Abstract
Purpose: :
The MALT (mucosa-associated lymphoid tissue) is the part of the immune system located at mucosal surfaces. In ophthalmology it is present in the orbit, conjunctiva and lacrymal ducts. The MALT is divided in different parts of the conjunctiva but its existence at the sclero-corneal limbus eye helps us better understand the ocular surface’s pathologies, mainly why the cornea, an avascular structure, is the site of abnormal neovascularization; the underpinning processes still require further study. The objective of our study is the characterization of the ocular MALT and its role in inflammation.
Methods: :
2 conjunctival samples were taken from 31 patients. The first sample was fixed in formalin for standard coloration and microscopy. The second (fresh) sample was sent on a compress soaked with saline to a freezer and kept for immunolabeling. The processing of the samples is done on the spot, including the frozen section. Each slide, whether HPS (hematoxylin, phloxine, saffron ) stain or immunostaining, is read by two different examinators ; in case of discordant interpretation between the two readers, we operate a crossmatch of the diagnosis.
Results: :
We found 2 cases of MALT in 31 patients (6%), which is in keeping with the literature, because the sources of surgical areas (sclero-corneal limbus) are not the most rich in MALT. Our results are more consistent with semi-quantitative study than quantitative. There are differences in counting antibodies tested (CD3, CD4, CD8, C20, CD138, CD68, CD1, CD56, IgA, IgG, IgM), but should be interpreted with caution because these are layered cuts and not contiguous, especially for Ig (less tissue).
Conclusions: :
It is not easy to find the constituents of MALT. In the conjunctiva, there are many secretory IgA lymphocytes. As for IgM, we expected the preoperative actions to result in a local inflammatory reaction, which explains the predominance of IgM producing lymphocytes. All the results should help to better understand the pathophysiology of MALT and enable us to shed some light on the immune dysregulation in some inflammatory or tumoral conditions of the eye.
Keywords: conjunctiva • pathology techniques • anatomy