Alterations in Phenotypes and Responses of T Cells Within 6 Months of Recovery from COVID-19: A Cohort Study.

Affiliation

Zhao B(1)(2), Zhong M(3), Yang Q(1)(4)(5), Hong K(4)(5), Xia J(6), Li X(4)(5), Liu Y(5)(7), Chen YQ(8), Yang J(9), Huang C(10)(11), Yan H(12)(13)(14).
Author information:
(1)State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, CAS, Wuhan, 430071, China.
(2)University of Chinese Academy of Sciences, Beijing, 100049, China.
(3)Institute of Infection, Immunology and Tumor Microenvironment, Hubei Province Key Laboratory of Occupational Hazard Identification and Control, Medical College, Wuhan University of Science and Technology, Wuhan, 430065, China.
(4)Joint Laboratory of Infectious Diseases and Health, Wuhan Institute of Virology & Wuhan Jinyintan Hospital, Wuhan Jinyintan Hospital, Wuhan, 430023, China.
(5)Center for Translational Medicine, Jinyintan Hospital, Wuhan, 430023, China.
(6)Department of Laboratory Medicine, Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430070, China.
(7)The Office of Drug Clinical Trial Institution, Jinyintan Hospital, Wuhan, 430023, China.
(8)School of Public Health
(Shenzhen), Sun Yat-Sen University, Shenzhen, 518107, China. [Email]
(9)Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China. [Email]
(10)Joint Laboratory of Infectious Diseases and Health, Wuhan Institute of Virology & Wuhan Jinyintan Hospital, Wuhan Jinyintan Hospital, Wuhan, 430023, China. [Email]
(11)Center for Translational Medicine, Jinyintan Hospital, Wuhan, 430023, China. [Email]
(12)State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, CAS, Wuhan, 430071, China. [Email]
(13)Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China. [Email]
(14)University of Chinese Academy of Sciences, Beijing, 100049, China. [Email]

Abstract

The COVID-19 pandemic, caused by the SARS-CoV-2 infection, is a global health crisis. While many patients have clinically recovered, little is known about long-term alterations in T cell responses of COVID-19 convalescents. In this study, T cell responses in peripheral blood mononuclear cells of a long-time COVID-19 clinically recovered (20-26 weeks) cohort (LCR) were measured via flow cytometry and ELISpot. The T cell responses of LCR were comparatively analyzed against an age and sex matched short-time clinically recovered (4-9 weeks) cohort (SCR) and a healthy donor cohort (HD). All volunteers were recruited from Wuhan Jinyintan Hospital, China. Phenotypic analysis showed that activation marker PD-1 expressing on CD4+ T cells of LCR was still significantly lower than that of HD. Functional analysis indicated that frequencies of Tc2, Th2 and Th17 in LCR were comparable to those of HD, but Tc17 was higher than that of HD. In LCR, compared to the HD, there were fewer IFN-γ producing T cells but more IL-2 secreting T cells. In addition, the circulating Tfh cells in LCR were still slightly lower compared to HD, though the subsets composition had recovered. Remarkably, SARS-CoV-2 specific T cell responses in LCR were comparable to that of SCR. Collectively, T cell responses experienced long-term alterations in phenotype and functional potential of LCR cohort. However, after clinical recovery, SARS-CoV-2 specific T cell responses could be sustained at least for six months, which may be helpful in resisting re-infection.