Table 1.

Overview of human diseases and conditions associated with altered systemic properdin levels

Disease/condition	Findings	Reference
a. Diseases and conditions associated with reduced systemic properdin levels
C3 glomerulopathy	Reduced P levels compared to controls. Average P levels were almost two times lower in C3GN compared with DDD, while sC5b-9 levels were elevated in C3GN compared with DDD.	Zhang et al. 2014 [12]
	Reduced P levels compared to controls (i.e., below the mean-2sd) in 53% of the patients negative for C3NeF. C3GN was more frequent in the C3NeF-negative group, but no difference in C3GN frequency between the groups with normal versus reduced P. P consumption correlated with reduced C3 and C5 levels, with elevated sC5b-9 levels, and with a higher degree of proteinuria.	Corvillo et al. 2016 [11]
	Reduced P levels just below the lower limit of the reference range of controls in 4 out of 5 patients positive for C4NeF. Also decreased serum C3 and C5 levels, while C3c and sC5b-9 were increased.	Zhang et al. 2017 [13]
Anti-neutrophil cytoplasmic antibody-associated vasculitis	Reduced P levels in active phase versus controls and versus remission, while plasma C3a, Bb, C5a, and sC5b-9 were elevated in active stage compared to remission. P levels inversely correlated with the proportion of crescents in the renal specimen.	Gou et al. 2013 [21]
Lupus nephritis	Approximately two-times reduced P levels in active lupus nephritis compared to controls, accompanied by increased plasma C3a, Bb, C5a, and C5b-9.	Gou et al. 2013 [21]
Human sepsis	Reduced P levels in patients on admission to the intensive care unit compared to controls. Slightly lower P levels in non-survivors compared to survivors. Low P levels correlated to increased treatment duration.	Stover et al. 2015 [14]
Chronic heart failure	Reduced P levels compared to controls, especially in those with a more advanced clinical disease, while FD and sC5b-9 were increased. P levels correlated with measures of cardiac function and were associated with adverse outcome.	Shahini et al. 2017 [16]
Viral lower respiratory tract infections	Reduced P levels in patients with severe compared to mild diseasea, although no differences found in acute versus recovery samples.	Ahout et al. 2017 [96]
Chemotherapy-induced neutropenia	Reduced P levels in the neutropenic state versus the preneutropenic state with normal neutrophil counts.	Tsyrkunou et al. 2017 [9]
b. Diseases and conditions associated with increased properdin levels
Healthy first-degree relatives of type 2 diabetes subjects	Elevated P levels in healthy first-degree relatives of type 2 diabetes subjects compared to age-matched controls. FB and sC5b-9 were also significantly higher in first-degree relatives, but no differences in C3, Bb, C3a, or FH.	Somani et al. 2012 [15]
Hemodialysis	Elevated P levels (by approximately factor 1.3) compared to controls, and slightly higher levels at the end of the hemodialysis session compared to the start. Also increased levels of C3d and C5b-9 after hemodialysis.	Poppelaars et al. 2016 [18]
Antibody-mediated rejection in heart transplant recipients	Elevated P levels in AMR patients carrying a rare AMR-associated allele in the P gene compared to control patients not carrying the rare allele and without AMR.	Marrón-Liñares et al. 2017 [97]
Cardiovascular events	Elevated P levels were associated with endothelial dysfunction, and with the risk of cardiovascular events.	Hertle et al. 2016 [98]
IgA nephropathy	Elevated P levels (by approximately factor 1.5) compared to controls. Also in the patients followed over time, P levels remained higher.	Onda et al. 2007 [22]

^aNo data on age-matched controls in this study involving very young children and no correction for age between the disease groups

P properdin, C3GN C3 glomerulonephritis, DDD dense deposit disease, C3NeF C3 nephritic factor, C4NeF C4 nephritic factor, sC5b-9 soluble C5b-9, FD factor D, FB factor B, AMR antibody-mediated rejection