Novel therapeutic target and diagnostic marker for asthma and related conditions

Abstract

CD48, a surface-marker molecule present in eosinophils, is disclosed herein as a key molecule in allergic conditions, particularly in allergic airway inflammations like asthma, allergy and nasal polyposis. CD48 is thus presented as a target molecule in the treatment of said conditions. In addition, diagnostic methods, and a kit for the diagnosis of allergic inflammatory conditions are described, based on the detection of CD48 expression.

1 . A method of treating an allergic condition, said method comprising administering a therapeutically effective amount of an anti-CD48 agent, which blocks CD48 stimulatory pathway, to a subject in need of said treatment. 
     
     
         2 . The method according to  claim 1 , wherein said allergic condition is an allergic inflammation selected from the group consisting of allergic airway inflammation, atopic dermatitis, conjunctivitis and intestinal allergy. 
     
     
         3 . The method according to  claim 2 , wherein said allergic airway inflammation is any one of asthma and nasal polyposis. 
     
     
         4 . The method according to  claim 1 , wherein said anti-CD48 agent blocks CD48 stimulatory pathway by inhibiting the activity and/or the expression of CD48 or of a down-stream member molecule of said pathway, said agent being selected from the group consisting of: a protein based molecule which specifically binds to CD48, a nucleic acid-based molecule comprising at least one target specific sequence complementary to a target ribonucleic acid sequence comprised within CD48 mRNA and an antagonist molecule of CD48. 
     
     
         5 . The method of  claim 4 , wherein said protein-based anti-CD48 agent is an antibody which specifically binds to CD48 or a CD48 binding fragment of said antibody. 
     
     
         6 . The method according to  claim 4 , wherein said nucleic acid-based anti-CD48 agent is selected from the group consisting of: an antisense oligonucleotide specific to the CD48 sequence, a ribonucleic acid molecule selected from the group consisting of ribozyme, interfering RNA (RNAi), a small interfering RNA (siRNA) and microRNA. 
     
     
         7 . A method for the diagnosis of an allergic condition in a subject said method comprising the steps of:
 (a) obtaining a biological sample from said subject; and   (b) determining the level of expression of CD48 in said biological sample by any one of a protein-based or nucleic acid-based detection method;   whereby elevated expression of CD48, in comparison with negative control, indicates the presence of said allergic condition.   
     
     
         8 . The method according to  claim 7 , wherein said biological sample is a body fluid sample selected from the group consisting of a leucocyte-containing body fluid, blood, lymph, milk, urine, faeces, semen, appendix, spleen, extractstears, sputum, nasal, mucus, amniotic fluid, bronchoalveolar lavage, pleuric fluid, peritoneal fluid and tonsillar tissue extractstears. 
     
     
         9 . The method according to  claim 8 , wherein said CD48 expression is detected by a protein-based method comprising the steps of:
 (i) contacting said sample with a CD48 binding agent; and   (ii) measuring the level of binding of said agent to said CD48 protein;   
       whereby elevated binding of CD48, in comparison with a negative control, indicates the presence of said allergic condition. 
     
     
         10 . The method according to  claim 9 , wherein said CD48 binding agent is an anti-CD48 antibody. 
     
     
         11 . The method according to  claim 10 , wherein measuring the levels of binding according to step (ii) is performed by a protein based detection assay, said assay is any one of immunohistochemical staining, Western blot analysis, immunopercipitation, flow cytometry, ELISA, competition assay and any combination thereof. 
     
     
         12 . The method according to  claim 8 , wherein said nucleic-acid based detection method is any one of in-situ hybridization, RT-PCR, nucleic acid based ELISA, RNAse protection assay, Northern blot analysis and any combinations thereof. 
     
     
         13 . The method according to  claim 12 , wherein said method is an RT-PCR assay comprising the steps of:
 (a) obtaining a biological sample from said subject;   (b) isolating nucleic acids from said sample;   (c) providing primers for specific amplification of CD48 transcripts, together with nucleotides and amplification reagents;   (d) providing conditions for allowing CD48 amplification;   (e) performing reversed transcription followed by a PCR amplification on said nucleic acids; and   (f) determining the level of CD48 amplification products in said sample;   whereby elevated levels of CD48 amplification products, in comparison with a negative control, indicates the presence of said allergic condition.   
     
     
         14 . The method according to  claim 7 , wherein said allergic condition is an allergic inflammation selected from the group consisting of allergic airway inflammation, atopic dermatitis, conjunctivitis and intestinal allergy. 
     
     
         15 . The method according to  claim 14 , wherein said allergic airway inflammation is any one of asthma and nasal polyposis. 
     
     
         16 . A kit for the diagnosis of an allergic condition, said kit comprising as follows:
 (a) an agent for determining the presence of an analyte of interest, wherein said analyte of interest is one of CD48 protein or CD48 mRNA; and   (b) calibration means.   
     
     
         17 . The kit according to  claim 16 , wherein when said analyte of interest is CD48 protein, said agent is an anti-CD48 antibody. 
     
     
         18 . The kit according to  claim 16 , wherein when said analyte of interest is CD48 mRNA, said agent is one of a CD48-specific primer or a CD48-specific probe. 
     
     
         19 . The kit according to  claim 16 , wherein said allergic condition is an allergic inflammation selected from the group consisting of allergic airway inflammation, atopic dermatitis, conjunctivitis and intestinal allergy. 
     
     
         20 . The kit according to  claim 19 , wherein said allergic airway inflammation is any one of asthma and nasal polyposis.