Different profiles of cytomegalovirus RNA transcripts and anti-cytomegalovirus IgM antibodies in renal transplant recipients

BACKGROUND: A difference in anti-cytomegalovirus IgM antibody profile has been found between sera from acutely cytomegalovirus (CMV)-infected patients and sera from CMV-infected patients with subclinical infection.

OBJECTIVES: The aim of this study is to investigate whether such different IgM antibody responses are correlated with differences in the expression of CMV immediate early and late mRNAs.

STUDY DESIGN: We have investigated the anti-CMV IgM response in 46 renal transplant recipients by employing two commercially available IgM kits (AxSYM and IMX) as well as two novel enzyme-linked immunosorbent assays (ELISAs), which were developed using recombinant ppUL32 (pp150) and pUL80a (p38), respectively. The results were compared with four direct CMV diagnostic tests: pp65 antigenemia, viral culture and nucleic acid sequence-based amplification (NASBA), detecting either CMV immediate early 1 (IE1) mRNA (IE1-NASBA), or CMV pp67 (late) mRNA (pp67-NASBA).

RESULTS: Analysis of all CMV-infected recipients (n=28) showed that in 16 recipients (group I) more than one direct test became positive after transplantation, while in the other 12 recipients (group II), IE1-NASBA was the only direct test to become positive. In group I, 100, 81, 100 and 50% of the recipients were IgM-positive with AxSYM, IMX, p38 and pp150, respectively. In group II, 100, 83, 17 and 83% of the recipients were IgM-positive with AxSYM, IMX, p38 and pp150, respectively.

CONCLUSIONS: Our data indicate that the IgM-response against p38 and pp150 differs significantly (P<0.01) between group I recipients with productive CMV infection, and group II recipients with a non-productive CMV infection which may be of diagnostic and prognostic relevance.