Kanvinde, et al. [3] describe 13 episodes of CMV in 11 cases of hematological malignancy, which were treated with intravenous gancyclovir. These cases were diagnosed based on detection of antigen or DNA, of which, nearly half were diagnosed by a qualitative PCR which is not the standard method for diagnosing CMV infection. Further, none of these cases had demonstration of virus by culture or histopathology. Few of these episodes were associated with other documented viral or bacterial infections which by themselves are known to cause prolonged cytopenias. Further, two of these patients had resolution of their symptoms even before initiation of gancyclovir. It would be reasonable to state that these patients may have had evidence of CMV infection but certainly CMV disease was not demonstrated in any case, and thus none of these patients can be attributed to have CMV-related cytopenia.

Even the term "CMV syndrome" should be avoided. Although it is recognized that CMV can cause the combination of fever and bone marrow suppression that is usually used to define the disease entity, the same symptoms can have several other different viral etiologies such as human herpesvirus 6 (HHV-6), possibly human herpesvirus 7, and adenovirus infections. Antiviral drugs might have some effect against these viruses, making the interpretation of causality difficult. Thus, if the term "CMV syndrome" is to be used, it must be used only after testing has been done for HHV-6, at the very least [4].

Intravenous gancyclovir remains the standard of care for symptomatic CMV infection and/or CMV disease. But there are limitation of gancyclovir treatment as it causes myelosupression which may lead to superadded bacterial or fungal infection. It is important not to treat every episode of asymptomatic CMV infection to avoid undesired toxicity. This argument is supported by Ng, et al. [5], who described 35 patients with CMV DNAemia, with six having CMV disease; in this series, none of the untreated 20 patients developed CMV infection or disease on follow-up.

In countries with population congestion like India, where CMV seropositivity is as high as 90%, CMV reactivation may be more common than in the Western world. It is possible that many of our patients have undiagnosed asymptomatic CMV infection, as they are not routinely screened for CMV. But at the same time, they may also be recovering from CMV infection without any antiviral therapy as described by Ng, et al. [5]. If CMV infection or disease has to be evaluated in hematological malignancies, then perhaps these patients should be serially tested from diagnosis for change in viral load, if any, from diagnosis and to attempt diagnostic biopsies in suspected cases of CMV disease. A previous study showed that on serial monitoring, 15.3% patients of acute lymphoblastic leukemia showed evidence of CMV reactivation but none of these patients at reactivation or thereafter showed evidence of CMV disease [6]. Thus, in the absence of strong evidence of CMV disease, it may not be appropriate to initiate gancyclovir therapy for patients with hematological malignancies who have either a positive pp65 antigen or PCR positivity, as toxicity of intravenous gancyclovir outweighs the effectiveness.

Competing interests: None stated; Funding: Nil

1. Ljungman P, Reusser P, de la Camara R, Einsele H, Engelhard D, Ribaudi P, et al. Management of CMV infections: recommendations from the infectious diseases working party of the EBMT. Bone Marrow Transplant. 2004;33:1075-81.

2. Nguyen Q, Estey E, Raad I, Rolston K, Kantarjian H, Jacobson K, et al. Cytomegalovirus pneumonia in adults with leukemia: an emerging problem. Clin Infect Dis. 2001;32:539-45.

3. Kanvinde S, Bhargava P, Patwardhan S. Cytomegalovirus is an important cause of cytopenia after chemotherapy in haematological malignancies. Indian Pediatr. 2013;50:197-201.

4. Ljungman P, Griffiths P, Paya C. Definitions of cytomegalovirus infection and disease in transplant recipients. Clin Infect Dis. 2002;34:1094-7.

5. Ng AP,　Worth L,　Chen L, Seymour JF, Prince HM, Slavin M, et al. Cytomegalovirus DNAemia and disease: incidence, natural history and management in settings other than allogenic stem cell transplantation. Haematologica.　2005;90:1672-9

6. Lunghi M, Riccomagno P, De Paoli L, Vendramin C, Conconi A, Gaidano G, et al. Monitoring of cytomegalovirus reactivation during induction and nontransplant consolidation of acute leukemia. Am J Hematol.　2009;84:697-8.