The invention relates to a method for determining alleles of the 27 allelic group of B locus of human leukocyte antigen (HLA-B27) from a nucleic acid sample and to a kit for performing this method. The kit comprises allele-specific primers for using in real-time polymerase chain reaction (PCR), and allele-specific fluorescently labelled probes or an intercalating agent, for detecting fluorescence signals. The analysis is completed with the determination of the melting temperatures of the amplified nucleic acid sequences. It overcomes some of the limitations of conventional DNA-based typing methods, in terms of time, possibility of automation, and increase in resolution, while reducing the number of PCR reactions. It is useful e.g. for determining susceptibility for a specific disease.