Absence of Chlamydial Infection in Japanese Patients with Ocular Adnexal MALT Lymphoma.

The extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a distinct type of B-cell lymphoma that develops in extranodal sites and usually has an indolent clinical course as a localized disease. Recent clinicopathological studies suggest a strong relationship between MALT lymphoma and inflammatory diseases of the epithelium such as autoimmune diseases and infections (Sjogren’s syndrome, Hashimoto’s thyroiditis, Helicobacter pylori infection, and etc.), because chronic antigen stimulation has been causally linked to the development of lymphoproliferative diseases in B cells. MALT lymphoma grows in extranodal lymphoid tissue and exists in epithelium tissues, and it is often difficult to distinguish malignant lymphoid tissue from benign inflammation. However, this is only one of the possible causes; recent positive and negative correlations between ocular adnexal MALT lymphomas and chlamydial infections reported by different researchers indicate several different possible explanations. Here, we analyze twenty-three cases of ocular adnexal MALT lymphoma whose monoclonality was confirmed by immunoglobulin heavy chain gene rearrangement and/or the analysis of cell surface antigens for evidence of expected causative factors, using both ELISA analysis to detect antibodies and specific PCR gene amplification followed by Southern blot analysis. Our series of patients did not show any serological relations to the Epstein-Barr virus, the Hepatitis C virus, or to Chlamydophila psittaci. Two cases had positive serum antibodies for autoimmunity, another two cases had positive antibodies against Chlamydia trachomatis. None of our cases showed the presence of chlamydial 16S rRNA or 16S-23S spacer rRNA genes (C. psittac, C trachomatis, C. pneumoniae, and C. felis) after PCR amplification. These results indicate that the inflammatory agents are still unknown in our series of ocular adnexal MALT lymphomas, and that some types of chlamydial infections are not associated with ocular adnexal MALT lymphoma in southern regions of Japan.