Normal Splenic Lymphoid Subsets Mimic Aberrant Antigen Expression
Nidhi Aggarwal, Jason Fischer, Steven H Swerdlow, Fiona E Craig. University of Pittsburgh School of Medicine, Pittsburgh, PA
Background: Flow cytometry (FC) assists in the diagnosis of lymphoma through identification of aberrant antigen expression. However, normal lymphoid subsets with less well-recognized phenotypes can mimic lymphoma. This study characterizes lymphoid subsets in normal spleen using 8-color FC.
Design: 20 spleens removed for traumatic rupture, with cell viability >50%, were analyzed within 24 hrs with the following FC combinations: CD16&57/CD7/CD4/CD2/CD56/CD3/CD5/CD8; K/λ/CD5/CD19/CD10/CD38/CD20/CD45; αβ/γδ/CD3/CD25 and CD14/CD13&33/CD45/CD34.
Results: This study reveals the normal variation in splenic lymphoid subsets (Table) and demonstrates some subsets with phenotypes that have been associated with lymphoid neoplasms.
Well recognized lymphoma-associated phenotypes identified in this study include CD7- T-cells and CD5+ B-cells.
Less-well recognized phenotypes encountered in all cases, except as indicated, include: CD5- to dim+ CD8+ T-cells, CD3+ bright (br.) γδ T-cells (15/20), CD5- γδ T-cells (Fig. 1a), CD2- NK-cells and CD7+dim NK-cells (Fig 1b). The latter two NK-cell phenotypes were seen more often in the mature subtype (p<0.01).
|Population (Parent)||% of Parent Indicated|
|T cells (Lymphoid cells)||34||21||55|
|CD4+ (T cells)||56||37||78|
|CD8+ (T cells)||33||13||46|
|CD4+ CD8+ (T cells)||3||1||12|
|CD4- CD8- (T cells)||7||1||19|
|αβ+ (T cells)||93||79||99|
|γδ+ (T cells)||5||0.5||19|
|CD7- (T cells)||11||6||19|
|CD5- (γδ T cells)||16||5||82|
|CD5- (CD8+ T cells)||5.5||2||30|
|CD25+ (T cells)||32||18||52|
|NK cells (Lymphoid cells)||7.7||4||18|
|CD2- (NK cells)||36||23||53|
|Immature, CD56+br. CD16&57- (NK cells)||51||25||74|
|Mature, CD56+dim CD16&57+br. (NK cells)||29||13||63|
|Int., CD56+br. CD16&57+dim (NK cells)||10||4||23|
|B-cells (Lymphoid cells)||46||30||67|
|CD10+ (B cells)||3.5||1||24|
|CD5+ (B cells)||8.5||1||15|
|Plasma cells (Total cells)||0.2||0.1||0.9|