[Mucopolysaccharidoses in children. Experience of a general pediatric service. 11 cases]

The mucopolysaccharidosis are hereditary diseases. The neurological attack constitutes the principal factor of gravity of these affections. We conducted a retrospective study over a period of 12 years (1988-1999) in the pediatric department of Sfax University Hospital. This study allowed us to observe 11 cases of mucopolysaccharidosis confirmed by an enzymatic proportioning, with 3 cases of Hurler disease (IH), 3 cases of the disease of sanfilippo, (two II A and one III B), 3 cases of the disease of Morquio A (type IVA) and 2 cases of the disease of Maroteaux Lamy (type VI). A sex ratio of 1.75. The parents were cousins in 90% of the cases. The age of revelation ranged between 6 months to 4 years. The clinical examination has found a staturo-pondral delay in 81.8% of the cases, a craniofacial dysmorphy in 100%, deformations of the rachis in 63.6% of the cases, a psychomotor regression in 54.5% of the cases, a medullary compression in 18% of the cases, hepatosplenomegaly in 36.4%, and corneal opacities in 45.4% of the cases. The therapeutic treatment was limited to the symptomatic measures with genetic consulting and antenatal diagnosis.

Anti-inflammatory actions of lipoxin A(4) stable analogs are demonstrable in human whole blood: modulation of leukocyte adhesion molecules and inhibition of neutrophil-endothelial interactions

We have examined in whole blood the actions of 2 lipoxin A(4) (LXA(4)) stable analogs, 15-R/S-methyl-LXA(4) and 16-phenoxy-LXA(4), for their impact on the expression of adhesion molecules on human leukocytes and coronary artery endothelial cells (HCAEC) and on neutrophil adhesion to HCAEC in vitro. Both LXA(4) analogs in nanomolar to micromolar concentrations prevented shedding of L-selectin and downregulated CD11/CD18 expression on resting neutrophils, monocytes, and lymphocytes. Changes in CD11/CD18 expression were blocked by the mitogen-activated protein kinase kinase inhibitor PD98059. The LXA(4) analogs also attenuated changes in L-selectin and CD11/CD18 expression evoked by platelet-activating factor (PAF), interleukin-8, or C-reactive protein-derived peptide 201-206 with IC(50) values of 0.2 to 1.9 micromol/L, whereas they did not affect lipopolysaccharide (LPS)- or tumor necrosis factor-alpha-stimulated expression of E-selectin and intercellular adhesion molecule-1 on HCAEC. These LXA(4) analogs markedly diminished adhesion of neutrophils to LPS-activated HCAEC. Inhibition of adhesion was additive with function blocking anti-E-selectin and anti-L-selectin antibodies, but was not additive with anti-CD18 antibody. Combining LXA(4) analogs with dexamethasone (100 nmol/L) almost completely inhibited PAF-induced changes in adhesion molecule expression on leukocytes and gave additive inhibition of neutrophil adhesion to HCAEC. Culture of HCAEC with dexamethasone, but not with LXA(4) analogs, also decreased neutrophil attachment. Together, these results indicate that LXA(4) stable analogs modulate expression of both L-selectin and CD11/CD18 on resting and immunostimulated leukocytes and inhibit neutrophil adhesion to HCAEC by attenuating CD11/CD18 expression. These actions are additive with those of glucocorticoids and may represent a novel and potent regulatory mechanism by which LXA(4) and aspirin-triggered 15-epi-LXA(4) modulate leukocyte trafficking.

