Sequence of events in hypersensitivity reaction type I - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 03-01-2011
surez18's Avatar
USMLE Forums Veteran
 
Steps History: Step 1 Only
Posts: 208
Threads: 30
Thanked 183 Times in 74 Posts
Reputation: 193
List Sequence of events in hypersensitivity reaction type I

1. Degranulation of mast cells and basophils occurs when allergen binds to two adjacent IgE antibodies on the membrane of the cell
2. Interleukin 4 released by CD4 helper T cells causes activated B cells to switch from making IgM to IgE
3. Processed allergen is associated with a class II molecule on an antigen presenting cell and recognized by
CD4+ TH2 cells
4. Prostaglandins and leukotrienes are released
5. The allergen is phagocytized and processed by a macrophage or a dendritic cell
Based on the numbered list above, which of the following is the correct sequence of events in the Type I
hypersensitivity reaction?
A. 1,2,3,5,4
B. 1,4,3,5,2
C. 1,5,2,3,4
D. 5,3,1,4,2
E. 5,3,2,1,4
Reply With Quote Quick reply to this message
The above post was thanked by:
aktorque (03-02-2011), Mondoshawan (03-02-2011), roodiemd (03-11-2011)



  #2  
Old 03-02-2011
USMLE Forums Guru
 
Steps History: Not yet
Posts: 417
Threads: 74
Thanked 131 Times in 94 Posts
Reputation: 141
Default

my answer E!!!
ruling out a b c on the fact that 1 is not the 1st one to come into act. and then i am left on options d and e and before the degranulation, there has to be isotype switching! so i am going with E!!
Reply With Quote Quick reply to this message
The above post was thanked by:
aktorque (03-02-2011), Mondoshawan (03-02-2011)
  #3  
Old 03-02-2011
mle2resident's Avatar
USMLE Forums Veteran
 
Steps History: 1 + CS
Posts: 252
Threads: 51
Thanked 185 Times in 94 Posts
Reputation: 195
Default E

I will go with E as i believe thats the sequence of reactions.
Reply With Quote Quick reply to this message
The above post was thanked by:
aktorque (03-02-2011)
 
  #4  
Old 03-02-2011
USMLE Forums Addict
 
Steps History: CK+CS
Posts: 144
Threads: 34
Thanked 82 Times in 37 Posts
Reputation: 92
Save It! E

IT is the most logic sequence
__________________
“Learn from yesterday, live for today, hope for tomorrow. The important thing is not to stop questioning. ”
Albert Einstein
Reply With Quote Quick reply to this message
The above post was thanked by:
aktorque (03-02-2011)
  #5  
Old 03-02-2011
USMLE Forums Guru
 
Steps History: Step 1 Only
Posts: 487
Threads: 95
Thanked 1,459 Times in 357 Posts
Reputation: 1469
Arrow E) 5,3,2,1,4

My ans is E) 5,3,2,1,4

Let me put it in an order:


1-->The allergen is phagocytized and processed by a macrophage or a dendritic cell.

2-->Processed allergen is associated with a class II molecule on an antigen presenting cell and recognized by CD4+ TH2 cells.

3-->Interleukin 4 released by CD4 helper T cells causes activated B cells to switch from making IgM to IgE.

4-->Degranulation of mast cells and basophils occurs when allergen binds to two adjacent IgE antibodies on the membrane of the cell.

5-->Prostaglandins and leukotrienes are released.
Reply With Quote Quick reply to this message
The above post was thanked by:
m82_ghasemi (08-24-2011), Mondoshawan (03-02-2011), roodiemd (03-11-2011)



Reply

Tags
Immunology-, Step-1-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Non Cytotoxic Type II hypersensitivity Diseases Firas USMLE Step 1 Mnemonics 1 01-25-2012 09:33 AM
Type IV Hypersensitivity Mnemonic jackat1000 USMLE Step 1 Mnemonics 0 07-22-2010 11:46 AM
Mnemonic for Non-cytotoxic Type II Hypersensitivity Rxns Neutrophil USMLE Step 1 Mnemonics 0 05-02-2010 08:59 PM
Kaplan Medical Center Houston EVENTS KMH0512 USMLE Links & Free Ads 2 03-23-2010 04:53 PM
Type II or Type III Hypersensitivity? US-Colar USMLE Step 1 Forum 2 10-19-2009 10:27 AM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)