Introduction: Chronic lymphocytic leukemia (CLL) is characterized by expansion of mature, long-lived B cells. The diagnosis of CLL requires the presence of monoclonal B cells exhibiting a characteristic immunophenotype. The modified Matutes scoring system proposed 15 years ago requires strong expression of CD5 and CD23, lack of FMC7 as well as low or absent expression of CD79b and or CD22, whereby the term "low" expression is open for interpretation by the investigator. Moreover, the newly identified marker CD200 is not included in the current score in spite of its highly informative value in the differential diagnosis of B-cell disorders. Since therapeutic options vary significantly for different B-cell lymphoma subtypes, diagnostic precision is of utter importance.
Recently, a new scoring system has been suggested to replace the modified Matutes score. This, newly suggested, score system "CLLflow score", evaluates the percentage of expression of five different surface antigens expressed on CD19 positive cells including CD200. The CLLflow score showed comparable sensitivity (97.1%) versus the modified Matutes score (98.6%). However, the CLLflow score showed markedly increased specificity (87.2% vs. 53.8%).
Aim: Our aim was to test the correlation of this new scoring system to the previous modified Matutes scoring system and verify that both scoring systems amount to the same diagnosis in ambiguous cases.
Methods: We retrospectively searched for patient results compatible to mature B cell neoplasms, and more specifically patients whose score in the modified Matutes score was between 0-2 (incompatible to CLL) to 3 or higher (compatible to CLL). 32 patient results were obtained and for each a CLLflow score was calculated. Each CLLflow score was compared to the score given by the modified Matutes scoring system to verify both scoring systems amounted to the same diagnosis and validated according to clinical diagnosis.
Results: All patients who received scores between 0-2 in the modified Matutes scoring system also received a negative value in CLLflow score, thus unsuitable to a CLL diagnosis. Similarly, all patients who a received a score of 4 also received a positive value in CLLflow score consistent with a positive CLL diagnosis. Patients, who received a score of 3 in the modified matutes score (a score that was considered borderline, also received a positive score in CLLflow score.
Conclusion: The comparison between the CLLflow score and the modified Matutes scoring system yielded a 100% correlation. Utilizing the new CLLflow score seems more appropriate than the modified Matutes scoring system, due the fact that it eliminates any discordance that may arise from inter-investigator variabilities concerning expression intensity and it includes CD200 which has an important diagnostic value.