Class: Immunology, what role does the spleen normally play in the human immune system?
2. What is the difference between “primary” and “secondary” lymphoid centers in the human body?
3. In sickle cell anemia, the spleen is commonly infarcted and destroyed, resulting in “asplenia” and, therefore, a lack of splenic function. Given this, what types of infections would be more common?
4. Also, Given the “asplenia” associated with sickle cell anemia, what type of vaccinations should patients with sickle cell take care to receive annually?
Sickle Cell Anemia is among the most commonly diagnosed genetic disorders in the United States. It is also one that, unfortunately, can be extremely difficult to manage on many fronts, from medical to socioeconomic perspectives. It is a disease which can debilitate adults and cripple children (even at the ages of infancy), and the medical management of sickle cell anemia requires medical knowledge, patience, and hope.
Characterized as an autosomal recessive mutation in the hemoglobin molecule, sickle cell anemia involves the substitution of a valine (a non-charged amino acid) for a glutamic acid (a polar amino acid); as you have probably learned in many of your biology, chemistry, and possibly genetics courses, changing the amino acid conformation of a protein effectively changes the function of that protein! This is the case with the hemoglobin molecule in SCA; the mutation effectively changes the overall conformation of the hemoglobin molecule, effectively conferring a “sickle” shape to the red blood cell.
This has a plethora of pathophysiologic implications, however! In particular, sickle-shaped cells are very adherent to one another and the blood vessel wall (tunica intima); this can result in the formation of arterial microthrombi (blockages of arterial blood flow) which can result in tissue death/ischemia. This can particularly affect the spleen, an important lymphoid center in the human body.