We therefore investigated whether EBV infects bystanders lymphocytes, macrophages, and Langerhans cells in samples from patients #1, 9, & 15, which tested positive by PCR, using in situ hybridisation with a probe against EBV EBERs RNA on paraffin sections of LCH granuloma, followed by immunohistochemistry with antibodies against B-cells (CD20 & CD79a), T-cells (CD3), macrophages (CD68), or Langerhans cell (CD1a) antigens on the same tissue sections. This evidence concerns the gene CD1A and Langerhans cell histiocytosis.