CD8A and lymphoproliferative syndrome: This was also true for RCD I, a subtype of RCD that is characterised by a polyclonal expansion of IE CD8+ TCRαβ T cells, as opposed to RCD II, which represents a clonal lymphoproliferative disorder of IELs manifesting an aberrant immunophenotype.45 The detection of lower clonality and higher T cell density in RCD I, ascertained by TRB (and TRG) sequencing, indicates persistence of an inflammatory process that is similar in nature to ACD, in line with previous findings.29