Persistent Bacteriuria and Antibodies Recognizing Curli/eDNA Complexes From Escherichia coli Are Linked to Flares in Systemic Lupus Erythematosus.

OBJECTIVE: Infections contribute to morbidity and mortality in systemic lupus erythematosus (SLE). Uropathogenic Escherichia coli (UPEC) are known to trigger urinary tract infections (UTIs) and form biofilms, which are multicellular communities of bacteria that are strengthened by amyloids such as curli. We previously reported that curli naturally form complexes with bacterial extracellular DNA (eDNA), and these curli/eDNA complexes induce hallmark features of lupus in mouse models. The present study was undertaken to investigate whether anti-curli/eDNA complex antibodies play a role in the pathogenesis of SLE or development of flares in SLE. METHODS: In total, 96 SLE patients who met at least 4 Systemic Lupus International Collaborating Clinics disease criteria were investigated. Anti-curli/eDNA complex antibodies in the plasma were tested for both IgG and IgA subclasses. Results were compared to that in 54 age-, sex-, and race/ethnicity-matched healthy controls. Correlations of the levels of anti-curli/eDNA antibodies with clinical parameters, lupus disease status, and frequency of bacteriuria were assessed. RESULTS: Anti-curli/eDNA antibodies were detected in the plasma of SLE patients and healthy controls, and their levels correlated with the presence of asymptomatic persistent bacteriuria and occurrence of disease flares in lupus patients. Persistent bacteriuria contained curli-producing UPEC, and this was associated with an inflammatory phenotype. Finally, curli/eDNA complexes cross-reacted with lupus autoantigens, such as double-stranded DNA, in binding autoantibodies. CONCLUSION: These results suggest that UTIs and persistent bacteriuria are environmental triggers of lupus and its flares. Antibodies against curli/eDNA could serve as a sign of systemic exposure to bacterial products in SLE.

UTI patients have pre-existing antigen-specific antibody titers against UTI vaccine antigens.

Urinary tract infection (UTI) is most frequently caused by uropathogenic Escherichia coli (UPEC). Our laboratory has been developing an experimental vaccine targeting four UPEC outer membrane receptors involved in iron acquisition - IreA, FyuA, IutA, and Hma - to elicit protection against UTI. These vaccine targets are all expressed in humans during UTI. In the murine model, high titers of antigen-specific serum IgG or bladder IgA correlate with protection against transurethral challenge with UPEC. Our aim was to measure levels of pre-existing serum antibodies to UTI vaccine antigens in our target population. To accomplish this, we obtained sera from 64 consenting female patients attending a clinic for symptoms of cystitis. As a control, we also collected sera from 20 healthy adult male donors with no history of UTI. Total IgG and antigen-specific IgG titers were measured by ELISA. Of the 64 female patients, 29 had significant bacteriuria (>104 cfu/ml urine) and uropathogenic E. coli (UPEC). Thirty-five patients had non-significant bacteriuria (<104 cfu/ml). Antigen-specific IgG titers did not correlate with the presence or absence of the gene encoding the antigen in the infecting strain (when present), but rather titers were proportional to prevalence of genes encoding antigens among representative collections of UPEC isolates. Surprisingly, we obtained similar results when sera from healthy male patients without history of UTI were tested. Thus, unvaccinated adults have non-protective levels of pre-existing antibodies to UTI vaccine antigens, establishing an important baseline for our target population. This suggests that a UTI vaccine would need to boost pre-existing humoral responses beyond these background levels to protect from infection.

The Urinary Microbiome and Anticancer Immunotherapy: The Potentially Hidden Role of Unculturable Microbes.

Several urinary disorders, including overactive bladder, urinary incontinence, and interstitial cystitis, are often characterized by negative urine cultures. The application of metagenomics (i.e., 16S rRNA microbial profiling or whole-genome shotgun sequencing) to urine samples has enabled the identification of previously undetected bacteria, contributing to the discovery and characterization of the urinary microbiome. The most frequent species isolated are Lactobacillus (15%), Corynebacterium (14.2%), Streptococcus (11.9%), Actinomyces (6.9%), and Staphylococcus (6.9%). Although several studies are emerging in this context, the role of urinary microbiota in the pathogenesis of infections and in tumor carcinogenesis remains unclear. Furthermore, data on the activity of gut microbiota in modulating sensitivity to immune checkpoint inhibitors in advanced cancer patients suggest that the influence of urinary microbiota on tumor response to anticancer therapy should also be investigated. Moreover, its possible relationship with tumor mutational burden, which is in turn correlated with response to immunotherapy, should be the focus of future studies. Of note, the effect of antibiotics on this complex scenario seems to deserve careful consideration.

