Fig. 1.

Proliferation of primary human mesangial cells stimulated with serum or cord-blood serum supplemented with Gal-deficient IgA1 myeloma protein. Gal-deficient IgA1 (Mce) myeloma protein was added to serum samples (final concentrations were 0.5%, 2%, and 5% serum; negative control was serum-free, denoted by 0%). Serum samples were from a healthy control (Control), an IgAN patient (IgAN1), and two samples of cord-blood serum (CBS1 and CBS2). IgA final concentrations were 0, 20, and 50 μg/ml of culture medium (marked by white, black, and gray columns, respectively). After 1-h incubation at 4 °C to allow formation of immune complexes, the samples were added with culture medium to serum-starved human mesangial cells, and cellular proliferation was measured after 20-h incubation. Data for cellular proliferation were expressed relative to the proliferation of cells with medium alone, considered 1. Mean and SD are shown (n = 8).