Lipoxin (LX)A4 and aspirin-triggered 15-epi-LXA4 inhibit tumor necrosis factor 1alpha-initiated neutrophil responses and trafficking: regulators of a cytokine-chemokine axis

The impact of lipoxin A4 (LXA4) and aspirin-triggered lipoxins (ATLs) was investigated in tumor necrosis factor (TNF)-alpha-initiated neutrophil (polymorphonuclear leukocyte) responses in vitro and in vivo using metabolically stable LX analogues. At concentrations as low as 1-10 nM, the LXA4 and ATL analogues each inhibited TNF-alpha-stimulated superoxide anion generation and IL-1beta release by human polymorphonuclear leukocytes. These LXA4-ATL actions were time and concentration dependent and proved selective for TNF-alpha, as these responses were not altered with either GM-CSF- or zymosan-stimulated cells. TNF-alpha-induced IL-1beta gene expression was also regulated by both anti-LXA4 receptor antibodies and LXA4-ATL analogues. In murine air pouches, 15R/S-methyl-LXA4 dramatically inhibited TNF-alpha-stimulated leukocyte trafficking, as well as the appearance of both macrophage inflammatory peptide 2 and IL-1beta, while concomitantly stimulating IL-4 in pouch exudates. Together, these results indicate that both LXA4 and ATL regulate TNF-alpha-directed neutrophil actions in vitro and in vivo and stimulate IL-4 in exudates, playing a pivotal role in immune responses.

[Renal needle biopsy in children. Technical aspects and results]

Renal needle biopsy is still irreplaceable in children. The objectives of this retrospective study were to specify the technical aspects and the main nephropathies encountered. 152 children under the age of 16 years (13 +/- 3), 79 boys and 73 girls, underwent renal biopsy. The biopsy was performed after radiographic detection in 71 cases, and under continuous ultrasound guidance in 81 cases. The comparative study of these 2 techniques revealed the superiority of continuous ultrasound guidance, allowing biopsy of an essentially cortical fragment, rich in glomeruli with a limited number of punctures. Histological examination showed a predominance of glomerular nephropathy with, especially, visually normal kidney and membranoproliferative glomerulonephritis. These data encourage us to perform ultrasound-guided RNB in children and to eradicate sites of infection, particularly involving the upper respiratory tract.

Regulation of chemokine gene expression in human peripheral blood neutrophils phagocytosing microbial pathogens

Production of chemokines (chemotactic cytokines) by neutrophils is likely to be important in the regulation of inflammation and the control of infection. In this study we show that exposure of human neutrophils to various microbial pathogens leads to the production of both macrophage inflammatory protein 1alpha (MIP-1alpha) and IL-8. The bacterial microbes, Salmonella typhimurium and Pseudomonas aeruginosa, and Staphylococcus aureus all strongly induced both IL-8 and MIP-1alpha secretion, whereas Streptococcus pneumoniae, Staphylococcus epidermidis, and the opportunistic yeast Candida albicans were less potent. Saccharomyces cerevisiae and zymosan both induced IL-8 secretion but failed to stimulate that of MIP-1alpha. Coincubation of neutrophils with the proinflammatory cytokine TNF-alpha and the micro-organisms also led to differential expression of MIP-1alpha and IL-8. Significant enhancement of the induction of both MIP-1alpha and IL-8 by S. typhimurium, P. aeruginosa, and S. pneumoniae as well as by C. albicans was observed. In contrast, while IL-8 production in response to S. cerevisiae and zymosan was enhanced in the presence of TNF-alpha, no MIP-1alpha was produced. These combined results indicate that while neutrophils exposed to some micro-organisms alone or in the presence of inflammatory cytokines such as TNF-alpha will produce both MIP-1alpha and IL-8, resulting in generation of signals for the recruitment of mononuclear leukocytes and neutrophils, respectively, certain types of microorganisms can skew this response toward synthesis of IL-8.

