CD200 Expression and Progression Free Survival in Plasma Cell Dyscrasia
Andrew P Laramore, Wing-Keung Chiu, Cherie H Dunphy. University of North Carolina, Chapel Hill, NC
Background: CD200, formerly known as OX-2, is a membrane glycoprotein, expressed by neural, endothelial, dendritic, thymic, B-, and activated T-cells. Normal plasma cells (PCs) do not express CD200. Using microarray technology, flow cytometry, and immunohistochemistry (IHC), CD200 positivity(+) has been identified in a majority of plasma cell dyscrasias (PCDs). Since there is a paucity of data, suggesting that CD200+ in PCD may confer a worst prognosis, we further investigated the significance of CD200+ in PCD.
Design: 103 bone marrow biopsies (BMBxs) at initial diagnosis of PCD were identified. Neoplastic PCs were quantified/evaluated by IHC for CD138, CD200, and CD56 and by in-situ hybridization for κ/λ. The PC burden was determined by percentage of CD138-positive cells in the BMBx. CD200+ and CD56+ was defined as expression by ≥ 20% of PCs. The following clinical data was compiled on each case: age, sex, Durie-Salmon stage, and cytogenetic results. Using univariate(UVA), bivariate(BVA), and multivariate(MVA) statistical analyses, CD200+ and the above-listed factors were assessed for impact on progression free survival (PFS), defined as the time from start of therapy to disease progression or death. Lastly, a Chi-square test was performed to examine the relationship between CD200+ and CD56+ in PCD. A p value of <0.05 was considered statistically significant.
Results: By UVA, increasing age and stage, PC burden, and cytogenetic abnormalities (abns) (any abn and specifically with del 13q or cyclin D1) showed a significant association with decreased(↓) PFS. By UVA, there was no significant association between CD200+ and PFS. However, a CD200+/CD56- phenotype was associated with ↓PFS with borderline significance (p=0.0596). By BVA, a CD200+/CD56- phenotype paired with age, PC burden, Durie-Salmon Stage, and the presence of any cytogenetic abn demonstrated a significant association with ↓PFS. Of interest, a Chi-square test detected a strong significant association between CD200+ and CD56+.
Conclusions: CD200+ in PCD is not an independent marker of PFS. However, a CD200+/CD56- phenotype has borderline significance for ↓PFS and when paired with age, PC burden, Durie-Salmon Stage, or the presence of any cytogenetic abn is significantly associated with ↓PFS. Additionally, a significantly strong association exists between CD200+ and CD56+ in PCD. The significance of this finding is unclear and warrants further examination.
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 220, Wednesday Afternoon