A 32-year-old woman develops symptoms secondary to a dry mouth and dry eyes. She has enlarged salivary glands. Studies for autoantibodies to Ro (SS-A) are positive. A salivary gland biopsy reveals lymphocytic infiltration. Which of the following is the most likely diagnosis?

The sicca syndrome is a recognized feature of Sjogren's syndrome. It can be primary or secondary to other autoimmune disorders such as RA, SLE, scleroderma, or vasculitis. Primary Sjogren's syndrome is most common in middle-aged women; sicca symptoms can also occur as a complication of HIV infection or in sarcoidosis. Sjogren's syndrome is more likely to have positive serology, while the serology in sarcoid or HIV is negative. Both HIV and Sjogren can have lymphocytic infiltration, but in HIV it is predominantly by CD8+ lymphocytes, whereas in Sjogren's syndrome, the infiltration is by CD4+ lymphocytes. In sarcoidosis, biopsy reveals granulomas.