To characterise the renal histopathological lesions in patients with primary Sjögren's syndrome and to correlate the findings with the clinical manifestations.
Kidney and labial salivary gland biopsies from ten patients with primary Sjögren's syndrome were studied. The protocol included semiquantitative assessments of the inflammatory focus scores and the levels of atrophy, interstitial fibrosis, glomerular sclerosis and vessel wall thickening.
No statistically significant correlation was found between the kidney and labial inflammatory scores; this was probably the result of observation of the lesions at different stages. The level of chronic tubulointerstitial nephritis was correlated to the glomerular filtration rate and to the extent of glomerular sclerosis but not to vessel wall thickening. These findings indicate a primary injury of the tubules in primary Sjögren's syndrome that secondarily compromises the glomeruli.
A semiquantitative approach to the assessment of histopathological features, as used in this study, appears to be valuable for characterising the lesions in kidney biopsies.