Do serum C-reactive protein and interleukin-6 predict kidney scarring after urinary tract infection?

The Impact of Lactobacillus Plantarum PCS26 Supplementation on the Treatment and Recurrence of Urinary Tract Infections in Children-A Pilot Study

Urinary tract infections (UTI) are frequent bacterial infections in childhood. Considering the known beneficial effects of probiotics in the gastrointestinal field, they could also help to alleviate UTIs. In our clinical pilot study, we sought to verify the positive effects of the specific probiotic strain on the course and prevention of UTI in children. Thirty children with UTIs were enrolled and sequentially sampled into two groups (placebo/control and probiotic/test) in a double-blind, randomized, placebo-controlled clinical pilot study. We chose Lactobacillus plantarum PCS 26 (Lp26) derived from local Slovenian cheese in Pathogen Combat Project, which showed a good in vitro antimicrobial effect on Escherichia coli (E. coli). Several parameters were followed to look for differences between both groups in the acute phase of the UTI and after 6 months of taking probiotic or placebo supplementation. Our results showed no statistically significant differences between both groups; however, two children in the placebo group suffered a recurrence of febrile UTI within 6 months of the follow-up period, while there were no recurrences of UTI in the probiotic group. In the test group, the number of febrile days after the initiation of antibiotics with probiotics was shorter, although not reaching statistical significance (p = 0.084). According to our results, probiotics might be helpful in alleviating UTI symptoms and in UTI prevention. Further research with a larger sample size is warranted. Additionally, basic scientific studies for the selection of proper immunobiotic strains of probiotics should be performed.

Urinary interleukin-6 is a potentially useful diagnostic and prognostic marker of acute kidney injury in dogs

BACKGROUND

Interleukin-6 (IL6) is a pro-inflammatory cytokine implicated in the pathophysiology of urinary tract diseases. The objective of this study was to evaluate the diagnostic and prognostic utilities of urinary IL6 (uIL6) in dogs with acute kidney injury (AKI) and other urinary tract diseases.

METHODS

Eighty client-owned dogs were included and divided into four groups: AKI, chronic kidney disease (CKD), urinary tract infection and healthy controls. Urine samples were analysed for uIL6 and normalised to urinary creatinine (uIL6/uCr).

RESULTS

Dogs in the AKI group had higher uIL6/uCr compared with the control and CKD groups (p < 0.001 and 0.012, respectively). Receiver operator characteristic (ROC) curve analysis of uIL6/uCr as a diagnostic marker for AKI had an area under the curve (AUC) of 0.91 (95% confidence interval [CI], 0.81-1.0) with 82% sensitivity and 90% specificity (cutoff point 4.5 pg/mg) when including the AKI and control groups. ROC analysis including AKI compared with all other groups had an AUC of 0.77 (95% CI, 0.67-0.87) for the diagnosis of AKI with sensitivity and specificity of 71% and 78%, respectively (cutoff point 10.4 pg/mg). The 30-day mortality of the AKI group was 34%, and there was no difference in uIL6/uCr between survivors and non-survivors of AKI.

CONCLUSIONS

uIL6/uCr is a potentially sensitive and specific diagnostic marker for AKI in dogs.

Serum and Urine Interleukin-6 and Interleukin-8 Levels Do Not Differentiate Acute Pyelonephritis from Lower Urinary Tract Infections in Children

Background

Urinary tract infection (UTI) is common in pediatrics. Infection of the upper urinary tract may cause renal scarring, and subsequently renal failure and hypertension. Permanent renal damage has been suggested to be caused by the host inflammatory response. Therefore, it is crucial to understand the host defense mechanisms against such infection in order to make timely diagnosis. The aim of this study was to evaluate interleukin-6 (IL-6) and IL-8 as potential biomarkers in differentiating acute pyelonephritis (AP) from cystitis (Cys) in children.

Methods

Forty-three children (21 with AP and 22 with Cys) were included. Serum and urinary IL-6 and IL-8 were measured during the acute phase (within 12 hours of presentation) and the convalescent phase (8 weeks post-infection). Thirty-eight healthy children were included as controls.

Results

During the acute phase, the mean urinary IL-6 level in the Cys group was significantly higher than that in the controls (17.8 pg/mL vs 14.8 pg/mL, P=0.03), while the serum levels were significantly higher in both the Cys and AP groups than in the controls (19.5 pg/mL, 19.4 pg/mL, 15 pg/mL, P=0.005 and 0.02, respectively). During the convalescent phase, serum and urinary IL-6 levels were higher in patients than in controls. Urinary IL-8 levels were significantly higher in both the AP and Cys groups compared to controls (206.5 pg/mL, 291.8 pg/mL, 89.4 pg/mL, P=0.05 and 0.02, respectively) during the acute phase. Serum IL-8 was not significantly different between the 3 groups. Nonetheless, no significant differences were found between the AP and Cys groups, in urinary or serum levels of IL-6 or IL-8, during both phases.

Conclusion

IL-6 and IL-8 levels are elevated in patients with UTI. However, the levels did not differentiate between AP and cystitis. Further studies are warranted to evaluate their roles as indicators of the site of UTIs.

Trans IL-6 signaling does not appear to play a role in renal scarring after urinary tract infection

INTRODUCTION

While inflammation is an important innate defense mechanism against infection, it can also lead to local tissue damage. The trans signaling pathway of interleukin (IL)-6 is a known mediator of inflammation. We hypothesized that the trans IL-6 signaling pathway is associated with the development of post febrile urinary tract infection (UTI) renal scarring.

