Making medical devices safer: impact of plastic and silicone oil on microbial biofilm formation.

BACKGROUND: Medical devices face the challenge of microbial biofilm attached to the surface. Ultimately, this may jeopardize the function of the device and increase the patient's risk of infection. However, reliable methods to prevent biofilm are lacking. AIM: To investigate the effect of silicone oil-coated polypropylene plastic, used in a new automatic urinometer, on biofilm formation; furthermore, to explore the impact of silicone oil viscosity and compare polypropylene with polystyrene, another common medical plastic. METHODS: Common pathogens, including extended-spectrum beta lactamase (ESBL) -producing and multi-drug-resistant bacteria, as well as Candida albicans, were investigated. Isogenic Escherichia coli strains deficient in the important biofilm forming factors curli, cellulose and type 1 fimbriae (fim D) were used to determine the possible mode of action by silicone oil. Clear flat-bottomed polypropylene or polystyrene wells were pretreated with either low- or medium-viscosity silicone oil and microbes were added. After 72 h, biofilm formation was quantified using crystal violet assay. FINDINGS: Silicone oil-coated polypropylene plastic surfaces, regardless of the oil viscosity, significantly inhibited biofilm formation of all tested Gram-negative and Gram-positive bacteria, including ESBL-producing and multi-drug resistant strains, as well as C. albicans. Silicone oil did not affect bacterial or candida growth and curli fimbriae were found to be the main target of silicone oil. Polypropylene plastic itself without oil had a better effect in preventing biofilm formation than polystyrene. CONCLUSION: These findings suggest a new strategy to decrease microbial biofilm formation, which may reduce hospital-acquired infections and prevent dysfunction of medical devices.

Association between vitamin D, antimicrobial peptides and urinary tract infection in infants and young children.

AIM: Vitamin D stimulates production of the endogenous antimicrobial peptides cathelicidin and ß-defensin-2, which are expressed in the urinary tract. We investigated vitamin D status and levels of cathelicidin and ß-defensin-2 and their association with urinary tract infection (UTI). METHODS: The study included 120 children under three years of age: 76 children with UTIs and 44 otherwise healthy children with congenital hydronephrosis. Serum 25-hydroxycholecalciferol levels were measured by direct competitive electro-chemiluminescence immunoassay, and plasma cathelicidin and ß-defensin-2 concentrations were analysed by enzyme-linked immunosorbent assay. RESULTS: We found that vitamin D insufficiency and deficiency are prevalent in young children (21%). Serum vitamin D levels negatively correlated with age and were significantly lower in girls. Levels of vitamin D positively correlated with levels of cathelicidin but not with ß-defensin-2. Low concentrations of vitamin D were associated with UTIs in girls, but we did not see any correlation with the recurrence of infection at one-year follow-up. CONCLUSION: Vitamin D deficiency is common and may prove to be a risk factor for UTIs especially in girls. We hypothesise that adequate supplementation with vitamin D may become a way to prevent first-time UTIs.

Statins influence epithelial expression of the anti-microbial peptide LL-37/hCAP-18 independently of the mevalonate pathway.

Anti-microbial resistance increases among bacterial pathogens and new therapeutic avenues needs to be explored. Boosting innate immune mechanisms could be one attractive alternative in the defence against infectious diseases. The cholesterol-lowering drugs, statins, have been demonstrated to also affect the immune system. Here we investigate the effect of statins on the expression of the human cathelicidin anti-microbial peptide (CAMP) LL-37/hCAP-18 [encoded by the CAMP gene] and explore the underlying mechanisms in four epithelial cell lines of different origin. Simvastatin induced CAMP expression in bladder epithelial cells telomerase-immortalized uroepithelial cells (TERT-NHUCs), intestinal cells HT-29 and keratinocytes HEKa, but not in airway epithelial cells A549. Gene induction in HEKa cells was reversible by mevalonate, while this effect was independent of the cholesterol biosynthesis pathway in TERT-NHUCs. Instead, inhibition of histone deacetylases by simvastatin seems to be involved. For HT-29 cells, both mechanisms may contribute. In addition, simvastatin increased transcription of the vitamin D-activating enzyme CYP27B1 which, in turn, may activate LL-37/hCAP-18 production. Taken together, simvastatin is able to promote the expression of LL-37/hCAP-18, but cell line-specific differences in efficacy and the involved signalling pathways exist.

