[A case of subclinical Sjögren syndrome associated with high levels of serum IgM, thrombocytopenia and splenomegaly].

A 13-years-old girl was admitted to our hospital with high levels of serum IgM, thrombocytopenia and splenomegaly. Not only IgG but also IgM were found on the surface of platelets by flow-cytometry. Direct Coombs' test was positive, and IgG was also found on the surface of red blood cells. After splenectomy, platelet count was increased and serum IgM was decreased. The biopsy of salivary glands showed infiltration of lymphocytes around the ducts, and Shirmer test revealed slightly decreased secretion of tears, suggesting subclinical Sjögren syndrome.