Regulation of Chemokine Gene Expression in Human Peripheral Blood Neutrophils Phagocytosing Microbial Pathogens

Production of chemokines (chemotactic cytokines) by neutrophils is likely to be important in the regulation of inflammation and the control of infection. In this study we show that exposure of human neutrophils to various microbial pathogens leads to the production of both macrophage inflammatory protein 1α (MIP-1α) and IL-8. The bacterial microbes, Salmonella typhimurium and Pseudomonas aeruginosa, and Staphylococcus aureus all strongly induced both IL-8 and MIP-1α secretion, whereas Streptococcus pneumoniae, Staphylococcus epidermidis, and the opportunistic yeast Candida albicans were less potent. Saccharomyces cerevisiae and zymosan both induced IL-8 secretion but failed to stimulate that of MIP-1α. Coincubation of neutrophils with the proinflammatory cytokine TNF-α and the micro-organisms also led to differential expression of MIP-1α and IL-8. Significant enhancement of the induction of both MIP-1α and IL-8 by S. typhimurium, P. aeruginosa, and S. pneumoniae as well as by C. albicans was observed. In contrast, while IL-8 production in response to S. cerevisiae and zymosan was enhanced in the presence of TNF-α, no MIP-1α was produced. These combined results indicate that while neutrophils exposed to some micro-organisms alone or in the presence of inflammatory cytokines such as TNF-α will produce both MIP-1α and IL-8, resulting in generation of signals for the recruitment of mononuclear leukocytes and neutrophils, respectively, certain types of micro-organisms can skew this response toward synthesis of IL-8.

Lipoxin A4 stable analogs are potent mimetics that stimulate human monocytes and THP-1 cells via a G-protein-linked lipoxin A4 receptor

Lipoxins (LX) are bioactive eicosanoids that activate human monocytes and inhibit neutrophils. LXA4 is rapidly converted by monocytes to inactive products, and to resist metabolism, synthetic analogs of LXA4 were designed. Here, we examined the bioactivity of several LXA4 analogs in monocytes and found, for chemotaxis, 15(R/S)-methyl-LXA4 and 15-epi-LXA4 were equal in activity, and 16-phenoxy-LXA4 was more potent than native LXA4. Both 15(R/S)-methyl-LXA4 and 16-phenoxy-LXA4 were approximately 1 log molar more potent than LXA4 in stimulating THP-1 cell adherence (EC50 approximately 1 x 10(-10) M). Dimethylamide derivatives of the LXA4 analogs also possessed agonist rather than antagonist properties for monocytes. Neither LXA4 nor 16-phenoxy-LXA4 affected monocyte-mediated cytotoxicity. We cloned an LXA4 receptor from THP-1 cells identical to that found in PMN. Evidence of receptor-mediated function of LXA4 and the stable analogs in monocytes included desensitization of intracellular calcium mobilization to a second challenge by equimolar concentrations of these analogs, but not to LTB4. Increases in [Ca2+]i by LXA4 and the analogs were specifically inhibited by an antipeptide antibody to the LXA4 receptor; and both LXA4- and analog-induced adherence and increments in Ca2+ were sensitive to pertussis toxin. Together, these results indicate that the LXA4 stable analogs are potent monocyte chemoattractants and are more potent than native LXA4 in stimulating THP-1 cell adherence, at subnanomolar concentrations. Moreover, they provide additional evidence that the LXA4 stable analogs retain selective bioactivity in monocytes and are valuable instruments for examining the functions and modes of action of LXA4.

Inflammatory microcrystals differentially regulate the secretion of macrophage inflammatory protein 1 and interleukin 8 by human neutrophils: a possible mechanism of neutrophil recruitment to sites of inflammation in synovitis

Human neutrophils at inflammatory sites may be an important source of the chemotactic cytokines macrophage inflammatory protein 1 alpha (M1P-1 alpha; a C-C chemokine) and interleukin 8 (IL-8; a C-X-C chemokine). In this study, we show that the inflammatory microcrystals monosodium urate monohydrate (MSU) and calcium pyrophosphate dihydrate (CPPD), the major mediators of gout and pseudogout, differentially regulate the production of these two chemokines by human neutrophils. Both MSU and CPPD increased the secretion of IL-8 by neutrophils in a dose- and time-dependent manner, but had no effect on that of MIP-1 alpha. Since inflammatory cytokines are likely to be present in the synovium during crystal-induced inflammation, we examined the interaction between TNF-alpha and GM-CSF and the crystals. Both TNF-alpha and GM-CSF stimulated IL-8 production; however, only TNF-alpha exerted a significant effect on MIP-1 alpha secretion in neutrophils. IL-8 production induced by TNF-alpha and GM-CSF was synergistically enhanced in the presence of MSU or CPPD, whereas MIP-1 alpha secretion induced by TNF was completely inhibited in the presence of either MSU or CPPD. Interestingly, no interaction between the crystals and the inflammatory cytokines was observed with respect to synthesis of the C-X-C chemokine MGSA in neutrophils. These results suggest that the combination of TNF-alpha and GM-CSF with MSU or CPPD will lead to the production of IL-8 by neutrophils and abolish the release of MIP-1 alpha, an event that will theoretically lead to recruitment of neutrophils but not mononuclear cells. These results are in accordance with the pathological state of gout and pseudogout, where the predominant inflammatory cell is the neutrophil.

