Detection of HLA IgG antibodies by two enzyme-linked immunoassays, solubilized HLA class I and PRA-STAT. Comparison with the AHG PRA.
HLA class I-directed IgG antibodies have traditionally been detected with a complement-dependent lymphocytotoxicity (CDL) technique. We have evaluated two solid-phase enzyme-linked immunoassays (EIA) and compared them with the CDL antihuman globulin (AHG) dithiothreitol-treated (DTT) PRA in their ability to discriminate between the presence or absence of HLA class I-directed IgG antibodies in serum from patients awaiting transplantation. The EIA were: (1) an EIA that uses solubilized HLA class I antigens (sHLA-I) isolated from a 240-member platelet donor pool, and (2) the PRA-STAT ELISA kit. For the first comparison, we used 691 serum samples from 272 patients taken before they had been transplanted. The data show a significant (P < 0.0001) linear correlation (r = 0.77 between the AHG DTT PRA and the sHLA EIA. They also demonstrate that the mean sHLA-I EIA ratio significantly increases (P < 0.01) above background levels with each stepwise increase in AHG DTT PRA level. Discordant results were 1.0% (7/691) for sHLA-I EIA+ PRA- and 6.3% (44/691) for PRA+ sHLA-I EIA-. However, a lower correlation was noted between the AHG DTT PRA and the PRA-STAT (Nextran) PRA results (n = 230; r = 0.42). The sHLA-I EIA is able to determine whether or not HLA Class I IgG antibodies are present in serum from transplant candidates and is an appropriate adjunct to the traditional CDL PRA assay, whereas the PRA-STAT is not.
Midwest Organ Bank, Inc., Westwood, Kansas, USA.
C F
CF
Bryan
K A
KA
Baier
G
G
Flora-Ginter
C F
CF
Shield
B A
BA
Warady
M I
MI
Aeder
A M
AM
Borkon
T H
TH
Estep
J
J
Forster
M D
MD
Landreneau
D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D012680:Sensitivity and Specificity
D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G