The impact of vitamin D on the innate immune response to uropathogenic Escherichia coli during pregnancy.

Urinary tract infections are highly common during pregnancy, and can cause serious complications for the mother and baby. Vitamin D, predominantly obtained from the sunlight, is known to have an effect on the urothelium, with immunomodulatory capacity against Escherichia coli infection. However, its influence at this site remains to be further explored. This study therefore investigated its impact during pregnancy in a population of women who have the possibility of adequate year-round sun exposure. Serum from pregnant Ugandan women (n = 32) in each trimester of pregnancy, from women after delivery (n = 29) and from never-pregnant controls (n = 25) was collected. 25-Hydroxyvitamin D (25-OHD), cathelicidin LL-37, human ß-defensin 2, interleukin (IL)-8 and soluble CD14 serum concentrations were measured by chemiluminescence immunoassay or ELISA. The ability of serum to inhibit E. coli growth was tested. The immunomodulatory capacities of these serum samples and 1,25-dihydroxyvitamin D3 were investigated in urothelial cells. Increases in 25-OHD and LL-37 levels were observed as pregnancy progressed, peaking in the third trimester. Serum 25-OHD levels were higher in multigravidae than in primigravidae, and correlated positively with maternal age. IL-8 levels were lower in the third trimester than in the first trimester, increased after delivery, but remained below those of never-pregnant women. Similarly, soluble CD14 concentrations increased after delivery. As gestation advanced, serum had an increased capacity to inhibit E. coli growth. In vitro, it modulated the IL-8 response to infection in a vitamin D concentration-dependent manner. Our findings demonstrate that increasing vitamin D levels as pregnancy advances modulate the innate immune system towards a protective response to infection.

Markers of innate immune activity in patients with type 1 and type 2 diabetes mellitus and the effect of the anti-oxidant coenzyme Q10 on inflammatory activity.

Major long-term complications in patients with diabetes are related to oxidative stress, caused by the hyperglycaemia characteristic for diabetes mellitus. The anti-oxidant coenzyme Q10 (CoQ10) has therefore been proposed as a beneficial supplement to diabetes treatment. Apart from its anti-oxidative function, CoQ10 appears to modulate immune functions by largely unknown mechanisms. The aim of this study was therefore to investigate the effect of CoQ10 on antimicrobial peptides and natural killer (NK) cells, both innate immune components implicated in the pathogenesis of diabetes and diabetes-associated long-term complications such as cardiovascular disease. We determined serum levels of antimicrobial peptides and the phenotype of NK cells isolated from peripheral blood of patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM) and from healthy controls. In addition, the same parameters were determined in diabetic patients after a 12-week period of CoQ10 supplementation. Two antimicrobial peptides, the human cathelicidin antimicrobial peptide (CAMP) and the human beta defensin 1 (hBD1), were reduced in serum from patients with T1DM. This defect was not reversible by CoQ10 supplementation. In contrast, CoQ10 reduced the levels of circulating hBD2 in these patients and induced changes in subset distribution and activation markers in peripheral NK cells. The results of the present study open up novel approaches in the prevention of long-term complications associated to T1DM, although further investigations are needed.

Cellulose and PapG are important for Escherichia coli causing recurrent urinary tract infection in women.

