Study of Trisomy 12 in Morphologically Typical and Atypical b-cell Chronic Lymphocytic Leukemia

This study included 20 patients with CLL and 10 apparently healthy individuals serving as control group. All patients were subjected to:(1) Complete history taking and full clinical examination.(2) Complete blood picture and stained blood films(3) Reticulocytic count and direct coomb’s test.(4) Serum LDH and uric acid.(5) Immunophenotyping of cases on the peripheral blood(6) Conventional karyotyping by using G-banding technique.A higher incidence of the disease in males was observed with male female ratio 1.8:1.Patients were divided into two groups according to the morphology of lymphocytes in peripheral blood films:Typical morphology group: accounted for 70% of the cases. It is defined by the presence of > 85% small mature looking lymphocytes with clumped chromatinAtypical morphology group:representing 30% of cases and defined by the presence of > 10% circulating prolymphocytes or > 15% cleaved cells or lymphoplasmacytic lymphocytes in the peripheral blood smears.The typical morphology group was associated with lower WBC count, absolute lymphocytic count, lower incidence of lymphadenopathy and splenomegaly. However, no significant difference was found between both groups as regards hemoglobin, platelet count, serum LDH and uric acid.The typical morphology group was also associated with higher percentage of hepatomegaly and autoimmune complications.As regards trisomy 12, it was found in 4 cases representing 20% of the studied cases all of them associated with atypical morphology.Trisomy 12 was also associated with a higher mean of total leucocytic count, lymphocyte count and higher percentage of lymphadenopathy and splenomegaly. In addition, it was associated with higher levels of serum LDH and uric acid.As regards the imunophenotyping performed for all cases, no significant correlations were observed between the surface markers and both typical and atypical groups. However,a significant correlation was found between total leucocytic counts, absolute lymphocytic counts and CD20 and CD22 as regards all studied cases. No atypical immunophenotypic patteren detected with either atypical group or in patients with trisomy 12.ConclusionAtypical morphology is associated with bad prognostic factorsTrisomy 12 is a common cytogenetic abnormality in CLL cases (20%)Inspite of having 100% of trisomy12 cases found in atypical morphology group, trisomy 12 can not be excluded in typical morphology group except after larger studies to be conducted as our cases are too few to conclude thatRecommendationsInspite of the need to study a larger number of cases specially those with atypical morphology and trisomy12 as our groups were of small number, we recommend: Besides staging system and other prognostic factors such as LDH, a useful and simple use of peripheral blood film morphology in cases of CLL would confer a guideline to the expected course of the disease. A cytogenetic study in cases of CLL is an important prognostic tool in determining the course of this disease. Trisomy 12 is one of the cytogenetic abnormalities in CLL which is associated with some bad prognostic factors and might give an indication for an early treatment or a more intensive one.