No role of common NOD2 gene variants in predicting sepsis related outcomes in Indian patients undergoing hematopoietic stem cell transplant.

Background: High-risk single nucleotide polymorphisms (SNPs) in nucleotide-binding oligomerization domain-2 (NOD2) gene are associated with high susceptibility for infections and inflammation due to risk of inappropriate cytokine production and NF-B activation. We studied the incidence of three high-risk NOD2 gene SNPs (8, 12 and 13) among BM-transplant (BMT) recipients.

Methods: Sequential patients undergoing BMT over 1-year period were prospectively studied. Patients were tested with MspI/HhaI or NlaIV restriction-endonucleases (Euryx, Gdansk, Poland) for NOD2 gene SNPs 8, 12, and 13, respectively. Regimen-related organ toxicity was graded using the Seattle-Bearman criteria.

Results: Forty patients were enrolled, their median age was 38 years (range 3-64), and 52.5% were males. Twenty patients each (50%) underwent autologous and allogeneic BMT. Majority of the patients (n = 38, 95%) developed febrile-neutropenia in the post-transplant period and 4 patients died due to overwhelming sepsis within day +100. Acute graft-versus-host disease (GVHD) [grade I-II (n = 3) and grade III-IV (n = 6)] was observed in 9/20 allogeneic HSCT recipients. None of our 40 patients showed presence of any of the three NOD2 gene SNPs.

Conclusion: The 3 commonly observed high risk SNPs (8,12, and 13) of NOD2 genes were not present in study population. It is quite likely that due to geographical and racial variations these polymorphisms are completely absent in North India. NOD2 gene is highly diverse and polymorphic variants can be absolutely different in various populations. Larger studies targeting sequencing of the whole NOD2 gene can convincingly rule out or confirm the role of NOD2 gene variants in Indian population.