Increased Age, but Not Parity Predisposes to Higher Bacteriuria Burdens Due to Streptococcus Urinary Tract Infection and Influences Bladder Cytokine Responses, Which Develop Independent of Tissue Bacterial Loads.

Streptococcus agalactiae causes urinary tract infection (UTI) in pregnant adults, non-pregnant adults, immune-compromised individuals and the elderly. The pathogenesis of S. agalactiae UTI in distinct patient populations is poorly understood. In this study, we used murine models of UTI incorporating young mice, aged and dam mice to show that uropathogenic S. agalactiae causes bacteriuria at significantly higher levels in aged mice compared to young mice and this occurs coincident with equivalent levels of bladder tissue colonisation at 24 h post-infection (p.i.). In addition, aged mice exhibited significantly higher bacteriuria burdens at 48 h compared to young mice, confirming a divergent pattern of bacterial colonization in the urinary tract of aged and young mice. Multiparous mice, in contrast, exhibited significantly lower urinary titres of S. agalactiae compared to age-matched nulliparous mice suggesting that parity enhances the ability of the host to control S. agalactiae bacteriuria. Additionally, we show that both age and parity alter the expression levels of several key regulatory and pro-inflammatory cytokines, which are known to be important the immune response to UTI, including Interleukin (IL)-1ß, IL-12(p40), and Monocyte Chemoattractant Protein-1 (MCP-1). Finally, we demonstrate that other cytokines, including IL-17 are induced significantly in the S. agalactiae-infected bladder regardless of age and parity status. Collectively, these findings show that the host environment plays an important role in influencing the severity of S. agalactiae UTI; infection dynamics, particularly in the context of bacteriuria, depend on age and parity, which also affect the nature of innate immune responses to infection.

Urinary shedding of leptospires and presence of Leptospira antibodies in healthy dogs from Upper Bavaria.

Leptospirosis is classified as a re-emerging zoonotic disease with global impor- tance. The aim of this study was to determine urinary shedding of leptospires in healthy dogs and to identify the shedded leptospire species. Furthermore, antibody presence against leptospires was evaluated. In a prospective study urine samples of 200 healthy dogs from Upper Bavaria were randomly collected and evaluated by real-time polymerase chain reaction (PCR) specific for the lipL32 gene of pathogenic Leptospira (L) spp. Positive samples were further character- ized via multilocus sequence typing (MLST) to identify the Leptospira species. Microagglutination test (MAT) was performed to determine serum antibody titers. Three of 200 urine samples were found to be PCR-positive resulting in a urinary shedding prevalence of 1.5% (95% confidence interval 0.3-4.5%). All three dogs had been vaccinated before with a bivalent vaccine, covering the serogroups Canicola and lcterohaemorrhagiae. One dog shed leptospires of the species L. borgpetersenii, and two of the species L. interrogans. Of all dogs, 17.0% had antibody titers ≥ 1:100, and 3.5% titers ≥ 1:400 to serovars of non-vaccinal sero- groups. Healthy dogs that shed leptospires represent a possible risk for humans and other animals. The study emphasizes the importance of general hygiene measures in veterinary practice while handling urine of all dogs, and the use of vaccines that protect against a broader range of serogroups and that prevent urinary shedding.

Mouse model for sublethal Leptospira interrogans infection.

