NFKBIA and heavy chain disease: As shown previously, although NF-kB mRNA expression and NF-kB and IkBα protein expression did not differ between the HCD group and LCD group, phosphorylated NF-kB and phosphorylated IkBα protein expression significantly increased in the HCD group compared with that in the LCD group, which indicated that the NF-kB signalling pathway was activated after HCD administration.