Chlamydia psittaci Infection in Nongastrointestinal MALT Lymphomas and Their Precursor Lesions

Abstract

To the Editor We read with interest the article by Aigelsreiter and colleagues1 reporting that Chlamydia psittaci infection is associated with nongastrointestinal extranodal mucosa-associated lymphoid tissue (MALT) lymphomas and autoimmune precursor lesions, suggesting possible involvement of C psittaci –induced antigenic-driven MALT lymphomagenesis. In this study, Aigelsreiter et al1 analyzed the presence of C psittaci , Chlamydia pneumoniae , and Chlamydia trachomatis DNA in 47 nongastrointestinal and 14 gastrointestinal MALT lymphomas, 37 nonmalignant control samples, and 27 autoimmune precursor lesions by polymerase chain reaction (PCR) amplification and direct sequencing. While the results are potentially interesting, the results should be interpreted with caution. First, Aigelsreiter et al1 used a PCR with a very high number of reaction cycles. Performing PCR with 60 cycles may increase sensitivity; it is also prone to yield false-positive results by amplification of contamination in the absence of measures to prevent this.2 Indeed, the difference between the 47 nongastrointestinal MALT lymphoma specimens and the 37 nonmalignant control samples did not reach significance. Second, positive results were confirmed by sequence analyses of the PCR products in 9 instances. Although …