Reduced cellularity of lymphoid organs in SLY1-/--mice. A. Mean cell count of thymus, spleen and pooled axial and inguinal lymph nodes was determined (n = 4). B. Reduced number of visible Peyer's patches in SLY1-/--mice. C. FACS analysis of splenic lymphocyte subpopulations. T cells were determined as Thy1.2+, B cells as B220+, marginal zone B cells as CD21highCD23- of B220+, and NK cells as CD3-CD56+ (n = 9). D. Absolute cell counts/spleen (n = 9). **p ≤ 0.01; *** p ≤ 0.001.