Response to immunosuppressive therapy (IST) in younger patients with myelodysplastic syndrome (MDS) has been linked to a T-cell-dominant autoimmune process that impairs hematopoiesis. Analysis of the age-adjusted CD4:CD8 ratio in 76 MDS patients compared with 54 healthy controls showed that inadequate CD4+, rather than expansion of CD8+ T cells, was associated with a lower ratio in a group that included both lower and higher risk MDS patients defined by the International Prognostic Scoring System. In younger MDS patients, naive and memory phenotypes defined by CD45RA and CD62L display showed depletion of naive CD4+ and CD8+ T cells, suggesting a possible relationship to IST responsiveness. To determine the correlation between T-cell subset distribution, T-cell turnover and autoimmunity, a cohort of 20 patients were studied before and after IST. The CD4:CD8 ratio correlated inversely with the proliferative T-cell index before treatment in IST-responsive patients, suggesting that proliferation may be linked to accelerated CD4+ T-cell turnover and hematopoietic failure. Our data show seminal findings that both CD4+ and CD8+ T-cell subsets are dysregulated in MDS. Association between these T-cell defects and response to IST suggests that aberrant T-cell homeostasis and chronic activation are critical determinants influencing autoimmune hematopoietic suppression in younger patients.

Nonsynonymous TP53 exon 4 single-nucleotide polymorphism (SNP), R72P, is linked to cancer and mutagen susceptibility. R72P associations with specific cancer risk, particularly hematological malignancies, have been conflicting. Myelodysplastic syndrome (MDS) with chromosome 5q deletion is characterized by erythroid hypoplasia arising from lineage-specific p53 accumulation resulting from ribosomal insufficiency. We hypothesized that apoptotically diminished R72P C-allele may influence predisposition to del(5q) MDS. Bone marrow and blood DNA was sequenced from 705 MDS cases (333 del(5q), 372 non-del(5q)) and 157 controls. Genotype distribution did not significantly differ between del(5q) cases (12.6% CC, 38.1% CG, 49.2% GG), non-del(5q) cases (9.7% CC, 44.6% CG, 45.7% GG) and controls (7.6% CC, 37.6% CG, 54.8% GG) (P=0.13). Allele frequency did not differ between non-del(5q) and del(5q) cases (P=0.91) but trended towards increased C-allele frequency comparing non-del(5q) (P=0.08) and del(5q) (P=0.10) cases with controls. Median lenalidomide response duration increased proportionate to C-allele dosage in del(5q) patients (2.2 (CC), 1.3 (CG) and 0.89 years (GG)). Furthermore, C-allele homozygosity in del(5q) was associated with prolonged overall and progression-free survival and non-terminal interstitial deletions that excluded 5q34, whereas G-allele homozygozity was associated with inferior outcome and terminal deletions involving 5q34 (P=0.05). These findings comprise the largest MDS R72P SNP analysis.

matter (PM) is a complex mixture and consideration of geographic variability and mixture components may impact observed associations with breast cancer.

Keratinocyte carcinoma and risk of all-cause and cancer-related mortality: A systematic review