Detection of HBsAg and HBsAb in sweat

HBsAg was detected in the sweat of 9/18 seropositive, but 0/20 seronegative probands. Frequency of detection correlated to serum titer of HBsAg, blood contamination and efficiency of sweat concentrating. On base of quantitative evaluations it is assumed, that blood and/or plasma contaminations are responsible for the presence of HBsAg in sweat. Since HBsAg and hepatitis virus B are of similar diameter, this mechanisms should work on the infectious agent too. Thus HBsAg could prove a marker, to calculate the infectivity of sweat in comparison to the corresponding serum specimen (10(-6) to 10(-7). HBsAb was detected in sweat too and was confined to HBsAb-seropositive probands (4/5). It is discussed, that the presence of HBsAb in sweat could provide protection against reinfections by contact and thus contribute to homologous immunity in hepatitis B.