (IDDM), both in terms of clinical and histological features. The incidence of IDDM was significantly reduced when these animals were treated with 2 or 4 mg fusidic acid (FA)/day i.m. from day 30 to day 120 of age. In addition, the mean insulitis score was significantly diminished in the animals treated with FA compared to both vehicle-treated and untreated controls. Finally, 2 mg/day of FA i.m. prevented cell proliferation and interferon-gamma secretion from peripheral blood mononuclear cells upon ex vivo stimulation with concanavalin A. The capacity of FA to substantially reduce the incidence of autoimmune diabetes in a well-known animal model of human IDDM supports previous observations regarding the immunosuppressive properties of FA and its potential use in the treatment of human autoimmune diabetes.

Nicotinamide decreases nitric oxide production and partially protects human pancreatic islets against the suppressive effects of combinations of cytokines

It has been recently reported that human pancreatic islets in tissue culture produce nitric oxide (NO) and show a decreased function when exposed for 6 days to combinations of cytokines (interleukin-1 beta (IL-1 beta) + tumor necrosis factor-alpha (TNF-alpha) + interferon-gamma (IFN-gamma). Here we study the effects of nicotinamide (Nic; 10 or 20 mmol/l) on these deleterious effects of cytokines (50 U/ml IL-1 beta + 1000 U/ml TNF-alpha + 1000 U/ml IFN-gamma). Islets were isolated from 8 human pancreata at the Central Unit of the beta-Cell Transplant, Brussels, sent to Uppsala and, after 3-5 days in culture, exposed for 6 additional days to the cytokines and/or Nic. The cytokines induced a 6-fold increase in islet NO production (P < 0.001), and this effect was partially counteracted by Nic (50-60% decrease in NO production; P < 0.001). The cytokines severely decreased the islet insulin content and glucose-induced insulin release (16.7 mmol/l glucose; 90% decrease; P < 0.001). Both these effects of cytokines were partially counteracted by Nic, especially at the highest concentration (20 mmol/l; 2-4-fold increase compared to islets exposed to cytokines alone; P < 0.01). Nic by itself did not affect the insulin content or insulin release by control islets. In conclusion, the present data indicate that Nic counteracts the deleterious effects of cytokines on human pancreatic islets. This effect of Nic may be relevant for the beneficial effects of the drug in early IDDM.

Nitric oxide production is not involved in the effects of interleukin-1 beta on cAMP, thyroglobulin and interleukin-6 in TSH-stimulated human thyroid cells

Interleukin (IL)-1 inhibits the function of insulin-producing rat pancreatic beta-cells in vitro and in vivo, and it has been postulated that the IL-1 effect is mediated through the cytokine inducible nitric oxide (NO) synthase. IL-1 inhibits the function of cultured human thyroid cells too, and in this study human thyroid cell production of NO in response to the TSH-stimulated influence of IL-1 beta (10(5) U/l) and TNF-alpha (10(6) U/l), alone or in combination was measured. IL-1 beta, but not TNF-alpha, induced an increase in nitrite production, which was significantly reduced by the competitive inhibitor of nitric oxide synthase L-NG-monomethyl-arginine (L-NMMA) (0.1 mmol/L and 0.5 mmol/L). However, the nitrite production was unrelated to the IL-1 beta-induced inhibition of thyroglobulin (Tg) and cyclic AMP (cAMP) and the IL-1 beta-induced IL-6 production. Thus, it is unlikely that NO is a second mediator of the demonstrated effects of IL-1 beta and TNF-alpha on human thyroid cells in culture.

Tumor necrosis factor-alpha increases myocardial microvascular transport in vivo

Tumor necrosis factor-alpha (TNF-alpha) is a primary mediator in the pathogenesis of tissue injury, and high circulating levels of TNF-alpha are found in a variety of pathological conditions. In open-chest anesthetized dogs, the effects of intracoronary recombinant human TNF-alpha (rTNF-alpha; 100 ng/kg for 60 min) on myocardial microvascular transport of a small hydrophilic indicator was examined by the single-injection, residue-detection method. Intracoronary infusion of rTNF-alpha increased myocardial microvascular transport after 120 min. This increase was preceded by a sustained decline in cardiac output and was associated with the appearance of areas with myocardial necrosis in the regional left ventricular wall. The myocardial plasma flow rate and maximum plasma flow rate in response to a 30-s coronary occlusion were not influenced by rTNF-alpha, although a decrease in the myocardial plasma flow rate was observed after 180 min. Circulating neutrophil counts were increased by rTNF-alpha, but the increase in myocardial capillary permeability could not be ascribed to regional neutrophil infiltration. We conclude that picomolar levels of rTNF-alpha can influence the movement of small hydrophilic molecules across the myocardial microvascular barrier in vivo and induce a prolonged decrease in cardiac performance. These effects may be important elements in myocardial pathophysiology.

