Autoimmunity in patients with selective IgA deficiency.

BACKGROUND AND OBJECTIVE: Selective immunoglobulin A deficiency (SIgAD) is the most common primary antibody deticiency. Patients with SIgAD have a greater risk of concomitant autoimmune disorders than healthy individuals. The exact mechanism underlying the relationship between autoimmunity and SIgAD is not fully understood. The aim of this study was to evaluate potential associations between autoimmunity and specific clinical or immunological findings in patients with SIgAD. METHODS: The study population comprised 57 symptomatic patients (65% males) with confirmed SIgAD who were referred to our center. Demographic data and history of autoimmunity were recorded both for patients and for their relatives. Comprehensive clinical and laboratory examinations were performed to investigate autoimmune complications in all the patients. RESULTS: Autoimmune disorders were documented in 17 cases (29.8%; 9 males and 8 females). The most common manifestations were thyroiditis, vitiligo, and hemolytic anemia (3 cases each). Ten patients (17.5%) had a family history of autoimmunity. Significant associations were detected between autoimmunity and increased duration of follow-up (P = .003), serum level of IgM (P = .01), regulatory T-cell count (P = .03), and class-switched memory B-cell count (P = .01). Four cases of autoimmune SIgAD (23.5%) progressed to common variable immunodeficiency during the follow-up period (P = .006). CONCLUSIONS: Autoimmune disorders, autoimmune cytopenia, and Ig subclass deficiency can lead to severe clinical manifestations in patients with SIgAD. Therefore, immunologists and pediatricians should be aware of these conditions.

IgG anti-IgA antibodies in paediatric antibody-deficient patients receiving intravenous immunoglobulin.

BACKGROUND: Immunoglobulin replacement therapy is an effective route of management for both infections and non-infectious complications in predominantly antibody deficiency (PAD). Trace levels of IgA (ranged from 0.4 to 2500 mg/ml), which exist in all immunoglobulin products, could lead to an increased susceptibility for adverse reactions in PAD patients. Furthermore, the exact mechanism which stimulates the anti-IgA antibody production in PAD is still unknown. The aim of this study was to evaluate IgG anti-IgA antibodies in PAD patients receiving intravenous immunoglobulin (IVIg) and its predisposing factors. METHODS: Available patients with confirmed diagnosis of PAD, who underwent regular IVIg replacement therapy in our centre, were enrolled in the study. Control group included 24 healthy individuals as the negative control and eight symptomatic patients with IgA deficiency as the positive control groups. IgG anti-IgA antibodies level was measured by the ELISA method. RESULTS: A significant difference was observed between Anti-IgA level of common variable immunodeficiency (CVID) and other PAD groups (p=0.02). Moreover, six CVID patients were seropositive for the IgG anti-IgA antibody, with higher susceptibility to the adverse reactions (p<0.001). IgG anti-IgA level has a negative relationship with serum IgA level (r=-0.06) and IVIg treatment duration (r=-0.006). CONCLUSION: Our data suggested that there was a significant association between anti-IgA antibody presence and the adverse reactions, especially in CVID patients with higher susceptibility to produce this constitutional antibody.