Localization of Infection in HIV Antibody Positive Patients With Fever Comparison of the Efficacy of Ga‐67 Citrate and Radiolabeled Human IgG

Patients who are human immunodeficiency virus (HIV) antibody positive are at increased risk of life threatening infection. Scintigraphic imaging with Ga-67 citrate has been used to identify the presence and site of focal infection. However, focal accumulation of Ga-67 is not specific for Infection. A retrospective study was performed to compare the accuracy of Ga-67 citrate and pooled human polyclonal immunogiobulin G (HIG) labeled with Tc-99m HIG and In-111 HIG in identifying infection In HIV antibody positive patients. Twenty-five studies were performed using Ga-67 and Tc-99m HIG were compared with a second group of 25 studies using ln-111 HIG in HIV antibody positive patients presenting with fever, but without localizing symptoms or signs. In-111 HIG identified 20 of 22 sites of infection and also accumulated in 5 sites without Infection (accuracy = 90%). This was significantly more accurate (X2, P < 0.05) than Ga-67 which identified 19 of 20 sites of infection, but accumulated in 18 sites without infection (accuracy = 74%) and Tc-99m HIG which identified infection in 11 of 20 sites, but accumulated in 8 sites without infection (accuracy = 77%). There was no significant difference between the accuracy of Ga-67 and Tc-99m HIG. From this preliminary study In-111 HIG would seem to be the best agent for identifying infection in HIV antibody positive patients with fever.