Relation Between pp65 Antigenemia, RT-PCR and Viruria for Cytomegalovirus Detection in Kidney Transplant Recipients

Relation Between pp65 Antigenemia, RT-PCR and Viruria for Cytomegalovirus Detection in Kidney Transplant Recipients R. Solà, N. Rabella, L.L. Guirado, J.M. Dı´az, C. Facundo, and R. Garcı´a ABSTRACT Introduction. We compared the efficiency of detection using pp65 antigenemia, reverse transcription-polymerase chain reaction (RT-PCR), and viruria for the diagnosis of cytomegalovirus (CMV) infections after kidney transplantation. Patients and Methods. We evaluated 40 renal transplant recipients between weeks 5 and 12 after transplantation, including 179 blood and 181 urine specimens. Results. All positive samples by antigenemia were also positive by PCR. However, in 52 cases only PCR was positive (kappa ⫽ 0.134 [P ⬍ .001]). Viruria was positive in 66 cases, but only 26 were CMV PCR positive. In 34 cases, viruria was negative and PCR positive (P ⫽ .192). Conclusion. Detection of DNA in serum is a more sensitive method than antigenemia for the diagnosis of CMV infection. Viruria was not related to the presence of CMV in blood.

C

YTOMEGALOVIRUS (CMV) infections are frequent in the first months after kidney transplantation and may cause severe disease, multiorgan involvement, and death. CMV infection has also been associated with chronic nephropathy, even without CMV disease.1 There are several techniques for diagnosis of CMV infection: pp65 in blood (antigenemia), DNA detection by polymerase chain reaction (PCR) in sera and CMV isolation in urine (viruria). We compared the efficiency of diagnosis by antigenemia and by PCR as well as their relation to viruria for the diagnosis of a CMV infection. PATIENTS AND METHODS Forty kidney transplant patients included one with CMV infection, three with CMV disease, and 36 without either problem. During the second and third month posttransplantation, 179 blood samples were obtained for assay of pp65 antigen and viral DNA by PCR. Urine samples to detect the presence of the virus were also obtained in the same period of time. Blood specimens were processed for antigenemia using CHEMICON International reagents following the manufacturer’s protocols. CMV DNA was assessed in serum samples with the QIAagen kit processed by Real Time (LightCycler 2.0) using Artus reagents following their instructions.

RESULTS

The results obtained are reflected in Table 1. All positive samples by antigenemia were also positive by PCR. How-

Table 1. Determinations

Antigenemia Antigenemia Antigenemia Antigenemia

⫹ ⫺ ⫺ ⫹

PCR PCR PCR PCR

n

⫹ ⫺ ⫹ ⫺

6 121 52 0

Determinations

Viruria Viruria Viruria Viruria

⫹ ⫺ ⫺ ⫹

PCR PCR PCR PCR

⫺ ⫺ ⫹ ⫺

n

26 81 34 40

Kappa ⫽ 0.134 (P ⬍ .001). P ⫽ .192.

ever, in 52 cases only PCR was positive. This relation was statistically significant on assessing the results using the coefficient of concordance (Cohen’s kappa). Viruria was positive in 66 cases, but only 26 were CMV PCR positive. On the other hand, in 34 cases viruria was negative and PCR was positive. DISCUSSION

There is no current unanimity on the most efficient method for CMV detection after kidney transplantation.2– 4 The From the Unitat de Transplantament Renal, Fundació Puigvert (R.S., L.L.G., J.M.D., C.F., R.G.), and Laboratory de Microbiologı´a, Hospital de la Santa Creu i Sant Pau (N.R.), Universitat Autònoma de Barcelona, Barcelona, Spain. Address reprint requests to Dr R. Solà, Fundacio Puigrert, C/Cartajena 340-350, Barcelona, 08025 Spain. E-mail: rsola@ fundacio-pvigvert.es

0041-1345/05/$–see front matter doi:10.1016/j.transproceed.2005.09.107

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Transplantation Proceedings, 37, 3768 –3769 (2005)

CYTOMEGALOVIRUS DETECTION IN RECIPIENTS

results obtained in our study suggest that the technique for detection of DNA of CMV by PCR is more sensitive than that for of pp65 antigenemia and that viruria was not related to the presence of virus in blood. REFERENCES 1. Solá R, Dı´az JM, Guirado L, et al: Significance of cytomegalovirus infection in renal transplantation. Transplant Proc 35: 1753, 2003

3769 2. Meyer-Koening U, Weidmann M, Kirste G, et al: Cytomegalovirus infection in organ-transplant recipients: diagnostic value of pp65 antigen test, qualitative polymerase chain reaction (PCR) and quantitative Taqman PCR. Transplantation 77:1962, 2004 3. Schoroeder R, Michelon T, Fagundes I, et al: Comparison between RFLP-PCR and antigenemia for pp65 antigen for diagnosis of cytomegalovirus disease after kidney transplantation. Transplant Proc 36:891, 2004 4. Kalpoe JS, Kroes AC, de Jong MD, et al: Validation of clinical application of treatment criteria by analysis of correlation to antigen detection. J Clin Microbiol 42:1498, 2004