Table 1.

Summary of studies quantifying the increased activation or protein expression of TLR and NLR for various syndromes associated with cytokine storms. Blank squares indicate that no data were found regarding the activity or expression pattern of the receptor. – indicates no change, ^ indicates increased activation or protein expression, V indicates downregulation or decreased protein expression, +/− indicates conflicting reports about whether there is increased activity or protein expression and -/V indicates conflicting reports about whether there is no change or downregulation. ALI stands for acute lung injury; ARDS stands for acute respiratory distress syndrome; Gram- = expressed by Gram-negative bacteria; PGN = peptidoglycan; LTA = lymphotoxin alpha; HSP = heat shock protein; HMGB1 = High Mobility Group Box 1 protein; dsRNA = double-stranded ribonucleic acid; polyI:C = polymer composed of inosine and cytosine; DAMP = damage-associated proteins; Gram+ = expressed by Gram-positive bacteria; lipopeps = lipopolypeptides; ssRNA = single-stranded ribonucleic acids; CpG DNA = deoxyribonucleic acid high in cytosine and guanine, typifying a microbial genomic origin; mtDNA = deoxyribonucleic acid derived from mitochondria; DAP = diaminopimelic acid, a bacterial cell wall component; MDP = muramyl dipeptide, a bacterial cell wall component and ? = activators not presently known.

Receptors	TLR1	TLR2	TLR3	TLR4	TLR5	TLR6	TLR7	TLR8	TLR9	TLR10	NOD1	NOD2	NL-RP3	RIG1
Activated by:	Lipo-peptides	Gram-PGN, LTA & HSP, HMGB1	ds-RNA, polyI:C, DAMP	Gram+ LPS & HSP, HMGB1	Flagellin	LTA, lipopeps	ss-RNA	ss- RNA & pyogenic Bacteria	CpG DNA & mtDNA	Retroviral RNA	Meso-DAP	MDP	?	Viral RNA
COVID-19 SEVERE	-	^	+/-	^	-	-	^	-	+/-	-	-	-	^	-
INFLUENZA-ASSOCIATED ALI/ARDS		v	^	^			^	-	^		+/-	^	^	v
SEPSIS/ALI (murine)		^	+/-	^	-		^		^		-	-	^
SEPSIS human patients	-	+/-	-	^	+/-	-	+/-	-	-/v	-	-	-	^
Polymicrobial SEPSIS murine model	-	^	-	^	-	-	^	-	-		-	-	^
SEPSIS CONCENSUS	-	^	-	^	-	-	^	-	-		-	-	^