Serum immunoglobulins in a rural and an urban population of Greece with special reference to immunoglobulin A.

The serum concentration of immunoglobulins G, A, and M was studied in 390 inhabitants of a rural community and in 204 residents of an urban area of Greece. It was found that serum IgA levels were significantly higher in the rural area where intestinal infections were more prevalent. No significant difference in serum IgG was found between the two groups. IgM was found to be lower among residents of the rural area. The present findings suggest a possible ecological association between increased IgA and chronic exposure to intestinal infection.