HLA types and ABO blood groups in patients with infectious mononucleosis.

Investigations of HLA and blood-groups were carried out in 68 patients with infectious mononucleosis comprising all known cases diagnosed within one year in a restricted geographical area of Denmark. The HLA distribution of these patients did not differ significantly from that of controls. Combining the results of the present investigation with two previous studies did not show any significantly different distribution from that of combined control groups. The ABO and Rhesus typing was in accordance with that found in a major Danish control group. However, available studies do not exclude the possibility that HLA-D/DR or still unknown HLA factors may be involved in the susceptibility to mononucleosis.