Although Leptospira can infect a wide range of mammalian species, most studies have been conducted in golden Syrian hamsters, a species particularly sensitive to acute disease. Chronic disease has been well characterized in the rat, one of the natural reservoir hosts. Studies in another asymptomatic reservoir host, the mouse, have occasionally been done and have limited infection to mice younger than 6 weeks of age. We analyzed the outcome of sublethal infection of C3H/HeJ mice older than age 10 weeks with Leptospira interrogans serovar Copenhageni. Infection led to bloodstream dissemination of Leptospira, which was followed by urinary shedding, body weight loss, hypothermia, and colonization of the kidney by live spirochetes 2 weeks after infection. In addition, Leptospira dissemination triggered inflammation in the kidney but not in the liver or lung, as determined by increased levels of mRNA transcripts for the keratinocyte-derived chemokine, RANTES, macrophage inflammatory protein 2, tumor necrosis factor alpha, interleukin-1ß, inducible nitric oxide synthase, interleukin-6, and gamma interferon in kidney tissue. The acquired humoral response to Leptospira infection led to the production of IgG mainly of the IgG1 subtype. Flow cytometric analysis of splenocytes from infected mice revealed that cellular expansion was primarily due to an increase in the levels of CD4(+) and double-negative T cells (not CD8(+) cells) and that CD4(+) T cells acquired a CD44(high) CD62L(low) effector phenotype not accompanied by increases in memory T cells. A mouse model for sublethal Leptospira infection allows understanding of the bacterial and host factors that lead to immune evasion, which can result in acute or chronic disease or resistance to infection (protection).

Similar Neutrophil-Driven Inflammatory and Antibacterial Responses in Elderly Patients with Symptomatic and Asymptomatic Bacteriuria.

Differential diagnosis of asymptomatic bacteriuria (ASB) and urinary tract infection (UTI) is based on the presence of diverse symptoms, including fever (≥38.5°C), rigors, malaise, lethargy, flank pain, hematuria, suprapubic discomfort, dysuria, and urgent or frequent urination. There is consensus in the medical community that ASB warrants antibiotic treatment only for patients undergoing urological procedures that lead to mucosal bleeding, catheterized individuals whose ASB persists for more than 48 h after catheter removal, and pregnant women. Pyuria is associated with UTI and implicates host immune responses via release of antibacterial effectors and phagocytosis of pathogens by neutrophils. Such responses are not sufficiently described for ASB. Metaproteomic methods were used here to identify the pathogens and evaluate molecular evidence of distinct immune responses in cases of ASB compared to UTI in elderly patients who were hospitalized upon injury. Neutrophil-driven inflammatory responses to invading bacteria were not discernible in most patients diagnosed with ASB compared to those with UTI. In contrast, proteomic urine analysis for trauma patients with no evidence of bacteriuria, including those who suffered mucosal injuries via urethral catheterization, rarely showed evidence of neutrophil infiltration. The same enzymes contributing to the synthesis of leukotrienes LTB4 and LTC4, mediators of inflammation and pain, were found in the UTI and ASB cohorts. These data support the notion that the pathways mediating inflammation and pain in most elderly patients with ASB are not quantitatively different from those seen in most elderly patients with UTI and warrant larger clinical studies to assess whether a common antibiotic treatment strategy for elderly ASB and UTI patients is justified.

Innate immunity and genetic determinants of urinary tract infection susceptibility.

PURPOSE OF REVIEW: Urinary tract infections (UTIs) are common, dangerous and interesting. Susceptible individuals experience multiple, often clustered episodes, and in a subset of patients, infections progress to acute pyelonephritis (APN), sometimes accompanied by uro-sepsis. Others develop asymptomatic bacteriuria (ABU). Here, we review the molecular basis for these differences, with the intention to distinguish exaggerated host responses that drive disease from attenuated responses that favour protection and to highlight the genetic basis for these extremes, based on knock-out mice and clinical studies. RECENT FINDINGS: The susceptibility to UTI is controlled by specific innate immune signalling and by promoter polymorphisms and transcription factors that modulate the expression of genes controlling these pathways. Gene deletions that disturb innate immune activation either favour asymptomatic bacteriuria or create acute morbidity and disease. Promoter polymorphisms and transcription factor variants affecting those genes are associated with susceptibility in UTI-prone patients. SUMMARY: It is time to start using genetics in UTI-prone patients, to improve diagnosis and to assess the risk for chronic sequels such as renal malfunction, hypertension, spontaneous abortions, dialysis and transplantation. Furthermore, the majority of UTI patients do not need follow-up, but for lack of molecular markers, they are unnecessarily investigated.

