T6-antigen—bearing Langerhans' cells were detected in a touch imprint of eosinophilic granuloma involving a thoracic vertebra of an 11-year-old boy. It is interesting to note that in this localized form of histiocytosis X, no T6-antigen-bearing Langerhans' cells were found in the peripheral blood. Immunofluorescence detection of T6 antigenicity has not been described in this disease and may serve as a rapid diagnostic test.
Fox JL, Berman B. T6-Antigen—Bearing Cells in Eosinophilic Granuloma of Bone. JAMA. 1983;249(22):3071-3072. doi:10.1001/jama.1983.03330460053032