CD22 and splenic diffuse red pulp small B-cell lymphoma: A scoring system, based on five membrane markers (CD11c, CD22, CD76, CD27 and CD38) was proposed to distinguish SDRPL from SMZL: one point was attributed when the ratio of fluorescence intensity (RFI) CD11c was higher than 25, the CD22 RFI higher than 130, the CD76 positive, the CD27 negative and the CD38 negative.