Unique cellular immune signatures of multisystem inflammatory syndrome in children

Abstract

The clinical presentation of MIS-C overlaps with other infectious/non-infectious diseases such as acute COVID-19, Kawasaki disease, acute dengue, enteric fever, and systemic lupus erythematosus. We examined the ex-vivo cellular parameters with the aim of distinguishing MIS-C from other syndromes with overlapping clinical presentations. MIS-C children differed from children with non-MIS-C conditions by having increased numbers of naïve CD8+ T cells, naïve, immature and atypical memory B cells and diminished numbers of transitional memory, stem cell memory, central and effector memory CD4+ and CD8+ T cells, classical, activated memory B and plasma cells and monocyte (intermediate and non-classical) and dendritic cell (plasmacytoid and myeloid) subsets. All of the above alterations were significantly reversed at 6-9 months post-recovery in MIS-C. Thus, MIS-C is characterized by a distinct cellular signature that distinguishes it from other syndromes with overlapping clinical presentations. Trial Registration: ClinicalTrials.gov clinicaltrial.gov. No: NCT04844242.

Fig 1. CD4⁺ and CD8⁺ T cell subsets are altered in MIS-C.

(A) Analysis of WBC, RBC, Hb, HCT and platelets (B) Analysis of absolute count of WBC, lymphocytes, monocytes, neutrophils, eosinophils, basophils and neutrophils/lymphocyte ratio were shown for children with MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). (C) Absolute numbers of CD4⁺ T cell subsets in MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). The data are represented as scatter violin plots with each circle representing a single individual. p values were calculated using the Kruskal-Wallis test with Dunn’s post-hoc for multiple comparisons. (D) Absolute numbers of CD8⁺ T cell subsets in MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). The data are represented as scatter violin plots with each circle representing a single individual. p values were calculated using the Kruskal-Wallis test with Dunn’s post-hoc for multiple comparisons.

Fig 2. B cell subsets are altered in MIS-C.

Absolute numbers of B cell subsets in MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). The data are represented as scatter violin plots with each circle representing a single individual. p values were calculated using the Kruskal-Wallis test with Dunn’s post-hoc for multiple comparisons.

Fig 3. Altered numbers of DC and monocyte subsets are associated with MIS-C.

Title. (A) Absolute numbers of DC subsets in MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). The data are represented as scatter violin plots with each circle representing a single individual. p values were calculated using the Kruskal-Wallis test with Dunn’s post-hoc for multiple comparisons. (B) Absolute numbers of monocyte subsets in MIS-C (n = 21), acute COVID-19 (n = 23), other infectious (n = 23), other non-infectious diseases (n = 21) and controls (n = 14). The data are represented as scatter violin plots with each circle representing a single individual. p values were calculated using the Kruskal-Wallis test with Dunn’s post-hoc for multiple comparisons.

Fig 4. T cell subsets were altered post-recovery in MIS-C.

(A) Absolute numbers of CD4⁺ T cell subsets in MIS-C children (n = 12) at pre-treatment and post-recovery were determined. (B) Absolute numbers of CD8⁺ T cell subsets in MIS-C children (n = 12) at pre-treatment and post-recovery were determined. p values were calculated using the Wilcoxon matched pair test.

Fig 5. B cell, DC and monocyte subsets were altered post-recovery in MIS-C.

(A) Absolute numbers of B cell subsets in MIS-C children (n = 12) at pre-treatment and post-recovery were determined. (B) Absolute numbers of DC and Monocyte subsets in MIS-C children (n = 12) at pre-treatment and post-recovery were determined. p values were calculated using the Wilcoxon matched pair test.

Fig 6. Hematology and Cellular subset markers can strongly discriminate MIS-C from acute COVID-19 and other infections, other non-infections and control children.

(A). PCA (Principal component analysis) plot computing normalized cellular subsets after excluding those factors with commonalities as low as 0.5 we used hematology parameters like RBC, Hb, HCT, PLT, WBC, lymphocytes and eosinophils, cellular subsets absolute counts of CD4⁺ and CD8⁺ Naïve, central memory, stem cell memory, Regulatory T cells, Naïve B cells, Immature B cells, Classical B cells, Activated, Atypical memory B cells, plasma cells, pDC, mDC, MDSC and non-classical monocytes in a combination of five different experimental groups first MIS-C (Colored in blue) vs acute COVID-19 (Colored in red) vs other infections (Colored in brown) vs other non-infections (Colored in light green) and controls (Colored in dark green). The PCA shows the two principal components of variation, accounting for 15.5% (x-axis) and 37.7% (y-axis). (B). Hematology and cellular subsets are illustrated according to the score denoted in the color-scale bar. Associated horizontal dendrograms denote the patient’s clustering, standing out clusters containing MIS-C (enclosed in blue), acute COVID-19 children (enclosed in red), other infections (Colored in brown), and other non-infections (enclosed in green) or controls children (enclosed in light green). On the color scale, blue color indicates lower expression and red color indicates higher expression.