[Serum and salivary immunoglobins A in atopic dermatitis. Prospective and comparative case control study]

IgA system has been poorly studied in patients with atopic dermatitis (AD). Previous studies have showed that a transient serum IgA deficiency in infancy could lead to atopic disease. In addition, decrease in salivary IgA has been demonstrated in patients with AD. The purpose of our work was to study the IgA system both in serum saliva in patient with AD.

We conducted a controlled prospective study from January 1994 to May 1996. 46 patients with AD and 52 healthy volunteers matched for sex and age were included. Atopic patients fulfilled at least three major and three minor features defined by Hanifin and Rajka. None above atopic criteria were present in the control group. Saliva was collected using a small cylinder of a cotton-wool-like substance (Salivette) kept in the buccal fold. Serum and saliva samples were assayed for IgA using standard nephelometric method and time-resolved immunofluorometric assay. Secretory IgA were assayed by a sandwich-type enzyme linked immunosorbent assay. Blood eosinophils and serum IgE were also evaluated.

IgA and secretory IgA were detected in all serum and saliva collected. No statistically significant difference were observed in serum or in saliva for both IgA and secretory IgA between patients with AD and controls. As expected, blood eosinophils and serum IgE were significantly increased in patients with AD.

None patients (atopic or control) exhibited IgA deficiency. Although no statistically significant, a trend to higher concentrations of serum and salivary IgA was observed in patients with AD suggesting a stimulation of mucosa-associated lymphoid tissue in these patients.