Here is an interesting concept.
We know that in Hyper IgM syndrome, there is an inability to undergo normal class-switching or somatic hypermutation in B cells.
It is characterized by normal level of B cells with diminished levels of IgG, IgE and IgA and with high levels of IgM.
That is why, these patients are susceptible to infections by extracellular pathogens that require class-switched antibodies for clearance, such as pyogenic bacteria.
But why would it predispose to P jirovecii (P. carni) infections? Pneumocystis doesn't require antibodies for clearance!
Here's why: The interaction between T cells and dendritic cells via CD40L-CD40 is essential for upregulating co-stimulatory molecules on dendritic cells. Dendritic cells activate T cells, which in turn, activate macrophages. Intracellular pathogens, such as mycobacteria are P jirovecii are normally killed by activated macrophages which is why patients with CD40L deficiency are prone to these infections.
That's all!
-IkaN
We know that in Hyper IgM syndrome, there is an inability to undergo normal class-switching or somatic hypermutation in B cells.
It is characterized by normal level of B cells with diminished levels of IgG, IgE and IgA and with high levels of IgM.
That is why, these patients are susceptible to infections by extracellular pathogens that require class-switched antibodies for clearance, such as pyogenic bacteria.
Here's why: The interaction between T cells and dendritic cells via CD40L-CD40 is essential for upregulating co-stimulatory molecules on dendritic cells. Dendritic cells activate T cells, which in turn, activate macrophages. Intracellular pathogens, such as mycobacteria are P jirovecii are normally killed by activated macrophages which is why patients with CD40L deficiency are prone to these infections.
That's all!
-IkaN
agreed! I am really impressed by the fact that you actually have this question in mind! good job! I really enjoy reading your blog and find it very helpful! thank you IkaN... in Malay, ikan means fish! which I find your name really cute! =)
ReplyDeleteGreat blog. Loved your approach to medical science. Making everything fun and interesting. Keep up the good work.
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