Effect of Plasmodium falciparum infection on blood parameters and their association with clinical severity in adults of Odisha, India.

The extent of abnormalities in blood indices and their subsequent effects on clinical severity in malaria differ among populations of different endemicity. However, these alterations have not been well investigated in Odisha, India and their prognostic implications in the context of multi-organ dysfunction (MODS) in severe malaria (SM) are not identified so far. The present study was carried out in 200 adult patients each from uncomplicated malaria and severe malaria groups to examine whether host haematological and biochemical parameters in Plasmodium falciparum infection can act as diagnostic marker for SM in adults patients of Odisha. The results showed thrombocytopenia as a potential risk factor for SM irrespective of disease features with least median platelet counts observed in patients with MODS (Platelet count: 144.5, P = < 0.0001) compared to mild malaria. Logistic regression analysis identified anemia (<10 mg/dl) as independent predictor of MODS (OR = 12.78, 95% CI = 4.93-33.2). The prognostic utility of thrombocytopenia (platelet count: ≤100,000/µl) as marker of MODS was largely modulated by hemoglobin and blood glucose level. Co-existence of hypoglycemia and thrombocytopenia was also observed. Our study revealed changes in blood indices such as low platelet, hemoglobin and blood glucose during falciparum infection in adults can be used as diagnostic criteria for predicting SM in combinations. The study also provides important clue for plausible hypoglycemia mediated platelet necrosis and clearance. Further studies in different endemic regions need to be conducted for validation of these findings and their implication as criteria for diagnosing SM in adults.

Genetic predisposition of variants in TLR2 and its co-receptors to severe malaria in Odisha, India.

Although the role of TLRs signalling in malaria pathogenesis is well established, contribution of individual TLR to clinical outcome of malaria still remains inconclusive. Given the importance of TLR2 and its co-receptors in recognising distinct structural forms of key malaria toxins and mediating innate immune response, it is essential to delineate their genetic contribution. Variants in TLR1 (I602S) and TLR6 (P249S) were genotyped by PCR-RFLP methods, and TLR2 (I/D) was genotyped by PCR in 200 samples each from uncomplicated malaria (UM) and severe malaria (SM). Further, SM was categorised into its sub-clinical groups (CM and NCSM or SOD and MODS) and analysed. The results showed the PP genotype of TLR6 (P249S) to be significantly more common in UM (P < 0.0001), whereas the 'SS' genotype was the risk factor for SM including its sub-clinical categories. The TLR1 (602S) and TLR2 (D) variants were significantly high in patients with CM; however, negative LD was observed between TLR2 and TLR6 in NCSM and MODS. Haplotype analysis showed significantly high frequency of I-I-S haplotype in all forms of subclinical SM and was associated with low parasite load in SM (P = 0.013). The haplotypes I-D-S and S-I-P were significantly high in SOD and CM, respectively. The TLR6 '249S' variant appeared to be the dominant determinant for genetic predisposition to SM and that its association with either TLR2 'D' or TLR1 '602S' modulates for CM development. The present study opens up several new avenues for their exploration and validation in future studies in different global settings for malaria.

Influence of common variants of TLR4 and TLR9 on clinical outcomes of Plasmodium falciparum malaria in Odisha, India.

BACKGROUND: In malaria, the toll-like receptors (TLRs) have recently emerged as major player of innate immunity. However, implication of TLR variants on clinical manifestations of malaria is conflicting. The present study aims to provide relevant information of growing interest in understanding the role of TLR4D299G, TLR9T-1237C and TLR9T-1486C polymorphisms on clinical outcomes of malaria. METHODS: We genotyped TLR4D299G, TLR9T-1237C and TLR9T-1486C polymorphisms by PCR-RFLP methods and subsequently analyzed in 200 uncomplicated patients and 200 severe patients. Further, the severe malaria categorized into sub-clinical groups such as cerebral malaria (CM), non-cerebral severe malaria (NCSM), single organ dysfunction (SOD) and multi-organ dysfunctions (MODS) are analyzed. RESULT: The TLR9-1237CC genotype was observed at significantly low frequency in MODS (p=0.0008), while in heterozygous state (TC) it was proportionately more frequent in SOD (p=0.087) as compared to mild malaria. The TLR9T-1486C heterozygote was more common in all categories of severe malaria. However, pair wise LD analysis revealed significant linkage between T-1237C and T-1486C, whereas haplotype analysis showed significantly low frequency of C-T haplotype in CM (p=0.005, pc=0.02) and high frequency of T-C haplotype in NCSM as compared to mild malaria. CONCLUSION: Although TLR9-1237C could be a risk factor for severe malaria in heterozygous state, negative association of CC genotype with MODS warrants caution of segregating severe malaria into its sub-clinical groups while interpreting data. Further, clinical outcome in malaria was observed to be apparently modulated by LD between TLR9 promoter variants.