Persistent polyclonal B-cell lymphocytosis in chronic smokers: more than meets the eye.
BACKGROUND
Persistent neutrophiliais awell-recognized phenomenon in some chronic cigarette smokers. In contrast, persistent polyclonal B-cell lymphocytosis (PPBL) is considered a rare entity affecting this patient population.


METHODS
We analyzed a cohort of 21 patients with chronic smoking histories presenting with persistent leukocytosis. None of the patients was on steroids, lithium preparations, or other medications known to increase the white blood cell (WBC) counts. We excluded any myeloproliferative or lymphoproliferative conditions in our patient cohort. WBC differential was obtained during repeated visits and the mean values calculated. The results were subsequently compared to known upper normal limits and tested for statistical significance.


RESULTS
The absolute leukocyte count in our cohort was 17.8 +/- 3.2 x 10(9)/L and the absolute neutrophil count was 12.0 +/- 2.8 x 10(9)/L. The difference proved statistically significant for both values when compared to upper normal limits (P < 0.001). Six patients (five females and one male) were also found to have a significant and persistent lymphocytosis at 5.1 +/- 0.5 x 10(9)/L (P < 0.001).


CONCLUSIONS
We have identified the presence of -29% PPBL cases in a series of consecutive patients with persistent leukocytosis/neutrophilia related to chronic cigarette smoking. Similar to the results obtained by other investigators, our PPBL patients showed a younger female predominance. Given the findings in our cohort, we believe that PPBL might be more common than previously thought and discuss further its potential implications for general and specialty practice.
Department of Hematology-Oncology, Saint Francis Hospital and Medical Center, Hartford, USA.
Constantin A
CA
Dasanu
Ion
I
Codreanu
D000328:Adult; D017677:Age Distribution; D001402:B-Lymphocytes / Q000473:pathology*; D001706:Biopsy; D001856:Bone Marrow Examination; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008218:Lymphocytosis / Q000209:etiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects*