What Is a COVID-19 S1-Immune Subset Test?
The S1 Immune Subset looks for the presence of SARS COV 2-S1 protein in monocytes resulting from either the COVID-19 vaccine or natural infection. This test also includes CD3, CD4 and CD8 % and absolute count in addition to monocyte subset percentage with and without S1 protein in all classical, non-classical, and intermediate monocytes.
The S1 Immune subset simply tells if the S1 is in your system and if the present most likely cause for the long hauler symptoms.
Post-acute sequelae SARS-CoV-2 infection (PASC) is a disabling and sometimes debilitating condition that occurs in 10%-30% of individuals infected by SARS-CoV-2 and has recently been proposed to cause neurologic symptoms in 30% of those infected.
Recently Dr. Patterson and his team identified characteristic immune cell subset abnormalities that accompanied the unique cytokine/chemokine profile. They also found kinetic differences in the proportions of monocyte subsets in severe cases and PASC, as well as the presence of SARS-CoV-2 protein unaccompanied by corresponding viral RNA in CD14lo, CD16+ monocytes in PASC patients up to 16 months post-acute SARS-CoV-2 infection.
The predominant immune cell abnormality they observed in their work was elevations in monocyte subsets. Monocyte subpopulations are divided into 3 phenotypes, and they are functionally distinct from each other.
Classical monocytes: Exhibit the CD14++, CD16- phenotype. The classical monocytes express high levels of the ACE-2 receptor, the putative receptor for SARS-CoV-2. classical monocytes express low levels of the chemokine receptors CX3R1 and CCR5.
Intermediate monocytes: Exhibit a CD14+, CD16+ phenotype, express very little ACE-2 receptor, and express high levels of CCR5.
Non-classical monocytes: Exhibit CD14lo, CD16+ phenotype, express very little ACE-2 receptor, express high levels of CX3R1.
Identifying the immune subset population may provide information in understanding symptoms associated with inflammatory phenotype of these senescent nonclassical monocytes and assist in the treatment of PSAC.
T LYMPHOCYTE SUBPOPULATION
CD4+T and CD8+T play a vital role in maintaining immune function and viral clearance in the body. It has been reported that CD4+T and CD8+T counts significantly decreased in COVID-19 patients. Several studies revealed that CD3+ T cells, CD4+ T cells, CD8+ T cells, and natural killer cells were significantly decreased in patients with COVID-19. These patients had a relatively slight decrease in CD4+ T cells but a severe decrease in CD8+ T cells. A significantly elevated CD4/CD8 ratio was observed in COVID-19 patients. T-cell subset counts were related to the severity and prognosis of COVID-19, suggesting that the counts of CD8+ T and CD4+ T cells can be used as diagnostic markers of COVID-19 and predictors of disease severity.
Results must be interpreted together with other clinical information available to the physician.
This test is based on flow cytometry methodology and involves following CPT codes: 88184, 88185, 88188, 86356.
This S1 Protein-Immune subset assay is a Laboratory Developed Test (LDT). The assay was developed by incellDx and its performance characteristics were verified by Radiance Diagnostics. The LDT tests comprising this panel have not been reviewed by the U.S. Food and Drug Administration or approved. However, FDA approval is not required to perform an LDT of clinical value. Results must be interpreted together with other clinical information available to the physician.
- Patterson et al, Persistence of SARS CoV-2 S1 Protein in CD16+ Monocytes in Post-Acute Sequelae of COVID-19 (PASC) up to 15 Months Post-Infection, Frontiers in Immunology.12, 2022.
- Kapellos T et al.,.Human Monocyte Subsets and Phenotypes in Major Chronic Inflammatory Diseases Frontiers in Immunology; 10, 2019
- Patterson BK, et al. CCR5 Inhibition in CriticalCOVID-19 Patients Decreases Inflammatory Cytokines, Increases CDS T- Cells, and Decreases SARS-CoV2 RNA in Plasma by Day 14. IntiJ Infect Dis 2020
- Patterson Bruce K., Guevara-Coto Jose, Yogendra Ram, Francisco Edgar B., Long Emily, Pise Amruta, Rodrigues Hallison, Parikh Purvi, Mora Javier, Mora-Rodríguez Rodrigo A.Immune-Based Prediction of COVID-19 Severity and Chronicity Decoded Using Machine Learning Frontiers in Immunology, 12, 2021;2520.
- Patterson BK, et al. CCR5 Inhibition in Critical COVID-19 Patients Decreases Inflammatory Cytokines, Increases CDS T- Cells, and Decreases SARS-CoV2 RNA in Plasma by Day 14. Inti J Infect Dis 2020
- Patterson BK, et al. Immune-Based Prediction of COVID-19 Severity and Chronicity Decoded Using Machine Learning. BioRxiv 2020
- Zhang, JM, An J. Cytokines, Inflammation, and Pain. lnt Anesthesia! Clin 2007;45(2):27-37.
- Sokol, CL, Luster AD. The Chemokine System in Innate Immunity. Cold Spring Harb Perspect Biol2015;7: a016303.
- CD4+T, CD8+T counts and severe COVID-19: A meta-analysis. Zhang H, Wu T. J Infect. 2020 Sep;81(3): e82-e84.
- Lymphocyte subset (CD4+, CD8+) counts reflect the severity of infection and predict the clinical outcomes in patients with COVID-19. Liu Z et al., J Infect. 2020 Aug;81(2):318-356.
- T-Cell Subset Counts in Peripheral Blood Can Be Used as Discriminatory Biomarkers for Diagnosis and Severity Prediction of Coronavirus Disease 2019. Jiang M, Guo et al., J Infect Dis. 2020 Jun 29;222(2):198-202.