Some possible causes of associations between HL-A antigens and disease

Relationships between 34 HLA-A, HLA-B and HLA-DR antigens and three serological markers of viral infections in alcoholic cirrhosis

In order to study the genetic risk of alcoholic cirrhosis, the frequency of 26 HLA-A and -B antigens was compared in 184 normal controls, 175 alcoholic cirrhotic patients and 83 alcoholic patients with hepatic steatosis of carefully selected ethnic origin. Eight HLA-DR antigens were also determined in 95 subjects of the normal control group and 63 patients of the alcoholic cirrhosis group. The incidence of hepatitis B virus antibodies (anti-HBc and anti-HBs) was defined in 74 patients of the alcoholic steatosis group, 170 patients of the alcoholic cirrhosis group and 111 normal controls different from the previously mentioned normal control group. The incidence and the titers of cytomegalovirus and rubella antibodies were also determined in 93 patients of the alcoholic cirrhosis group and the 111 normal controls. Serum immunoglobulin concentrations were measured in the same 93 cirrhotic patients. Compared with the controls, the alcoholic cirrhosis group revealed a significantly higher frequency of HLA-B15 (21.7 vs. 9.8%, p less than 0.00025, corrected p less than 0.050) and HLA-DR4 (38.1 vs. 17.9%, p less than 0.005, corrected p less than 0.050) and a significantly lower frequency of HLA-B13 (2.9 vs. 11.4%, p less than 0.025, corrected p less than 0.050). As for the frequency of all other HLA antigens, there was no significant difference between the three groups (normal controls, alcoholic cirrhosis and alcoholic steatosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Unexpected lower prevalence of HBsAg in diabetics than in controls. (A study on 2,465 patients)

Serum samples from 2,465 diabetics were examined by radioimmunoassay for HBsAg, anti-HBs and anti-HBc at the Centro Antidiabetico of the Ospedale Maggiore di Lodi; during the same period, the same tests were carried out on serum samples from 2,176 control subjects, who had been admitted to the surgical, casualty and obstetrical departments for reasons that had nothing whatsoever to do with any form of liver disease. The ages of the two groups ranged from 6 to 90 years. The diabetics were divided into three groups; insulin-dependent, non-insulin-dependent and diabetics treated with insulin for diabetic complications. The overall frequency of HBsAg in the various groups of diabetics was 3.5%, while in the controls it was 6.1% (p less than 0.001). In the group of young insulin-dependent diabetics, the frequency was 1.7%, as compared to 6.9% for the controls in the same age group (p less than 0.05). In the group of patients treated with insulin for diabetic complications, the frequency increased to 11.5%, while for the controls in the same age group it was 5.5%. The levels of HBsAg were practically the same in the diabetics and in the controls, whereas the level of anti-HBc was higher in the diabetics: 55.6% compared to 50% (p less than 0.005). This last result indicates that the chances of hepatitis B virus infection were greater for the diabetics than for the controls. Diabetics, and especially those insulin-dependent are, therefore, believed to possess a greater capacity of resistance through their T cell-mediated immune response to the hepatitis B virus.

HLA antigens and HBV infection: evaluation in the chronic carrier state and in a large family

HLA antigens were determined in 65 apparently well chronic carriers of HBsAg, in race-matched controls and in 42 members of a family with a high frequency of hepatitis B virus infection. The only apparent significant association in the chronic carriers was negative, i.e., no HLA-B7 specificities were found among whites. B7 may confer resistance for whites to chronic infection with hepatitis B. In the family neither active (HBsAg) nor prior (anti-HBs) hepatitis B infection was associated with HLA specificities. HLA antigens in this family failed to provide a clue to the genetics of hepatitis B infection.

Hepatitis-B virus infection in patients with leprosy: a serological study in a leprosarium in Northern Nigeria

The prevalence rates of hepatitis-B surface antigen (HGsAg) and its homologous antibody (anti-HBs) were determined in 62 patients in a leprosarium (42 tuberculoid and 20 lepromatous) and in 40 adults living near the locality. The exposure rate (HBsAg + anti-HBs) was high in both controls and patients, 72.5% and 70.9% respectively, The frequency of HBsAg was significantly higher in patients with lepromatous leprosy (40%) compared with controls (10%) (chi 2 = 5.7 p less than 0.025) but there was no difference in the prevalence rate of HBsAg between patients with lepromatous leprosy (40%) compared with those with tuberculoid leprosy (23.8%) (chi 2 = 1.7 p greater than 0.1). The exposure rate was higher in the lepromatous group (80%) compared with the tuberculoid group (59.5%) but the difference was not significant (chi 2 = 2.87 p greater than 0.05). It is concluded that the high rate of infection in patients with leprosy if not due to a peculiar genetic defect but the result of living in an environment where the virus is highly endemic. The observed significance increase in carriage of HBsAg in lepromatous leprosy is probably due to depressed cellular immune function characteristic of this group of patients. The slightly increased exposure rate to HBV of lepromatous versus the tuberculoid type of leprosy is probably due to increased opportunity for infections from repeated and prolonged stay in hospital.

Immune mechanisms and the action of interferon in chronic hepatitis B virus infection

Cytotoxic T lymphocytes can eliminate cells infected with hepatitis B virus. A defect of T lymphocyte-mediated cytolysis seems to exist in chronic hepatitis B infection. T cell-mediated lysis is dependent on HLA antigens of the infected host and this may explain the increased or decreased frequency of particular HLA antigens in chronic carriers of hepatitis B virus. This virus may decrease the concentration of HLA antigens expressed on liver cells. Interferon increases the HLA antigen expression on T lymphocytes and hepatocytes, thereby enhancing T lymphocyte-mediate lysis of infected liver cells and elimination of the hepatitis B virus.

Associations of hepatitis B surface antigenemia with HLA locus B specificities

To test whether HLA histocompatibility phenotypes might be associated with circulating hepatitis B surface antigen (HBsAG), we performed chisquare and Scheffé analyses on findings in 144 renal patients with known HLA types and HBsAg status. A significant relation between locus B HLA type (or types) and HBS antigenemia was demonstrated (P = 0.01, adjusted for dual testing) with positive associations suggested between Bw15, Bw17 and Bw35 types and transient or persistent (or both) antigenemia. The latter associations individually were statistically significant only if multiple testing was disregarded, but the contrast by the Scheffé method between the three implicated specificities and all other specificities was significant, even after adjustment for multiple testing (P less than 0.02). Associations of genetically determined HLA specificities with hepatitis B infection may constitute the basis for previously observed population differences in HBS Ag prevalences, and suggest that susceptibility to hepatitis B infection may be in part genetically determined.

Products of the major histocompatibility complex and their relationship to the immune response

The genes of the major histocompatibility complex were first known for the part they played in transplant rejection. Recently, however, it has become clear that the products of that region have an important part to play in the control of the immune response, through their effects both on cooperative and on aggressive interactions between cells. It is now possible to guess at the mechanisms which may underly the association of some major histocompatibility antigens with disease.