Germinal centres in diagnostic labial gland biopsies of patients with primary Sjögren’s syndrome are not predictive for parotid MALT lymphoma development

Abstract

Presence of GCs in labial gland biopsies does not differ between patients with pSS that develop parotid MALT lymphoma and patients with pSS who do not develop lymphoma. The presence of GCs in labial gland biopsies is therefore not a predictive factor for pSS-associated parotid MALT lymphomas.

Standardisation of the detection of germinal centres in salivary gland biopsies of patients with primary Sjögren’s syndrome is needed to assess their clinical relevance

“…However, importantly, only one of the seven non-Hodgkin lymphomas observed in the pSS cohort of the study of Theander et al 12 was a parotid MALT lymphoma, that is, the type of lymphoma that is characteristically associated with pSS. In our retrospective study,2 we could not demonstrate that the presence of well-defined germinal centres in diagnostic minor salivary gland biopsies (both H&E and Bcl-6-defined) was also predictive for the development of parotid MALT lymphoma. We agree with Alunno et al 1 that histopathological analysis of salivary gland biopsies from larger cohorts of patients scored using standardised protocols and with well-defined definitions are needed to assess the clinical relevance of the presence of germinal centres in salivary gland biopsies of patients with pSS.…”

“…Bcl-6 is consistently expressed at high levels by germinal centre B-cells and is commonly applied by pathology laboratories for lymphoma subtyping. In our study,2 we observed slightly more germinal centres in Bcl-6 stained sections of pSS salivary gland biopsies compared with H&E stained sections, which was due to the fact that also small germinal centres (defined as clusters of > 5 Bcl-6 + B-cells) could easily be detected. Larger cohorts of salivary gland biopsies are obviously needed to establish the higher sensitivity and specificity of Bcl-6 stained sections, compared with H&E salivary gland stained sections.…”

“…As we2 and others also noted before,3–6 Alunno et al 1 underpin in their comments the need for standardisation of the detection method of germinal centres in salivary gland biopsies in patients with pSS. Germinal centres are structures that arise in B-cell follicles of secondary lymphoid organs as a response to antigenic stimulation.…”

“…We thank Alunno et al 1 for their comments, as a response to our recent publication2 in which we describe that, in contrast to the prevailing view, germinal centres in diagnostic labial gland biopsies are not predictive for the development of mucosa-associated lymphoid tissue (MALT) lymphoma in parotid salivary glands in patients with (primary) Sjögren’s syndrome (pSS). As we2 and others also noted before,3–6 Alunno et al 1 underpin in their comments the need for standardisation of the detection method of germinal centres in salivary gland biopsies in patients with pSS.…”

The challenge to interpret conflicting results and the need of a univocal definition for germinal centres in primary Sjögren’s syndrome

“…We read with interest the article by Haacke et al 1 demonstrating that the presence of germinal centres (GCs) in minor salivary glands (MSG) of patients with primary Sjögren’s syndrome (pSS) does not differ between subjects developing non-Hodgkin’s lymphoma (NHL) and those who do not develop this complication. In recent years the prognostic role of MSG histopathology has been a matter of intense debate.…”