1. Kumar SK, Rajkumar SV, Dispenzieri A, et al. Improved survival in multiple myeloma and the impact of novel therapies. Blood 2008;111:2516–2520.

2. Kumar SK, Lee JH, Lahuerta JJ, et al. Risk of progression and survival in multiple myeloma relapsing after therapy with IMiDs and bortezomib: a multicenter international myeloma working group study. Leukemia 2012;26:149–157.

3. Blair HA. Daratumumab: a review in relapsed and/or refractory multiple myeloma. Drugs 2017;77:2013–2024.

4. Lokhorst HM, Plesner T, Laubach JP, et al. Targeting CD38 with daratumumab monotherapy in multiple myeloma. N Engl J Med 2015;373:1207–1219.

5. Lonial S, Weiss BM, Usmani SZ, et al. Daratumumab monotherapy in patients with treatment-refractory multiple myeloma (SIRIUS): an open-label, randomised, phase 2 trial. Lancet 2016;387:1551–1560.

6. Usmani SZ, Weiss BM, Plesner T, et al. Clinical efficacy of daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma. Blood 2016;128:37–44.

7. Facon T, Kumar S, Plesner T, et al. Daratumumab plus lenalidomide and dexamethasone for untreated myeloma. N Engl J Med 2019;380:2104–2115.

8. Voorhees PM, Kaufman JL, Laubach J, et al. Daratumumab, lenalidomide, bortezomib, and dexamethasone for transplant-eligible newly diagnosed multiple myeloma: the GRIFFIN trial. Blood 2020;136:936–945.

9. Menetrier-Caux C, Ray-Coquard I, Blay JY, Caux C. Lymphopenia in cancer patients and its effects on response to immunotherapy: an opportunity for combination with cytokines? J Immunother Cancer 2019;7:85.

10. Kim DH, Kim JG, Sohn SK, et al. Clinical impact of early absolute lymphocyte count after allogeneic stem cell transplantation. Br J Haematol 2004;125:217–224.

11. Siddiqui M, Ristow K, Markovic SN, et al. Absolute lymphocyte count predicts overall survival in follicular lymphomas. Br J Haematol 2006;134:596–601.

12. De Angulo G, Yuen C, Palla SL, Anderson PM, Zweidler-McKay PA. Absolute lymphocyte count is a novel prognostic indicator in ALL and AML: implications for risk stratification and future studies. Cancer 2008;112:407–415.

13. Krejcik J, Casneuf T, Nijhof IS, et al. Daratumumab depletes CD38+ immune regulatory cells, promotes T-cell expansion, and skews T-cell repertoire in multiple myeloma. Blood 2016;128:384–394.

14. van de Donk NW, Usmani SZ. CD38 antibodies in multiple myeloma: mechanisms of action and modes of resistance. Front Immunol 2018;9:2134.

15. Rajkumar SV, Dimopoulos MA, Palumbo A, et al. International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma. Lancet Oncol 2014;15:e538–e548.

16. Kumar S, Paiva B, Anderson KC, et al. International Myeloma Working Group consensus criteria for response and minimal residual disease assessment in multiple myeloma. Lancet Oncol 2016;17:e328–e346.

17. Krejcik J, Frerichs KA, Nijhof IS, et al. Monocytes and granulocytes reduce CD38 expression levels on myeloma cells in patients treated with daratumumab. Clin Cancer Res 2017;23:7498–7511.

18. Fauci AS, Dale DC, Balow JE. Glucocorticosteroid therapy: mechanisms of action and clinical considerations. Ann Intern Med 1976;84:304–315.

19. Kitadate A, Kobayashi H, Abe Y, et al. Pre-treatment CD38-positive regulatory T cells affect the durable response to daratumumab in relapsed/refractory multiple myeloma patients. Haematologica 2020;105:e37–e40.

20. Ege H, Gertz MA, Markovic SN, et al. Prediction of survival using absolute lymphocyte count for newly diagnosed patients with multiple myeloma: a retrospective study. Br J Haematol 2008;141:792–798.

21. Narwani V, Gabriel J, Boyd K, Chevassut T. Absolute lymphocyte count at day 29 of treatment is a powerful predictor of outcome in multiple myeloma. Clin Lymphoma Myeloma Leuk 2015;15:222–226.

22. Jimenez-Zepeda VH, Reece DE, Trudel S, et al. Absolute lymphocyte count as predictor of overall survival for patients with multiple myeloma treated with single autologous stem cell transplant. Leuk Lymphoma 2015;56:2668–2673.

23. Gavriatopoulou M, Kastritis E, Ntanasis-Stathopoulos I, et al. The addition of IMiDs for patients with daratumumab-refractory multiple myeloma can overcome refractoriness to both agents. Blood 2018;131:464–467.

24. Oostvogels R, Jak M, Raymakers R, Mous R, Minnema MC. Efficacy of retreatment with immunomodulatory drugs and proteasome inhibitors following daratumumab monotherapy in relapsed and refractory multiple myeloma patients. Br J Haematol 2018;183:60–67.