MCt

Tryptase

Found in:

Alveolar Wall, Respiratory epithelium, Small intestine MUCOSA

Memonic:

T is in trachea (respiratory tract) and small inTestine

MCtc

Tryptase/chymase

Found in:

Skin, Intestinal SUBmucosa, Conjunctiva, Heart

Memonic:

1. Hard C(chymase) sound in:   sCin, submuCosa, Conjunctiva, Cardiac
2. Connective Tissue (TC)

IgE receptor (FceRI) crosslinking    S    L     B

Morphine                                    S

Substance P                                S    L

C5a                                           S           B

F-met-leu-phe                                          B

S-Skin    L-lung   B-basophils

MC Baso

Histamine       +++                       +

Tryptase       +++                       +/-

LT's              +++                        +

PG's             +++                         -

IL-4              +/-                           +++

IL-13              +                          +++

Other cytokines       +++    +

Memonic:  'Bees have no p's'   (but they do have 4 and 13)

Granules (histamine, tryptase, chymase, heparin, chondroitin SO4, cathepsin G, carboxypetidase A3):5-15 minutes

Lipid bodies: (LTC4, PGD2 in MC, PAF in baso)  10-30 min

Cytokines/chemokines: IL-4 (B),

IL-13 (M,B),

TNF-a, GM-CSF, IL-5,6,8,16, MCP-1, MIP-1a (M)

                Minutes, hours, days

 a & b pro-tryptases are spontaneously secreted by resting mast cells

In Mastocytosis, protryptases contribute most significantly to the Total tryptase measured. Protryptases are represented in the numerator in the Total/Mature ratio , therefore the Ratio is increased

Mature b-tryptase

is retained by mast cells until these cells are activated to degranulate.

PEARL:  in anaphylaxis, mature(B) tryptase predominates and total/mature ratio has a large denominator and therefore is <10