[Type A/H1N1 influenza: a clinical summary of 24 imported cases]

Abstract

Objective: To study the clinical characteristics and laboratory results of 24 confirmed H1N1 influenza cases.

Methods: The characters of clinical, laboratory, iconography and etiology of 24 patients with A/H1N1 were studied, and the changes of T-lymphocyte subsets that between the pre- and post-treatment were evaluated.

Results: The ages of patients were ranged from 6 to 65 years old; average age was 26 years old.15 patients were under 25 years old. 22 (22/24, 91.7%) patients had recently traveled to USA or Canada. The most common presenting symptoms were: fever (22/24, 91.7%); sore throat (22/24, 91.7%); cough (20/24, 83.3%); dry cough (14/24, 58.3%); expectoration (6/24, 25.0%); nasal discharge (6/24, 25.0%). Six had pneumonia in sixteen patients (6/16, 37.5%) who took CT scan; seven (7/24, 29.2%) had headache and four (4/24, 16.7%) had muscular soreness; two (2/24, 8.3%) had sneeze and nasal obstruction; only one(1/24, 4.2%) had diarrhea; one (1/24, 4.2%) had conjunctivitis. The result of 23 patients about T-Lymphocyte subsets: most of CD4 and CD8 were decreased (18/23, 78.3%), ranging from 122 to 691 cells/microl (normal was 706 - 1125 cells/microl), with the average of 408 cells/microl, but ratios of CD4/CD8 were normal. Fourteen patients were detected CD4 and CD8 after received the treatment during 5 to 7 days.the results of CD4 (cells/microl) were different between the pre- and post-treatment: 436.29 +/- 189.06, 976.71 +/- 332.96 (paired-samples t test: t = -5.416, P < 0.05) while the results of CD8 (cells/microl) were: 323.64 +/- 176.47, 703.14 +/- 211.77 (t = -5.319, P < 0.05); the results of leukocytes in 22 patients were different between pre- and post-treatment: (5.13 +/- 1.47) x 10(9)/L, (6.25 +/- 1.37) x 10(9)/L (t = -2.900, P < 0.05) while the results of lymphocytes were: (1.16 +/- 0.43) x 10(9)/L, (2.30 +/- 0.37) x 10(9)/L (t = -6.819, P < 0.05); but the ratios of CD4/CD8 were: 1.44 +/- 0.41, 1.40 +/- 0.26 (t = 0.507, P > 0.05). All the patients were received antivirus treatment (Oseltamivir) and the virus conversed during 1 - 10 days (average 4.5 days). The temperature was normal after onset during 3 - 4 days and the patients were recovered during 3 - 13 days (with the average of 7.3 days).

Conclusion: Influenza A virus H1N1 subtype was identified as the cause of outbreaks of febrile respiratory infection which was self-limited. There was no evidence to show that the changes of T-Lymphocyte subsets could indicate the prognosis of patients.