Differences in virological and immunological risk factors for Non-Hodgkin and Hodgkin lymphoma. Journal of the National Cancer Institution.
Shepherd et al. on behalf of the Data Collection on Adverse events Cohort (D:A:D) aimed to identify independent risk factors of Non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) and to identify factors that differentially affect NHL and HL risk in order to develop an understanding of different mechanistic pathways, which may then suggest different preventive approaches for reducing NHL and HL risk.
- Among 41’420 people followed for 337’020 person-year, 392 developed NHL (incidence rate = 1.17/1000 person-years of follow-up [PYFU], 95% confidence interval [CI] =1.06 to 1.30) and 149 developed HL (incidence rate = 0.44/1000 PYFU, 95% CI=0.38 to 0.52).
- Higher risk of both NHL and HL was associated with lower current CD4 cell count (adjusted HR [aHR] of NHL for CD4 <100 vs>599 cells/mm3 = 8.08, 95% CI=5.63 to 11.61; HL=4.58, 95% CI=2.22 to 9.45), whereas higher current HIV viral load (aHR of NHL for HIV-VL >1000 vs<50 copies/mL = 1.97, 95% CI=1.50 to 2.59) and higher AUC of HIV-VL (aHR of NHL for highest vs lowest quintile = 2.91, 95% CI=1.92 to 4.41) were associated with NHL only.
- Both current and AUC of HIV-VL were factors that had different associations with NHL and HL, where the hazard ratio for NHL was progressively higher than for HL with increasing HIV-VL category. Lower current CD4 cell count had a strong but similar association with both NHL and HL.
In conclusion, the study shows that whereas CD4 depletion similarly increased risk of both types of lymphomas, current and accumulated HIVVL was more predictive of NHL than HL. This suggests that NHL development is related to both CD4 cell depletion and added immune dysfunction derived from ongoing HIV replication. This latter factor was not associated with HL risk. These findings stress the importance of early HIV diagnosis and treatment, and of ensuring sustained viral suppression.