Prevalence of IgA2 Deposits in IgA Nephropathies

Changes in size, subclass, and metabolic properties of serum immunoglobulin A in liver diseases and in other diseases with high serum immunoglobulin A.

“…3 (33) at similar concentrations as in other mammals (2), but large additional amounts of m-IgA, not found in most mammals (34) make it the minor component of IgA in human serum. The higher proportions of plasma cells staining for p-IgA (35,36) or for IgA2 (37) in mucosae than in bone marrow (35,38), and the higher proportions of p-IgA (1, 2) or of IgA2 (6, 7) in secretions than in serum, led some authors to regard serum p-IgA and/or IgA2 as being mainly of mucosal origin (2,10,13). In contrast, mIgA and IgAl in serum are likely to originate predominantly from bone marrow (39) where IgAl plasmacytes predominate and are the largest producers of m-IgA in vitro (40).…”

“…IJBP, ileojejunal bypass; IRMA, immunoradiometric assay; LD, liver disease(s); m-IgA, monomeric IgA; PBC, primary biliary cirrhosis; PBS, phosphatebuffered saline; p-IgA, polymeric IgA; RA, rheumatoid arthritis; SC, secretory component; SDGU, sucrose density gradient ultracentrifugation; sIgA, secretory IgA; SLE, systemic lupus erythematosus. p-IgA was found (1,10,11), whereas conflicting results regarding serum p-IgA in Berger's disease exist (12)(13)(14). Some experimental (15) and clinical evidence (16,17) suggests that p-IgA may be directly involved in tissue injury in some diseases.…”

“…Some experimental (15) and clinical evidence (16,17) suggests that p-IgA may be directly involved in tissue injury in some diseases. Changes in subclass proportions in pathological sera have not been studied but there are conflicting data about the IgA subclass deposits in Berger's disease (13,18,19).…”

Pathogenesis of IgA nephropathy: A Review

“…18,19 Certain observations suggest IgA nephropathy is associated with abnormalities of IgA regulation. IgA derived from mesangial deposits has been shown to be remarkably homogenous in anionic charge, which may be related to its affinity for the mesangium, 20,21 IgA may be deposited in the mesangium because some of its physicochemical properties trap it there, bound to deposited antigen or to intrinsic mesangial antigen, or because it has structural abnormalities.…”

“…21 More recent studies, however, have shown that the IgA1 subclass is deposited selectively in the mesangium. [22][23][24][25] Structural abnormalities of the IgA1 may play a role in its mesangial deposition, IgA1 is one of the 2 immunoglobulin subclasses (the other is IgD) that is O-glycosylated on a number of asparagine, serine, and threonine residues in a special proline-rich hinge region.…”