Cytokines (immunoinflammatory hormones) and their natural regulation in inflammatory bowel disease (Crohn's disease and ulcerative colitis): a review

Cytokines, particularly the proinflammatory cytokines, whose role and natural regulation in inflammatory bowel disease are reviewed here, are produced by many cell types, including immune cells. Cytokines function as important hormones of the immune system, and many act both regionally and systemically via specific receptors. The demonstration of increased circulating and mucosal levels of proinflammatory (and other) cytokines (and receptors) in active inflammatory bowel disease does not by itself constitute any proof as to the primary involvement of these mediators. However, they may contribute significantly to disease manifestations, and specific therapeutic intervention at the cytokine or cytokine receptor level may show up to be clinically most relevant. This is underscored by the increasing evidence that proven therapies of inflammatory bowel disease to a great extent seem to function through cytokine modulation.

Measurement of eosinophil cationic protein (ECP) and eosinophil protein X/eosinophil derived neurotoxin (EPX/EDN). Time and temperature dependent spontaneous release in vitro demands standardized sample processing

The measurement of eosinophil derived proteins such as eosinophil cationic protein (ECP) and eosinophil protein X/eosinophil derived neurotoxin (EPX/EDN) in biological fluids may be a useful indicator of eosinophil activity in ongoing inflammatory processes. This study was performed on blood samples and illustrates that serum values of ECP in particular, but also of EPX, are mainly a result of spontaneous release during the processing of blood samples. In the presence of divalent cations (Ca2+ and Mg2+), the amount of released ECP and EPX is dependent upon the incubation temperature and the time before centrifugation and recovery of serum. Moreover, the utensils used for blood sampling may influence the serum levels of ECP and EPX. Thus, standardized sample processing is of paramount importance if the results are to have optimal diagnostic or clinical value.

Cytokines in plasma and ultrafiltrate during continuous arteriovenous haemofiltration

Cytokines are considered to be important mediators in the pathophysiology of sepsis and septic shock. We investigated if continuous arteriovenous haemofiltration (CAVH) could be used to remove excessive amounts of the cytokines tumour necrosis factor-alpha (TNF alpha), interleukin (IL)-1 alpha and IL-6 from peripheral blood in critically ill patients. Nine septic patients with renal failure were treated with CAVH. Ultrafiltrate and plasma were tested for cytokines by ELISA. All patients had detectable TNF alpha and IL-6 plasma levels, ranging from 10-750 pg/ml and 50-4,575 pg/ml, respectively. TNF alpha was removed by the ultrafiltrate with concentrations ranging from 10-1,000 pg/ml. The TNF alpha levels were significantly higher in the ultrafiltrate samples than in the corresponding plasma samples (P < 0.003). IL-6 was undetectable in the ultrafiltrate from five of the patients despite concomitant high plasma levels. IL-1 alpha was detectable in both plasma and ultrafiltrate in four patients. All patients developed multi-organ failure and septic shock and seven died. It is concluded that TNF alpha and IL-1 alpha but not IL-6 can be removed by CAVH in patients with sepsis.

