Cytokine Levels in Plasma Samples of Individuals with HIV Infection

CD4+ T helper cells play a vital role in the immune system by secreting cytokines, which regulate the immune response. Cytokines are secreted by T cells when an intracellular infection is detected as in case of HIV infection. HIV is known to infect T cells that have CD4+ receptors present on their surface. These cells, among others in the immune system, secrete cytokines. The levels of cytokines present in the plasma become an indicator of the nature of the immune response. In this study we are measuring levels of plasma cytokines in HIV infected individuals and healthy control subjects using ELISA. Our results indicate that cytokine plasma levels between the two groups are substantially different. In general, we observed that there was an increase in anti-inflammatory cytokines and a decrease in pro-inflammatory cytokines in individuals that were positive for HIV infection, likely due to the role of HIV in suppressing the appropriate immune response in HIV positive individuals. that activate T helper cells, causing them to differentiate into effector cells specialized in cytokine secretion and function. Th1 activation also requires interleukin 12 (IL-12) [5]. IL-12 is secreted by a class of APC called dendritic cells (DC). IL-12 induces native T-cells into the Th1 (CD4+) subset. Th1 cells then go onto produce cytokines IL-2 and interferon gamma (IFN-γ). IFN-γ acts by activating macrophages and is essential for eliminating intracellular pathogens [6]. Interleukin 2 (IL-2) is crucial for growth, proliferation and differentiation of T-cells, acting as a growth factor for T-cells [3]. Studies conducted earlier have revealed that HIV-infected individuals have a weaker immune system; this is due to the inability of CD4+ T cells to proliferate, due to the decrease in the levels of IL-12 [7]. A consequence of this decrease in IL-12 results in a decrease in IL-2 and IFN-γ, leading to immunosuppressive effects and allowing room for opportunistic infections, which is a trademark of HIV progression. This shows how CD4+ T cells play a central role in disease progression [8]. CD4 T cell counts are important biomarkers for AIDS progression in HIV patients [9]. A range of 500-1000 cells/ mm3 is considered a normal range for healthy individuals, while a CD4 count of 200 cells/mm3 is diagnostic for AIDS [10]. Given HIV’s role in dampening the immune response towards intracellular pathogens, pro-inflammatory cytokines should be decreased in HIV infected individuals, while the opposite effect would be true of anti-inflammatory cytokines. Levels of anti-inflammatory cytokines interleukin 10 (IL-10), for example, should be relatively decreased in healthy individuals with intracellular infections, allowing the infection to be better cleared by the appropriate Th1 response. Likewise, Transforming Growth Factor Beta (TGF-β), a cytokine with an important role in augmenting a regulatory T cell response (T-regs) [11] that inhibits the immune system, should be decreased in healthy individuals with intracellular infection. Another cytokine, interleukin 6 (IL-6), has been found to serve as a growth factor for the HIV [12]. Because HIV infection weakens the cell mediated immune response and directs it to allow for its own survival, we would expect levels Introduction Having claimed more than 36 million lives so far and with approximately 35.3 million people infected with HIV as of October 2013, HIV is a major global health issue [1]. The Human Immunodeficiency Virus (HIV) targets the immune system and weakens the surveillance and defense system of the body against infections, resulting in HIV infected individuals becoming more susceptible to a wide range of infections normally cleared by the immune system of a healthy individual [1]. Cytokine levels are indicative of the nature of the immune response in a particular individual. When immune cells detect intracellular pathogens, the immune response that results is specifically tailored to optimize the clearance of the pathogen [2]. T helper cells, also named CD4+ T helper cells (Th), are immune cells with an important role in directing the response necessary to accomplish this task. When the response calls for the clearance of an intracellular pathogen, a Th1 response is induced [2]. On the contrary, when removal of an extracellular pathogen is necessary, the resultant Th2 response is induced [2]. In contrast to the Th1 response, the Th2 response mediates antibody production [3]. Cytokines generally can be divided into 2 major categories, the pro-inflammatory cytokines, which stimulates the immune system, or the anti-inflammatory cytokines which suppresses the immune system [2]. Not only are CD4+ T helper (Th) lymphocytes crucial regulators of the immune system, but they also play a major role in inflammatory disease progression. One of the most important factors in directing CD4+ T helper cells towards the appropriate response are cytokines produced by cells of the innate immune system [4]. Antigen presenting cells (APC) are innate cells Research Article Cytokine Levels in Plasma Samples of Individuals with HIV Infection Enrique Vera Tudela1, Manpreet Kaur Singh1, Minette Lagman1, Judy Ly2, Nishita Patel3, Cesar Ochoa3 and Vishwanath Venketaraman1, 2* 1Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA 2Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766-1854, USA 3Western Diabetes Institute, Pomona, CA 91766, USA *Corresponding author: Vishwanath Venketaraman, Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 East Second Street, Pomona, CA 91766-1854, USA, Tel: 909-706-3736; Email: [email protected] Received: January 04, 2014; Accepted: January 30 , 2014; Published: February 06, 2014 Austin Publishing Group A