PURPOSE: To identify Escherichia coli factors associated with bacterial persistence in the human urogenital tract using well-defined clinical isolates from women with cystitis. METHODS: E. coli were isolated from women suffering from recurrent cystitis. For comparison, isolates from sporadically infected patients and healthy volunteers were included in the analysis. Samples were taken on three occasions from the urine, periurethra, and vagina. Isolates were typed by pulsed-field gel electrophoresis, and virulence factors were detected by PCR and morphotypic analysis. RESULTS: In all patients, the original E. coli strain was isolated repeatedly and from different regions. The presence of papG coding for a P fimbriae subtype linked to pyelonephritis was associated with strains isolated from patients with recurrent cystitis, including both among urinary and vaginal isolates. The biofilm component cellulose was detected at a higher frequency in urinary isolates from recurrent versus sporadic cystitis. CONCLUSION: The hypothesis of a periurethral/vaginal E. coli reservoir is supported by the results of this study. Our results also indicate an impact of cellulose on E. coli persistence in the human urogenital tract.

Serotyping of Proteus mirabilis clinical strains based on lipopolysaccharide O-polysaccharide and core oligosaccharide structures.

The aim of this work was to serotype Proteus mirabilis urinary tract infection (UTI) strains based on chemically defined O-antigens with the use of two clinical collections from Sweden and Poland consisting of 99 and 24 UTI strains, respectively. A simple two-step serotyping scheme was proposed using enzyme immunoassay with heat-stable surface antigens of Proteus cells and immunoblotting with isolated lipopolysaccharides (LPSs). Using polyclonal anti-P. mirabilis rabbit antisera, 50 Swedish and 8 Polish strains were classified into serogroups O10, O38, O36, O30, O17, O23, O9, O40, O49, O27, O5, O13, O24, O14, and O33. From the Swedish strains, 10 belonged to serogroup O10 and five to each of serogroups O38, O36, and O9. Therefore, none of the O-serogroups was predominant. The majority of the serotyped clinical strains possess acidic O-antigens containing uronic acids and various acidic non-carbohydrate substituents. In immunoblotting, antisera cross-reacted with both O-antigen and core of LPSs. The core region of 19 LPSs bound a single serum, and that of 12 LPSs bound more than two sera. Following bioinformatic analysis of the available sequences, a molecular approach to the prediction of Proteus core oligosaccharide structures was proposed. The identification of the core type of P. mirabilis R110, derived from a serogroup O3 wild strain, using restriction fragments length polymorphism analysis of galacturonic acid transferase is shown as an example. In summary, the most frequent O-serogroups among P. mirabilis UTI stains were identified. The diversity of serological reactions of LPSs is useful for serotyping of P. mirabilis clinical isolates. A possible role of the acidic components of O-antigens in UTI is discussed.

Characterisation of uropathogenic Escherichia coli from children with urinary tract infection in different countries.

Uropathogenic Escherichia coli (UPEC) carry many virulence factors, including those involved in long-term survival in the urinary tract. However, their prevalence and role among UPEC causing urinary tract infection (UTI) in children is not well studied. To further understand the virulence characteristics of these bacteria, we investigated the prevalence of antibiotic resistance, antigen 43 genes, curli and cellulose among UPEC in children from different countries. Isolates (n = 337) from five countries were tested for antibiotic susceptibility, phylogenetic groups, prevalence of flu, fluA(CFT073), fluB(CFT073), curli and cellulose. High prevalence of multidrug resistance and extended spectrum beta lactamase production was found among Iranian and Vietnamese isolates. Resistance was associated with phylogenetic group D while group B2 was associated with fluA(CFT073) and fluB(CFT073). Fewer Iranian isolates carried fluA(CFT073), curli and cellulose. fluB(CFT073) was most prevalent among Slovak isolates. Ampicillin and amoxicillin/clavulanic acid resistance was prevalent among fluA(CFT073)- and fluB(CFT073)-positive Australian, Iranian and Swedish isolates. Lack of curli and cellulose was associated with resistance among Vietnamese isolates. We conclude that major differences exist in the prevalence of antibiotic resistance among UPEC from different countries. Associations observed between resistance and virulence factors may, in different ways, promote the long-term survival of UPEC in the urinary tract.

