Peripheral blood CD4+ cell counts but not CD3+ and CD8+ cell counts are reduced in SARS-CoV-2 infection.

Background: The world is facing the global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). T cell-induced immune responses during acute SARS-CoV-2 infection have rarely been reported.

Methods: We use cell counting chips and PCR arrays to offer the first insights into the T cell involved in the course of acute SARS-CoV-2 infection. All consecutive patients with suspected SARS-CoV-2 infection treated at the designated hospital between January 2020 and February 2020 were recruited for the study, and cases were confirmed by real-time RT-PCR. Baseline characteristics for inpatients were prospectively collected and analyzed.

Results: 96 patients with suspected SARS-CoV-2 infection in our center were screened for inclusion in the study. The median age of the patients was 39.0 years, and 47 (49.0%) were female. Multivariate logistic regression analysis showed that only the CD4+ cell counts were significantly lower in the infection group and slightly higher in the control group. Receiver operating characteristic curve analysis showed good discrimination power between subjects with and subjects without infection.

Limitations: This is a single-center study of patients with a specific ethnic background and lacks a mechanism.

Conclusions: These findings imply the importance of CD4+ T cells (but not CD8+ and CD3+ T cells) in SARS-CoV-2 infection associated pneumonia and indicate that CD4+ T cells might be important for the control of SARS-CoV-2.