Pyelonephritis during pregnancy: A cause for an acquired deficiency of protein Z

Figures & data

Figure 1. Factor X activation and protein Z/protein Z-dependent protease inhibitor (ZPI) inhibition of activated factor X. (a) The formation of the complex of tissue factor (TF) and factor VIIa (FVIIa) at the site of injury and activation of extrinsic coagulation cascade. (b) Activation of circulating factor X by the TF + FVIIa complex in the presence of exposed phospholipids and Ca²⁺. (c) Inhibition of factor Xa (FXa) by the protein Z/ZPI complex by binding to its active site. Modified from Broze JG, Lancet 2001;357:900–901.

Table I.  Demographic and clinical characteristics of the study population.

	Normal pregnancy (n = 71)	Pyelonephritis (n = 42)	p-Value
Maternal age (years)	24.2 ± 4.5	23.8 ± 6.7	0.2
Gravidity*
1	14 (20.3%)	9 (21.43%)
2–5	45 (65.2%)	30 (71.43%)	0.4
≥6	10 (14.5%)	3 (7.14%)
Parity**
1	39 (55.7%)	30 (71.4%)
2–5	30 (42.9%)	12 (28.6%)	0.3
≥6	1 (1.4%)	0
Ethnic origin^†
African-American	53 (77.9%)	31 (75.6%)
Caucasian	11 (16.1%)	6 (14.6%)	0.3
Hispanic	2 (3%)	4 (9.8%)
Asian	2 (3%)	0
Gestational age at blood collection (weeks)	30.8 ± 5.1	29.8 ± 5.9	0.4
Gestational age at delivery (weeks)	39.4 ± 1.5	38.7 ± 2.6	0.3
Birth weight (grams)	3340 ± 392	3086 ± 584	0.02

Data are presented as mean ± standard deviation or number (%). *Normal pregnancy (n = 69). **Normal pregnancy (n = 70). ^†Normal pregnancy (n = 68); pyelonephritis (n = 41).

Figure 2. Maternal plasma protein Z concentrations in patients with normal pregnancy (N = 71) according to gestational age.

Figure 3. Maternal plasma protein Z concentrations in patients with normal pregnancy and patients with pyelonephritis. The median maternal plasma concentration of protein Z was significantly lower in patients with pyelonephritis than in normal pregnant women (2.14 μg/mL (range 0.44–3.42) vs. 2.36 μg/mL (range 1.09–3.36; p = 0.029).

Table II.  Plasma concentrations of anti-protein Z antibodies in both study groups.

	Normal pregnancy (N = 71)	Pyelonephritis (N = 42)
Antiprotein Z IgG (AU/mL)	2.93 (0, 500.5)	2.48 (0, 101.42)
Antiprotein Z IgM (AU/mL)	12.67 (0, 44.03)	10.71 (1.58, 61.28)

Data presented as median (minimum, maximum).