Genetic relatedness and virulence gene profiles of Escherichia coli strains isolated from septicaemic and uroseptic patients.

We investigated the relationship between clonality and virulence factors (VFs) of a collection of Escherichia coli strains isolated from septicaemic and uroseptic patients with respect to their origin of translocation. Forty septicaemic and 30 uroseptic strains of E. coli were tested for their phylogenetic groupings, genetic relatedness using randomly amplified polymorphic DNA (RAPD), biochemical fingerprinting method (biochemical phenotypes [BPTs]), adherence to HT-29 cells and the presence of 56 E. coli VF genes. Strains belonging to phylogenetic groups B2 and D constituted 93% of all strains. Fifty-four (77%) strains belonged to two major BPT/RAPD clusters (A and B), with cluster A carrying significantly (P = 0.0099) more uroseptic strains. The degree of adhesion to HT-29 cells of uroseptic strains was significantly (P = 0.0012) greater than that of septicaemic strains. Of the 56 VF genes tested, pap genes was the only group that were found significantly (P < 0.0001) more often among uroseptic isolates. Phylogenetic group B2 contained a significantly higher number of strains carrying pap genes than those in group D. We conclude that uroseptic E. coli are clonally different from septicaemic strains, carry more pap genes and predominantly adhere more to the HT-29 cell model of the gut.

Host species-specific translocation of Escherichia coli.

The purpose of this paper is to investigate the rate of translocation of Escherichia coli strains in different experimental/animal models. Four proficient translocating E. coli strains isolated from mesenteric lymph nodes (MLNs) and/or the blood of rats (strains KIC-1 and KIC-2), from a fatal case of pancreatitis (HMLN-1) and from pigs (PC-1 isolated in this study) were tested for their ability to translocate across two host species and the Caco-2 cell line as a model of the human gut epithelium. HMLN-1 was found in the MLNs of all 15 pigs tested. This strain, however, did not translocate in any rats and only colonised the caecum of four rats in small numbers. HMLN-1 and PC-1 were the dominant translocating strains in Caco-2 cells compared to KIC-1 and KIC-2, which were found to translocate at a lower rate in pigs and in Caco-2 cells. The rate of translocation of PC-1 in rats was also very low compared to KIC-1 and KIC-2. We suggest that, in studies aiming to investigate the mechanism of translocation of E. coli strains isolated from humans, rats may not be an appropriate animal model and that the Caco-2 cells or pigs are more suitable in vitro and in vivo models, respectively.

[Study of medicine: "full" load as a parameter for the organization of a successful curriculum]. / Medizinstudium: "Gefühlte" Belastung als Parameter für die Organisation eines erfolgreichen Curriculums.

QUESTION: The licensing regulations for doctors (AAppO) allow medical faculties a wide range of possibilities in their implementation. Are there parameters which are easy to survey and which at the same time contribute to the speedy detection of possible undesirable developments? METHOD: The results of a retrospective student evaluation of the preclinical period clearly revealed that there are extreme fluctuations in the "perceived" stress of students in Semester one to four. In succession, classes were restructured so that stress was as equally balanced as possible throughout the four semesters. RESULTS: Over a period of half a decade, the "perceived" stress of students in the four semesters of the preclinical period was stabilised at an optimum level. At the same time, the students' satisfaction with organisation of curriculum increased and their exam results improved significantly. CONCLUSIONS: The parameter "perceived" stress has been conducive to developing the curriculum to such an extent that teaching in Lübeck has improved considerably. Simultaneously, new space for development has been created for both students and lecturers, which makes it possible to shape the academic aspect of medical studies in a more challenging manner.

Virulence characteristics of Escherichia coli strains causing acute cystitis in young adults in Iran.

