B cells disorders

Remember about the factories? well now we will explain the B cells disorders. 

In general in this kind of deficiencies, we will have increase risk of recurrent infections with encapsulated bacterias, enteroviral, hepatitis viruses and sinopulmonary infections. They have in common in the physical exam that this will be normal (that means no increase in size of tonsils, nodes). And in the history we will have a patient who is healthy until he is around 6 to 9 months old, when he presents with recurrent infections as we said before.

Knowing this, here we go:

1. Bruton Agammaglobulinemia (also know as X-linked agammablobulinemia)

Ok, let's start from the name: A - gammaglobulinemia, "A" means lack, so in this case we will have a lack or absence of B cells and therefore we will have in the laboratory findings very low levels of Ig G,A,M,E (GAME) This means decrease CD19+ which is the marker for B cells, BUT having normal levels of T cells with their marker CD3+.

Treatment: regular use of what we lack: Ig, so we will give IVIG (intravenous immunoglobulin)

2. CVID (a.k.a. common variable immunodeficiency)

The main issue in this disorder is that even having a NORMAL number of B cells, they don't produce the amounts of Ig needed. So again in common with the B cell disorder our risk of having recurrent infections will increase. One specific characteristic of this disorder is the increase risk of autoimmune disorders like pernicious anemia and seronegatives diseases, and also the increase risk of lymphoma specially in females.

Treatment: again is using IVIG, but prior to this we will need to make screening for anti-IgA antibodies, if they are present is safer to use IVIG without IgA.

3. Selective IgA deficiency

Do we have to say more about this? Well yes. Obviously we will have a selective deficiency of IgA, this will increase the risk of respiratory and GI infections, like Giardia (remember where do we have IgA). But also this will have a increased risk of anaphylaxis in those who receive blood from a person with normal level of IgA and a increase risk of autoimmune disorders like in CVID.

Treatment: this one will have a different one, DON'T USE IVIG, why? because of the increase risk of anaphylaxis from anti-IgA antibodies, plus IVIG is almost 100% IgG. So just treat the infections as they appear.

So in summary:

Bruton: absence of B cells (low level of Ig), treated with IVIG

CVID: normal number of B cells with defective production of Ig (low level of Ig), lymphoma associated and treated with IVIG (screening for antiIgA needed prior to treatment)

Selective IgA Def: normal number of B cells with defective production of IgA, anaphylaxis with blood from normal patient, DON'T USE IVIG (again risk of anaphylaxis)

This is all for today, I hope you enjoy the lesson

See you on the next post: T cells disorders

Carlos Albrecht