Comparative analysis of intrathecal antibody synthesis and DNA amplification for the diagnosis of cytomegalovirus infection of the central nervous system in AIDS patients

Abstract

We evaluated 49 paired cerebrospinal fluid (CSF) and serum samples of 35 patients infected with the human immunodeficiency virus type 1 (HIV-1) for laboratory evidence of cytomegalovirus (CMV) infection. The patients were grouped according to clinical criteria as probable CMV encephalitis/polyradiculomyelitis, CMV retinitis, cerebral toxoplasmosis, progressive multifocal leukoencephalopathy, HIV-1-related cognitive/motor complex, HIV-1-associated myelopathy, and other neurological diseases. Paired CSF and serum samples were analysed for CMV deoxyribonucleic acid (DNA) by polymerase chain reaction (PCR), quantitative intrathecal synthesis of immunoglobulin G (IgG) antibodies specific for recombinant phosphoprotein 150 (pp150) of CMV and CMV-specific serum IgM. Intrathecal synthesis of pp150-specific IgG was detected in 26% of patients (9/35), serum IgM was found in 23% of patients (8/35), and PCR of CSF was positive in 11% of patients (4/35). Detection of CMV-specific DNA in CSF preceded the intrathecal antibody synthesis in three patients for whom serial samples were available. PCR results of the CSF became negative in one patient with CMV polyradiculomyelitis after successful therapy with 9-[2-hydroxy-1-(hydroxymethyl) ethoxymethyl] guanine (DHPG). PCR has a higher diagnostic specificity in the acute phase of CMV infection than intrathecal antibody synthesis. The serum IgM response to CMV cannot be used to monitor a compartmentalized immune response in the central nervous system while an intrathecal immune response seems to be associated with recovery either spontaneously or as a result of treatment.