Association of common variable immunodeficiency with vitamin B6 deficiency.

OBJECTIVE

To study the prevalence of vitamin B(6) deficiency in common variable immunodeficiency and the impact of vitamin B(6) supplementation on immune function in the disorder.

DESIGN

Open, non-blinded.

SETTING

Medical School Hannover, Hannover, Germany.

SUBJECTS

Plasma vitamin B(6) concentrations were measured in all the 54 common variable immunodeficiency (CVID) patients visiting our outpatients' clinics in 2005.

INTERVENTIONS

The 17 patients with a decreased vitamin B(6) concentration were recommended to take 50 mg of vitamin B(6)/day for 3 months. Then, vitamin B(6) concentrations, absolute number of lymphocyte populations and immunoglobulin concentrations were controlled.

RESULTS

Vitamin B(6) concentrations were reduced in 17/54 patients. All 11/17 patients following our advice to substitute vitamin B(6) had normal vitamin B(6) plasma concentrations 3 months later. In parallel, the number of CD4(+) T cells significantly increased. In contrast, concentrations of serum immunoglobulins were not improved.

CONCLUSIONS

Vitamin B(6) deficiency is common in CVID. The vitamin deficiency is not the cause of CVID and vitamin supplementation does not relieve humoral immunodeficiency. Nevertheless, vitamin B(6) should be measured in CVID to avoid possible long-term complications of its deficiency.