Dysfunction of Memory B Cells in HIV Infected Persons

Dysfunction of Memory B Cells in HIV Infected Persons

Written by Lisa M Roberts

              The working definition of the lymphatic system as provided by the website Patients Against Lymphoma (2004) is as follows,

                         “The lymphatic system consists of organs, ducts and nodes. It transports a watery clear fluid called lymph.  This fluid distributes immune cells and other factors throughout the body.  It also interacts with the blood circulatory system to drain fluid from cells and tissues.  The lymphatic system contains immune cells called lymphocytes, which protect the body against antigens (viruses, bacteria, etc.) that invade the body “(Lymphoma.org, 2004).

     More specifically the lymphatic system is composed of several bodily organs.  The bone marrow, spleen, thymus gland, and lymph nodes are all a part of this system.  The Text book The Language of Medicine describes the lymphatic system as an immune system of the Body (Saunders, 2007. P.531).   It is a specialized system which defends against invasive antigens.  The lymphatic system includes lymphoid organs, their products (lymphocytes and antibodies) and macrophages (phagocytes) which are used to resist foreign organisms and toxins, to keep tissues and organs undamaged by hostile agents or invaders (Saunders, 2007. P.531).  

     The breakdown of the lymphatic system is a precursor to immune deficiency and the many diseases that prey on the body.  Immune reaction is vital to an organism’s survival. Millions of simple bacterial and fungal antigens would wreak havoc in our bodies without the intervention of the lymphatic reaction of phagocytes and macrophages which fight the infection in the first place and then sweep up the debris.  There are also other disease fighting cells such as natural killer T cells and memory B cells with specialized functions within the lymphatic system. These cells go after hostile antigens killing and destroying tumor and viraly affected cells.

            Current research confirms that persons infected with the HIV-1 virus are subject to lymphatic system damage within 14 – 27 days of the initial infection (Levesque, 2009).  The HIV-1 virus extensively damages the immune system by targeting B cells.  Lymphatic B cells are phenotypically damaged and their levels reduced in the host organism. Once compromised  T lymphocytes such as Helper T cells and B cells are unable to respond properly to antigenic substances.  This leaves the organism open to systemic damage and disease.

            The B cell lymphocyte originates within the bone marrow.  It’s major function is to produce antibodies for an healthy immune response to pathogenic invaders.  The B cell is a precursor to the plasma cell. The Plasma cell generates the B memory cells which incite a rapid response to an antigen that has been encountered at least once before.  The patients with HIV-1 infection have damaged memory B cells which have been primed for apoptosis (De Milito, 2004).  The memory cells are not only reduced in number they are phenotypically altered, damaged and permanently impaired.  They no longer maintain the ability to recognize antigens that have been dormant in the body or that have been previously encountered.  This gives rise to invasion of the organism by secondary and opportunistic infection and disease that the organism would normally fight off with a rapid immune response.  In an article for the Journal of Current HIV Research, A. De Milito states that the cellular and humoral arms of the immune system are no longer able to control infection and that this results in the inability for lymphocytes to function thus creating the avenue of pathogenic opportunistic invasion.  De Milito further states that,

     “ a pathological feature induced by the persistent viral replication is the aberrant activation of cells of the immune system.  Among these cells, B lymphocytes are severly damaged and show signs of functional alterations.” (De Milito, 2004).

     After researching  peer reviewed medical journal articles from Pubmed it was discovered that the researched data confirmed the information reported in the De Militos research for  Duke University.  Research has shown that within human patients which are infected with HIV-1 the memory B cells are quickly damaged, altered and permanently impaired in the host organism due to HIV-1 virus related pathogenic mechanisms (De Milito, 2004).  Research data also confirms that this gives rise to increased infection by secondary and opportunistic antigens and disease causing agents which continue to weaken the comprimised human organism.  The research data further confirmed that the altering of the memory B cell function and structure somehow enabled the HIV-1 virus to replicate freely without evoking a response from the antibodies circulating within the hosts immune response system. The data also pointed to the inability to regenerate the B cell once it is damaged by the interactions with the HIV-1 virus despite treatment with antiretroviral therapy (Titanji et al, 2006).  Though early treatment with antiretroviral therapy did restore T cell counts in the infected patients, the B cells and their memory B cell counterparts were never regenerated to normal phenotypic or functional levels within the infected individual  (Titanji et al , 2006).

     Researchers are still looking for further data to aid in the understanding of the process of the HIV-1 virus and it’s replication processes within the human organism.  A furthering of scientific research may one day bring about a cure for the incredibly complex process of organism destruction and ultimately death brought about by HIV-1 infection.

De Milito, A. (2004). B lymphocyte dysfunctions in HIV infection. Current HIV Research, Jan;2910: 11-21. Retrieved on October 13, 2012 from Pubmed.

Levesque MC, Moody MA, Hwang KK, Marshall DJ, Whitesides JF, Amos JD, et. AL. (2009). Polyclonal B cell differentiation and loss of gastrointestinal tract germinal centers in the earliest stages of HIV-1 infection. Procedings of the National Academy of Science. Jul 7;6(7):e1000107. Retrieved on September 13, 2012 from Pubmed.

Lymphatic System (2004) Patients Against Lymphoma, retrieved October 30, 2012 from Lymphoma.org.

Titanji K, De milito, A, Cagigi A, Thorstensson R, Grutzmeier S, Atlas A, et. Al. (2006). Loss of memory B cells impairs maintenance of long-term serologic memory during HIV-1 infection. Blood, Sep 1; 108(5): 1580-7. Retrieved on October 13, 2012 from Pubmed.