Binding of cytokines to pharmaceutically prepared human immunoglobulin

Pharmaceutically prepared IgG, pooled from sera of over 2,000 normal individuals, contained both monomeric and dimeric IgG. Each type of IgG bound 125I-labeled interleukin (IL)-1 alpha, IL-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha. Increased binding to IgG was observed if 125I-IL-1 beta was denatured by heating to 39 degrees C. However, the binding of both nondenatured and denatured 125I-IL-1 beta was not inhibited by unlabeled IL-1 beta. In contrast, binding of 125I-IL-1 alpha, 125I-IL-6, and 125I-TNF alpha was inhibited by the corresponding unlabeled cytokine. Papain-digestion of IgG abolished binding of 125I-TNF alpha but failed to influence the displaceable binding of 125I-IL-1 alpha and 125I-IL-6. 125I-TNF alpha was a mixture of trimeric and monomeric forms, the latter being the predominant form at lower concentrations. The apparent saturability of 125I-TNF alpha was explained by a higher nonspecific binding of monomeric than of trimeric 125I-TNF alpha to IgG. The amounts of cytokine antibodies in IgG preparations would contribute approximately 2 micrograms anti-IL-1 alpha IgG and 1 microgram anti-IL-6 IgG per kg body wt during high dose immune globulin therapy. In conclusion, pharmaceutical preparations of human IgG contain specific and neutralizing, high affinity antibodies against IL-1 alpha and IL-6, but not against TNF alpha or IL-1 beta. There are significant methodological pitfalls that hamper detection of IgG autoantibodies against cytokines.

Marginal periodontitis and cytokines: a review of the literature

Recent research on the immunopathogenesis of marginal periodontitis has focused on cytokines, because these mediators govern biological activities in inflammatory tissue destruction. Several studies have been carried out to elucidate the involvement of cytokines in periodontitis, including cytokine measurements in samples from gingival tissue, gingival crevicular fluid, and in supernatants of stimulated in vitro grown cells from gingival tissue and peripheral blood. The results, summarized in this review, suggest that cytokines are involved in the progress of periodontitis. Furthermore, cytokines may be valuable as markers of tissue breakdown. At the present stage, however, there are difficulties in detecting and quantifying cytokines by immunochemical methods and, in particular, by bioassays. Increased knowledge of the cytokine network may open new pathways of periodontitis treatment by controlling processes involved in tissue breakdown.

Production of interferon-gamma and interleukin-4 by human T cells recognizing Leishmania lipophosphoglycan-associated protein

The Leishmania protein LPGAP which is co-isolated with lipophosphoglycan is a specific activator of T cells from individuals who have recovered from American leishmaniasis. We have tested the effect of LPGAP on peripheral blood mononuclear cells (PBMC) from Kenyan donors cured from L. donovani infections. LPGAP induced vigorous proliferation and production of interferon-gamma (IFN-gamma) by the cells. In addition PBMC incubated with LPGAP released interleukin-4 (IL-4) after pulsing with ionomycin and phorbol myristate acetate. Single cells were isolated from LPGAP-stimulated cell lines and expanded as T-cell clones. LPGAP-reactive T-cell clones were activated by crude preparations of both promastigotes and axenic grown amastigote-like parasites. Among 9 CD4+ T-cell clones recognizing LPGAP, cells secreting predominantly IFN-gamma as well as cells secreting predominantly IL-4 were identified. The results show that both IFN-gamma producing (Th1-like) and IL-4 producing (Th2-like) T cells recognizing LPGAP are expanded after infection with L. donovani in humans.

Specific binding of interleukin 1 (IL-1) beta and IL-1 receptor antagonist (IL-1ra) to human serum. High-affinity binding of IL-1ra to soluble IL-1 receptor type I

Molecules that bind recombinant interleukin 1 (rIL-1) beta and rIL-1 receptor antagonist (rIL-1ra) with high affinity were detected in sera of healthy individuals. rIL-1 beta bound with dissociation constants in the nanomolar range, and the serum binding capacity was 40-50 ng/ml. rIL-1ra bound with 30 times higher affinity, and the serum binding capacity was 0.7-1 ng/ml. Rabbit antibodies against the recombinant-derived extracellular part of human IL-1 receptor type I (rsIL-1RI) selectively inhibited the binding of 125I-rIL-1ra to the serum factor(s). Almost 70% of the high-affinity IL-1ra-binding capacity was recovered after immunosorption with these antibodies. Binding of 125I-rIL-1ra to rsIL-1RI was blocked by rIL-1 alpha and by rIL-1 beta. In contrast, the purified rIL-1ra-binding factor (IL-1raBF) failed to bind rIL-1 alpha and rIL-1 beta. Gel filtration chromatography indicated a 1:1 binding of rIL-1 beta and rIL-1ra to their respective serum factors. The apparent molecular size of both serum factors was 70-80 kDa. Using SDS-PAGE and autoradiography, IL-1raBF had a molecular size of 60 kDa. We conclude that IL-1raBF, a serum factor which selectively and with high affinity binds IL-1ra (Kd = 70 pM), is related to or identical with a soluble form of IL-1RI. If upregulated during disease, IL-1raBF may constitute yet another level of natural regulation of IL-1 bioactivities.

