The HL‐A System: Antigenic Heterogeneity and Four New Antigens

Abstract

Four new antigens of the second HL—A series are reported. They were established by means of lymphocytotoxic and platelet complement‐fixing antisera, and they behaved in population and family studies as determined by alleles at the second HL—A sublocus. It was found that three of them were parts of a previously assumed monofactorial antigen: SL. The antigen SL thus is heterogeneous, as also seems to be true of several other HL—A antigens. If all HL—A genetic determinants presently identified in our laboratories are taken into account, 18,145 different genotypes are possible. Implications of heterogeneous HL—A antigens for histocompatibility testing and matching are discussed.

HL‐A Haplotype Frequencies in Denmark and Norway

“…From the haplotype frequencies in Table 6 it is possible to calculate the chances of finding suitable unrelated donors for prospective kidney transplant recipients (Svejgaard et al 1971a). These calculations are, of course, rather tedious and computer assistance is relevant (Hogmari et al 1971 ) .…”

“…A total of 218 Danish and 1 10 Norwegian families were included in the study. Some of these families were included in previous studies (Svejgaard et al 1970a, Thorsby et al 1970, Svejgaard et al 1971a). They were selected for typing for one or more of the following reasons: (1) they were large or the family members were easily available (normal families), ( 2 ) the mother was HL-A immunized, ( 3 ) they included members with one of the other conditions listed in Table 1.…”

HL‐A Polymorphism of Norwegian Lapps

“…HL-A tyfiing was performed using the rriicrolymphocytotoxicity test ( Kissrneyer-Nielsen & Thnrsby 1970) and highly selected typing antisera, which have been described elsewhere (Kissmeyer-Nielsen et 2x1. 1970, 1971a. I n addition some cytotoxic anti-4a and anti-4b scra were included (kindly provided by Prof. van Rood, Leiden, Holland).…”

Second Locus HL–A Antigens and 4a or 4b

“…A similar situation to the one described above seems to apply to the specificity W2 1. In fact, this specificity is already known to be split into two components; SL-ET and ET* by reactivity with serum SL (Thorsby et al 1971). +ve individuals, defined by serum TH-ET, who react with serum SL seem to have this as 4a associated.…”