Mutations in CD37 cause aberrant CD37 glycosylation and localization. Western blot analysis of CD37 protein expression in BJAB lymphoma B cells transfected with CD37-WT-GFP, CD37-Gly88Asp-GFP (A), or CD37-Gly65Glu-GFP (B). Blots were probed with α-GFP to detect CD37-GFP expression (50-75 kDa; upper blot). α-Tubulin was used as a loading control (lower blot). Protein expression level of CD37-mutant-GFP was normalized to CD37-WT-GFP for each experiment (n = 3). ns, not significant (P = .73 [left], P = .96 [right]), paired t test. (C) Confocal microscopy images of BJAB cells expressing CD37-WT-GFP and CD37-Gly88Asp-GFP or CD37-Gly65Glu-GFP (green) costained for MHC-I (red) to identify the plasma membrane. Overview images (top) and single-cell images (bottom left) show representative cells of 3 independent experiments for both CD37-WT-GFP and CD37-mutant-GFP. Scale bar, 10 µm. Ratio between membrane and cytoplasmic GFP expression was quantified from 10 representative cells of 3 independent experiments. *P = .023 (left), P = .011 (right), paired t test. All data represent mean ± standard error of the mean.