Levels of complement C3 and C4 components in Amerindians living in an area with high prevalence of tuberculosis

the levels of complement c3 and c4 components were determined in non-indigenous (creoles) and indigenous (warao) populations, the latter with an extremely high tuberculosis (tb) rate. serum samples from 209 adults were studied and classified in 4 groups taking into account tuberculin skin tests (tst): (1) the group of warao patients (58 positive for the tst, wp tst+ and 9 negative for the tst, wp tst-), (2) the group of creole patients (34 positive for the tst, cp tst+ and 9 negative for the tst, cp tst-), (3) the group of healthy warao controls (38 positive and 14 negative for tst, wc tst+ and wc tst-, respectively), (4) the creole controls (26 positive and 21 negative for the tst, cc tst+ and cc tst-, respectively). with respect to the results concerning the measurement of both complement c3 and c4 components with the exception of the wc tst and the cc groups, the wp tst+ and wp tst- as well as wc tst+ groups showed a significant frequency of individuals with decreased levels of complement c3 component (20.6, 33.3, and 26.3%, respectively) and also c4 component (12.0, 11.1, and 13.3%, respectively) in comparison to both creole patients (cp tst+, 8.82% and cp tst-, 0% and cp tst+, 5.88% and cp tst-, 0%) for c3 and c4, respectively. the study of these parameters carried out in 15 warao subjects with active infection, before and after anti-tb chemotherapy,statisticallyconfirmedthat the effective chemotherapy did not restore normal levels of the complement c3 and c4 components among warao patients. aditional tests for hepatitis b or hepatitis c infection, and the profile of the hepatic proteins were not associated to the deficiency in production of the complement components.in conclusion, the results show that within the warao population, a high percentage of subjects exhibit decreased levels of both complement c3 and c4 components independent of latent or active infection and the status of tst.