Intérêt de l’étude morphologique des lymphocytes binucléés pour le diagnostic des lymphocytoses Morphologic features of the binucleated lymphocytes for the assesment of persistent B-cell polyclonal lymphocytosis

Observation of binucleated lymphocytes on a blood film is a cornerstone event to assess persistent polyclonal B-cell lymphocytosis diagnosis (PPBL). But seldom case reports mentioned their finding in other contexts, mainly B-cell lymphoproliferative neoplasms such chronic lymphocytic leukemia or in reactive circumstances as multiple sclerosis undergoing natalizumab treatment. We aimed to check if some particular morphologic features were more specificaly linked to PPBL, reviewing blood films of series of patients affected by PPBL or harbouring binucleated lymphocytes whatever the diagnosis was. We found that binucleated cells in PPBL were heterogeneous but mostly midde653 Pour citer cet article : Lesesve JF, Gressot AL, Cornet E, Mossafa H, Troussard X. Intérêt de l’étude morphologique des lymphocytes binucléés pour le diagnostic des lymphocytoses. Ann Biol Clin 2013 ; 71(6) : 653-61 doi:10.1684/abc.2013.0916 rticle reçu le 19 mars 2013, ccepté le 5 avril 2013 sized cells, asymetricaly bilobed with nucleoli, and with a moderately basophilic cytoplasm. Though mainly observed in PPBL patients, all that criteria remained unspecific. Conversely, the morphologic features of the other lymphoid cells were of good clinical value to affirm PPBL, either monocytoid or hyperbasophilic cells being systematically found. We think that a substantial percentage of binucleated lymphocytes, harbouring morphologic features such as described, and in a context of monocytoid and/or hyperbasophilic lymphocytes is predictive of PPBL diagnosis.