Objective：To explore the therapeutic effect of expanded autologous peripheral blood mononuclear cells(PBMC)in vitro on patients with amyotrophic lateral sclerosis(ALS)，and the correlation between the peripheral blood lymphocyte subgroup classification and the improvement of symptoms. Methods：Between October 2019 and August 2021，a total of 65 ALS cases were enrolled from the Department of Neurology at Sir Run Run Hospital affiliated of Nanjing Medical University and Nanjing Hospital affiliated of Nanjing University of Traditional Chinese Medicine. The patients were randomly assigned to two groups：the PBMC group (33 cases)received a treatment of PBMCs(1×10⁶ /kg body weight)and 20% human albumin(100 mL)，while the control group(32cases)received only 20% human albumin(100 mL). The revised ALS Functional Rating Scale(ALSFRS-R)was scored before and on the day 5 and day 14 after the treatment. The number of CD4⁺ T cells，CD8⁺ T cells，CD4⁺ CD25⁺ Foxp3⁺ Treg cells，and CD16⁺ CD56⁺ NK cells in peripheral blood were measured. Results：①The ALSFRS-R scores in PBMC group were significantly higher on the 5th day (30.1 ± 3.4 points)and the 14th day(26.5 ± 2.0 points)after treatment than that before treatment(25.3 ± 1.4 points)(P ＜ 0.05). There was no significant difference in ALSFRS-R score before and after treatment in the control group(P ＞ 0.05)；②CD8+ T cells and CD4+ CD25⁺ Foxp3⁺ Treg cells in PBMC group were increased on the 5th and 14th day after treatment，which were significantly higher than those in control group and PBMC group before treatment(P ＜ 0.05). There was no statistical significance in CD4+ T cells and CD16⁺ CD56 ⁺ NK cells before and after treatment in PBMC group and compared with the control group(P ＞ 0.05). Also there was no statistical significance in all the changes of the above in control group before and after treatment(P ＞ 0.05)；③At the 5th and 14th day after PBMC treatment，the number of CD8⁺ T cells was negatively correlated with the ALSFRS-R score(P ＜ 0.05)；The number of CD4⁺ CD25 ⁺ Foxp3 ⁺ Treg cells was positively correlated with the ALSFRS-R score(P ＜ 0.05). Conclusion：The reinfusion therapy of autologous PBMC expanded in vitro can improve the clinical symptoms of ALS patients in a short time，and the changes in the number of CD8⁺ T cells and CD4⁺ CD25⁺ Foxp3⁺ Treg cells in peripheral blood are correlated to the clinical progression of the disease.