Why does Hyper IgM syndrome predispose to P jirovecii infections?

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!

Hairy cell leukemia

I am raising awareness about hematological malignancies this month.

Today, it's all about hairy cell leukemia.

Acute myelogenous leukemia fighter

I am raising awareness about hematological malignancies this month.

Immunoglobulin A and IgA deficiency mnemonic

IgA occurs as a monomer in the bloodstream and as a dimer when secreted (linked by the secretory component or a J chain attained from epithelial cells before secretion).

IgA is secreted onto mucosal surfaces (gastrointestinal, genitourinary, and respiratory) to block attachment of pathogens to mucous membranes.

Mnemonic: “ABCDE”
A: Alone (Monomer)
B: in Blood
C: Component (Secretory component) or Chain (J chain) makes
D: Dimer
E: in Epithelial surfaces

What happens in IgA deficiency? Mnemonic!

Hypophosphatemia

Happy phosphorous and a science y new year!

Panton-Valentine leukocidin

Panton-Valentine leukocidin

It's never lupus mnemonics

 Systemic Lupus Erythematosus and related antibodies mnemonics

Leukocyte adhesion deficiency

Leukocyte adhesion deficiency comic
PS: And this is how the Leukocyte & the Endothelial cell broke up </3

Hairy cell leukaemia simplified

Hairy cell leukaemia is a chronic type of leukaemia caused due to neoplastic proliferation of mature B cells.

Hairy cell leukemia comic

Rh incompatibility

Introduction: A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of RBC.
The Rh blood group system is the second most important blood group system out of the 30 human blood group system after the ABO blood groups.

If you are Rh-positive, it means you have rhesus antigen on your red blood cells.
Rh-negative means you don't have rhesus antigen.
A Rh-negative person can develop antibodies to the Rh-positive antigen.

Disclaimer: The cartoon comics, humor and analogies are pedagogical tool to promote learning. It is not intended to mock or downplay the seriousness of these conditions.

Analogy: Think of Rh-positive antigen as a target and antibodies as arrows.

What is Rh incompatibility?
Rh incompatibility occurs when an Rh-negative person is exposed to Rh-positive red blood cells (RBCs).
His immune system will destroy the Rh-positive cells by making antibodies (Anti-D antibodies or the arrows).
This person is now sensitized.
(Simply put, a sensitized person has arrows against the target or can rapidly make arrows from his memory if exposed to the same target again.)

Rh antigen and antibody

Systemic Lupus Erythematosus and related antibodies

It's not Lupus. It's never Lupus.