Increased immunoglobulin A and immunoglobulin A1 cells in bone marrow trephine biopsy specimens in immunoglobulin A nephropathy.
The origin of mesangial immunoglobulin A (IgA) in IgA nephropathy remains unknown. To investigate potential abnormalities within the bone marrow in this condition, bone marrow trephine biopsy specimens from seven patients and matched controls were studied using two-color immunofluorescence. In addition, serum levels of IgA and IgA1 were determined by radial immunodiffusion. Serum levels of IgA and IgA1 were higher in patients than in controls (4.53 +/- 1.38 g/L v 2.56 +/- 1 g/L, P < 0.01 and 3.68 +/- 1.11 g/L v 1.92 +/- 0.7 g/L, P < 0.005, respectively). In addition, patient trephine biopsy specimens contained an increased percentage of IgA plasma cells (61.6% +/- 4.4%) compared with controls (47.3% +/- 2.5%) (P < 0.02). The proportion of IgA plasma cells bearing subclass IgA1 was also greater in the patient biopsy specimens (91.6% +/- 1.9%) compared with controls (81.4% +/- 2.7%) (P < 0.01). In patients a positive correlation between the percentage of marrow IgA plasma cells and serum IgA levels was found (r = 0.94, P < 0.002). However, our studies failed to demonstrate a similar correlation between serum IgA1 levels and IgA1 marrow cells. These findings support the hypothesis that mesangial IgA may derive from the bone marrow.
Harper
S J
SJ
Department of Nephrology, Leicester General Hospital, UK.
Allen
A C
AC
Layward
L
L
Hattersley
J
J
Veitch
P S
PS
Feehally
J
J
D000328:Adult; D001853:Bone Marrow / Q000276:immunology*; D001854:Bone Marrow Cells; D002452:Cell Count; D005260:Female; D005922:Glomerulonephritis, IGA / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis* / Q000097:blood; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000276:immunology*
D007070:Immunoglobulin A