Synergistic effect of interleukin-1 beta and tumor necrosis factor alpha on interleukin-8 gene expression in synovial fibroblasts. Evidence that interleukin-8 is the major neutrophil-activating chemokine released in response to monokine activation

OBJECTIVE

To investigate both the involvement of chemokines in general and the relative importance of specific chemokines in rheumatoid arthritis (RA), we characterized the effect of the monokines tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta) on the synthesis of neutrophil-activating factors by synovial fibroblasts isolated from the joints of patients with RA.

METHODS

Neutrophil-stimulating activity was assessed by determining intracellular calcium mobilization. IL-8 synthesis and secretion was assessed by specific enzyme-linked immunosorbent assay, and IL-8 messenger RNA (mRNA) levels were determined by Northern blot.

RESULTS

Treatment of synovial fibroblasts with IL-1 beta and TNF alpha resulted in the production of an activity which induced intracellular calcium mobilization in peripheral blood neutrophils. The 2 monokines combined had a synergistic effect on the release of the neutrophil-stimulating activity. The effect of the 2 monokines required gene transcription and translation, and closely mimicked the pattern of IL-8 secretion induced in these cells by the monokines. We confirmed that the majority of the neutrophil-stimulating activity was IL-8 by 3 different approaches: cross-desensitization experiments with IL-8, melanoma growth-stimulatory activity, and neutrophil-activating peptide 2, stimulation of calcium mobilization in cells transfected with the IL-8 receptor complementary DNA, and inhibition of the activity following pretreatment of the supernatants with an anti-IL-8 antibody. TNF alpha and IL-1 beta induced a time- and dose-dependent release of immunoreactive IL-8. A synergistic effect of TNF alpha and IL-1 beta was also observed for both IL-8 production and accumulation of IL-8 mRNA.

CONCLUSION

These results indicate that the monokines TNF alpha and IL-1 beta synergistically activate IL-8 expression and protein secretion by synovial fibroblasts, and that under these conditions, IL-8 appears to be the major neutrophil-activating factor released.

Uncoupling of early signal transduction events from effector function in human peripheral blood neutrophils in response to recombinant macrophage inflammatory proteins-1 alpha and -1 beta

