維生素B6營養狀況會影響重症病人免疫功能、發炎反應與血漿同半胱胺酸

維生素B6參與胺基酸、核酸、肝醣、紫質及脂肪的代謝，進而可能影響免疫功能。維生素B6也已被證實與體液免疫及細胞免疫功能有關。此外，當病人維生素B6營養狀況缺乏時，亦可能造成血漿同半胱胺酸濃度增加。因此本研究的目的為：（1）比較重症病人與健康對照者的維生素B6營養狀況、免疫功能、發炎反應與血漿同半胱胺酸的濃度；（2）探討維生素B6營養狀況對於免疫功能、發炎反應與血漿同半胱胺酸之影響。本研究之對象由台中榮總健檢科募集38位健康對照者與40位在台中榮總第一加護病房停留超過8天之重症病人。病人進入加護病房第一天與第八天及健康對照者分別接受體位測量、血液生化值（白蛋白、血紅素、血比容與高敏感度C-反應蛋白）、免疫功能（白血球、總淋巴球計數、嗜中性白血球、CD3、CD19、CD4及CD8）、維生素B6營養指標（血漿磷酸比哆醛及比哆酸、尿液比哆酸、紅血球天門冬胺酸轉胺酶活性係數、紅血球丙胺酸轉胺酶活性係數）、血漿同半胱胺酸濃度、血清葉酸及維生素B12的分析。結果顯示健康受試者的白蛋白、總淋巴球計數、CD3、CD19、CD4及CD8絕對計數與血漿磷酸比哆醛之數值皆顯著高於重症病人；但健康受試者的白血球、高敏感度C-反應蛋白、血漿同半胱胺酸及血漿比哆酸濃度顯著低於重症病人。重症病人於第8天的血漿比哆酸、總淋巴球計數、CD3及CD4絕對計數顯著高於第一天；但高敏感度C-反應蛋白及APACHE II score則顯著低於第一天。此外，血漿磷酸比哆醛分別與總淋巴球計數（r =0.543, p < 0.001）、CD3（r =0.497, p < 0.001）、CD19（r =0.417, p < 0.001）、CD4（r =0.430, p < 0.001）及CD8（r =0.439, p < 0.001）絕對計數呈正相關；與白血球（r =-0.418, p < 0.001）、嗜中性白血球（r =-0.503, p < 0.001）、高敏感度C-反應蛋白（r =-0.594, p < 0.001）及血漿同半胱胺酸濃度（r =-0.222, p < 0.05）呈顯著負相關。本研究結果顯示血漿磷酸比哆醛濃度不僅會影響體內免疫反應亦會影響發炎反應。

Vitamin B6 is involved in the metabolism of amino acid, nucleic acid, glycogen, porphyrin and lipid. Vitamin B6 thus has major effects on immune functions. Vitamin B6 deficiency has been found to significantly impair both humoral- and cell-mediated immunity. In addition, critically ill patients may have marginal vitamin B6 deficiency which may further contribute to a decrease in plasma homocysteine concentrations. The purposes of this study were: (1) to compare vitamin B6 status, immune responses, inflammation and homocysteine concentrations in critically ill patients with that of healthy controls; (2) to investigate the effect of vitamin B6 status on immune responses, inflammation and plasma homocysteine concentrations. Forty patients who stayed over 8 days in the intensive care unit of Taichung Venteran General Hospital and thirty-eight healthy control subjects were recruited. The levels of serum albumin, hemoglobin, hematocrit, high sensitive- C reactive protein (hs-CRP), and immune responses [white blood cell (WBC), neutrophil, total lymphocyte count (TLC), T- (CD3) and B- (CD19) lymphocyte, T-helper (CD4) and T-suppressor (CD8) were determined. Vitamin B6 status was assessed by using plasma pyridoxal 5’-phosphate (PLP) and 4-pyridoxic acid (4-PA), urine 4-PA, erythrocyte aspartate transaminase activity coefficient (EAST -AC) and erythrocyte alanine transaminase activity coefficient (EALT -AC). Plasma homocysteine concentrations, serum folic acid and vitamin B12 were also measured. Results show that control healthy subjects had normal and significantly higher levels of albumin, TLC, CD3, CD19, CD4, CD8 and plasma PLP concentrations and significantly lower levels of WBC, hs-CRP, plasma 4-PA and plasma homocysteine concentrations than these of critically ill patients at baseline. After day 8 critically ill patients had significant increases in plasma 4-PA concentrations, TLC, CD3 and CD4 but significant decreases in hs-CRP, APACHE II score. Plasma PLP concentrations was positively correlated with TLC (r =0.543, p < 0.001), CD3 (r =0.497, p < 0.001), CD19 (r =0.417, p < 0.001), CD4 (r =0.430, p < 0.001) and CD8 (r =0.439, p < 0.001). Plasma PLP concentrations was negatively correlated with WBC (r =-0.418, p < 0.001), neutrophils (r =-0.503, p < 0.001), CRP (r =-0.594, p < 0.001) and plasma homocysteine concentrations ( r =-0.222, p < 0.05). The data suggest that plasma PLP is a strong indicator of immune responses and inflammation in human subjects.