THE COLLAGEN DISEASES 



remains to consider the nature of the process responsible for 

 the appearance of AIGF 'antibody'. 



In any discussion of the AIGF test, it seems advisable to 

 include some consideration of the L.E. cell test. Results 

 show a significant correlation between the two tests but it is 

 by no means complete. A positive L.E. cell test is nowadays 

 almost an essential before the diagnosis of D.L.E. can be 

 accepted but this perhaps represents a rather unnatural 

 convention. Both tests are found positive far more frequently 

 in the 'collagen' diseases than in any other group and both 

 are commonly associated with an increased gamma globulin 

 level in the blood and with other serological findings such 

 as Rose's reaction. 



The evidence from Table 4, that the AIGF reagent is not 

 active in most instances against an autologous antigen, 

 almost eliminates any possibility that we are dealing with 

 an auto-immune reaction of the Hashimoto type. It is much 

 more likely that the appearance of both the AIGF 'antibody' 

 and the L.E. cell factor is related to change in the antibody- 

 producing cells. 



This is possible, irrespective of whether the clonal selection 

 hypothesis is acceptable or not. On any hypothesis of anti- 

 body production one can conceive of antibody-producing 

 cells undergoing mutation and producing excessive amounts 

 of pathological globulins with wide and rather random 

 adventitious reactivity. The only additional feature supplied 

 by the clonal selection hypothesis is that if the mutation 

 produced 'sites' corresponding to body determinants, con- 

 ditions which allowed those determinants to be present in 

 the blood or lymph would, by hypothesis, favour the pro- 

 liferation of the clones carrying the mutant pattern. 



5. Somatic mutation as a basis 



In order to cover what seems to be a continuous range of 

 conditions from normal to grossly pathological, the minimal 

 requirements for a theoretical interpretation are : 



139 