Cutoff values for bacteria and leukocytes for urine sediment analyzer FUS200 in culture-positive urinary-tract infections.

OBJECTIVES: The microscopic analysis of urine is essential for the diagnosis of patients with urinary tract infections. Quantitative urine culture is the 'gold standard' method for definitive diagnosis of urinary-tract infections, but it is labor-intensive, time consuming, and does not provide the same-day results. The aim of this study was to evaluate the analytical and diagnostic performance of the FUS200 (Changchun Dirui Industry, China), a new urine sedimentation analyzer in comparison to urine culture as the reference method. METHODS: We evaluated 1000 urine samples, submitted for culture and urine analysis with a preliminary diagnosis of urinary-tract infection. Cut-off values for the FUS200 were determined by comparing the results with urine cultures. The cut-off values by the receiver operating characteristic (ROC) curve technique, sensitivity, and specificity were calculated for bacteria and white blood cells (WBCs). RESULTS: Among the 1000 urine specimens submitted for culture, 637 cultures (63.7%) were negative, and 363 were (36.3%) positive. The best cut-off values obtained from ROC analysis were 16/µL for bacteriuria (sensitivity: 82.3%, specificity: 58%), and 34/µL for WBCs (sensitivity: 72.3%, specificity: 65.2%). The area under the curve (AUC) for the bacteria and WBCs count were 0.71 (95% CI: 0.67-0.74) and, 0.72 (95% CI: 0.69-0.76) respectively. CONCLUSIONS: The most important requirement of a rapid diagnostic screening test is sensitivity, and, in this perspective, an unsatisfactory sensitivity by using bacteria recognition and quantification performed by the FUS200 analyzer has been observed. After further technical improvements in particle recognition and laboratory personnel training, the FUS200 might show better results.

Bacterial control of host gene expression through RNA polymerase II.

The normal flora furnishes the host with ecological barriers that prevent pathogen attack while maintaining tissue homeostasis. Urinary tract infections (UTIs) constitute a highly relevant model of microbial adaptation in which some patients infected with Escherichia coli develop acute pyelonephritis, while other patients with bacteriuria exhibit an asymptomatic carrier state similar to bacterial commensalism. It remains unclear if the lack of destructive inflammation merely reflects low virulence or if carrier strains actively inhibit disease-associated responses in the host. Here, we identify a new mechanism of bacterial adaptation through broad suppression of RNA polymerase II­dependent (Pol II­dependent) host gene expression. Over 60% of all genes were suppressed 24 hours after human inoculation with the prototype asymptomatic bacteriuria (ABU) strain E. coli 83972, and inhibition was verified by infection of human cells. Specific repressors and activators of Pol II­dependent transcription were modified, Pol II phosphorylation was inhibited, and pathogen-specific signaling was suppressed in cell lines and inoculated patients. An increased frequency of strains inhibiting Pol II was epidemiologically verified in ABU and fecal strains compared with acute pyelonephritis, and a Pol II antagonist suppressed the disease-associated host response. These results suggest that by manipulating host gene expression, ABU strains promote tissue integrity while inhibiting pathology. Such bacterial modulation of host gene expression may be essential to sustain asymptomatic bacterial carriage by ensuring that potentially destructive immune activation will not occur.

Intravesical bacille Calmette-Guérin eradicates bacteriuria in antibiotic-naïve bladder cancer patients.

