Improved measurement of anti-thyroglobulin IgG in urine of patients with autoimmune thyroid diseases by sensitive enzyme immunoassay (immune complex transfer enzyme immunoassay

Mucosal immunity and primary biliary cirrhosis: presence of antimitochondrial antibodies in urine

We have shown that IgA-class antimitochondrial autoantibodies (AMA) can be detected in the bile and saliva of patients with PBC, suggesting that AMA are secreted into the luminal fluid across bile ducts and salivary glands. These data prompted us to determine whether AMA of the IgA isotype may be transported across other epithelial mucosa. Therefore, we tested for the presence of AMA in the urine specimens of 83 patients with PBC and 58 non-PBC controls including healthy individuals and patients with other liver diseases. Patients enrolled in this study had no history of renal disease, and we confirmed there was less than 50 microgram/mL of protein in each of the urine specimens. Interestingly, we found that AMA were present in the urine of 71/83 (86%) of all patients with PBC and in 71/78 (91%) of patients with PBC that were serum AMA positive. In contrast, AMA were not detected in any of the 58 control urine specimens. Of particular interest, AMA of the IgA isotype was present in 57/83 (69%) of patients with PBC, and in 52 of these 57, we found secretory-type IgA. In a nested random subgroup of urine samples, the prevalence of the IgA2 AMA was 6/18 (33%), significantly lower than in matched serum samples, 13/16 (81%, P =.007). These data show that AMA of the IgA isotype is secreted into urine from the uroepithelium of patients with PBC, and support the thesis that PBC originated from either a mucosal challenge or a loss of mucosal tolerance.

Immune complex transfer enzyme immunoassay that is more sensitive and specific than western blotting for detection of antibody immunoglobulin G to human immunodeficiency virus type 1 in serum with recombinant pol and gag proteins as antigens

Antibody immunoglobulin G (IgG) to human immunodeficiency virus type 1 (HIV-1) in serum was detected by ultrasensitive enzyme immunoassays (immune complex transfer enzyme immunoassays) with recombinant reverse transcriptase (rRT), p17 (rp17) and p24 (rp24) of HIV-1 as antigens and beta-D-galactosidase from Escherichia coli as the label. The immune complex, comprising 2,4-dinitrophenyl-bovine serum albumin-recombinant protein conjugate, antibody IgG to HIV-1, and recombinant protein-beta-D-galactosidase conjugate, was trapped on polystyrene beads coated with affinity-purified (anti-2,4-dinitrophenyl group) IgG, eluted with epsilon N-2,4-dinitrophenyl-L-lysine, and transferred to polystyrene beads coated with affinity-purified (anti-human IgG gamma-chain) IgG. Bound beta-D-galactosidase activity was assayed by fluorometry. The assays were highly reproducible with no serious serum interference, and they were much more sensitive than Western immunoblotting for the corresponding antigens. Signals with rRT, rp17, and rp24 for asymptomatic carriers were at least 56,000-, 680-, and 22-fold higher, respectively, than those for seronegative individuals, and neither indeterminate nor false-positive results were observed, whereas some serum samples were false negative or false positive by Western blotting for p17 and/or p24 antigen. In some cases, seroconversion was detected earlier than by conventional methods. Therefore, these assays are suggested to be more useful than conventional methods not only for the confirmation of antibody IgGs to RT, p17, and p24 of HIV-1 in serum but also for the detection of seroconversion.