Macrophage inflammatory proteins-1 (MIP-1) alpha and beta are members of the C-C branch of the platelet factor 4 superfamily of cytokines, recently designated the "chemokine" superfamily. It has been suggested that the major cellular targets for the biologic activities of the C-C chemokines are the mononuclear leukocytes. However, the original designation of murine MIP-1 proteins as inflammatory mediators was based on suggestions that they activated neutrophil functions such as chemotaxis, the respiratory burst, and degranulation. In this study, we have evaluated the ability of human (Hu) MIP-1 alpha and beta to affect purified human neutrophil function. Although both rHuMIP-1 alpha and -1 beta stimulated significant calcium mobilization in human monocytes, only HuMIP-1 alpha exerted a detectable effect on neutrophils. HuMIP-1 alpha stimulated a small, dose-dependent increase in intracellular calcium, which was accompanied by a simultaneous change in right-angle light scatter, the latter indicating induction of shape change. While the effect of HuMIP-1 alpha on calcium mobilization in neutrophils was small when compared with that elicited by IL-8 or Gro alpha, it had similar characteristics to that by other receptor-dependent neutrophil agonists in that it was dependent on pertussis toxin-sensitive G proteins and on both mobilization of calcium from intracellular sources as well as influx from the extracellular environment. In addition, stimulation of neutrophils with HuMIP-1 alpha led to desensitization to subsequent additions of HuMIP-1 alpha. The stimulatory effect of HuMIP-1 alpha on neutrophil calcium mobilization and shape change was not coupled to other standard measures of neutrophil effector function. For instance, neither HuMIP-1 alpha nor -1 beta had any detectable stimulatory effect on the Na+/H+ antiport, degranulation, actin polymerization, or chemotaxis. Moreover, although HuMIP-1 alpha binding could easily be measured on monocytes or monocytic cell lines, the number of sites were too few to characterize on neutrophils by the same technique. Taken together, these results show that neither HuMIP-1 alpha nor -1 beta stimulate significant neutrophil activation and support the concept that the biologic effects of members of the C-C branch of the platelet factor 4 superfamily are not primarily directed toward neutrophils.

Uncoupling of early signal transduction events from effector function in human peripheral blood neutrophils in response to recombinant macrophage inflammatory proteins-1 alpha and -1 beta

Macrophage inflammatory proteins-1 (MIP-1) alpha and beta are members of the C-C branch of the platelet factor 4 superfamily of cytokines, recently designated the "chemokine" superfamily. It has been suggested that the major cellular targets for the biologic activities of the C-C chemokines are the mononuclear leukocytes. However, the original designation of murine MIP-1 proteins as inflammatory mediators was based on suggestions that they activated neutrophil functions such as chemotaxis, the respiratory burst, and degranulation. In this study, we have evaluated the ability of human (Hu) MIP-1 alpha and beta to affect purified human neutrophil function. Although both rHuMIP-1 alpha and -1 beta stimulated significant calcium mobilization in human monocytes, only HuMIP-1 alpha exerted a detectable effect on neutrophils. HuMIP-1 alpha stimulated a small, dose-dependent increase in intracellular calcium, which was accompanied by a simultaneous change in right-angle light scatter, the latter indicating induction of shape change. While the effect of HuMIP-1 alpha on calcium mobilization in neutrophils was small when compared with that elicited by IL-8 or Gro alpha, it had similar characteristics to that by other receptor-dependent neutrophil agonists in that it was dependent on pertussis toxin-sensitive G proteins and on both mobilization of calcium from intracellular sources as well as influx from the extracellular environment. In addition, stimulation of neutrophils with HuMIP-1 alpha led to desensitization to subsequent additions of HuMIP-1 alpha. The stimulatory effect of HuMIP-1 alpha on neutrophil calcium mobilization and shape change was not coupled to other standard measures of neutrophil effector function. For instance, neither HuMIP-1 alpha nor -1 beta had any detectable stimulatory effect on the Na+/H+ antiport, degranulation, actin polymerization, or chemotaxis. Moreover, although HuMIP-1 alpha binding could easily be measured on monocytes or monocytic cell lines, the number of sites were too few to characterize on neutrophils by the same technique. Taken together, these results show that neither HuMIP-1 alpha nor -1 beta stimulate significant neutrophil activation and support the concept that the biologic effects of members of the C-C branch of the platelet factor 4 superfamily are not primarily directed toward neutrophils.

