Table 1.
Baseline Characteristics and Phosphatidylserine Immunoglobulin M and Immunoglobulin G Antibodies in Controls and Patients With Malaria
| Characteristic | Controls (n = 50) | Plasmodium falciparum (n = 269) | Plasmodium vivax (n = 176) | Plasmodium knowlesi (n = 42) | Plasmodium malariae (n = 21) |
|---|---|---|---|---|---|
| Age, y, mean (range) | 35 (14–69) | 28 (7–78) | 24 (2–79) | 43 (17–75) | 17 (5–54) |
| Male sex, No. (%) | 34 (68) | 202 (75) | 127 (72) | 30 (77) | 16 (76) |
| Previous malaria | NA | 34 (13) | 51 (29) | 14 (34) | 51 (29) |
| Fever duration, d | … | 5 (3–7) | 5 (3–7) | 5 (4–7) | 6 (3–7) |
| Parasite count, parasites/μL | … | 10 011 (2902–32 472) | 4000 (1775–9548) | 4215 (2372–29 922) | 1313 (162–2778) |
| Severe malaria, No. (%) | … | 29 (11) | 12 (7) | 10 (26) | 0 (0) |
| Hb on enrollment, g/dL, mean (SD) | … | 12.9 (2.0) | 12.2 (2.1) | 12.4 (2.2) | 11.6 (2.2) |
| Hb nadir, g/dL, mean (SD) | … | 11.3 (1.8) | 10.8 (1.9) | 11.2 (2.3) | 10.5 (1.9) |
| Hb decline, g/dL | … | 1.4 (0.8–2.2) | 1.3 (0.7–2.1) | 1.2 (0.2–2.0) | 1.2 (0.9) |
| Anemiaa on admission, No. (%) | … | 97 (36) | 89 (51) | 21 (50) | 14 (67) |
| Anemiaa during follow-up, No. (%) | … | 251 (93) | 167 (95) | 39 (93) | 20 (95) |
| Admission Hb <10 g/dL, No. (%) | … | 23 (9) | 30 (17) | 6 (14) | 6 (29) |
| Nadir Hb <10 g/dL, No. (%) | … | 56 (21) | 61 (35) | 13 (31) | 9 (43) |
| CFHb, ng/mL | 15 146 (9641–25 256) | 34 309 (15 330–527 779) (n = 171) | 32 498 (16 813–44 489) (n = 62) | 20 042 (15 072–44 242) (n = 15) | … |
| RBC-D (at 1.7 Pa), EI | 0.197 (0.178–0.227) (n = 7) | 0.182 (0.163–0.198) (n = 90) | 0.196 (0.160–0.214) (n = 25) | 0.168 (0.147–0.190) (n = 11) | … |
| RBC-D (at 30 Pa), EI | 0.587 (0.520–0.590) (n = 7) | 0.518 (0.480–0.557) (n = 90) | 0.543 (0.518–0.572) (n = 25) | 0.492 (0.448–0.550) (n = 11) | … |
| PS IgM day 0, U/mL | 27 (19–41) | 85 (55–134) | 93 (62–181) | 60 (41–108) | 91 (58–146) |
| PS IgM, day 7, U/mL | … | … | … | … | 103 (42–142) (n = 15) |
| PS IgM, day 14, U/mL | … | 130 (80–183) (n = 32) | 143 (49–2686) (n = 15) | 81 (50–116) (n = 33) | … |
| PS IgM, day 28, U/mL | … | 83 (66–131) (n = 69) | 84 (51–124) (n = 22) | 62 (36–92) (n = 22) | 55 (39–63) (n = 14) |
| PS IgG, day 0, U/mL | 17 (14–21) | 49 (35–72) | 59 (39–92) | 44 (21–85) | 63 (41–77) |
| PS IgG, day 7, U/mL | … | … | … | … | 58 (20–85) (n = 15) |
| PS IgG, day 14, U/mL | … | 94 (64–112) (n = 32) | 62 (37–251) (n = 15) | 68 (30–93) (n = 33) | … |
| PS IgG, day 28, U/mL | … | 43 (19–63) (n = 69) | 49 (22–120) (n = 22) | 46 (26–70) (n = 22) | 38 (20–47) (n = 14) |
Data are presented as median (interquartile range) unless otherwise indicated. For PS IgG and IgM antibodies at baseline, P < .0001 for healthy controls compared to all Plasmodium species.
Abbreviations: CFHb, cell-free hemoglobin; EI, elongation index; Hb, hemoglobin; IgG, immunoglobulin G; IgM, immunoglobulin M; NA, not available; RBC-D, red blood cell deformability; PS, phosphatidylserine; SD, standard deviation.
aSelf-reported. Anemia based on World Health Organization 2011 hemoglobin measurement criteria [26]: age 6–59 months, ≤10.0 g/dL; age 5–11 years, <11.5 g/dL; age 12–14 years, <12.0 g/dL; nonpregnant women age ≥15 years, <12.0 g/dL; pregnant women, <11.0 g/dL; men age ≥15 years, <13.0 g/dL.