Relative lymphopenia and monocytosis may be considered as a surrogate marker of pandemic influenza a (H1N1).
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ABSTRACT: Leukocyte counts and differentials are commonly acquired in patients with suspected respiratory viral infections and may contribute diagnostic information. However, most published work is limited to a single timepoint at initial presentation to a medical provider, which may correspond to widely varying points in the course of disease. To examine the temporal development and time-dependent utility of routine leukocyte differentials in the diagnosis of respiratory viral infections. We analyzed data from recent experimental human challenges with influenza A/H3N2, human rhinovirus (HRV), and respiratory syncytial virus (RSV). Routine clinical lab cell counts and differentials were measured daily from the time period immediately prior to inoculation through the eventual resolution of symptomatic disease. Approximately 50% of challenged individuals developed symptoms and viral shedding consistent with clinical disease. Subpopulations of WBC showed marked differences between symptomatic and asymptomatic individuals over time, but these changes were much more profound and consistent in influenza infection. Influenza-infected subjects develop both relative lymphopenia and relative monocytosis, both of which closely mirror symptom development in time. A lymphocyte:monocyte ratio of <2 correctly classifies 100% of influenza (but not RSV or HRV) infected subjects at the time of maximal symptoms. Leukocyte differentials may suggest a viral etiology in patients with upper respiratory infection, but are not sufficient to allow differentiation between common viruses. Timing of data acquisition relative to the disease course is a key component in determining the utility of these tests.Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 09/2013; · 3.12 Impact Factor
- Journal of Tropical Pediatrics 06/2011; 58(2):160-1. · 1.01 Impact Factor
- The Journal of infection 07/2013; · 4.13 Impact Factor
Journal of Clinical Virology 47 (2010) 388–389
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Journal of Clinical Virology
journal homepage: www.elsevier.com/locate/jcv
Letter to the Editor
Relative lymphopenia and monocytosis may be considered as a
surrogate marker of pandemic influenza a (H1N1)
spread rapidly across the globe. In March and April 2009, an out-
break of respiratory illness was first noted in Mexico, which was
eventually identified as being related to PI.1The outbreak dissem-
inated rapidly to the other countries. Turkey is among the mostly
The clinical features of PI are very similar to those of seasonal
influenza. The most common clinical findings of PI are fever, cough,
cough or sore throat in the absence of a known cause other than
influenza. A confirmed case of PI is defined as an individual with
an ILI with laboratory-confirmed H1N1 virus detected by real-time
reverse transcriptase (rRT)-PCR or viral culture.6Rapid spread of PI
infection, high expense of accurate diagnostic tests requiring refer-
ence laboratories have arisen the need for surrogate or reminiscent
In this study, we compared the results of complete blood counts
(CBC) of patients with ILI signs and symptoms in Gulhane and
Ankara Numune Hospitals. These two hospitals manage significant
number of PI cases in Ankara. H1N1 rRT-PCR was performed in all
patients with an age range of 17–81 years (average 32.1±2 years).
Eighty-seven patients were positive and 66 cases were negative
for H1N1 rRT-PCR test. Independent t test and chi square test were
used for statistical analysis. We found significant difference in
white blood cell (WBC) counts, monocyte percentile, lymphocyte
and neutrophil counts among PI and ILI groups (p=0.016, p=0.007,
p=0.011 and p=0.042 respectively). White blood cell value was
found to be high in 30.4% of ILI, but only in 16.1% of PI patients.
Among all WBCs, the neutrophil count was found to be over
reference limits in 43.5% of ILI and 32.3% of PI cases. Monocytes
were increased in 16% of ILI and 30% of PI and lymphopenia
was seen in 27% of PI infections. The probability of having a low
lymphocyte percentage while the monocyte count is high in PI
patients was observed 13.8% while being 2.2% in ILI patients; this
difference indicated statistical significance (p=0.032, chi square
In a study comparing hematological parameters of 272 con-
firmed PI infections; leucopenia was reported in 20% and
leukocytosis in 18% of the patients.7In the present study, a sig-
nificant increase in WBC was detected in accurately diagnosed ILI
cases when compared to PI. Moreover neutrophil count was sig-
nificantly high in ILI patients; this parameter was also increased in
non-viral infections and it might cause misleading in the evalua-
tion of PI patients. It was recorded that relative lymphopenia can
be seen in likely patients for PI.8In our study, we observed sig-
nificant decrease in lymphocyte count and significant increase in
monocyte percentile. That is why we declare that the possibility of
monocytosis and lymphopenia could be regarded as highly proba-
ble in PI cases (positive and negative predictive values were estimated
92.3% and 37.5%, respectively). Larger scale studies are required to
corroborate this evidence.
Conflict of interest
March–April 2009. MMWR 2009;58:467–70.
2. Khan K, Arino J, Hu W, Raposo P, Sears J, Calderon F, et al. Spread of a novel
influenza A (H1N1) virus via global airline transportation. The New England Jour-
nal of Medicine 2009;361:212–4.
3. Monto AS, Gravenstein S, Elliott M, Colopy M, Schweinle J. Clinical signs
and symptoms predicting influenza infection. Archives of Internal Medicine
4. Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, Garten RJ, et al. Emergence
of a novel swine-origin influenza A (H1N1) virus in humans. The New England
Journal of Medicine 2009;360:2605–15.
in California. JAMA 2009;302:1896–902.
6. Thorner AR. Treatment of pandemic H1N1 influenza (‘swine influenza’).
In: McGovern BH, editor. In “UpToDate”, 2010. cited available from http://
7. Jain S, Kamimoto L, Bramley AM, Schmitz AM, Benoit SR, Louie J, et al. Hospital-
ized patients with 2009 H1N1 influenza in the United States, April–June 2009.
The New England Journal of Medicine 2009;361:1935–44.
8. Cunha BA, Pherez FM, Schoch P. Diagnostic importance of relative lymphope-
nia as a marker of swine influenza (H1N1) in adults. Clinical Infectious Diseases
Ömer Cos ¸kun∗
Ismail Yasar Avci
GMMA Infectious Disease and Clinical Mic. Dep.,
GMMA Virology Department, Turkey
GMMA Biochemistry Department, Turkey
GMMA Public Health and Epidemiology Department,
1386-6532/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
Letter to the Editor / Journal of Clinical Virology 47 (2010) 388–389
Ankara Numune Hospital, Infectious Disease and
Clinical Mic. Dep., Turkey
Can Polat Eyigün
GMMA Infectious Disease and Clinical Mic. Dep.,
∗Corresponding author at: Genaral Tevfik Sa˘ glam
Caddesi, GATA Enfeksiyon Hastalıkları ve Klinik
Mikrobiyoloji, Klini˘ gi Etlik, Ankara 06018, Turkey.
Tel.: +90 3123044308; fax: +90 3123044300.
E-mail addresses: email@example.com,
firstname.lastname@example.org (Ö. Cos ¸kun),
email@example.com (I.Y. Avci),
firstname.lastname@example.org (K. Sener),
email@example.com (H. Yaman),
firstname.lastname@example.org (R. Ogur),
email@example.com (H. Bodur),
firstname.lastname@example.org (C.P. Eyigün)
6 January 2010