Elevated IgE in a patient with monoclonal gammopathy of undetermined significance
Question:
5/11/2022
A 78-year-old female referred to me for evaluation of elevated IgE. She does follow with Derm for contact dermatitis and Rheum for connective tissues disease vs. SLE. She has history of MGUS (follow with Heme),
IgE 482, 473 9/26/19 (baseline IgE level).
IgE 6615 4/26/21
Repeat IgE level 10/12/21 4226.
10/5/21. Lab results
CMP: Cr 0.58 low.
Anti DS DNA 5 H
Sjogrens' AB SS-A 2.6 positive; SS-B negative.
UA wnl
CBC w/diff wnl
ANA screen negative
C3C 101 wnl
C4 22 wnl
Anti SM antibody negative.
She does not have history of asthma or eczema.
Mild environmental allergies with minimal small + SPT to aeroallergens that seem out of context of the IgE elevations.
I would have inferred the the elevated IgE was related to MGUS. Heme/Onc specifically did not feel that this was related. I do not understand why other immunoglobulin levels may be elevated with MGUS but not IgE. I would appreciate your thoughts.
Answer:
I had difficulty finding recent medical literature that mentions IgE in MGUS, so I imagine that this is extremely rare, if it exists at all. Overproduction of monoclonal immunoglobulin is the result of clonal expansion of a single plasma cell, so this is likely to explain the answer to your question, at least in part. From my reading, there are three distinct types of MGUS:
●Non-IgM MGUS (IgG, IgA, or IgD MGUS) – Non-IgM MGUS is the most common subtype of MGUS
●IgM MGUS – accounts for approximately 15 percent of MGUS cases.
●Light chain MGUS
There is also the issue of an incomplete understanding of the cause of MGUS. There are certainly genetic mechanisms at play. Kyle et al reported that the monoclonal cells in IgG and IgA MGUS arise from a mature, somatically mutated, post-switch plasma cell. Half of cases have evidence of translocation in the Ig heavy-chain region at 14q32. In IgM MGUS, the monoclonal cells arise from somatically mutated, postgerminal center B lymphocytes that have not undergone isotype class switching and consequently do not have the 14q32 translocation.
If you have done a thorough allergy/immunology evaluation of the patient’s elevated IgE that doesn’t explain why it is elevated, then I suggest a multi-disciplinary conference with the hematologist and rheumatologist.
References
Kyle RA and Rajkumar SV. Monoclonal gammopathy of undetermined significance. Br J Haematol 2006; 134(6):573-89.
Kyle RA, Therneau TM, Rajkumar SV et al. Long-term follow-up of IgM monoclonal gammapathy of undetermined significance. Blood. 2003;102(10):3759-64.
I hope this information is of help to you.
Jacqueline A. Pongracic, MD, FAAAAI