BACKGROUND: Escherichia coli strains that cause cystitis posses virulence properties that facilitate their colonisation and persistence in the bladder. In Iran, despite the high number of the urinary tract infections, very few studies has been done to determine the role of these virulence properties in the pathogenesis of E. coli cyctitis. PATIENTS AND METHODS: Eighty-seven strains of E. coli, isolated from young adults with cystitis in Shiraz, Iran, were examined for the expression of type 1 and P-fimbriae, mannose resistant haemagglutination, haemolysin production, aerobactin-mediated iron uptake, O:K serotypes, biochemical phenotypes (BPTs) and their antibiotic susceptibility patterns. RESULTS: Seventy-six percent of the strains expressed multiple virulence properties. There was a significant correlation between the presence of aerobactin and the expression of type 1 fimbriae. All P-fimbriated strains produced aerobactin with 50% of them also coexpressing haemolysin. Of the 29 different O:K serotypes identified, 42% belonged to serotypes not commonly found among European serotypes associated with UTI. Strains of O groups 4 and 6 expressed more virulence factors than the others. A high resistance against ampicillin, trimethoprim and cotrimoxasol was observed among the isolates with 53% of the isolates showing multiresistance to these three antibiotics. Certain BPTs were also found among O:K serotypes with some containing strains of the same virulence profile. CONCLUSION: We conclude that certain colonal groups of E. coli are commonly associated with cystitis in young adults in Iran with strains possessing a combination of aerobactin and type 1 fimbriae being the dominant ones and belonging to serotypes not commonly found in Europe. We also conclude that the multiple antibiotic resistant E. coli strains causing cyctitis are highly prevalent in this part of the country.

Enhanced chemokine response in experimental acute Escherichia coli pyelonephritis in IL-1beta-deficient mice.

The aim of the present study was to investigate the effects of IL-1beta and Escherichia coli on the expression and secretion of MIP-2, the mouse equivalent to human IL-8, MCP-1 and RANTES in the kidneys of mice with acute pyelonephritis. Female Bki NMRI, as well as IL-1beta deficient mice and their wild-type littermates, were transurethrally infected with either E. coli CFT 073 or injected with NaCl 0.9% (w/v) and thereafter obstructed for 6 h. The Bki NMRI mice were killed at 0, 24, 48 h and 6 days and the IL-1beta-deficient mice at 48 h. Chemokine mRNA and protein levels peaked at 24 h for the tested chemokines with the mRNA expression localized in the tubular epithelial cells and for MIP-2 also in neutrophils. Obstruction per se, also induced a chemokine expression similar to E. coli infection although at a lower level. Interestingly, MIP-2 levels were higher in the IL-1beta deficient mice as compared with the wild-type littermates. Likewise, the inflammatory changes were more frequent and, when present, more widespread in the IL-1beta-deficient mice than in the wild-type mice. Stimulation of a human renal tubular epithelial cell line (HREC), A498 and of primary human mesangial cells (HMC) with the same bacterial antigen depicted gene expression of the same chemokines. A rapid release of IL-8 and MCP-1 was observed from both cell types. RANTES response was delayed both in the HREC and the HMC. We conclude that acute E. coli pyelonephritis induces a MIP-2/IL-8, MCP-1 and RANTES expression and secretion localized primarily to the epithelial cells and that this production is confirmed after in vitro stimulation with the same bacterial antigen of human epithelial and mesangial cells. Blockade of induction of chemokine response may thus be an attractive target for possible therapeutic intervention.

Inhibition of macrophage proinflammatory cytokine expression by steroids and recombinant IL-10.

