INCREASED SERUM CONCENTRATION OF IGA2 SUBCLASS AND IGA2 IGA1 RATIO - SPECIFIC MARKERS OF CHRONIC-ALCOHOLIC ABUSE/

Enhanced serum IgA concentrations are common in alcoholic liver cirrho sis, but functional differences between IgA subclasses and their relat ion with interleukin-g (IL-6) have not been described. Distinct immuno regulatory mechanisms may exist that selectively affect one subclass. This possibility prompted us to investigate the distribution of IgA1 a nd IgA2 subclasses in the serum of 25 heavy alcohol drinkers (alcohol: 80 to 200 g per day) without clinical disorders, in comparison with 3 5 patients affected by alcoholic liver cirrhosis, 29 viral hepatitis p atients and 33 social drinkers as a control group. Mean (+/- SD) IgA2 concentration (0.56 +/- 0.31 g/l) was significantly increased (p < 0.0 1) in heavy alcohol drinkers, with an IgA2/IgA1 ratio of 0.33 +/- 0.12 , while the mean total IgA concentration was similar to the control gr oup. Mean IgA1 and IgA2 concentrations were significantly increased (p < 0.001) in alcoholic liver cirrhosis patients (6.13 +/- 4.52 g/l and 1.83 +/- 1.93 g/l respectively, with an IgA2/IgA1 ratio of 0.32 +/- 0 .19) and viral hepatitis patients (3.66 +/- 2.59 g/l and 0.69 +/- 0.67 g/l respectively, with an IgA2/IgA1 ratio of 0.21 +/- 0.14) High seru m IL-6 concentrations (34 +/- 33 ng/l) were correlated with elevated I gA1 and IgA2 concentrations only in patients with alcoholic liver cirr hosis. IgA2 subclass and IgA2/IgA1 ratio could therefore be used as ma rkers of chronic alcohol abuse directly related to the extent and dura tion of the alcohol abuse and the effectiveness of alcohol withdrawal.