CD19 and Buschke-Ollendorff syndrome: In a prospective study including 136 patients (46 BOS, 41 no cGvHD, 49 cutaneous cGvHD) to define novel biomarkers for early diagnosis of NIH-defined BOS, diagnosed a median of 11 months after HSCT patients with newly diagnosed BOS had significantly higher percentages of CD19+CD21low B cells, BAFF levels, and BAFF/CD19+ ratios compared with patients without cGvHD.