To the Editor.
—We are writing in regard to the article entitled "Posterior Corneal Crystalline Deposits in Benign Monoclonal Gammopathy" by Rodrigues et al, which appeared in the January issue of the Archives (97:124-128, 1979).Using a modification of the peroxidase-antiperoxidase technique of Sternberger et al,1 the crystalline deposits in the corneal button stained with antiserum to IgG, IgA, and IgM heavy chains and both κ and λ light chains. Both the control slides—one where the primary antiserum is replaced by normal rabbit serum and the second where the primary antiserum is omitted—were positive. Thus, the crystalline deposits were not identified as deposits of IgG κ immunoglobulin, as stated by the authors. The findings seem to indicate that the crystalline deposits are composed of a material with rheumatoid-factor-like activity. Rheumatoid factors are immunoglobulins, usually of the IgM class, that react with the Fc fragments of various immunoglobulins. It should
Callihan TR, Jaffe ES. Identification of Crystalline Deposits. Arch Ophthalmol. 1980;98(2):386. doi:10.1001/archopht.1980.01020030382031