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[Blocking antibodies and desensitization]
1Service de médecine interne, Hôpital Rothschild, Paris.
Specific IgG1 and IgG4 antibodies synthesis is well known after immunotherapy. IgG4 may act as "blocking antibodies" and IgG1 may inhibit the synthesis of specific IgEs. However, the dosage of these antibodies by a technic using a solid phase is sometimes unreliable. Moreover these technics do not appreciate the functional activity of IgGs, which is best studied by incubating the allergen with IgG and then, measuring the allergen potential (using histamine release or basophil degranulation). Our studies regarding rush immunotherapy with mites by measuring the human basophil degranulation indicate the following: 1. the blocking activity is induced by rush; 2. is significant the 7th day; however there are some individual variations which do not depend on the cumulate dose of the allergens; 3. it is due to IgG and not to IgA or IgM (fractionation on column); 4. it disappears under the effect of the anti-human-IgG antibodies; 5. it increases with the time of incubation but it appears significant activity even at time 0 min. We conclude that the role of these IgGs during rush to mite is fundamental.
Specific IgG1 and IgG4 antibodies synthesis is well known after immunotherapy. IgG4 may act as "blocking antibodies" and IgG1 may inhibit the synthesis of specific IgEs. However, the dosage of these antibodies by a technic using a solid phase is sometimes unreliable. Moreover these technics do not appreciate the functional activity of IgGs, which is best studied by incubating the allergen with IgG and then, measuring the allergen potential (using histamine release or basophil degranulation). Our studies regarding rush immunotherapy with mites by measuring the human basophil degranulation indicate the following: 1. the blocking activity is induced by rush; 2. is significant the 7th day; however there are some individual variations which do not depend on the cumulate dose of the allergens; 3. it is due to IgG and not to IgA or IgM (fractionation on column); 4. it disappears under the effect of the anti-human-IgG antibodies; 5. it increases with the time of incubation but it appears significant activity even at time 0 min. We conclude that the role of these IgGs during rush to mite is fundamental.