Renal tubular acidosis as the initial presentation of Sjögren's syndrome.

We present a 44-year-old female with an initial presentation with distal renal tubular acidosis (RTA) after she presented with hypokalaemia and normal anion gap acidosis. Three years following the diagnosis, she presented with progressive renal impairment. In the absence of any clinical, biochemical and radiological clues, she underwent a renal biopsy which showed severe tubulitis secondary to lymphocytic infiltration. Serological investigations subsequently revealed positive anti-nuclear, anti-Sjögren's syndrome related antigen A (SS-A), and anti-Sjögren's syndrome related antigen B (SS-B) antibodies, supporting the diagnosis of Sjögren's syndrome. This case is unique in that distal RTA was the presenting clinical manifestation of Sjögren's syndrome. We hope that a consideration for Sjögren's syndrome is made in patients with seemingly idiopathic RTA.

Treatment with cytotoxic immunosuppression agents increases urinary excretion of JCV in patients with autoimmune disease.

Human JC virus is ubiquitous in human populations and is reactivated frequently in immunosuppressed patients. Fifty-one patients with autoimmune disease receiving immunomodulating therapy were evaluated to study the possible relationship between immunosuppression and JCV viruria. Patients were divided into cytotoxic and noncytotoxic treatment groups based on their prescription. The incidence of JCV viruria in the cytotoxic treatment group was significantly higher than that in the noncytotoxic group (67% vs. 28%; P < 0.05). Most patients with JCV viruria were receiving corticosteroid (P = 0.03 for any dose and P < 0.001 for higher-dose treatments) and cytotoxic agents (P = 0.02). Age, disease duration, and medication duration appeared not to be the precipitating factors of JCV viruria in this study. The results of clinical evaluation indicate that cytotoxic immunosuppression may play an important role in JC virus reactivation.

Urinary monoclonal free light chains in primary Sjögren's syndrome: an aid to the diagnosis of malignant lymphoma.

Three patients, two with typical primary Sjögren's syndrome (SS) and the third with several features of SS, including abnormal sialography and reduced tear secretion, developed B cell non-Hodgkin's lymphoma (NHL) of parotid or lung, or both. Isoelectric focusing of concentrated urine specimens in agarose, followed by immunofixation, demonstrated the presence in each patient's urine of monoclonal free light chains of the same class as that shown on the tumour cells. In one patient the level of urinary free light chains was monitored and found to correlate with disease activity. Similar techniques showed no monoclonal light chains in the urine from a further 26 cases of SS with no clinical evidence of lymphoma. The detection of monoclonal urinary free light chains may provide an early diagnostic clue to the development of lymphoma in patients with SS and be a means of tumour monitoring.