The objective of this preliminary study was to describe alleles of bovine major histocompatibility complex class II BoLA-DRB3.2 gene associated with resistance and susceptibility to Persistent Lymphocytosis (PL) in Bovine leukaemia virus (BLV) infected cattle, to set a direction for the future studies. A total of 81 dairy cattle in Argentina were investigated for the distribution of BoLA-DRB3.2 alleles. The study cattle were categorized into 3 groups as follows: Category PL+ (BLV seropositive with PL); Category PL- (BLV seropositive without PL) and Category BLV- (BLV seronegative). The alleles were identified by polymerase chain reaction with subsequent analysis of restriction fragment length polymorphism. The association between the BoLA-DRB3.2 alleles and the PL+ and PL- categories was determined as the odds ratio. Some alleles BoLA-DRB3.2 mediating (1) resistance and (2) susceptibility to PL were observed, respectively. A stochastic model including Shannon's diversity index calculation was run based on Markov-Chain Monte Carlo simulation method. The Shannon's diversity indices in each of the cattle categories indicated that the richness of gene diversity decreased as leading to a clinical stage of BLV. This relates to the existence of alleles mediating resistance and susceptibility to PL. The stochastic prediction with inclusion of uncertainty is important which can serve as a future study beacon.