Infections in sickle cell disease.

Bacterial infections are considered a major cause of morbidity and mortality in patients, particularly children, with sickle cell disease. Infections including pneumonia, meningitis, osteomyelitis, pyelonephritis and general sepsis are more prevalent in patients with these genetic abnormalities than in normal individuals. Generally, infections are more prevalent in children than in older patients. The most common cause of severe infections in hemoglobinopathies include Diplococcus, Staphylococcus, Pneumococcus, Salmonella and Streptococcus. Several investigations have been conducted to determine the possible defects in the host defense mechanisms. Functional asplenia, defects in alternate pathway and in opsonic activity and phagocytosis of Streptococci, Staphylococci and Salmonella in sickle cell anemia patients are considered important factors predisposing these patients to bacteremia. On the other hand, a beneficial association has been demonstrated between the sickle cell gene and malaria. The hemoglobin S (Hb S) provides a natural resistance against the malarial parasite resulting in an improvement in fitness and survival over the normal (Hb AA) individuals. This communication reviews infections in sickle cell disease with a comparison of results in various populations.