Relationship between ABO blood groups and malaria with clinical outcome in rural area of South India

Background A number of studies have shown that susceptibility to several infectious diseases is related to the patient’s blood group. Although the relationship between blood group and susceptibility to malaria has been studied by several researchers, the results have been contradictory. Since malaria has re-emerged as a major problem in India during the past few years, it would be useful to know whether there is any relationship between blood group and infection. Objectives The study will be undertaken to correlate the blood groups and clinical presentations in malaria patients and to understand the differential host susceptibility in malaria. Method Over a period of 4 years malaria positive samples identified by peripheral smear (thin and thick smears) will be evaluated in this study. Haemoglobin, total leucocyte count, differential leucocyte count and platelet count of each patient done on an automated cell counter will be retrieved from the data. Blood group was determined by forward and reverse method. The demographic details of the patients and clinical details were obtained from case records of the patients. Malarial species and the severity of clinical course were correlated with blood groups Results A total of 205 patients were included in the study, of which 123 cases were positive for plasmodium falciparum and 78 cases were positive for P. vivax infection and 4 patients had mixed infection. The results of blood groups showed 33 -‘A’ group, 84 -‘B’ group, 70 -‘O’ group and 18 were ‘AB’ group. When the clinical courses between different groups were compared using the following parameters for severe infection- a parasitic load of > 10/1000 RBCs, severe anemia with haemoglobin <6gm%, platelet count of <10,000/mm3, hepato or splenomegaly or clinical signs of severe malaria such as fever >101o F and the other organ involvement, it was observed that there was no significant relationship between ABO blood group and malaria in our population, this could be due to various demographic reasons. Conclusions The present study indicate that individuals of blood group A and B are more susceptible to malaria infection as compared with individuals of blood group O, however the severity of infection differs due to differential host susceptibility