Successful treatment of a patient with primary Sjögren's syndrome with Rituximab.

We report the course of a 55-year-old woman, the first patient with primary Sjögren's syndrome and distal renal tubular acidosis but without lymphoma to be treated with B-cell depletion using Rituximab. Rapidly after B-cell depletion, remarkable improvement in xerostomia occurred, while serological findings and tubular acidosis have been unchanged. In labial salivary gland biopsy, lymphocyte infiltration and particularly CD20-positive cells decreased strikingly. Aquaporin 1 (AQP-1) expression in myoepithelial cells was very low before treatment and increased noticeably. Apical AQP-5 in acinus cells likewise increased following Rituximab. In contrast, basolateral NKCC1 was expressed at unchanged intensity before and following Rituximab. The improvement has been sustained and still is most gratifying 10 months after treatment. B-cell depletion may be effective treatment in Sjögren's syndrome. Likewise, it may now be possible to separate the immunologic phenomena in Sjögren's syndrome from the consequences of prolonged hyposalivation when studying the pathophysiology of xerostomia.