Envelope cross-reactivity in Western blot for HIV-1 and HIV-2 may not indicate dual infection.

Serological identification of infection with human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) by western blot alone may not be sufficient to diagnose dual infection. Extensive cross-reactions (eg, to envelope glycoprotein antibody) are seen on heterologous western blots. The use of other techniques, in this case competitive enzyme-linked immunosorbent assays, indicates that blot patterns previously thought to demonstrate simultaneous dual infections should be interpreted with caution.