Racial/Ethnic Variations in Nasal Gene Expression of TMPRSS2 in COVID-19

In patients with coronavirus disease 2019 (COVID-19), nasal gene expression of transmembrane serine protease 2 (TMPRSS2) has demonstrated racial/ethnic variations. Investigators conducted a cross-sectional study using nasal epithelium collected between 2015 and 2018 from patients within the Mount Sinai Health System in New York, New York. Results of the analysis were published in JAMA.

In the current study, healthy individuals and persons with asthma aged 4 to 60 years underwent nasal brushing to carry out research on asthma biomarkers. Based on prior associations reported between race/ethnicity and asthma, investigators performed RNA isolation of brushings, followed by RNA sequencing, sequence alignment, and normalization. The patient cohort totaled 305 individuals, among whom 8.2% were Asian, 15.4% were Black, 26.6% were Latino, 9.5% were of mixed race/ethnicity, and 40.3% were White.  

Of the various racial/ethnic groups, nasal gene expression of TMPRSS2 was highest in Black individuals (n=47; mean, 8.64 [95% CI, 8.41-8.86] log₂ counts per million) compared with Asian individuals (n=25; mean, 8.07 [95% CI, 7.74-8.40] log₂ counts per million), Latino individuals (n=81; mean, 8.02 [95% CI, 7.90-8.14] log₂ counts per million), individuals of mixed race/ethnicity (n=29; mean, 7.97 [95% CI, 7.77-8.16] log₂ counts per million), and White individuals (n=123; mean, 8.04 [95% CI, 7.94-8.15] log₂ counts per million).

Expression of TMPRSS2 was significantly higher in Black participants compared with Asian, Latino, mixed race/ethnicity, and White individuals (P <.001 for all comparisons), according to linear regression. No significant associations were observed between TMPRSS2 expression and age, sex, or presence of asthma.

Major limitations of the current study included its modest size, the constraint to a single metropolitan region, and the participant age range.

The investigators concluded that although the study results imply that a single factor — that is, TMPRSS2 expression — may contribute partially to the risk for COVID-19 in Black individuals who reside in the New York City area, many other factors are likely responsible as well, particularly because gene expression and race/ethnicity are both reflective of multiple environmental, social, and geographic issues.

Reference

Bunyavanich S, Grant C, Vicencio A. Racial/ethnic variation in nasal gene expression of transmembrane serine protease 2 (TMPRSS2). JAMA. Published online September 10, 2020. doi:10.1001/jama.2020.17386