Final answer:
Certain drugs like penicillin can cause direct Coombs-positive hemolytic anemia by acting as haptens that bind to red blood cells, causing the immune system to produce antibodies against them. These antibodies activate the complement system, leading to red blood cell destruction and anemia.
Step-by-step explanation:
Direct Coombs-Positive Hemolytic Anemia and Drug Induction Direct Coombs-positive hemolytic anemia can be caused by certain drugs that lead to an immune reaction in which the body's immune system creates antibodies that mistakenly target and bind to red blood cells. This binding can be detected using the direct Coombs' test, also known as the direct antiglobulin test. The drugs known to induce this type of anemia include penicillin and other antibiotics, which can act as haptens, binding to red blood cell membranes and forming a complex that the immune system interprets as foreign, leading to the production of antibodies against the red blood cells. The antibodies that bind to the red blood cells can then activate the complement system, which leads to the lysis of the red blood cells and the resulting anemia. In the context of jaundice in newborns, the direct Coombs' test can be used to confirm whether the baby's red blood cells are being destroyed due to antibodies from the mother that have crossed the placenta. Conditions other than drug-induced anemia, such as blood transfusion reactions, infections like Mycoplasma pneumonia, and autoimmune disorders can also result in a positive direct Coombs' test.