We had three patients with different haematological malignancies in varied phases of treatment who were found to have H1N1 infection between December 2009 and March 2010. The clinical details are shown in Table I. Diagnosis of H1N1 infection was based on quantitative polymerase chain reaction from nasopharyngeal swabs. Chest radiological findings mimicked invasive aspergillosis in two patients. Galactomanan assay was also supporting fungal infection in these patients thereby suggesting a diagnosis of probable invasive aspergillosis. Bronchoalveolar lavage could be performed in only one patient (patient 3) who grew Pseudomonas species in the lavage fluid. All children were neutropenic at the onset of symptoms. One patient (patient 1) died due to respiratory failure and shock. In this patient, there was a delay of more than 10 days to initiate treatment with oseltamivir, H1N1 infection was not suspected initially. The diagnosis and treatment of H1N1 infection was delayed in patient 3 also, but he improved with treatment as his disease was in remission and total leucocyte counts and neutrophil counts were showing on improving trend.

TABLE I  Children with H1N1 Infection and Leukemia

It is interesting to study the course of this infection during the recent pandemic in this subgroup of patients as pediatric age group and malignancies both are considered to be risk factors for severe illness due to this infection. Patients with hematological malignancies are expected to have more morbidity and mortality due to the already compromised immunity, associated neutropenia, and coexistent bacterial and fungal infections. Usually a diagnosis of bacterial infection is considered in the setting of neutropenic fever and thereafter a fungal infection is considered if fever persists. It is for this reason that the diagnosis of H1N1 infection was not considered initially in our patients. The diagnosis was further delayed due to the radiological features being suggestive of invasive fungal infection in two patients. It is possible that H1N1 could have been a coexistent infection with other usual infections seen in our patients rather than isolated H1N1 infection. Interestingly, bacterial co-infections have been previously observed in lung tissues of 29% of fatal cases of H1N1 [3].

There is paucity of data on the course and outcome of this novel infection in patients with haematological malignancies [4-7]. Sidi, et al. [7] found in their series of 45 patients of different malignancies that H1N1 was more common in hematological malignancies than solid tumors; however, it was not associated with severe illness or death in any of their patients. There is no published data so far about this infection in pediatric patients with hematological malignancies.

In view of our findings, we suggest that in the setting of hematological malignancies, H1N1 infection should be considered and tested by PCR in all such children, with cough or upper respiratory symptoms during an epidemic; whether the patient is neutropenic or not, and even when radiology is suggestive of classical bacterial or fungal pneumonia. Further, empiric treatment with oseltamivir should be initiated early in these patients as this infection appears to have an adverse outcome either due to its own course or by having an additive effect on an underlying coexistent pulmonary infection.

1. Writing Committee of the WHO Consultation on Clinical Aspects of Pandemic (H1N1) 2009 Influenza, Bautista E, Chotpitayasunondh T, Gao Z, Harper SA, Shaw M, et al. Clinical Aspects of Pandemic 2009 Influenza A (H1N1) Virus Infection. N Engl J Med. 2010;362:1708-19.

2. Press Release from Press Information Bureau, Press Release. Government of India, May 26,2010, http://pib.nic.in/h1n1/h1n1.asp.

3. Bacterial coinfections in lung tissue specimens from fatal cases of 2009 pandemic influenza A (H1N1) – United States, May-August 2009. MMWR Morb Mortal Wkly Rep. 2009;58:1071-4.

4. Seiter K, Nadelman RB, Liu D, Ahmad T,Montecalvo MA. Novel influenza A (H1N1) in patients with hematologic malignancies. J Clin Oncol. 2010; 28: e27-e29.

5. Saurez JG, Martin Y, Callejas M, Rodriguez-Dominguez M, Galán JC, Burgaleta C, et al . Favourable outcome of pneumonia due to novel influenza A/H1N1 2009 virus in a splenectomised adult patient undergoing therapy for non Hodgkin lymphoma. Br J Haematol. 2010;148: 805-14.

6. Patel P, Sweiss K, Shatavi S, Peace D, Clark N, Rondelli D. The impact of novel influenza A (H1N1) after hematopoietic SCT. Bone Marrow Transplant. 2010; 45:1756-7.