CD22 and primary cutaneous T-cell non-Hodgkin lymphoma: Using the primer set specifically recognizing CD22ΔN, 39 out of 60 (65%) of CTCL patients expressed this variant of CD22 (Fig. 4A), while only 6 out of 60 patients (10%) were positive for CD22wt (Fig. 4A) indicating that a substantial number of patients display expression of CD22ΔN mRNA in lesional skin, whereas expression of CD22wt was relatively rare (10%) among CTCL patients.