HLA in Chileans with intrahepatic cholestasis of pregnancy.

A possible association between intrahepatic cholestasis of pregnancy (ICP) and human-leukocyte histocompatibility (HLA) antigens--used as genetic markers--was studied in 100 women with ICP compared to 100 multiparous women without a past history of the disease. Because we previously found a higher frequency of ICP in women with an overt Araucanian Indian descent than in Chilean Caucasoids, women from both ethnic groups were studied. Among the 37 specificities of the HLA system studied (17 of HLA-A, 16 of HLA-B, and 4 of HLA-C series), only HLA-BW16 showed a tendency to be more frequent in women with ICP rather than in control women. This finding appears to be related with ethnic origin and not ICP, HLA-BW16 was significantly more frequent in women with Araucanian Indian descent (43.4%) than in Chilean Caucasoids (16.3%) (p less than 0.01). The high frequency of HLA-BW16 in the predominantly Caucasoid population in Chile, in comparison with Caucasians in Europe and in North America, may be another indicator of their ethnic admixture with aborigine groups. The high frequency of HLA-BW16 reported in North American Indian-admixed groups (16%) suggests that HLA-BW16 may be a genetic characteristic common to some aboriginal populations in North and South America.

Demonstration of IgG EA (early antigen) and IgM MA (membrane antigen) antibodies in CMV infection of healthy infants and in those with liver disease.

The sequence of antibody production to various virus-specific antigens in CMV infection in infancy was studied. In healthy infants, IgG EA antibody was demonstrated in 18% of cord sera, and disappeared within two months after birth in all cases not shedding virus. The nonmaternal EA antibody was produced following virus excretion and decreased rapidly following cessation of virus excretion. Thus, demonstration of EA antibody in infants after 2 months of age was found to indicate acquired CMV infection, even when CMV could not be isolated. IgM MA antibody did not persist as long as EA antibody, disappearing before cessation of virus excretion. Both IgG EA and IgM MA antibodies were more frequently demonstrated in infants with hepatitis than in healthy infants. These findings suggest the possible association of CMV with hepatitis in infants.

Secretory IgA in the serum of infants with obstructive jaundice.

The liver is capable of transporting IgA from the plasma to bile in several experimental animals. After bile duct ligation, SIgA and free secretory component accumulate in the serum of these animals. In the present study, SIgA was found in the serum of all infants with extrahepatic biliary obstruction, and in 75% of those with intrahepatic cholestasis, but in only one of seven age-matched infants without hepatobiliary disease. Infants with EHBO had significantly higher serum levels of secretory IgA and total IgA than in normal infants or patients with IHC. This result suggests that the human liver is involved in SIgA metabolism and that the elevated serum IgA levels in infants with liver disease are caused by bile duct obstruction or proliferation. Quantitation of SIgA in serum may help to differentiate major categories of obstructive jaundice in infancy. The concentration of SIgA in serum was indicative of the site of obstruction in 12 of 19 infants with hepatobiliary disease.