Mean levels of anti-CD74 were significantly higher in axSpA patients compared to BD for IgG4 (1.29 vs. 0.58, p = 0.001), for IgA (1.03 vs. 0.73, p = 0.034) but not for IgA-Immune complexes (0.61 vs. 0.49, p = 0.089). This evidence concerns the gene CD74 and Behcet disease.