Fig. 2.
Secretory immunoglobulin A (SIgA) is present mainly in the high molecular weight fractions of immunoglobulin A (IgA). IgA of nasal wash and serum was size-fractionated with a HiLoadTM 16/60 HR200 Superdex prep grade gelfiltration column. Total IgA and SIgA was determined by specific enzyme-linked immunosorbent assay. In nasal wash the total IgA peak and SIgA peak overlap (a). In serum total IgA exists mainly of monomeric IgA and to a lesser extent of polymeric IgA. SIgA is present in the high molecular weight fractions of IgA (b). Shown are representative profiles of an IgA nephropathy patient.