Prevalence of human anti-mouse antibodies (HAMAs) in routine examinations.
BACKGROUND
Circulating heterophilic antibodies interfere with immunological assays in laboratory examinations; however, their rate of incidence is currently questionable. We developed an enzyme-linked immunosorbent assay (ELISA) to detect human anti-mouse antibodies (HAMAs) in routine examinations.


METHODS
The study samples were comprised of serum samples obtained from 290 inpatients and outpatients at our hospital. Mouse immunoglobulin G1 (mIgG1), mIgG2a, and mIgG2b were used as the antigens and horseradish peroxidase (HRP)-conjugated anti-human IgG and IgM were used to identify the HAMA isotype.


RESULTS
HAMAs were detected in 11.7% (34/290) of the samples. We observed 18 and 20 samples positive for IgG- and IgM-type HAMAs, respectively. Four samples contained both IgG- and IgM-type HAMAs. HAMAs against mIgG1, mIgG2a, and mIgG2b were found in 21, 14, and 13 samples, respectively. Existence of HAMAs was confirmed by western blotting using mIgG's as the antigens and HAMAs as the primary antibodies. Heterophilic blocking reagent (HBR) was also used to block the heterophilic interactions. Unexpectedly, a low HBR concentration rather enhanced the interactions instead of blocking them.


CONCLUSIONS
A considerable number of HAMA-positive samples, reacting with the heavy chain of mIg, were found in routine examinations. A sufficient amount of HBR should be used for blocking the heterophilic interactions.
Koshida
Saori
S
Division of Laboratory Diagnosis, Sapporo Medical University Hospital, Japan.
Asanuma
Koichi
K
Kuribayashi
Kageaki
K
Goto
Maki
M
Tsuji
Naoki
N
Kobayashi
Daisuke
D
Tanaka
Maki
M
Watanabe
Naoki
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000910:Antibodies, Heterophile / Q000097:blood* / Q000276:immunology; D000937:Antigen-Antibody Reactions; D001774:Blood Chemical Analysis; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D055815:Young Adult
D000910:Antibodies, Heterophile; D007074:Immunoglobulin G; D007075:Immunoglobulin M