OBJECTIVE

To compare soluble regulators of trans IL-6 signaling between patients with a history of febrile UTI who do or do not have renal scarring.

STUDY DESIGN

After IRB-approval, we collected urine samples in pediatric patients with a history of febrile (≥38 °C) UTI (urine culture >50 K uropathogen) with documented presence or absence of renal scarring on imaging. Samples were collected at a time when patients were not actively infected. Enzyme-linked immunosorbent assays were performed on samples for markers of trans IL-6 signaling: IL-6, soluble (s) IL-6 receptor (R), and soluble (s)gp130, a buffer in trans IL-6 signaling. Values were normalized to urine creatinine. Results were analyzed by t-test or Mann-Whitney U. Spearman rank correlation was used. A p-value of <0.05 was considered significant.

RESULTS

A total of 50 urines from patients with a history of febrile UTI were collected: 23 with and 27 without scarring. There was no difference between groups regarding age or gender. There was no significant difference in urine IL-6, sIL-6R, or sgp130 between those with and without scarring (Figure). While IL-6 values significantly correlated with sIL-6R and sgp130 in those without renal scarring, IL-6 did not correlate with sgp130 in those with scarring. Ratios of IL-6 to sgp130 and sIL-6R to sgp130 were not different between groups.

DISCUSSION

The inflammatory response generated in response to infection is believed to be largely responsible for the development of renal scarring after UTI. IL-6 is a cytokine known to be induced during UTI with a pro-inflammatory pathway, known as trans signaling. This study investigated for differences in markers of trans IL-6 signaling between patients with a history of febrile UTI with and without renal scarring. There was no significant difference between the absolute values or ratio of these markers between groups.

CONCLUSIONS

Markers of trans IL-6 signaling are not different between individuals with a history of febrile UTI with and without renal scarring in the non-acute setting.

Urine interleukin-6, interleukin-8 and transforming growth factor β1 in infants with urinary tract infection and asymptomatic bacteriuria

INTRODUCTION

Urinary tract infection (UTI) occurs in 1.1% of girls and 1.4% of boys during the first year of life. Asymptomatic bacteriuria (ABU) is usually detected incidentally in 0.9% of girls and 2.5% of boys at this age. The aim of the study was to assess the usefulness of measurement of pro-inflammatory urine interleukin (IL)-6 and IL-8 concentrations and anti-inflammatory transforming growth factor β1 (TGF-β1) level in infants with febrile UTI, non-febrile UTI and ABU.

MATERIAL AND METHODS

A total of 35 children, mean age 6.14 ±3.47 months, were divided into three groups: group I - febrile UTI (n = 13), group II - non-febrile UTI (n = 13) and group III - ABU (n = 9). At the time of enrollment urine IL-6, IL-8, TGF-β1 and serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WBC) were measured. Renal ultrasound was performed in all children, 99mTc-dimercaptosuccinic acid scintigraphy (DMSA) and voiding cystourethrography in children with UTI.

RESULTS

Urine concentrations of IL-6 and IL-8 were significantly higher in febrile UTI compared to those with non-febrile UTI and ABU (p < 0.5, p < 0.01) and positively correlated with CRP, ESR and WBC (p < 0.01). Urine levels of TGF-β1 were significantly higher in children with febrile UTI compared to those with ABU (p < 0.05) and positively correlated with WBC (p < 0.01). Inflammatory changes in the DMSA scan were detected in 66.6% of children with UTI. No significant difference in frequency of an abnormal DMSA scan compared to a normal scan was found in groups with febrile and non-febrile UTI. No relations between urine cytokines, systemic inflammatory markers and changes in DMSA scan were observed. The cutoff value for detection of inflammatory changes in the DMSA scan for IL-8 was 120 pg/mg creatinine (Cr) and 40 pg/mg Cr for TGF-β1. Based on this value, the sensitivity for IL-8 was 58.3%, specificity 100% and for TGF-β1 66.7% and 83.7%, respectively.

CONCLUSIONS

We found significant differences in children with febrile UTI and ABU regarding urine IL-6, IL-8 and TGF-β1 levels. Urine cytokines and systemic inflammatory markers do not differentiate between upper and lower UTI in infants.

Role of interleukin-6 in differentiating interleukin-11 induced fever and early bacterial infection

OBJECTIVE

To evaluate the role of Th1/Th2 cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ) in differentiating interleukin 11 induced fever with C-reactive protein elevation from early bacterial infection.

METHODS

A total of 74 patients were enrolled in this retrospective study. Serum Th1/Th2 cytokines were determined using cytometric bead array (CBA) techniques. Whenever the patients had febrile disease or elevated CRP, systemic inflammatory signs, procalcitonin (PCT), blood culture and X-ray examination were done. The patients were assigned into infected and non-infected groups based on the clinical and laboratory findings.

RESULTS

The CRP levels in both the groups were significantly increased, but no statistically significant difference was found (P = 0.574). IL-6 levels of the infected group were significantly elevated with simultaneously elevated IL-10 levels in a proportion of the patients. IL-6 levels of non-infected patients were normal. IL-6 and IL-10 levels of infected patients were significantly higher than those of non-infected patients (P = 0.005, 0.015, respectively).

CONCLUSIONS

For the patients treated with recombinant human interleukin 11 (rhIL-11), IL-6 and IL-10 measurements can be a useful adjuvant tool for the differentiation of rhIL-11 induced fever with C-reactive protein elevation from early bacterial infection.