Grasso Domenico Leonardo, Segat Ludovica, Zocconi Elisabetta, Radillo Oriano, Trevisiol Chiara, Crovella Sergio
Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy.
Int J Pediatr Otorhinolaryngol. 2009 Nov;73(11):1550-3. doi: 10.1016/j.ijporl.2009.07.022. Epub 2009 Aug 27.
We evaluated mannose binding lectin (MBL) protein production and histological localization, MBL2 gene expression and genotypes distribution in patients characterized by recurrent tonsillitis, with the aim of verifying the innate immune response to the infection and inflammation occurring in the tonsils.
MBL2 exon 1 and promoter polymorphims were detected by PCR amplification and subsequent direct sequencing of the amplicons. Monoclonal antibodies to MBL were used on frozen sections of tonsils for the immunohistochemical localization of MBL protein. MBL Oligomer ELISA kit was used to quantify the level of MBL in the serum of the 30 patients with recurrent tonsillitis. Quantitative RT PCR for the evaluation of MBL2 expression of MBL high producers (HP), low producers (LP) and deficient producers (DP) was performed using the Hs00175093 gene-expression Assay on Demand.
The distribution of the MBL2 combined genotypes was as follows: 21 HP (70%; 15 HYA/HYA, 6 HYA/LXA), 6 LP (20%; 5 HYA/0, 1 LXA/LXA) and 3 DP (10%, all 0/0). MBL levels were directly correlated to the MBL2 combined genotypes: HP patients showed higher mean MBL concentration of 4044 ng/mL, LP patients were characterized by a mean of 905 ng/mL whereas those with DP combined genotype presented extremely low levels of MBL (mean value of 74 ng/mL) (p=0.0005). Immunohistochemistry performed on tonsils sections demonstrated that MBL was widely distributed throughout the surface of the basal lamina of all the 21 HP subjects. MBL was undetectable in situ in both LP and DP patients. MBL2 expression, although at very low levels, was found for the HP group, the LP and the DP group as well.
We confirmed the genotype-phenotype correlation of MBL2 gene exon 1 and promoter polymorphisms with the quantitative production of serum MBL, we reported a very low MBL2 expression at local level in tonsils and we determined the in situ localization of MBL in the basal lamina of the tonsils of patients who underwent to tonsillectomy. Our findings suggest an important role of MBL protein in the innate immune response of the tonsil to pathogens, as in recurrent infection and inflammation.
我们评估了复发性扁桃体炎患者中甘露糖结合凝集素（MBL）蛋白的产生及组织学定位、MBL2基因表达和基因型分布，旨在验证扁桃体对感染和炎症的天然免疫反应。
通过PCR扩增及随后对扩增产物进行直接测序来检测MBL2外显子1和启动子多态性。使用针对MBL的单克隆抗体对扁桃体冰冻切片进行免疫组织化学定位MBL蛋白。使用MBL寡聚体ELISA试剂盒定量检测30例复发性扁桃体炎患者血清中MBL的水平。使用Hs00175093按需基因表达检测法对MBL高产生者（HP）、低产生者（LP）和缺陷产生者（DP）进行定量RT PCR以评估MBL2表达。
MBL2联合基因型的分布如下：21例HP（70%；15例HYA/HYA，6例HYA/LXA），6例LP（20%；5例HYA/0，1例LXA/LXA）和3例DP（10%，均为0/0）。MBL水平与MBL2联合基因型直接相关：HP患者的平均MBL浓度较高，为4044 ng/mL，LP患者的平均浓度为905 ng/mL，而DP联合基因型患者的MBL水平极低（平均值为74 ng/mL）（p = 0.0005）。对扁桃体切片进行的免疫组织化学显示，在所有21例HP受试者的基底膜表面MBL广泛分布。在LP和DP患者中未原位检测到MBL。HP组、LP组和DP组均发现有MBL2表达，尽管水平很低。
我们证实了MBL2基因外显子1和启动子多态性与血清MBL定量产生之间的基因型-表型相关性，报道了扁桃体局部水平MBL2表达非常低，并确定了接受扁桃体切除术患者扁桃体基底膜中MBL的原位定位。我们的研究结果表明MBL蛋白在扁桃体对病原体的天然免疫反应中起重要作用，如在复发性感染和炎症中。
