TABLE 1.
Demographic, hematologic, and clinical characteristics of study participants
| Characteristic | Value for groupd |
P value | |||
|---|---|---|---|---|---|
| Noninfected controls | P. vivax infections | P. falciparum infections | Mixed-species infections | ||
| No. of subjectsa | 18 | 43 | 19 | 14 | |
| Age (yr) | 32 (28-42) | 29 (21-40) | 41 (21-47) | 35 (28-47) | 0.111 |
| Gender (% male) | 55.5 | 62.8 | 63.2 | 50.0 | 0.816 |
| Time (yr) of malaria exposure | 28 (20-40) | 22 (15-30) | 25 (17-35) | 31 (19-39) | 0.155 |
| Hemoglobin level (g liter−1) | 141 (123-155) | 129 (117-141) | 130 (117-138) | 128 (110-138) | 0.107 |
| Anemia (%) | 22.2 | 34.7 | 26.3 | 35.7 | 0.530 |
| No. of WBCs (109 liter−1) | 7.5 (6.2-9.9) | 5.7 (4.8-6.7) | 5.1 (4.3-6.8) | 5.8 (4.6-6.4) | 0.003b |
| No. of lymphocytes (109 liter−1) | 2.6 (1.5-4.1) | 1.1 (0.7-1.6) | 1.5 (0.8-1.9) | 1.4 (1.0-1.7) | <0.0001b |
| No. of T lymphocytes (106 liter−1) | 948 (710-1,787) | 371 (180-729) | 464 (223-772) | 418 (322-650) | <0.0001b |
| No. of CD4+ T lymphocytes (106 liter−1) | 518 (356-914) | 140 (70-282) | 172 (106-303) | 184 (95-364) | <0.0001b |
| No. of platelets (109 liter−1) | 183 (120-220) | 201 (164-234) | 223 (128-266) | 0.248 | |
| Thrombocytopenia (%) | 39.5 | 15.8 | 28.6 | 0.217 | |
| Parasitemia (no. of parasites ml−1) | 1,068 (116-4,009) | 258 (20-1,365) | 12 (2-227) | 0.003c | |
| Geometric mean parasitemia | 422 | 135 | 18 | ||
| Clinical index | 0.91 (−1.87-2.85) | 1.12 (−1.31-3.33) | −1.04 (−2.71-1.90) | 0.296 | |
| Duration of symptoms (days) | 4 (2-6) | 5 (3-10) | 4 (2-5) | 0.445 | |
T lymphocytes and CD4+ T lymphocytes were quantified for 17 noninfected controls, 39 P. vivax-infected patients, 14 P. falciparum-infected patients, and 14 mixed-infection patients.
Post hoc Dunn's multiple comparison tests showed a significant difference between noninfected controls and all groups of patients but not between groups of patients.
Post hoc Dunn's multiple comparison tests showed a significant difference between P. vivax-infected patients and mixed-infection patients only (P = 0.001).
Data are presented as medians (interquartile ranges) unless stated otherwise and were compared across three or four groups with Kruskal-Wallis tests (continuous variables) or χ2 tests (proportions). Anemia was defined when the hemoglobin concentration was below the following cutoff values: 120 g liter−1 for adolescents aged 12 to 14 years and nonpregnant women and 130 g liter−1 for men aged ≥15 years. Thrombocytopenia was defined when the platelet count was below 150 × 109 liter−1.