Further Data on HBs Antigen Subtypes - Geographical Distribution

Abstract

605 HB antigens from silent carriers of different geographic areas were subtyped. Guinea pigs and goats were immunized with selected HB antigens. Subtyping was performed by CIEP using monospecific or duospecific antisera, and by ID with unabsorbed antisera if the antigen was strong enough. Eight categories of HB antigens previously described were confirmed: a1y(w), a2ly(w), a23y(w), a3y(w), ayr, a21d(w2) a3d(w) and adr. The relations between the four categories of a subdeterminants and ‘w’ are analysed. All the antigens with ‘w’ determinant are either a1 or a2l or a23 or a3. The ‘w' determinant can be subdivided into the system of a subdeterminants which are mutually exclusive among themselves, r appears to be allelic with the group of the four a subdeterminants. It cannot yet be stated if r may be considered as a fifth subdeterminant of a or if it is independant of a subdeterminant. For the present time we use the following terminology a1(w), a21l(w2), a23(w3), a3(w4) and r. By combining a(w) subdeterminants, r, d and y determinants, it is possible to greatly increase our knowledge about the geographical distribution of HB antigen: ay subtype is predominant in Africa and in Mediterranean countries but three areas can be distinguished by means of a subdeterminants : a3(w4)y being mainly found in West and Central Africa (87%) and a31(w2)y in Mediterranean countries (86%) except for Greece where a same ratio of a21(w2)y and a23(w3)y is encountered. This a23y subtype is the most frequent of ay subtypes in France and in Hungary. In these two countries, the subtypes ad(w) are predominant: 67% of a21(w2)d and 1.3% of a3(w4)d in France, adr is widespread in Asia and especially in the Thai area (Thailand and Laos), but we have found a1(w1)y in Vietnam. Many examples are given which show that the subtype of HB antigen is related to the country of origin and does not seem to depend of the host. These findings illustrate the importance of HB antigen subtyping for epidemiology and for study of populations.

Subtype of HBsAg in Chile

“…Couroucé and Soulier [4] found the adw2 subtype in 67% of asymptomatic carriers in France and in 1.18% of hepatitis B patients in Madagascar. Sandler et al [6] identified it in 13.8% of patients and asymptomatic car riers among native Israelis.…”

“…From the geographic distribution reported by Couroucé and Soulier [4] and by the WHO [7], it was postulated that the adw subtype is predominant in this area.…”

“…Sandler et al [6] identified it in 13.8% of patients and asymptomatic car riers among native Israelis. The adw4 subtype has been detected in 25-27% of French Polynesian viral hepati tis B patients [2,5], in 1.3% of French asymptomatic carriers [4] and in 4% of a native population of Brasil [Couroucé, personal commun. ].…”

Taxonomic Classification of Human Hepatitis B Virus

“…A group determinant (a) is shared by all HBsAg preparations, and 2 pairs of subtype determinants (d, y and w, r), which are, for the most part, mutually exclusive and thus usually behave as alleles, have been demonstrated [195,196]. Anti genic heterogeneity of the w de terminants and additional determi nants, such as q and x or g, have also been described [197,198]. To date, 8 HBsAg subtypes have been identi fied, namely ayw, aywi, aywj, ayw«, ayr, adwj, adw4, and adr [198].…”

“…To date, 8 HBsAg subtypes have been identi fied, namely ayw, aywi, aywj, ayw«, ayr, adwj, adw4, and adr [198]. Iso lated and usually single cases from the Far East with unusual combina tions of HBsAg subtype determi nants, such as awr, adwr, adyw, adyr, and adywr, have been re ported [197], In these cases, the subtype determinants are found on the same particles, suggesting phenoty pical mixing or unusual genetic re combinants that have formed dur ing mixed infections. The distribu tion of HBsAg subtypes occurs in uneven geographic distribution [199,200], …”