Aspects Cytologiques et Immunophénotypiques des Syndromes Lymphoprolifératifs Chroniques B à Petites Cellules à Dakar au Sénégal

RESUME Introduction. Le diagnostic des lymphoproliferations chroniques B (LPCB) a petites cellules est difficile en Afrique sub-saharienne du fait de l’insuffisance des techniques specialisees et tres peu de donnees sont disponibles sur ces pathologies. Notre etude avait pour objectif de decrire les aspects cytologiques et immuno-phenotypiques des LPCB a petites cellules au Senegal. Patients et methodes. Il s’est agi d’une etude transversale descriptive, d’une duree de 9 mois, realisee a l’hopital Aristide Le Dantec. Nous avons inclus les adultes ayant une hyperlymphocytose superieure ou egale a 5 giga/l et/ou des lymphocytes atypiques au frottis sanguin. L’hemogramme etait fait a l’aide du Sysmex XT2000i (Sysmex Japon) et l’etude immunophenotypique a l’aide du cymometre de flux FACS Calibur des Laboratoires Becton Dickinson (USA). Les variables etudiees etaient : âge et sexe, splenomegalie et adenopathies, hemogramme, frottis sanguin et les antigenes de surface a l’immunophenotypage. Resultats. Vingt et un patients ont ete inclus dont 18 hommes et 03 femmes, soit un sex-ratio de 6, et un âge moyen de 63 ans [48 ; 80]. Le syndrome tumoral, present dans 86 % des cas, etait constitue de splenomegalie n= 9 (42,9%) et d’adenopathies n= 18 (86%). La lymphocytose moyenne etait de 149,02 giga/l [9 ; 832,93]. Les lymphocytes matures etaient observes dans 18 cas, les lymphocytes monocytoides dans deux cas et les lymphocytes villeux dans un cas. Les patients atteints de leucemie lymphoide chronique (LLC) etaient au stade C n=11, au stade B n= 07 et au stade A n=01 de la classification de Binet. Les profils immunophenotypiques retrouves etaient 18 cas de LLC typique CD5 +, CD 23+, CD22 -, FMC7- et IgS faibles (score de Matutes a 5) ; deux cas de lymphome de la zone marginale CD5-, CD 23+, CD22+, FMC7+ et IgS + (Matutes a 1) et un cas de LLC atypique CD5+, IgS+, CD23-, CD22 et FMC7 faibles (Matutes a 3). Conclusion. La caracterisation des SLPB nous a permis de mieux faire la difference entre ces entites souvent similaires d’un point de vue cytologique. L’immunophenotypage est un outil complementaire de la cytologie pour le diagnostic differentiel des SLPB. ABSTRACT Introduction. Differential diagnosis of small cell chronic B lymphoproliferations (CBL) is difficult in sub-Saharan Africa due to insufficient specialized techniques and very little data is available on these diseases. The objective of our study was to describe the cytological and immuno-phenotypic aspects of small cell LPCBs in Senegal. Patients and methods. This was a 9-month cross-sectional descriptive study conducted at Aristide Le Dantec Hospital. We included adults with hyperlymphocytosis of 5 giga/l or more and/or atypical lymphocytes in the blood smear. The blood count was done using Sysmex XT2000i (Sysmex Japan) and the immunophenotypic study using the FACS Calibur flow cymometer from Becton Dickinson Laboratories (USA). The variables studied were: age and sex, splenomegaly and adenopathies, blood count, blood smear and surface antigens at immunophenotyping. Results. Twenty-one patients were studied, including 18 males and 03 females, (sex ratio =6), with an average age of 63 years [48; 80]. Mass syndrome was present in 86% of cases and consisted of splenomegaly n= 9 (42.9%) and adenopathies n= 18 (86%). The average lymphocytosis count was 149.02 giga/l[9; 832.93]. Mature lymphocytes were found in 18 cases, monocytoid lymphocytes in two cases and citrus lymphocytes in one case. The Binet classification stages of patients with CLL were as follows: stage C (n=11), stage B (n=07) and stage A (n=01). The immunophenotypic profiles found were 18 cases of typical CD5+, CD 23+, CD22-, FMC7- and low IgS CLL (Matutes score at 5); two cases of marginal lymphoma CD5-, CD 23+, CD22+, FMC7+ and IgS+ (Matutes at 1) and one case of atypical CD5+, IgS+, CD23-, CD22 and low FMC7 (Matutes 3). Conclusion. Characterization of SLPBs permits better differentiation of these often cytologically similar entities. Immunophenotyping is a complementary tool to cytology for the differential diagnosis of SLPB.