Absence of the V617F JAK2 Mutation in the Lymphoid Compartment in a Patient with Essential Thrombo- cythemia and B-Chronic Lymphocytic Leukemia and in Two Relatives with Lymphoproliferative Disorders

Abstract

Background: Myeloproliferative neoplasms likely involve both myeloid and lymphoid lineages. Nevertheless, the coincidence of chronic myeloproliferative and lymphoproliferative diseases in the same patient is a rare phenomenon. Methods: We report a case of a patient having essential thrombocythemia (ET) and B-chronic lymphocytic leukemia (B-CLL). In this patient and in 2 relatives with lymphoproliferative disorders, we searched for JAK2^V617F mutation in lymphocytes. Results: In the patient with ET and B-CLL, we identified homozygous JAK2^V617F mutation in the granulocytic compartment. Both relatives were heterozygous for JAK2^V617F mutation, whereas no mutation signal could be detected in the lymphoid compartment of all 3 patients. Conclusion: Our results seem to confirm that CLL cases are negative for JAK2^V617F mutation in B- and T-lymphocyte populations.Presence of JAK2^V617F mutation in subjects without myeloproliferative diseases could indicate an increased risk of a future myeloproliferative neoplasm development.

No Evidence for JAK2^V617F Mutation in Monoclonal B Cells in 2 Patients with Polycythaemia Vera and Concurrent Monoclonal B Cell Disorder

“…The coexistence of Ph – MPN and monoclonal B cell disorder in the same patient has been described in several case reports, but is considered to be rare [11,12,13,14,15,16]. Both disorders can be diagnosed simultaneously or subsequently like in our patients.…”

“…A 79-year-old patient with a JAK2 V617F -positive PV was described with a B-CLL without detection of JAK2 V617F in T cells as well as in the CD20+/CD5+ and CD20+/CD5– B cells [12]. In addition 2 patients with JAK2 V617F -positive ET and B-CLL were reported without detection of JAK2 V617F in circulating B and T lymphocytes, respectively [13,14]. Recently a patient with a JAK2 V617F -positive Ph – MPN with B-CLL was described.…”

“…However, overt lymphocytosis or monoclonal lymphoproliferative disorders are rare in Ph – MPN with approximately 30 reported cases of concomitant B-CLL [10,11,12,13,14,15]. In a recent large retrospective multicentric Italian study among patients with B-CLL and monoclonal B cell lymphocytosis 18 cases of ET and 10 cases of PV were additionally found [16].…”

“…In a recent large retrospective multicentric Italian study among patients with B-CLL and monoclonal B cell lymphocytosis 18 cases of ET and 10 cases of PV were additionally found [16]. Up to now 4 patients with JAK2 V617F -positive Ph – MPN and B-CLL were evaluated for the presence of JAK2 V617F in lymphocytes without definite proof for the presence of JAK2 V617F mutation in the B-CLL cells, although it was suggested in one case [12,13,14,15]. …”

Simultaneous and Sequential Concurrent Myeloproliferative and Lymphoproliferative Neoplasms

“…Concurrent manifestation of two chronic-phase myeloid and lymphoid neoplasms in one patient is rare and occurs in approximately 1% of patients [11,12]. Several case reports and a few case series have addressed this issue [13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91]. Due to its rarity, there has been no systematic evaluation of which combinations of myeloid and lymphoid neoplasms are frequent/infrequent, and it is still a matter of debate whether two concurrent diseases in one patient are clonally related or represent independent aberrations.…”