Effects of growth factors on cytokine production in serum-free cultures of human thymic epithelial cells

Human thymic epithelial cells (TEC) of medullary phenotype were cultured for 14 days in a growth factor-defined serum-free medium. The effects of added growth factors on cell numbers and the production of cytokines were investigated by separate exclusion of the various growth factors from the medium. We found that hydrocortisone stimulated cell proliferation but inhibited the differentiation of TEC and significantly reduced the production of interleukin-1 alpha, interleukin-6 and granulocyte-macrophage colony stimulating factor. Insulin was found to enhance the differentiation of TEC and the production of the three cytokines. Transferrin and choleratoxin were found to inhibit cell proliferation, but they did not affect production of the cytokines. Exclusion of epidermal growth factor, however, leads to cell death. We conclude that it is essential to exclude hydrocortisone from the medium to optimize production of cytokines, and that transferrin and choleratoxin seem to be unnecessary constituents in serum-free cultures of human TEC.

In vitro immunomodulatory effects of pentoxifylline

Pentoxifylline (PTX), a methylxanthine derivative and phosphodiesterase inhibitor, is known to influence production and/or function of some cytokines. We examined the effect of PTX on the in vitro expression of cytokine genes using endotoxin- or phytohaemagglutinin (PHA)-stimulated human blood mononuclear cells. The expression of tumour necrosis factor (TNF)alpha, TNF beta interleukin (IL)-2 and interferon (IFN)gamma was inhibited by PTX in a dose-dependent manner, whereas expression of IL-1 alpha, IL-1 beta, and IL-6 was unaffected at concentrations up to 300 microM of PTX. The amount of TNF beta mRNA in PHA-stimulated blood mononuclear cells was reduced by PTX. Finally, PTX stimulated PHA-induced cell proliferation whereas antigen-induced cell proliferation was inhibited in the presence of PTX. The PTX analogues HWA-138 and A-802715 inhibited TNF alpha mRNA expression from endotoxin-stimulated mononuclear cells. These data suggest that PTX-analogues affect the in vitro immune response at different target points and that the response depends upon the respective triggering mechanism(s).

Indirect assessment of eosinophiluria in urinary schistosomiasis using eosinophil cationic protein (ECP) and eosinophil protein X (EPX)

The pre- and post-treatment level of eosinophiluria, as measured indirectly by the amount of free or cell bound eosinophil cationic protein (ECP) and eosinophil protein X (EPX) in urine from Schistosoma haematobium-infected Kenyan school children, were measured and compared with intensity of infection (eggs/10 ml of urine), albuminuria and pathological changes as detected by ultrasonography. ECP and EPX were determined by means of specific ELISA methods and levels were determined in both urine supernatants and extracted urine deposits (cells and cell debris). The level of ECP was significantly raised in urine supernatants from infected children compared to controls, whereas high amounts of EPX were found in urine supernatants from infected children as well as from controls. However, the amounts of cell bound ECP and EPX were significantly raised in infected children. In pre-treatment observations significant correlations were demonstrated between egg counts, albuminuria and eosinophiluria as measured by the amount of cell bound ECP and EPX, or ECP in urine supernatants. No such correlations were demonstrated with the amount of EPX in the urine supernatants. Comparable amounts of ECP and EPX could be extracted from the urine deposits from infected children, but due to the high amounts of EPX in urine deposit extracts from controls, extracted ECP gave the best discrimination between infected and non-infected children. While albuminuria disappeared in most children at the 6 week post-treatment follow-up, eosinophiluria persisted in a significant proportion of the treated children indicating continued eosinophil activity in the bladder wall. Detection and quantification of early acute inflammatory reactions using ECP/eosinophils in combination with detection of later stages of bladder pathology using ultrasound may allow for a dynamic evaluation of the pathological process, the morbidity development and post treatment pathological changes in S. haematobium infections.