BACKGROUND: Intravesical bacille Calmette-Guérin (BCG) therapy is safe and effective in bladder cancer patients who have asymptomatic bacteriuria. BCG induces robust immune responses in the bladder that are responsible for its antitumor effect. We hypothesize that BCG-induced inflammation may eradicate bacterial infection. OBJECTIVE: To investigate whether intravesical BCG therapy alone can eradicate bacterial infection in antibiotic-naïve bladder tumor patients who have asymptomatic bacteriuria. DESIGN, SETTING, AND PARTICIPANTS: A single-institution prospective cohort study of bacteriuric adults with non-muscle-invasive bladder tumors who underwent outpatient BCG therapy or surveillance cystoscopy. INTERVENTION: Ninety high-risk patients received induction intravesical BCG without maintenance BCG, and 95 low-risk patients who had not received BCG underwent outpatient surveillance cystoscopy. Each patient had significant bacteriuria on urine culture, and none received routine antibiotics before, during, or after procedures. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Urine cultures were repeated after 3, 6, and 12 mo. All patients had follow-up cystoscopy every 3 mo and were followed for a minimum of 1 yr. The end point was number of BCG-treated and cystoscopy patients who became bacteria free at 3, 6, and 12 mo. RESULTS AND LIMITATIONS: Two BCG-treated patients (2.2%) and six patients after cystoscopy (6%) developed febrile urinary tract infection (p=0.21). All resolved with antibiotics. No patient was admitted for sepsis. Of 88 infected patients who received BCG without routine antibiotics, 58 (66%) were continuously bacteria free at 1 yr compared with 16 of 89 cystoscopy patients (18%; p=0.001). The prospective observational study design prohibits causal inference of antibacterial effects attributed to BCG over cystoscopy. CONCLUSIONS: Intravesical BCG therapy is associated with clearance of uropathogens in bladder cancer patients, possibly due to augmented innate host immunity.

Atg16L1 deficiency confers protection from uropathogenic Escherichia coli infection in vivo.

Urinary tract infection (UTI), a frequent and important disease in humans, is primarily caused by uropathogenic Escherichia coli (UPEC). UPEC forms acute cytoplasmic biofilms within superficial urothelial cells and can persist by establishing membrane-enclosed latent reservoirs to seed recurrent UTI. The host responds with an influx of innate immune cells and shedding of infected epithelial cells. The autophagy gene ATG16L1 has a commonly occurring mutation that is associated with inflammatory disease and intestinal cell abnormalities in mice and humans. Here, we show that Atg16L1-deficient mice (Atg16L1(HM)) cleared bacteriuria more rapidly and thoroughly than controls and showed rapid epithelial recovery. Atg16L1 deficiency was associated with a potent proinflammatory cytokine response with increased recruitment of monocytes and neutrophils to infected bladders. Chimeric and genetic studies showed that Atg16L1(HM) hematopoietic cells alone could increase clearance and that Atg16L1-deficient innate immune cells were required and sufficient for enhanced bacteriuric clearance. We also show that Atg16L1-deficient mice exhibit cell-autonomous architectural aberrations of superficial urothelial cells, including increases in multivesicular bodies, lysosomes, and expression of the UPEC receptor Up1a. Finally, we show that Atg16L1(HM) epithelial cells contained a significantly reduced number of latent reservoirs. Together, our results show that Atg16L1 deficiency confers protection in vivo to the host against both acute and latent UPEC infection, suggest that deficiency in a key autophagy protein can be protective against infection in an animal model of one of the most common diseases of women worldwide, and may have significant clinical implications for understanding the etiology of recurrent UTIs.

Immunoassays distinguishing between HNL/NGAL released in urine from kidney epithelial cells and neutrophils.

BACKGROUND: The distinction between monomeric human neutrophil lipocalin/neutrophil gelatinase-associated lipocalin (HNL/NGAL), secreted by injured kidney tubular cells, and dimeric HNL/NGAL, released by activated neutrophils, is important to accurately diagnose acute kidney injury (AKI). METHODS: 132 urine samples from 44 intensive care unit (ICU) patients and five urine samples from non-ICU patients with urinary tract infections (UTIs) were analyzed by two monoclonal enzyme-linked immunosorbent assays (ELISA-1 and ELISA-2). The presence of monomeric and/or dimeric HNL/NGAL in each sample was visualized by Western blotting. RESULTS: The ELISA-1 detected both monomeric and dimeric HNL/NGAL whereas the ELISA-2 almost exclusively detected dimeric HNL/NGAL with an area under the receiver-operating characteristics curve (AuROC) of 0.90. The ELISA-1/ELISA-2 ratio detected the monomeric form with an AuROC of 0.92. In 32 AKI patients, dimer-specific ELISA-2 levels decreased pre-AKI whereas the monomer-specific ELISA-1/ELISA-2 ratio gradually increased beyond AKI diagnosis. High ELISA-2 levels and/or low ELISA-1/ELISA-2 ratios detected a predominance of dimeric HNL/NGAL in urine from the patients with UTIs. CONCLUSIONS: In combination, our two ELISAs distinguish monomeric HNL/NGAL, produced by the kidney epithelium, from dimeric HNL/NGAL, released by neutrophils during AKI development, as well as reduce the confounding effect of neutrophil involvement when bacteriuria is present.

