Haematological profile of malaria patients with G6PD and PKLR variants (erythrocytic enzymopathies): a cross-sectional study in Thailand

BACKGROUND: Glucose 6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PKLR) deficiencies are common causes of erythrocyte haemolysis in the presence of antimalarial drugs such as primaquine and tafenoquine. The present study aimed to elucidate such an association by thoroughly investigating the haematological indices in malaria patients with G6PD and PKLR(R41Q) variants. METHODS: Blood samples from 255 malaria patients from Thailand, Myanmar, Laos, and Cambodia were collected to determine haematological profile, G6PD enzyme activity and G6PD deficiency variants. The multivariate analysis was performed to investigate the association between anaemia and G6PD Mahidol(G487A), the most common mutation in this study. RESULTS: The prevalence of G6PD deficiency was 11.1% (27/244) in males and 9.1% (1/11) in female. The MAFs of the G6PD Mahidol(G487A) and PKLR(R41Q) variants were 7.1% and 2.6%, respectively. Compared with patients with wildtype G6PD after controlling for haemoglobinopathies, G6PD-deficient patients with hemizygous and homozygous G6PD Mahidol(G487A) exhibited anaemia with low levels of haemoglobin (11.16 ± 2.65 g/dl, p = 0.041). These patients also exhibited high levels of reticulocytes (3.60%). The median value of G6PD activity before treatment (Day 0) was significantly lower than that of after treatment (Day 28) (5.51 ± 2.54 U/g Hb vs. 6.68 ± 2.45 U/g Hb; p < 0.001). Reticulocyte levels on Day 28 were significantly increased compared to that of on Day 0 (2.14 ± 0.92% vs 1.57 ± 1.06%; p < 0.001). PKLR(R41Q) had no correlation with anaemia in malaria patients. The risk of anaemia inpatients with G6PD Mahidol(G487A) was higher than wildtype patients (OR = 3.48, CI% 1.24–9.75, p = 0.018). Univariate and multivariate analyses confirmed that G6PD Mahidol(G487A) independently associated with anaemia (< 11 g/dl) after adjusted by age, gender, Plasmodium species, parasite density, PKLR(R41Q), and haemoglobinopathies (p < 0.001). CONCLUSIONS: This study revealed that malaria patients with G6PD Mahidol(G487A), but not with PKLR(R41Q), had anaemia during infection. As a compensatory response to haemolytic anaemia after malaria infection, these patients generated more reticulocytes. The findings emphasize the effect of host genetic background on haemolytic anaemia and the importance of screening patients for erythrocyte enzymopathies and related mutations prior to anti-malarial therapy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12936-022-04267-7.