Chronic lung disease (CLD) of prematurity is a prolonged respiratory failure in very-low-birth-weight neonates. Proinflammatory cytokines have been implicated in the development of CLD. Steroids have been shown to produce some improvement in neonates with this disease. The purpose of this study was to evaluate the downregulation of these proinflammatory cytokines by dexamethasone, budesonide and recombinant IL-10 (rIL-10) in order to elucidate the mechanism of the clinical benefit of steroids in babies. Our results showed that dexamethasone, budesonide and rIL-10 significantly inhibited both IL-6 and TNF-alpha production in the THP-1 cell line stimulated by lipopolysaccharide and Ureaplasma urealyticum antigen. Similar effects were found in macrophages from tracheobronchial aspirate fluid from newborn infants. In the rat alveolar macrophage cell line, steroids inhibited IL-6 and TNF-alpha production, while rat rIL-10 did not significantly decrease production. In conclusion, steroids and human rIL-10 were able to downregulate proinflammatory cytokine production, which may explain the beneficial effect of steroids and suggests that rIL-10 could be tried as an anti-inflammatory agent in neonates with a high risk of CLD.

Tetanus antibody levels of female volunteers after injection with solvent/detergent-treated human tetanus immunoglobulin (Tetabulin S/D).

BACKGROUND AND OBJECTIVES: The aim of this study was to analyse the increase of antitetanus titre in volunteers following injection with human tetanus immunoglobulin (HTI). MATERIALS AND METHODS: Twelve females with tetanus antibody titres of < or = 0.05 international units (IU)/ml were injected with 500 IU of human tetanus immunoglobulin (Tetabulin S/D). The tetanus antibody titres were determined before injection, and after 30 h, 48 h and 4 days. RESULTS: A fast and sustained increase of protective tetanus antibody levels was observed in 10 of 12 volunteers. No adverse events related to the study drug were reported. CONCLUSIONS: HTI confers rapid and effective immunity to tetanus.

Escherichia coli-induced expression of IL-1 alpha, IL-1 beta, IL-6 and IL-8 in normal human renal tubular epithelial cells.

The aim of the present study was to investigate whether the IL-1 family cytokines, in addition to IL-6 and IL-8, could be induced in normal human cortical epithelial cells in response to bacterial stimuli. Human renal tissue was obtained from 9 patients undergoing elective tumour nephrectomy. Renal cortical epithelial cells of tubular origin were prepared from the unaffected tissue. The proximal tubular cells were stimulated for 2, 6 and 24 h with a heat-inactivated pyelonephritogenic Escherichia coli strain DS-17. Cultured unstimulated tubular cells served as controls. IL-1 alpha, IL-1 beta, IL-1 receptor antagonist, IL-6, IL-8, IL-10, TNF-alpha, G-CSF and GM-CSF were analysed using immunohistochemistry at the single cell level. The nonstimulated cells were found to express low levels of IL-6 and IL-8 (mean value < 3% of total cells). In contrast, E. coli exposure resulted in significantly increased incidences of IL-6 and IL-8 expressing cells (mean values approximately 18% of total cells) peaking within two hours of stimulation (P < 0.008 and P < 0.02 versus non-stimulated cells, respectively). A gradual decrease was thereafter observed at 6 and 24 h, respectively, although persistently higher compared to controls. A different kinetic response was found for IL-1 alpha, IL-1 beta and IL-1 receptor antagonist-expressing cells, which peaked 24 h after E. coli stimulation (mean values 3--10%) (P < 0.008, P < 0.02, P < 0.02 versus non-stimulated cells, respectively). Low levels of TNF-alpha and GM-CSF were found in 3 of the 9 donated epithelial cells, peaking at 2 h, and IL-10 and G-CSF producing cells in 1 patient each. In conclusion we found that heat-inactivated pyelonephritic E. coli induced a proinflammatory cytokine response in the normal human proximal tubular cells including the IL-1 family, IL-6 and IL-8.

Meconium induces expression of inducible NO synthase and activation of NF-kappaB in rat alveolar macrophages.

