Multiple sclerosis (MS) is considered as an immune process influenced by genetic and environmental factors. HLA-DR2 and -DR4 have been documented to be associated with MS. The HLA-dependent differences of immune response to myelin and other antigens might point out some relevant mechanisms in MS development. The responses to myelin antigens and to PPD have been compared in 21 MS patients and 25 healthy controls (HCs) by primary proliferation and by short-term T-cell lines. There was a significantly higher response to MBP in DR2+ HCs compared to MS patients (SI: 5.9 versus 1.5, p=0.02). In short-term T-cell lines, we observed a higher response to PLP30-49 in both DR4+ HCs and MS patients. This response was significantly more frequent in DR4+ MS patients (34.6%) than both DR2+ MS patients (0%, p=0.0001) and DR4+ HCs (7.7%, p=0.001). The comparison between DR2+ and DR4+ MS patients has revealed that the response to MBP was also increased in DR4+ (p=0.02). Among DR4+ groups, an increased PPD response was detected in HCs compared to MS (65.2% versus 33.3%, p=0.01). These results may indicate that HLA-related differences to specific and recall antigens are detectable in MS and these differences may have implications in the disease pathogenesis.