Expression of the cytokine RANTES in human rheumatoid synovial fibroblasts. Differential regulation of RANTES and interleukin-8 genes by inflammatory cytokines

A chronic inflammatory disease may be characterized by an accumulation of activated leukocytes at the site of inflammation. Since the chemokine RANTES may play an active role in recruiting leukocytes into inflammatory sites, we investigated the ability of cultured human synovial fibroblasts isolated from patients suffering from rheumatoid arthritis to produce this chemokine and compared its regulation to that of the closely related chemokine gene, interleukin-8 (IL-8). In unstimulated synovial fibroblasts, the expression of mRNA for both chemokines was undetectable, but was increased in both a time- and dose-dependent manner upon stimulation with the monokines tumor necrosis factor alpha (TNF alpha) and interleukin-1 beta (IL-1 beta). Preincubation of the cells with cycloheximide "superinduced" the level of IL-8 mRNA stimulated by TNF alpha and IL-1 beta and RANTES mRNA stimulated by IL-1 beta, but decreased the expression of RANTES mRNA in response to TNF alpha. In addition, differential regulation of these genes was noted when synovial fibroblasts were stimulated with a combination of cytokines. IL-4 down-regulated and IFN gamma enhanced the TNF alpha- and IL-1 beta-induced increase in RANTES mRNA, whereas the induction of IL-8 mRNA by TNF alpha or IL-1 beta was inhibited by IFN gamma and augmented by IL-4. Moreover, a combination of TNF alpha and IL-1 beta synergistically induced IL-8 mRNA expression, whereas under the same conditions, the level of expression of RANTES mRNA was less than that induced by TNF alpha alone. These observations were also reflected at the level of chemokine secretion. These studies demonstrate that by expressing the chemokines RANTES and IL-8, synovial fibroblasts may participate in the ongoing inflammatory process in rheumatoid arthritis. In addition, the observation that these chemokine genes are differentially regulated, depending upon the presence of different cytokines, indicates that the type of cellular infiltrate and the progress of the inflammatory disease is likely to depend on the relative levels of stimulatory and inhibitory cytokines.

Production of monocyte chemotactic protein-1 in human type B synoviocytes. Synergistic effect of tumor necrosis factor alpha and interferon-gamma

OBJECTIVE

Since local secretion of chemotactic factors could contribute substantially to the homing of monocytes to the rheumatoid synovium, we investigated the ability of type B, or "fibroblast-like," synoviocytes isolated from the synovial tissue of patients with rheumatoid arthritis to synthesize and secrete the novel cytokine monocyte chemotactic protein 1 (MCP-1).

METHODS

Synthesis and secretion of MCP-1 was determined by immunoprecipitation following metabolic labeling of MCP-1 with 35S-cysteine. MCP-1 gene regulation was assessed by Northern blot analysis.

RESULTS

Unstimulated type B synoviocytes released little or no MCP-1, although low levels of MCP-1 messenger RNA (mRNA) were detected. However, incubation of these cells with tumor necrosis factor alpha (TNF alpha) resulted in a time- and dose-dependent release of MCP-1 into the supernatant, and expression of MCP-1 mRNA. Use of cycloheximide and actinomycin D confirmed that TNF alpha was inducing MCP-1 expression at both the transcriptional and translational levels. Treatment of the synoviocytes with interferon-gamma (IFN gamma) also stimulated an increase in both the steady-state levels of MCP-1 mRNA, as well as MCP-1 protein synthesis and secretion. In addition, TNF alpha and IFN gamma in combination exerted a synergistic effect on both MCP-1 mRNA accumulation and protein secretion.

CONCLUSION

These studies demonstrate that the MCP-1 gene is regulated by TNF alpha and IFN gamma in type B synoviocytes and indicate that these cells may play an important role in the recruitment of inflammatory cells to the rheumatoid synovial environment, via the production of novel chemotactic cytokines such as MCP-1.

[Hemopigmented villonodular synovitis of the knee. Apropos of 2 cases]

We report two cases of hemopigmented villonodular synovitis in two girls aged 5 years 9 months and 13 years respectively. This condition is a clinicopathologic entity of unknown pathogenesis and is exceedingly rare in childhood. Patients of both sexes can be affected, with no particular predominance. The clinical picture in our two patients consisted only in chronic hemarthrosis of the knee with occasionally tumor-like features. Arthrographic changes were not specific. Diagnosis was established upon arthrography and results of pathologic studies of biopsy specimens. Therapy of this condition is surgical and recurrences are infrequent.