Question

Does Hyper-IgM Syndrome (yes/no)

d.     results from defective CD40L on his T lymphocytes                          
e.     results from defective CD80/86 on his helper T lymphocytes                       
f.       is also associated with the presence of otherwise rare IgM class autoantibodies
g.     reduce life expectancy?
h.     can babies with hyper igM be prte3cted from symptoms by maternal igG for the first few months of life?

Answer 1

ANSWER:

d. YES

e. NO

f. YES

g. YES

h YES

EXPLANATION: Hyper IgM syndrome is immunoglobulin deficiency in which there is excess of IgM whereas deficiency of other types of immunoglobulin. There is a defect in the class switching of the immunoglobulins. Due to which the IgM is unable to convert into other immunoglobulins. It is of two types:

1.) X linked recessive - mutation in CD40L on T cells

2.) Autosomal recessive - mutation of CD40 on B cells

Clinical features : Recurrent pyogenic infections (due to decreased opsonising property of IgG)

  Giardiasis (due to deficiency of IgA)

   Pneumonia

It can even lead to death.

Since there is maternal IgG transferred through the placenta during uterine life of a baby, it is present in a newborn for the first 6 months of life. This IgG protects baby in the first few months from manifestation of the syndrome.