Objective To investigate specific changes of T cell repertoire in convalescent patients infected by influenza A (H7N9) virus. Methods Peripheral blood samples from 8 convalescent patients infected by H7N9 virus and 10 healthy donors were collected. After extracting whole DNA from these samples, arm-PCR were performed and the products were submitted to Illumina HiSeq2000 platform to produce deep sequencing data of the nucleotide sequences of complementary determining region 3 of T cell receptor β chain (TRB). Differences were compared in TRB diversity and V-D-J gene usage and similarities of sequences between the patients and the healthy donors. Results Frequency of V-D-J gene usage was different between the H7N9 patient group and the healthy group, such as TRBV30, TRBV27, and TRBV18 (Student's t test, P < 05). Main component analysis showed V-J pairing pattern was significantly different between two groups, which may have potential in identifying patients from healthy people. A considerable number of shared CDR3s were found in patient-patient pairs and normal-normal pairs, while seldom were found in patient-normal pairs. The similarity between patients was also confirmed by overlap distance analysis. Indexes for assessing diversity of immune repertoires, Shannon-Weiner index and Simpson index, were both lower in the patients (Student's t test, P < 05), suggesting that the immune system of the patients had not recovered 6 months after H7N9 infection. Compared with the healthy donors, the number of hyper-expression clones increased in the patient group, and some of them showed similarity among patients. Conclusions TRB repertoires are less diverse in patients with increased hyper-expressed clones and identifiable V-J usage pattern, which is identifiable from normal population. These results suggest that there are H7N9-specific changes in TRB repertoires of H7N9 infected patients in convalescent phase, which have potential implication in diagnosis and therapeutic T cell development.
ObjectiveTo analyze the clinical and epidemiological characteristics of hospitalized avian influenza A (H7N9) virus infections in Hunan province from 2013 to 2017, and provide evidences for control, diagnosis and treatment of this disease.MethodsNinety-one hospitalized patients were confirmed with H7N9 infection in Hunan. Excluding 2 patients less than 18 years old and 10 with missing data, 79 patients with H7N9 infection were analyzed.ResultsMost confirmed cases were affected in the second and fifth epidemic wave and number of patients in the fifth wave was more than the sum in prior 4 waves. Epidemiological characteristics, clinical symptoms and case fatality did not change significantly. Administration of antiviral drugs was more active in the fifth wave [from illness onset to antiviral drug: (6.3±2.4)d vs. (7.6±2.4)d, P=0.047]. Multiple logistic regression analysis showed that shock (OR=4.683, 95%CI 1.136–19.301, P=0.033) was the independent risk factor of H7N9 infections. There were no significant differences in case fatality among group oseltamivir, group oseltamivir+peramivir, and group peramivir.ConclusionsPatients with avian influenza A (H7N9) increased in the fifth wave but clinical characteristics changed little. Antiviral treatment should be more active. Shock is an independent risk factor of H7N9 infections. Oseltamivir-peramivir biotherapy can not reduce case fatality compared with oseltamivir or peramivir monotherapy.