Host-pathogen checkpoints and population bottlenecks in persistent and intracellular uropathogenic Escherichia coli bladder infection.

Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multidrug-resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic Escherichia coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity, and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the quiescent intracellular reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection, QIR, ASB, or chronic cystitis, is determined within the first 24 h of infection and constitutes a putative host-pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies.

Susceptibility to acute pyelonephritis or asymptomatic bacteriuria: host-pathogen interaction in urinary tract infections.

Our knowledge of the molecular mechanisms of urinary tract infection (UTI) pathogenesis has advanced greatly in recent years. In this review, we provide a general background of UTI pathogenesis, followed by an update on the mechanisms of UTI susceptibility, with a particular focus on genetic variation affecting innate immunity. The innate immune response of the host is critically important in the antibacterial defence mechanisms of the urinary tract, and bacterial clearance normally proceeds without sequelae. However, slight dysfunctions in these mechanisms may result in acute disease and tissue destruction. The symptoms of acute pyelonephritis are caused by the innate immune response, and inflammation in the urinary tract decreases renal tubular function and may give rise to renal scarring, especially in paediatric patients. In contrast, in children with asymptomatic bacteriuria (ABU), bacteria persist without causing symptoms or pathology. Pathogenic agents trigger a response determined by their virulence factors, mediating adherence to the urinary tract mucosa, signalling through Toll-like receptors (TLRs) and activating the defence mechanisms. In ABU strains, such virulence factors are mostly not expressed. However, the influence of the host on UTI severity cannot be overestimated, and rapid progress is being made in clarifying host susceptibility mechanisms. For example, genetic alterations that reduce TLR4 function are associated with ABU, while polymorphisms reducing IRF3 or CXCR1 expression are associated with acute pyelonephritis and an increased risk for renal scarring. It should be plausible to "individualize" diagnosis and therapy by combining information on bacterial virulence and the host response.

Genetic control of the variable innate immune response to asymptomatic bacteriuria.

The severity of urinary tract infection (UTI) reflects the quality and magnitude of the host response. While strong local and systemic innate immune activation occurs in patients with acute pyelonephritis, the response to asymptomatic bacteriuria (ABU) is low. The immune response repertoire in ABU has not been characterized, due to the inherent problem to distinguish bacterial differences from host-determined variation. In this study, we investigated the host response to ABU and genetic variants affecting innate immune signaling and UTI susceptibility. Patients were subjected to therapeutic urinary tract inoculation with E. coli 83972 to ensure that they were exposed to the same E. coli strain. The innate immune response repertoire was characterized in urine samples, collected from each patient before and after inoculation with bacteria or PBS, if during the placebo arm of the study. Long-term E. coli 83972 ABU was established in 23 participants, who were followed for up to twelve months and the innate immune response was quantified in 233 urine samples. Neutrophil numbers increased in all but two patients and in an extended urine cytokine/chemokine analysis (31 proteins), the chemoattractants IL-8 and GRO-α, RANTES, Eotaxin-1 and MCP-1, the T cell chemoattractant and antibacterial peptide IP-10, inflammatory regulators IL-1-α and sIL-1RA and the T lymphocyte/dendritic cell product sIL-2Rα were detected and variably increased, compared to sterile samples. IL-6, which is associated with symptomatic UTI, remained low and numerous specific immune mediators were not detected. The patients were also genotyped for UTI-associated IRF3 and TLR4 promoter polymorphisms. Patients with ABU associated TLR4 polymorphisms had low neutrophil numbers, IL-6, IP-10, MCP-1 and sIL-2Rα concentrations. Patients with the ABU-associated IRF3 genotype had lower neutrophils, IL-6 and MCP-1 responses than the remaining group. The results suggest that the host-specific, low immune response to ABU mainly includes innate immune mediators and that host genetics directly influence the magnitude of this response.

