Increased Lung Activity of 111In Labelled Polyclonal IgG in Patients with Aids and Active Chest Infection

Abstract

Patients infected with the human immunodeficiency virus (HIV) are at risk of life threatening infection. Consequently the most common cause of morbidity and death in HIV infected patients within the United Kingdom remains pulmonary infection often with Pneumocystis carinii, pneumonia¹. Functional imaging techniques using scintigraphic methods provide unique information which will demonstrate the presence of infection before there are changes on planar or computed tomography X-ray. Imaging with ⁶⁷Gallium citrate has become established as the method of choice in the initial investigation of HIV infected patients presenting with symptoms or signs of chest infection^2,3. Unfortunately the agent is non-specific and may accumulate in sites of tumour or benign pathology such as rib fractures⁴. 111Indium labelled polyclonal human immunoglobulin (111In-HIG) has been shown to have a high sensitivity and specificity in localising infection in immunocompromised patients and those who are infected with HIV⁵. In some patients the study demonstrates intense accumulation of 111In-HIG in the presence of active infection (Fig 1) but often the changes are more subtle.