Association between fever and the antibody response to Tamm-Horsfall protein in urinary tract infection

Study of antibody production to Tamm-Horsfall protein in renal transplant donors and recipients

The content of Tamm-Horsfall protein was measured in the urine of humans without renal diseases, pregnant women, and donors and recipients of renal transplant using a new test system for measuring Tamm-Horsfall protein including antigenic diagnostic agent and immune serum. Production of antibodies to Tamm-Horsfall protein was characterized using antigen diagnostic system.

Tamm-Horsfall protein: a multilayered defence molecule against urinary tract infection

Urinary tract infection (UTI) is the most common nonepidemic bacterial infection in humans, representing a constant danger for the host. Both innate and adaptive components of the immune system as well as stromal cells including bladder epithelium are involved in the prevention and clearance of UTI. However, the particular properties of the urogenital tract, which does not comprise typical physical barriers like a mucus or ciliated epithelium, necessitate soluble mediators with potent immunomodulatory capabilities. One candidate molecule capable of both mediating direct antimicrobial activity and alerting immune cells is the evolutionary conserved Tamm-Horsfall protein (THP). Tamm-Horsfall protein is exclusively produced by the kidney in the distal loop of Henle; however, its definite physiological function remains elusive. Mounting evidence indicates that beyond a mere direct antimicrobial activity, THP exerts potent immunoregulatory activity. Furthermore, the genetic ablation of the THP gene leads to severe infection and lethal pyelonephritis in an experimental model of UTI. Recent data are provided demonstrating that THP links the innate immune response with specific THP-directed cell-mediated immunity. In light of these novel findings we discuss the particular role of THP as a specialized defence molecule. We propose an integrated model of protective mechanisms against UTI where THP acts by two principle nonmutually exclusive mechanisms involving the capture of potentially dangerous microbes and the ability of this peculiar glycoprotein to induce robust protective immune responses against uropathogenic bacteria.

Tamm-Horsfall glycoprotein links innate immune cell activation with adaptive immunity via a Toll-like receptor-4-dependent mechanism

Tamm-Horsfall glycoprotein (THP) is expressed exclusively in the kidney and constitutes the most abundant protein in mammalian urine. A critical role for THP in antibacterial host defense and inflammatory disorders of the urogenital tract has been suggested. We demonstrate that THP activates myeloid DCs via Toll-like receptor-4 (TLR4) to acquire a fully mature DC phenotype. THP triggers typical TLR signaling, culminating in activation of NF-kappaB. Bone marrow-derived macrophages from TLR4- and MyD88-deficient mice were nonresponsive to THP in contrast to those from TLR2- and TLR9-deficient mice. In vivo THP-driven TNF-alpha production was evident in WT but not in Tlr4-/- mice. Importantly, generation of THP-specific Abs consistently detectable in urinary tract inflammation was completely blunted in Tlr4-/- mice. These data show that THP is a regulatory factor of innate and adaptive immunity and therefore could have significant impact on host immunity in the urinary tract.

Antibodies to Tamm-Horsfall protein in endemic nephropathy

BACKGROUND

The aim of the study was to investigate the possible role of antibodies to Tamm-Horsfall protein (anti-THP) in the early diagnosis of endemic nephropathy (EN).

METHODS

Anti-THP (IgA, IgM, IgG classes) antibodies were determined by direct ELISA in a random sample of 159 subjects from the endemic village of Kaniza who were divided into four groups according to the WHO criteria, i.e., 'diseased', 'suspect', 'at risk', and 'others'. These groups were compared to subjects from the non-endemic village of Klakar and healthy subjects from Zagreb.

RESULTS

No differences for all the classes of antibody were observed among the groups of subjects from the endemic village of Kaniza (P>0.05) or between these subjects and those from the non-endemic village of Klakar (P>0.05). The values of IgM anti-THP antibodies exceeded those of the IgA and IgG classes in all groups of subjects (P<0.05). The values for all three classes of antibodies were higher in the rural than the urban population (P<0. 05).

CONCLUSION

Determination of anti-THP antibodies was not found to be useful in the early diagnosis of endemic nephropathy. The results suggest that most of the anti-THP antibodies are 'natural' and/or cross reactive. The highest values observed in the rural population could probably be explained by exposure to some ubiquitous antigen or more likely they are consequences of fever.

Is interstitial cystitis an infectious disease?

