A 4-year-old male is exposed to latex gloves during a minor surgical procedure and is subsequently found to produce anti-latex IgM antibodies. Several months later he develops a severe allergic reaction to latex and is found to have a high level of serum anti-latex IgE antibodies. Which of the following cytokines is most likely responsible for this anti-latex antibody isotype change?

Question

A 4-year-old male is exposed to latex gloves during a minor surgical procedure and is subsequently found to produce anti-latex IgM antibodies.  Several months later he develops a severe allergic reaction to latex and is found to have a high level of serum anti-latex IgE antibodies.  Which of the following cytokines is most likely responsible for this anti-latex antibody isotype change?

Quizplus · Accepted Answer

11ec160b_37b6_5480_9249_d9862f9c2d9f_MD0001_00 This patient has a severe allergic reaction to latex several months after initial sensitization. During the first encounter with an antigen (allergen), antigen-presenting cells (eg, macrophages, B cells, and dendritic cells) take up the antigen and display it with MHC class II molecules. CD4+ T cells are activated when they detect the MHC class II-associated antigen and differentiate into either T_H1 or T_H2 subsets. T_H2 lymphocytes promote the humoral immune response by secreting IL-4 and IL-5, cytokines that activate B cells. IL-4 stimulates the proliferation and differentiation of T_H0 (naïve) T cells into T_H2 lymphocytes, thus increasing the T_H2 subpopulation and the stimulus for the primary humoral immune response (eg, IgM). It also induces B cell proliferation and immunoglobulin class switching to IgE which is responsible for the type I hypersensitivity reaction following repeated exposure to an allergen. IL-5 contributes to B cell differentiation in addition to its role in stimulating IgA production and eosinophil activity (eg, host defense against parasitic infections). (Choice A) IL-1 is produced by macrophages. It activates naïve T_H0 lymphocytes and promotes their differentiation into T_H1 and T_H2 subpopulations. IL-1 is also an endogenous pyrogen. (Choice B) IL-2 is the first interleukin produced by T cells after contact with antigen. It is secreted mainly by T_H1 cells and stimulates development of CD4+ T helper cells, CD8+ cytotoxic cells, and B cells. (Choice C) IL-3 stimulates growth and differentiation of bone marrow stem cells and is produced by T helper cells. (Choice E) IL-10 helps regulate the balance between the T_H1 and T_H2 subpopulations of T helper cells. It is produced by T_H2 lymphocytes and inhibits synthesis of interferon-γ leading to a decrease in the T_H1 subpopulation. IL-10 also plays a part in class switching from IgM to IgG antibodies. (Choice F) IL-12 is synthesized by macrophages and stimulates growth and development of the T_H1 subpopulation of T helper cells. Educational Objective: IL-4 is produced by the T_H2 subset of T helper cells. It facilitates proliferation of B cells and T_H2 lymphocytes and stimulates antibody isotype switching to IgE which mediates type I hypersensitivity (allergic) reactions.

A 4-Year-Old Male Is Exposed to Latex Gloves During a Minor