Chronic lymphocytic leukemia in Kenya: an immunophenotypic and clinicopathologic study

Abstract

Abstract Objective To define cases of chronic lymphocytic leukemia (CLL) by immunophenotypic criteria and describe the associated clinical features in patients diagnosed at Aga Khan University Hospital, Nairobi. Background Rising to the growing cancer challenge will require improved diagnostic services. CLL is common in elderly patients. The current international standard in diagnosis incorporates findings of immunophenotyping. Facilities for immunophenotyping have generally been unavailable in Kenya. Method A cross-sectional survey was conducted between August 2011 and April 2012. Potential cases were identified based on morphologic criteria. Consecutive samples were obtained and subjected to 3 colour immunophenotyping on a Cytomics FC 500 cytometer. CLL was defined using the Royal Marsden Hospital scoring system. Baseline clinical and diagnostic data were also obtained. Results Forty nine cases met the eligibility criteria. Thirty one were known CLL cases, and 18 were newly diagnosed. Median age at diagnosis was 62 years. Male:female ratio was 1.3:1. Black patients (42/49) were more likely to present with high risk disease (Rai stages III-IV) and with higher lymphocyte counts than non-blacks at diagnosis. Twenty six point five percent of patients in this study were diagnosed in Rai stage 0. The prevalence of CD5/CD23 co-expression was found to be 95.9%. CD5 was universally expressed, whereas CD23 was present in all but 2 cases. Both were associated with atypical morphology. Complete absence of light chain expression using a monoclonal antibody was found in 12.2% of cases. Five patients had their diagnosis revised. Of 31 patients on follow-up for CLL, only 5 had had any form of immunophenotyping done.