Simultaneous measurement of total and IgA-conjugated alpha 1-microglobulin by a combined immunoenzyme/immunoradiometric assay technique.
alpha 1-Microglobulin (alpha 1m), a glycoprotein (Mr = 30,000) found in serum and urine, is also present in serum conjugated to monomeric IgA (alpha 1-m-IgA). We have developed a simultaneous enzyme-linked immunoenzyme/immunoradiometric assay that involves three different monoclonal antibodies. Assay of serial dilutions of serum and urine demonstrated parallelism. Normal mean concentrations in serum (n = 75) were: total alpha 1m, 2.33 mumol/L; alpha 1m-IgA, 1.24 mumol/L; unconjugated (free) alpha 1m, 1.09 mumol/L; molar ratio (alpha 1m-IgA/total alpha 1m), 0.53. The mean concentration of alpha 1m in eight urine specimens from normal individuals was 0.19 mumol/L, with no detectable alpha 1m-IgA. A low urinary pH does not significantly affect assay results, unlike assays of beta 2-microglobulin. In patients with myeloma-related renal disease, total and free alpha 1m values for serum correlated well with values for creatinine and beta 2-microglobulin in serum.
DeMars
D D
DD
Department of Pathology, University of Vermont, Burlington 05405.
Katzmann
J A
JA
Kimlinger
T K
TK
Calore
J D
JD
Tracy
R P
RP
D000510:Alpha-Globulins / Q000032:analysis* / Q000097:blood / Q000652:urine; D000911:Antibodies, Monoclonal; D000917:Antibody Formation; D000918:Antibody Specificity; D006801:Humans; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis*; D008433:Mathematics; D010265:Paraproteinemias / Q000097:blood / Q000652:urine; D011863:Radioimmunoassay; D012016:Reference Values
D000510:Alpha-Globulins; D000911:Antibodies, Monoclonal; D007070:Immunoglobulin A; C016001:alpha-1-microglobulin