IVIGs reduce B-lymphocyte aggregation in the culture system.

Purified human B lymphocytes were cultured in the presence of irradiated L4.5 and IL-4 with 4 mM glycine and 10 mg/mL BSA (A) or with 10 mg/mL dialyzed IVIGs (B). Fibroblastic L4.5 single cells in the background are supporting the growth of B lymphocytes in large or small clusters; pictures were taken on day 8 at a × 100 magnification. These results are representative of 3 independent experiments with both IVIG preparations.