Pathogenesis symptoms and conditions

Singulair/Quinolinic acid - skin conditions and myalgia caused by eosinophils

Dear friends for this one I feel like Gomer Pyle "well g-o-o-l-l-l-y." I have been trying to solve the riddle as to whether Singulair might possibly cause skin conditions and myalgia. I found where a researcher actually injected himself with quinolinic acid to see if it caused a reaction from eosoniphils. So hypothetically if there were less than ideal metabolic or genetic conditions that cause the montelukast molecule to break up into a quinolinic acid by-product before it reached the liver then eosinophils will go to where-ever the quinolinic acid is. In the case of this researcher, the quinolinic acid caused skin inflamation conditions because he injected it into his arm.

This study could apply to any quinoline type drug that could break down into quinolinic acid. Now, we don't have proof whether Singulair can break down into quinolinic acid so the doctors won't buy this one as a fact. It is good, however, for a WHAT IF argument for those who would like to do a wait and see if Singulair caused the problem. This researchers eosinophil count took five weeks to drop back down to normal levels.

Clin Exp Med. 2006 Jun ;6 (2):60-4 16820992 (P,S,E,B) Is the L-tryptophan metabolite quinolinic acid responsible for eosinophilic fasciitis?

R Noakes, L Spelman, R Williamson
Qld Skin and Cancer Foundation, Greenslopes Private Hospital, Newdegate St, Greenslopes 4120, Qld, Australia. rnoakes@lagunacom.com.au
The eosinophilia-myalgia syndrome is accompanied by alterations in L-tryptophan metabolism with elevated levels of L-kynurenine and quinolinic acid having been recorded. It has been suggested that this is due to activation of indoleamine 2,3-dioxygenase by interferon-gamma. It is unknown whether these products of tryptophan metabolism play a role in the pathogenesis of this syndrome and the closely related condition of eosinophilic fasciitis. To explore this possibility, the principal author (RN) received a series of subcutaneous injections of quinolinic acid. A total of 1200 mg was administered over a 1-month period. Peripheral blood eosinophil counts were monitored and biopsies taken for H&E and immunohistochemical stains. Over the 1-month period the eosinophil count rose from 0.3x10(9)/l to 0.8x10(9)/l before falling to 0.4x10(9)/l approximately 5 weeks later. H&E sections showed a mixed infiltrate of eosinophils and neutrophils extending through the reticular dermis and septa of the panniculus. No deep fascia was obtained on biopsy. The immunohistochemical stain for transforming growth factor beta 1 showed staining of endothelial cells and dendritic cells. The interleukin-5 stain was negative. Our results suggest that quinolinic acid may play a role in cutaneous eosinophilic disorders.

Effective after two weeks for some people - not effective for others. Side effects for some people - others do not report side effects. So why does Merck have to grow their market before they have any idea what's going on?

This isn't a big group of people in the study but it makes sense from what we are reading here. These researchers did examine the mast cells. We need to know about mast cells (while suppressed by montelukast) on a longer term basis.

J Asthma. 2008 Apr;45(3):243-50. Links
The efficacy of montelukast and airway mast cell profiles in patients with cough variant asthma.Kawai S, Baba K, Matsubara A, Shiono H, Okada T, Yamaguchi E.
Division of Respiratory Medicine and Allergology, Department of Internal Medicine, Aichi Medical University School of Medicine, Aichi, Japan.

Background. Cough variant asthma (CVA) is characterized by chronic cough without apparent wheezing; its pathophysiology is considered to be similar to that of classic asthma. Objective. The clinical effects of montelukast, a cysteinyl-leukotriene receptor antagonist, on cough variant asthma were assessed, and the activation profile of airway mast cells was examined. Methods. Montelukast (10 mg/day) was given orally to 36 CVA patients (25 women and 11 men; median age, 37.5 years). Before treatment, the patients' bronchial mucosa underwent a biopsy with a fiberoptic bronchoscope. The biopsy specimens were double stained with anti-CD63 antibody and anti-human tryptase antibody. Results. After 2 weeks of montelukast treatment, cough symptoms improved in 22 patients (the effective group) but did not improve in 14 patients (the ineffective group); in the ineffective group, the symptoms disappeared 2 weeks after they were switched to fluticasone propionate (400 mug/day) inhalation therapy. In the effective group, the time interval from the onset of symptoms to the initiation of treatment was significantly shorter than in the ineffective group. The bronchial mucosa biopsy specimens showed that the proportion of CD63-positive cells in tryptase-positive mast cells was significantly higher in the effective group than in the ineffective group; although the total numbers of mast cells were not different between the two groups. Conclusion. There is a subgroup of CVA patients in whom leukotrienes are closely involved in the pathogenesis of their chronic cough; activation of airway mast cells may be an essential feature in these patients.

PMID: 18415834

Here is another who might know how to help.

I got stuck on trying to understand IgE. Here is somebody else who might know something.

Immunol Res. 2007;37(1):1-16.Links
Decoding IgE Fc receptors.Zhang M, Murphy RF, Agrawal DK.
Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE 68178, USA.

Immunoglobulin E (IgE) plays a central role in the pathogenesis of allergic diseases by interacting with two membrane receptors: high-affinity FcepsilonRI and low-affinity FcepsilonRII (CD23). Allergeninduced IgE-occupied FcepsilonRI aggregation on the mast cell or basophil cell surface leads to the activation of intracellular signaling events and eventually the release of pre-formed and de novo synthesized inflammatory mediators. The role of FcepsilonRII in allergic diseases has been proposed to include regulation of IgE synthesis, enhanced histamine release from basophils, and a contribution to Ag-IgE complex presentation but the exact function of CD23 remains poorly understood. This review summarizes some new developments in IgE Fc-receptor studies with an emphasis on regulation of FcepsilonRI expression and signal transduction, including monomeric IgE, lipid raft segregation, and some recently identified negative regulators. A better understanding of signaling events following IgE FcR aggregation will shed new light on how allergy patients might be treated more safely and effectively.

I know that many here would like the FDA to take a very serious took at the problem. I personally don't see how a review of their data is going to make any difference at all. But, if there are experts who can propose a model of the pathways of cell signalling that include the possibility that these symptoms can occur (and under what circumstance), then maybe the problem will look like something much more than statistics.

This is not my field. But I tried to follow the possible pathways to see if I could identify a possible area of concern. Then I looked for someone who had written in the area and read their abstract. A place to start may be to get an opinion from those who know something about "normal homeostasis of the mast cell." Singular blocks the cysteinyl leukotriene receptor 1 which is a site on the outer membrane of the mast cell (other cells also). The mast cell which is produced in the bone marrow is released in a immature state and matures after it arrives at it's destination. The mast cell does not become active unless it's receptor sites come in contact with the activating agent. So, what happens when a receptor site on the mast cell is suppressed by Singular, a receptor antagonist.

You see, I don't have a clue what the signals are that tell the bone marrow to make mast cells (or what the signals are that tell them where to go after they are made in the bone marrow). Does Singular interfere with something that tells the bone marrow what to do? If Singular does interfere with that process, then what is happening and what period of time does it take to happen? Could we wonder whether Singular is interfering with the NUMBER of mast cells that are produced over time? And, of course, maybe there is some OTHER kind of explanation for why the adverse drug reactions are happening. But, at this level, I got lost and can't go any further.

Maybe this group would be interested in the Singulair problems or could suggest somebody else?

http://www.edata-center.com/journals/2ff21abf44b19838,0a1257122f661a7e,0d8ee7116ef23452.html

I apologize if this lead doesn't produce any results but at least it could be a place to start.