New Research on the Immune System in MECP2 Duplication Syndrome

clinImmBauer, M. et al. (2015). Infectious and Immunologic Phenotype of MECP2  Duplication Syndrome, Journal of Clinical Immunology, DOI 10.1007/s10875-015-0129-5

Back in July 2012, a previous post on this blog discussed  a German research project on pneumonia in MECP2 Duplication Syndrome ed by Michael Bauer. Some of your children may have participated in the study. Now, the results of this study have been published and they are quite interesting. 

Perhaps of most interest to families of individuals with MECP2 Duplication Syndrome, is a clear recommendation for the use of pneumococcal vaccines such as Prevnar 13 or Pneumovax 23 and the suggestion for antibody titers to determine how well the child responded. This recommendation is not entirely new. For example in 2011, van Esch published a review of MECP2 Duplication Syndrome that included:

Interestingly, we and others have found that affected boys do not respond adequately to vaccines containing polysaccharide antigens (e.g. Streptococcus pneumoniae, Haemophilus influenzae type B, Neisseria meningitidis) and often require extra boosters [Friez et al., 2006; Prescott et al., 2009]. The same authors also performed immunological laboratory investigations, including T- and B-cell numbers, T-cell functional studies, serum immunoglobulin levels (IgM, IgE, IgA, IgD and IgG plus subclasses) and complement activity, but could not detect consistent abnormalities that could explain the occurrence of the recurrent infections.

THIS IS NOT INTENDED AS MEDICAL ADVICE, BUT IS WORTH DICUSSING WITH YOUR CHILD’S DOCTORS. From a parent’s perspective, the Bauer study may be of practical use because its recommendation is clear enough and worth sharing with your child’s doctor to determine if it should be implemented for your child and how. For example, some may choose to boost the pneumococcal vaccination every 2 or three years without checking antibody titers, some may want to alternate between the two versions of vaccines (as has been recommended for some vulnerable people). We have followed a version of this for our son for several years now and it does seem to have improved his resistance to pneumonia. Also, from a parents perspective, it is great to see focus on immunology and respiratory infections. MECP2 Duplication affects so many things in an affected individual’s life, but none of them are more life-threatening.

There are a number of other interesting aspects of the new Bauer study. It suggests the findings of Yang et al, (2012) suggesting that MECP2 overexpression  result in impaired immunity by suppression of IFN-γ (interferon gamma) are only partially supported. While they found evidence of this suppression, they also found evidence of other dysfunction of the immune system, and theorize that these other issues may result from other duplicated genes on Xq28. So in essence they are suggesting that the problem is more complex than just IFN-γ suppression.

They also provide a good inventory of which pathogens were isolated from blood, urine, and respiratory tracts of patients with MECP2 Duplication and how frequently they were found. This is very helpful, however, it is important to recognize that these were based on a small number of available cases and therefore it is hard to generalize from these results, particularly from negative findings. In other words, the lack of finding a particular pathogen in this sample does not provide evidence that missing pathogen is not a significant threat to individuals with MECP2 Duplication. Nevertheless, this provides a good start, and certainly produced some interesting results.

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