Meconium aspiration causes intensive inflammatory reactions in the lungs, and may lead to neonatal respiratory disorder. Infiltrated inflammatory cells, particularly macrophages, play an important role in such an inflammation. A rat alveolar macrophage cell line (ATCC8383) was exposed to meconium alone or in combination with dexamethasone, budesonide, or interferon-gamma. Nitric oxide (NO) accumulation in the supernatant of the cell culture was detected by Griess reaction, and mRNA of inducible NO synthase (iNOS) expression was detected by reverse transcriptase-PCR. Nuclear factor-kappa B was analyzed by electrophoretic mobility shift assay, and iNOS location and nuclear factor-kappa B transactivation were determined by immunostaining. Our results showed that meconium was capable of inducing production of NO and expression of iNOS in alveolar macrophages in a dose- (1-25 mg/mL, p < 0.05) and time- (4-48 h, p < 0.05) dependent manner. This capability of meconium could be further enhanced in the presence of interferon-gamma (100 IU/mL, p < 0.05). Budesonide (10(-4)-10(-10) M) or dexamethasone (10(-4)-10(-6) M) effectively inhibited the meconium-induced NO production (p < 0.05). Using the protein synthesis inhibitor cycloheximide, we demonstrated that meconium directly induced iNOS in macrophages. Furthermore, meconium also triggered nuclear factor-kappa B activation, a mechanism possibly responsible for the iNOS expression. Our findings suggest that meconium is a potent inflammatory stimulus, resulting in iNOS expression, leading to overproduction of NO from the macrophages, which may be of pathogenic importance in meconium aspiration syndrome. In vitro steroids down-regulated the iNOS expression, thus suggesting a potential to down-regulate NO-mediated inflammation in neonates with meconium aspiration syndrome.

Antibodies against a truncated Staphylococcus aureus fibronectin-binding protein protect against dissemination of infection in the rat.

Staphylococcus aureus bacteraemia (SAB) originating from local infections can lead to severe secondary infections such as endocarditis. The protective effect of antibodies against secondary infections was studied in a rat model, where a local joint infection leads to bacteraemia and endocarditis on damaged aortic valves. In this study, immunizations with a truncated D2-domain of the S. aureus fibronectin-binding protein displayed on a cow-pea mosaic virus (CPMV-D) carrier induced protection against endocarditis (P < 0.05). Opsonization of S. aureus with antibodies raised against CPMV-D stimulated both neutrophil activity and macrophage phagocytosis in vitro. Furthermore, intravenous administration of these antibodies protected mice from weight loss due to SAB.

Increased expression of CD25 and HLA-DR on lymphocytes recruited into the peritoneal cavity in non-infected CAPD patients.

The impact of uremia per se, peritoneal dialysis (PD) and hemodialysis (HD) treatment was evaluated on characteristics of lymphocytes. CD4, CD8, CD25 and HLA-DR were analyzed, with flow cytometry, in lymphocytes prepared from peripheral blood of uremic (n = 10) and hemodialysis patients (n = 10). Peritoneal dialysate was also obtained from patients on CAPD (n = 12). A decreased relative and absolute lymphocyte count was observed in peripheral blood from uremic, HD and CAPD patients compared to healthy controls (p < 0.03, p < 0.03 and p < 0.02, respectively). On the other hand, the relative distribution of lymphocytes was significantly higher in peritoneal dialysate compared to peripheral blood of CAPD patients (p < 0.02). Likewise, the absolute CD4 positive lymphocyte count was lower in the peripheral blood from uremic. HD and CAPD patients as compared to healthy controls (p < 0.001, respectively). In CAPD patients the relative distribution of CD4 positive cells (p < 0.001) was lower, while quantitative CD25 level (p < 0.01) and the relative count of HLA-DR (p < 0.0001) was increased in the peritoneal dialysate compared to blood. Taken together a selective activation of lymphocytes in peritoneal dialysate as compared to peripheral blood from uremic, HD and CAPD patients was observed. The altered biological function of the inflammatory cells may therefore explain the increased susceptibility to infectious diseases.