The effect of Tamm-Horsfall protein isolated from urine of healthy subjects on calcium oxalate precipitation was studied in model systems of precipitation. The study was performed using following conditions: concentrations of calcium chloride 10 mmol/1, sodium chloride 150 mmol/1, oxalic acid 300 μπιοΐ/ΐ; pH 6.0, and temperature 310 K. The concentration of Tamm-Horsfall protein varied between 1 -10mg/l. The kinetics of calcium oxalate precipitation was observed by measuring the number and volume of particles in the suspension, and the precipitate composition by an optic microscope. In all the studied systems, the precipitate morphology corresponded to pure calcium oxalate monohydrate. Tamm-Horsfall protein was found to inhibit the growth of calcium oxalate monohydrate crystals and stimulate their aggregation in the given experimental conditions. Both effects were enhanced by increase in the concentrations of Tamm-Horsfall protein and were most pronounced at the concentration of Tamm-Horsfall protein of 10 mg/1.

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.

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.

The relationship between glycosaminoglycans and β₂-microglobulin, glycosaminoglycans and N-acetyl-β-D-glucosaminidase as well as the relationship between the chondroitin sulfate/heparan sulfate ratio and SDS electrophoresis in the urine of subjects from the endemic area of Balkan nephropathy was studied in order to establish a method for early detection of this disease. The results show an unquestionable increase in urinary excretion of total glycosaminoglycans in subjects with or suspected of having Balkan endemic nephropathy while the chondroitin sulfate/heparan sulfate ratio was not statistically different between the groups studied. Thus, the chondroitin sulfate/heparan sulfate ratio cannot be used as a cheap and quick semiquantitative method for the diagnosis of early tubular damage in Balkan endemic nephropathy. However, the determination of total glycosaminoglycans in the urine of subjects from endemic areas proved to be valuable additional information helping with the diagnosis of Balkan endemic nephropathy.

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