To accomplish this, blood specimens from patients with acute myeloid leukemia, RAEB, RAEBT or acute lymphocytic leukemia, follicular or mantle cell lymphoma or recipients of allogeneic hematopoietic stem cell transplants (HSCT) will be collected. We will genotype the genes of innate immune receptors to identify genetic polymorphisms associated with higher frequency of invasive infections or susceptibility to lymphoma. All specimens will be processed in the Infectious Diseases Laboratory at MSKCC. RNA will be extracted from peripheral blood mononuclear cells (PBMCs). Genotyping will be done from genomic DNA or from cDNA generated from RNA by RT-PCR. Cell lines will be created from PBMCs and will be analyzed in functional assays for responses to bacterial and fungal products (cytokine secretion, upregulation of cell surface molecules). All patient samples including genomic DNA, RNA, cDNA and cell lines will be banked in the Infectious Disease laboratory at MSKCC.