The SARS-CoV-2 virus which emerged in late December 2019 had reached pandemic proportions by March 2020.1 Host defence mechanisms against this new member of the corona virus family will

include innate immunity, humoral, and cellular immune responses, of yet unknown relative importance. Conventional CD8+ αβTCR cytotoxic T cells and natural killer cells are mainly responsible

for detection and elimination of virus infected cells, with a special role for the CD94/NK group 2 member A (NKG2A) receptor as reported by Zheng et al. in this journal.2,3 We want to

report yet another brick in the wall against SARS-CoV-2 infection, made of a subset of γδTCR T cells.4 Poccia et al. previously described that in peripheral blood of health care workers who

SARS-CoV-2 infection (Supplementary Table 1). We find that the percentage of Vγ9Vδ2 T cells at the moment of hospital admission (on average 10 days after onset of clinical symptoms) is

significantly lower than that of matched healthy controls (Fig. 1) (healthy controls 1.82 ± 0.41 × 104 Vγ9Vδ2 T cells/ml, COVID-19 patients 0.38 ± 0.40 × 104/ml ; _p_ < 0.05). Six

patients died while being hospitalized (four of them in the ICU) and they showed T lymphocytopenia, including decreased numbers of Vγ9Vδ2 T cells (0.06 ± 0.38 × 104/ml; Fig. 1). In five

patients we could monitor the phenotype of Vγ9Vδ2 T cells during the 2 weeks they were admitted to the hospital. During that period, on average 26% of the Vγ9Vδ2 T-cell population shifts to

a phenotype of effector (memory) cells, as compared with 8% within the total T-cell population. It has been shown that Vγ9Vδ2 T cells have a so-called polycytotoxic profile.6 Vγ9Vδ2 cells

are the dominant γδ T-cell population in adults, but in the elderly this is more variable.6,7 Our data could indicate that elderly with reduced numbers of Vγ9Vδ2 T cells constitute the

SARS-CoV-2 vulnerable population. Alternatively, the Vγ9Vδ2 T cells in these patients have migrated to the lungs to kill SARS-CoV-2 infected cells. Long term monitoring of these patients

should make this clear. Vγ9Vδ2 T cells do not recognize antigens presented by HLA molecules but use the alternative antigen presenting molecule BTN3A.8 ICT01, a humanized activating

anti-BTN3A antibody, is currently in Phase 1 studies for potential use in anticancer therapy.9 In the context of the data presented here, this antibody could offer an alternative treatment

strategy for COVID-19. The study was performed in accordance with the guidelines for sharing of patient data of observational scientific research in emergency situations as issued by the

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Download references AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * St. Elisabeth Hospital, Tilburg, The Netherlands Ger Rijkers * Admiral De Ruyter Hospital, Goes, The Netherlands Ger

Rijkers, Trees Vervenne & Pieter van der Pol * Science Department, University College Roosevelt, Middelburg, The Netherlands Ger Rijkers Authors * Ger Rijkers View author publications

You can also search for this author inPubMed Google Scholar * Trees Vervenne View author publications You can also search for this author inPubMed Google Scholar * Pieter van der Pol View

author publications You can also search for this author inPubMed Google Scholar CORRESPONDING AUTHOR Correspondence to Ger Rijkers. ETHICS DECLARATIONS COMPETING INTERESTS The authors

declare no competing interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY TABLES RIGHTS AND PERMISSIONS OPEN ACCESS This article is licensed under a Creative Commons Attribution 4.0

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http://creativecommons.org/licenses/by/4.0/. Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Rijkers, G., Vervenne, T. & van der Pol, P. More bricks in the wall against

SARS-CoV-2 infection: involvement of γ9δ2 T cells. _Cell Mol Immunol_ 17, 771–772 (2020). https://doi.org/10.1038/s41423-020-0473-0 Download citation * Received: 10 May 2020 * Accepted: 16

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