Interstitial cystitis (IC) is manifest by years of urinary frequency, urgency, and bladder pain and on cystoscopy, is diagnosed by petechial hemorrhages or ulcers. The etiology is unknown; the prominent theories are that IC is an autoimmune disease or is linked to increased permeability of the bladder mucosa. Although sought, no infectious agent has ever been identified. The disease has many characteristics of a chronic infection and the author's opinion is that an infectious disease has not been properly ruled out. To do so would require culture of bladder epithelium (not just urine) using special culture and non-culture techniques such as polymerase chain reaction. Infection can easily be integrated into the autoimmune and permeability theories of IC pathogenesis. A possible analogue for this disease is chronic gastritis in which Helicobacter pylori has been identified as an etiological agent.

Antibodies to Tamm-Horsfall protein in patients with acute pyelonephritis

The role of antibodies to Tamm-Horsfall protein in the diagnosis of acute pyelonephritis was studied. Antibodies to Tamm-Horsfall protein were also determined in a group of normal subjects. Patients with acute pyelonephritis were divided into subgroups according to the concurrent presence of vesicoureteral reflux or nephrolithiasis. No statistically significant differences (p > 0.05) were observed for any class of antibodies (IgG, IgA and IgM) between the groups of healthy subjects and patients with acute pyelonephritis, regardless of the presence or absence of vesicoureteral reflux or nephrolithiasis. Values for different antibody classes showed that IgM antibodies were the most abundant in all the groups examined. A difference in the values of IgM relative to IgA and IgG antibodies was found to be statistically significant in the patient group only (p < 0.05). In patients with vesicoureteral reflux, there was no statistically significant difference (p > 0.05) between the values of IgM and of other antibody classes. In these patients, however, the highest values of all the three antibody classes were obtained, although these differences were also not statistically significant (p > 0.05). The results pointed to the need of further studies of the role of antibodies to Tamm-Horsfall protein in the diagnosis and pathogenesis of tubulointerstitial nephritis.

The relationship between urinary Tamm-Horsfall glycoprotein excretion and urinary activity of glycosidases in normal pregnancy and pre-eclampsia

Electrophoretic analyses of the urinary proteins of pre-eclamptic patients revealed a decrease in the staining intensity of the protein band representing the Tamm-Horsfall glycoprotein (THP). In the present study the quantitative analysis of the THP excretion rate and the urinary activity of THP oligosaccharide metabolizing glycosidases were investigated. The median THP excretion rate of non-pregnant women (n = 24) was 20 mg/g creatinine (crea.). An increase in the THP excretion rate was seen in pregnancy to a level between 43 mg/g crea. (II. trimester) and 32 mg/g crea. (III. trimester) (n = 29). Hypertension in pregnancy was associated with a decrease in the THP excretion rate to 9 mg/g crea. (n = 85). Post partum, a transient elevated THP excretion rate up to 109 mg/g crea was recorded in the group of hypertensive patients. The urinary activities of the lysosomal beta-mannosidase, alpha-fucosidase, alpha-mannosidase (pH 4.5) and beta-galactosidase increased in normal pregnancy. This effect was most pronounced in the beta-galactosidase activity which increased from 50 U/mg crea. before pregnancy to 280 U/mg crea. at term. Hypertension in pregnancy was associated with a further increase in the activities of the lysosomal glycosidases. In the case of the beta-galactosidase a significant rise from 68 to 310 U/mg crea. was found. The urinary activity of the alpha-mannosidase (pH 5.5) originating from the Golgi apparatus was only elevated in patients with severe pre-eclampsia. Casuistic post partum recordings demonstrated that an elevation of the lysosomal glycosidases activities was followed by a transient increase in the THP excretion rate.

Tamm-Horsfall autoantibodies in interstitial cystitis

Interstitial cystitis presents a diagnostic and therapeutic challenge. Although many etiologies, including autoimmunity, have been proposed its pathogenesis remains obscure. Tamm-Horsfall protein has been identified in the superficial urothelium of patients with interstitial cystitis demonstrating abnormal urothelial permeability. Eight patients with a clinical diagnosis of interstitial cystitis underwent cystoscopy and bladder biopsy. Characteristic cystoscopic findings were present, and each patient had chronic inflammation and mast cells by histopathological analysis. Preoperative anti-Tamm-Horsfall protein serum antibody (IgG) titers were determined by enzyme-linked immunosorbent assay (range 500 to 8,000, mean 2,750). A control group of 8 patients with a negative urological history also had titers of 0 to 500 (p = 0.02). The humoral response to Tamm-Horsfall protein in these patients suggests a role for Tamm-Horsfall protein in interstitial cystitis. Measurement of serum Tamm-Horsfall protein antibody may prove to be useful as a noninvasive diagnostic test in patients with this disease.