Lymphocyte activation: reactive lymphocytes (RE-LYMP) and antibody-synthesizing lymphocytes (AS-LYMP)
What are RE-LYMP and AS-LYMP?
RE-LYMP and AS-LYMP are parameters derived from a CBC plus DIFF measurement of an EDTA blood sample, indicating the presence of activated lymphocytes based on their increased fluorescence signal.
- RE-LYMP encompasses all lymphocytes with fluorescence higher than the normal lymphocyte population.
- AS-LYMP encompasses lymphocytes with very high fluorescence
The lymphocyte [research*] parameters AS-Lymph % and RE-Lymph % appeared very useful to distinguish between viral and bacterial infections.
* At the time of evaluation, the parameters were research parameters.
Benefits
The clinical benefit of the reactive and antibody-synthesizing lymphocyte parameters (RE-LYMP and AS-LYMP) focuses on providing additional information about the cellular activation of the innate and adaptive immune responses [1–6] and assisting in managing inflammatory diseases by:
- supporting differentiation between cell-mediated or humoral immune responses to pathogens.
- supporting differentiation between viral and bacterial infections.
- supporting differentiation between acute and subsiding infections.
- indicating the presence of an inflammatory condition without an infection.
A laboratory can benefit from measuring RE-LYMP and AS-LYMP by reporting these parameters in follow-up measurements of proven infections to assess disease trends and reduce the smear workload [7].
Reference ranges [8]
RE-LYMP# (absolute count): 0.03 – 0.17 × 109/L
RE-LYMP% (percentage): 0.4 – 2.5%
AS-LYMP# (absolute count): 0.00 × 109/L
AS-LYMP% (percentage): 0.0%
How are RE-LYMP and AS-LYMP measured?
RE-LYMP and AS-LYMP are diagnostic parameters obtained from the white blood cell differential channel (WDF) and are available on all Sysmex haematology analysers equipped with an Extended Inflammation Parameters licence.
- RE-LYMP are calculated when a continuous population of lymphocytes with increased fluorescence appears above the normal lymphocyte area.
- AS-LYMP are calculated when a separate and distinct population of lymphocytes with high fluorescence appears. AS-LYMP is always reported together with RE-LYMP and is included within the RE-LYMP values.
References
[1] Linssen J et al. (2007): Identification and quantification of high fluorescence-stained lymphocytes as antibody synthesizing/secreting cells using the automated routine hematology analyzer XE-2100. Cytometry B Clin Cytom 72(3): 157–166.
[2] Henriot I et al. (2017): New parameters on the hematology analyzer XN-10 (SysmexTM) allow to distinguish childhood bacterial and viral infections. Int J Lab Hematol 39(1): 14–20.
[3] Ho SF et al. (2023): Exploring Extended White Blood Cell Parameters for the Evaluation of Sepsis among Patients Admitted to Intensive Care Units. Diagnostics (Basel) 13(14).
[4] Nierhaus A et al. (2012): Use of a weighted, automated analysis of the differential blood count to differentiate sepsis from non-infectious systemic inflammation: the intensive care infection score (ICIS). Inflamm Allergy Drug Targets 11(2): 109–115.
[5] Prodjosoewojo S et al. (2019): A novel diagnostic algorithm equipped on an automated hematology analyzer to differentiate between common causes of febrile illness in Southeast Asia. PLoS Negl Trop Dis 13(3): e0007183.
[6] Linssen J et al. (2020): A novel haemocytometric COVID-19 prognostic score developed and validated in an observational multicentre European hospital-based study. Elife 9.
[7] Blomme S et al. (2021): The integration of Sysmex XN-9100' WPC channel reflex testing in the detection of reactive versus malignant blood samples. Int J Lab Hematol 43(2): 191198.
[8] L van Pelt J et al. (2022): Reference intervals for Sysmex XN hematological parameters as assessed in the Dutch Lifelines cohort. Clin Chem Lab Med 60(6): 907920.
