Leishmaniasis is a clinically heterogeneous syndrome caused by intracellular protozoan parasites of the genus Leishmania. The clinical spectrum of leishmaniasis encompasses subclinical ( not apparent), localized (skin lesion), and disseminated (cutaneous, mucocutaneous, and visceral) infection. This spectrum of manifestations depends on the immune status of the host, on the parasite, and on immunoinflammatory responses. Visceral leishmaniasis causes high morbidity and mortality in the developing world. Reliable laboratory methods become mandatory for accurate diagnosis, especially in immunocompromised patients such as those infected with HIV. In this article, we review the current state of the diagnostic tools for leishmaniasis, especially the serological test.

The vaccines designed against the SARS-CoV-2 coronavirus are based on the spike (S) protein. Processing of the S protein by antigen-presenting cells (APC) and its subsequent presentation to T cells is an essential part of the development of a humoral response. HLA-class II alleles are considered immune response genes because their codified molecules, expressed on the surface of APCs (macrophages, dendritic, and B cells) present antigenic peptides to T cell via their T cell receptor (TCR). The HLA-class II genes are highly polymorphic, regulating what specific peptides induce follicular helper T cells (TFH) and promote B lymphocyte differentiation into plasma or memory B cells. This work hypothesizes that the presence of certain HLA-class II alleles could be associated with the intensity of the humoral response (amount, length) to the SARS-CoV2 mRNA 1273 vaccine. We have studied the relationship between the HLA-class II typing of 87 health workers and the level of antibodies produced 30 days after vaccination. We show a possible association between the HLA-DRB1* 07:01 allele and the HLA-DRB1*07:01~DQA1*02:01~DQB1*02:02 haplotype to a higher production of antibodies 30 days after the administration of the second dose of mRNA-1273.