Modifications in B-Lymphocyte Number and Phenotype in the Course of Pregnancy in a Woman with Persistent Polyclonal B-Cell Lymphocytosis: A Flow Cytometric Study

Abstract

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare clinical condition, characterized by a persistent, generally moderate lymphocytosis, generally due to stimulation of central memory B-lymphocytes, and by a moderate increase of polyclonal IgM. In some patients, slight or moderate splenomegaly is observed. A variable percentage of circulating, bone marrow and splenic lymphocytes display an abnormal nucleus (generally bilobated) or are binucleated. The clinical course is benign in most cases and transformation into splenic B-cell lymphoma occurs in few cases. In the current paper we report the first case of pregnancy in PPBL. Our patient became pregnant 18 months after diagnosis. In the course of pregnancy, a marked down-regulation of lymphocytosis (from 6 × 10(9)/L to 2.1 × 10(9)/L) and a decrease in B-lymphocyte number was observed (from 3.6 × 10(9)/L to 1 × 10(9)/L), mainly due to a marked reduction in the percentage and absolute number of central memory B-cells. Such modifications were similar to those described in normal pregnant women. One year after the delivery of a healthy female baby, the number of total lymphocytes and B-lymphocytes showed an inverse behavior, with a new expansion of central memory B-cells. Our case shows that a normal pregnancy can occur in patients with PPBL and that pregnancy can induce marked modifications in B-lymphocyte kinetics and phenotype.

Successful Pregnancy and Persistent Polyclonal B Cell Lymphocytosis (PPBL): A Case Study of a Rare Co-Existence

“…However, the cause of PPBL remains unknown and an association with cigarette smoking has been suggested. It is worth mentioning that in 1 reported case, the lymphocytosis resolved after stopping smoking and returned on restarting [ 7 , 10 , 11 ].…”

“…It is worth noticing that aside from the fact that PPBL remains in most cases a benign disorder with indolent clinical course, pregnancy seems to be extremely rare in PPBL patients, and to the best of our knowledge, only 1 such case has been reported in the literature so far [ 10 ].…”

Eight‐year follow up of a case of persistent polyclonal B cell lymphocytosis: Immunophenotypic findings pre‐ and postsplenectomy

“…Such a follow up is what is taking place in our center for a woman affected by PPBL, whose clinical history was previously described and can offer valuable insight. (Carulli et al, 2015) In September 2011, a mild PPBL was diagnosed in a 33-year-old woman with an unremarkable clinical history save for smoking of about one package of cigarettes per day. At presentation, her parameters were: hemoglobin 12.6 g/dl, white blood cells 12 × 10 9 /L, lymphocytes 6.0 × 10 9 /L (with 3.42 × 10 9 /L B cells, 2.2 × 10 9 /L T cells and 0.4 × 10 9 /L NK cells) and platelets 168 × 10 9 /L, with a mild increase of serum polyclonal IgM concentrations (600 mg/dl; normal value 40-230); a computed tomography assessment showed only the modest spleen enlargement (longitudinal diameter of 14 cm), with no involvement of other lymphatic organs.…”

“…At presentation, her parameters were: hemoglobin 12.6 g/dl, white blood cells 12 × 10 9 /L, lymphocytes 6.0 × 10 9 /L (with 3.42 × 10 9 /L B cells, 2.2 × 10 9 /L T cells and 0.4 × 10 9 /L NK cells) and platelets 168 × 10 9 /L, with a mild increase of serum polyclonal IgM concentrations (600 mg/dl; normal value 40-230); a computed tomography assessment showed only the modest spleen enlargement (longitudinal diameter of 14 cm), with no involvement of other lymphatic organs. (Carulli et al, 2015) The patient underwent periodical examinations, including blood tests, lymphocyte immunophenotype, and abdomen ultrasound. Flow cytometry analyses were carried out with a FacsCanto II cytometer (Becton Dickinson) equipped with three lasers (405, 488, 633 nm); 100,000 events/tube were acquired.…”

“…In 2013 the patient carried out a pregnancy, during which a significant decrease of lymphocyte absolute number was registered (for an account of the variations in the number of lymphocytes during the follow up period, see Figure 1 panel d) caused by a progressive reduction of B-cells (which were 3.4 × 10 9 /L in April, 1.2 × 10 9 /L, in September and 1.1 × 10 9 /L in December). (Carulli et al, 2015) The pregnancy was normal, and a healthy female baby was delivered in January 2014. At a new complete evaluation 1 year after delivery, the number of lymphocytes was back to the levels registered before pregnancy, and these values remained stable for another year, with 2.9 × 10 9 /L B cells, 1.8 × 10 9 /L T cells, and 0.2 × 10 9 /L NK cells recorded in January 2016.…”