CONGENITAL AGAMM AGLOBULIN AEMIA 



arthritis provides an important clue to the nature of this 

 process. There is evidence from studies of allergic conditions 

 in man that classical-type antibody can protect against the 

 symptom-producing power of hay-fever type antibody in the 

 tissues. This suggests that if a potentially pathogenic pattern 

 develops in a clone of cells of the type that has been suggested 

 as responsible for one or other type of the collagen diseases, 

 the result will be less damaging if some of the cells concerned 

 develop into plasma cells and liberate the corresponding 

 soluble antibody than if they do not. If this is the case, some 

 delicately balanced equilibrium must be involved. One can 

 conceive that under certain conditions sufficient circulating 

 soluble antibody might be available to block all active 

 determinants before they could stimulate cells of the clone 

 to further proliferative and pathogenic activity. Equally 

 possible is the suggestion that a body component with deter- 

 minants reacting with cells carrying forbidden patterns 

 might also induce overproduction of a non-specific globulin 

 (? properdin) which prevented stimulation of specifically 

 modified cells. Until much more is known about the patho- 

 genesis of the collagen diseases and of the essential lesion in 

 agammaglobulinaemia these are only speculations, but the 

 phenomenon in question must eventually prove highly 

 relevant to each. 



7. The nature of the homeostatic mechanism 



Since the existence of a mechanism by which forbidden 

 clones can be prevented from developing is a vital part of the 

 clonal selection theory, some effort to provide possible ways 

 of implementing this requirement is needed. What is called 

 for is a mechanism which will assure that a cell carrying 

 a forbidden mutation will not give rise to a descendant clone 

 under normal conditions, that this inhibition is not effective 

 against mutations to other patterns, and that possibilities 

 exist to account for the fact that forbidden patterns can 

 flourish in certain pathological conditions. 



10 145 Bc 



