1. Successful use of Omalizumab for the prevention of anaphylaxis in a patient with non-clonal Mast Cell Activation (ncMCA) and Postural Tachycardia Syndrome (POTS)
SHARON CHAN1, SARAH DENMAN1 & SINISA SAVIC1*
Department of Clinical Immunology and Allergy, St James’ University Hospital, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
* Correspondence to
Background
Investigation
Result
Mast Cell Tryptase Level
10-20 ng/ml
Full Blood Count
Normal
Adrenaline, Renin, 5-aldosterone, H1AA
Bone Marrow Biopsy
No clonal mast cell expansion
No mutation of cKIT at codon 816
Tilt Table Test
Significant postural hypotension
Echocardiogram
Non-clonal mast cell activation (ncMCA) syndrome is a disorder characterised by seemingly unprovoked episodes of mast cell degranulation resulting in a multitude of symptoms including severe anaphylaxis.
In a proportion of patients this disorder is associated with postural tachycardia syndrome (POTS).
We describe the successful use of Omalizumab to treat the symptoms associated with ncMCA but not POTS.
Case Report
Outcome c
This 19 year old male presented at the age of 10 with unexplained episodes of anaphylaxis with associated hives/pruritis, episodes of flushing and feeling hot but (with no apparent change in core body temperature) and sweating to his hands and feet.
By the age of 16 his symptoms had increased in severity and he was now experiencing severe headaches, episodic wheeze and hypertensive episodes that were sometimes associated with tachycardia.
He was first reviewed at Leeds in 2014 (aged 18). He was now on clonidine for his unstable BP.
In 2015 he was initiated on Omalizumab 300mg 4-weekly. c
After 3 doses he had an improvement in his pruritis/hives and he had experienced no episodes of anaphylaxis. He was however finding his symptoms returned in the 3rd week post injection. His dose was subsequently increased to 300mg 3-weekly.
Following the dose increase he has experienced no episodes of anaphylaxis and has had a significant improvement in his pruritis/hives. He occasionally gets small outbreaks every few days but these are much less severe and shorter in duration.
It has had no impact on his POTS and he is currently being considered for a trial of octreotide.
Duration of omalizumab treatment = 13 months
Duration of omalizumab home treatment = 9 months
No of doses of omalizumab = 18
Previous Treatments
Previous Treatments
Response
Imatinib
Effective at controlling anaphylaxis
No improvement in sweating or BP control
Stopped due to weight loss and leg pain
Cetirizine 10mg QDS
Some benefit - continuing
Montelukast 10mg OD
Rantidine 300mg BD
Sodium Cromoglycate 200mg TDS
Conclusion
Omalizumab has been used successfully in a small number of patients with clonal and ncMCA.
Omalizumab has been shown to have mast cell stabilizing effects, although the precise mechanism underlying this pharmacological effect is still not fully elucidated.
This case report adds to the body of literature supporting the use of Omalizumab in patients with ncMCA refractory to standard evidence-based treatments.
References c
1. Akin C, Valent P, Metcalfe DD (2010) Mast cell activation syndrome: Proposed diagnostic criteria. J Allergy Clin Immunol. 126(6):