B cell infiltration and lymphonodular hyperplasia in bladder submucosa of patients with persistent bacteriuria and recurrent urinary tract infections.

PURPOSE: We defined chronic inflammatory cell types in bladder submucosa and the presence of umbrella cells on the surface of bladder epithelium in patients 5 to 21 years old with persistent bacteriuria due to neurogenic bladder and recurrent urinary tract infections associated with vesicoureteral reflux. MATERIALS AND METHODS: Bladder mucosa biopsies from 12 patients and 6 controls were fixed in Carnoy's solution and examined for T cells (CD3, CD4, CD8), B cells (CD79) and plasma cells (CD138). The number of cells in a defined area of submucosa was determined by counting all nuclei in the area. A contiguous section was also stained for uroplakin expression with a monoclonal antibody against uroplakin III to ascertain the integrity of bladder umbrella cells. RESULTS: B cells, plasma cells and lymphoid nodules were found only in patient biopsies. T cell expression was evident in patient and control biopsies. Uroplakin staining of surface epithelium was uniform from control biopsies but spotty or entirely absent from patient biopsies. CONCLUSIONS: Patients with persistent bacteriuria or recurrent urinary tract infections had significant B cell infiltration in the submucosa, including lymphoid nodules. These inflammatory changes are likely due to antigenic stimulation from repeated exposure to bacteria. These changes are associated with frequent absence of uroplakin on surface epithelium.

Antigenic specificity and expression of a natural idiotope on human pentameric and hexameric IgM polymers.

Natural antibodies (NAbs) are present in circulation even before the exposure to antigen and they exert various biological functions. They are polyreactive and mainly represented by immunoglobulin M (IgM), which is the first antibody produced in an ongoing immune response to infection and/or immunization. IgM is always secreted as a polymer with predominant pentameric structure, although other polymeric forms such as hexamer can be also formed. The biological functions of hexameric IgM are still not known and it is proposed that its existence as a NAb could be deleterious. However, the nature of IgM hexamers has not been investigated yet. In this paper, we have tested the expression of natural idiotope and antigenic specificities of pentameric and hexameric IgM polymers originating from sera of patients with Waldenström's macroglobulinemia, as well as patients suffering from recurrent urinary bacterial infections. We demonstrate that although pentameric IgM polymers can exist as natural and immune antibodies, IgM hexamers are exclusively immune and do not exist as NAbs.

Tolerance of bacteriuria after urinary diversion is linked to antimicrobial peptide activity.

OBJECTIVES: To compare the cationic antimicrobial peptide gene expression profiles and urinary cationic antimicrobial activities of patients after urinary diversion according to their urinary tract infection (UTI) status. Ileal conduit urinary diversion joins the bacterial-tolerant ileal epithelium and intolerant urothelium. After this procedure, one quarter of patients develop repeated symptomatic UTIs. Such development might reflect the altered innate immune mechanisms centered on epithelial expression and urinary activity of cationic antimicrobial peptides, such as defensins. METHODS: Ileal and ureteral biopsy specimens from ileal conduit subjects with (n = 18) and without (n = 18) recurrent symptomatic UTIs were assessed for cationic antimicrobial peptide gene expression using quantitative reverse transcriptase polymerase chain reaction. Overnight urine collections were analyzed for antimicrobial activity against a laboratory Escherichia coli strain, and infecting organisms were isolated from individual subjects. RESULTS: Overall, the ureteral epithelium showed increased expression of human α-defensin 5 and decreased expression of the human ß-defensin 1 after urinary diversion (P < .05). No significant changes were seen for the ileal epithelium. The expression levels of both defensins also did not differ significantly according to UTI status. Urinary cationic activity against infecting bacterial isolates from the individual subjects was significantly greater in those with symptomatic UTI (P < .001), and the activities against the laboratory E. coli strain were similar. CONCLUSIONS: The changes in the human ß-defensin 1 and human α-defensin 5 expression profiles and the link between symptomatic infection and high urinary antimicrobial activity suggest that innate mechanisms play significant roles in balancing bacterial tolerance and killing after ileal conduit urinary diversion. Future work needs to determine whether these changes can be therapeutically modulated to benefit the patients.