Comparative study of bone marrow and blood plasma levels of IL-2 in aplastic anaemia and their relationship with disease severity

ABSTRACT

Objectives: Interleukin-2 (alias: IL-2, TCGF, Lymphokine), a type of interleukin, is also a potent signalling molecule in the signalling cascade of the immune-mediated activation of T Lymphocytes leading to the destruction of haematopoietic stem cell (HSC) which is the basis of acquired aplastic anaemia (AAA). The objective was to study the association of IL-2 in the bone marrow plasma (BMP) and peripheral blood plasma (PBP) in AAA patients.

Methods: A total of 52 BMP and PBP-paired samples (both from the same patients) was collected from the confirmed AAA patients and 10 healthy individuals. The level of IL-2 was measured by the quantitative enzyme-linked immunosorbent assay (ELISA). The Mann–Whitney U test was used for statistical analysis.

Results: Significantly increased level of IL-2 was observed in the BMP than PBP of AAA patients. The level of IL-2 in PBP and BMP was found to be very low in the control cases. Considerably increased levels of IL-2 were found in the PBP and BMP of AAA patients as compared to controls (48.54 ± 21.89 vs. 1.99 ± 1.25 p-value < 0.00001) and (75.33 ± 41.9 vs. 3.12 ± 1.82; p-value < 0.00001) respectively. Among these patients, the IL-2 levels were higher in patients with Very Severe Aplastic Anaemia (VSAA) and Severe Aplastic Anaemia (SAA) than those with Non-severe Aplastic Anaemia (NSAA) in the PBP (65.6 ± 23.61 vs. 31.72 ± 7.64; p-value 0.00338) and (45.37 ± 16.25 vs. 31.72 ± 7.64; p-value 0.01468) respectively. Again the IL-2 levels were higher in patients with VSAA and SAA than those with NSAA in the BMP (115.01 ± 38.91 vs. 38.32 ± 19.49; p-value < 0.00001) and (66.44 ± 23.34 vs. 38.32 ± 19.49; p-value 0.0006). The IL-2 level was higher in VSAA than SAA in PBP (65.6 ± 23.61vs. 45.37 ± 16.25; p-value 0.0114) and BMP (115.01 ± 38.91 vs. 66.44 ± 23.34; p-value 0.00044).

Conclusion: This study emphasized on the bone marrow and blood plasma levels of IL-2 in aplastic anaemia and their relationship with disease severity. The results indicate towards the fact that IL-2 may have an important association with the marrow failure of AAA patients and thus can help in disease development. Further study is necessary for better understanding.

KEYWORDS:

• Interleukin-2
• acquired aplastic anaemia
• disease severity of aplastic anaemia
• destruction of stem cell
• enzyme-linked immunosorbent assay
• bone marrow plasma
• blood plasma

Acknowledgements

The authors are indebted to Swami Nityakamananda, Secretary, Ramakrishna Mission Seva Pratishthan, Vivekananda Institute of Medical Sciences, Kolkata for giving us inventory support. The authors are also obliged to the Department of Haematology, Nil Ratan Sircar Medical College & Hospital, Kolkata for providing samples and other kinds of assistances.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by the Department of Science of Technology, Government of West Bengal (Grant number 695(sanc)/ST/P/S&T/9G8/2015).