Increased frequency of late relapse in B-ALL patients with HLA-C2. Kaplan Meier analysis was performed for all B-ALL patients with available clinical and follow-up information. Patients not achieving remission during induction chemotherapy and patients undergoing hematopoietic stem cell transplantation without prior relapse were excluded from this analysis. Cases were divided into 3 groups based on C1/C1, C1/C2, and C2/C2 genotypes. (A) Kaplan-Meier estimates are shown for all patients for the full observation time starting at the time of diagnosis. (B) Only patients who achieved complete remission, finished standard treatment, and remained event free for at least 2.5 years were analyzed (qualifying for late relapse ≥30 months after diagnosis). P values were calculated by 2-sided log-rank test; A: P = .391).