Evaluation of humoral immune function in patients with chronic idiopathic thrombocytopenic purpura.

Coincidence of autoimmune diseases such as immune thrombocytopenic purpura (ITP) with immunodeficiencies has been reported previously in patients who suffered from primary antibody deficiency (PAD). But there is no original study on immunological profiles of ITP patients to find out their probable immune deficiency. In this case-control study, ITP patients' humoral immunity was investigated for diagnosis of PAD in comparison with normal population. To evaluate the humoral immune system against polysaccharide antigens, patients' serum immunoglobulin levels were measured and a 23-valent pneumococcal capsular polysaccharide vaccine (PPV23) was administrated to evaluate the antibody response to vaccination. In this study, 14 out of 36 patients (39%) were diagnosed with antibody mediated immune deficiency including 2 patients (5.5%) with immunoglobulin class deficiency and 4 (11%) with IgG subclass deficiency. The remaining patients suffered from specific antibody deficiency. The most frequent deficiency in ITP patients was specific antibody deficiency.Therefore, immunological survey on ITP patients may be important especially for those who have undergone splenectomy.