ABSTRACT
Mendelian Susceptibility to Mycobacterial diseases (MSMD) are a group of innate immune defects with more than 17 genes and 32 clinical phenotypes identified. Defects in the IFN-γ mediated immunity lead to an increased susceptibility to intracellular pathogens like mycobacteria including attenuated Mycobacterium bovis-Bacillus Calmette-Guérin (BCG) vaccine strains and non-tuberculous environmental mycobacteria (NTM), Salmonella, fungi, parasites like Leishmania and some viruses, in otherwise healthy individuals. Mutations in the IL12RB1 gene are the commonest genetic defects identified. This retrospective study reports the clinical, immunological, and molecular characteristics of a cohort of 55 MSMD patients from 10 centers across India. Mycobacterial infection was confirmed by GeneXpert, Histopathology, and acid fast bacilli staining. Immunological workup included lymphocyte subset analysis, Nitro blue tetrazolium (NBT) test, immunoglobulin levels, and flow-cytometric evaluation of the IFN-γ mediated immunity. Genetic analysis was done by next generation sequencing (NGS). Disseminated BCG-osis was the commonest presenting manifestation (82%) with a median age of presentation of 6 months due to the practice of BCG vaccination at birth. This was followed by infection with Salmonella and non-typhi Salmonella (13%), Cytomegalovirus (CMV) (11%), Candida (7%), NTM (4%), and Histoplasma (2%). Thirty-six percent of patients in cohort were infected by more than one organism. This study is the largest cohort of MSMD patients reported from India to the best of our knowledge and we highlight the importance of work up for IL-12/IL-23/ISG15/IFN-γ circuit in all patients with BCG-osis and suspected MSMD irrespective of age.
Subject(s)
Genetic Predisposition to Disease/genetics , Immunity, Innate/genetics , Mutation , Mycobacterium Infections/genetics , Mycobacterium Infections/immunology , Adolescent , Adult , BCG Vaccine/immunology , Child , Child, Preschool , Coinfection/epidemiology , Coinfection/microbiology , Female , Genetic Predisposition to Disease/epidemiology , Humans , India/epidemiology , Infant , Infant, Newborn , Male , Mycobacterium Infections/epidemiology , Mycobacterium Infections/microbiology , Phenotype , Receptors, Interleukin-12/genetics , Receptors, Interleukin-12/immunology , Retrospective Studies , Young AdultABSTRACT
BACKGROUND: In idiopathic autoimmune haemolytic anaemia (AIHA haemolytic antibodies are directed to every type of red cellsWestern blot studies have shown antibody positivity towards red cell anion channel complex which also includes band 4.2 a protein with similarities to tissue trans glutaminase. OBJECTIVE: Evaluation of AIHA for anti tissue transglutaminase antibody (Anti tTG). MATERIALS & METHODS: Twenty three AIHA patients were tested along with routine hamatogical work up, for a series of auto antibodies and red cell eluates and serum from the patents were tested against solubilised group O red cell ghosts on western blot. Other ancillary investigations were done to rule out complications and secondary causes of haemolysis. RESULTS: 11/23 patients (48%) were positive for anti tTG, Four, 3 and 8,7 patients were positive for anti thyroid, anti b2 glycoprotein, lupus anticoagulant and ANA respectively. One patient with anti tTG had biopsy proven celiac disease. Three patient developed DVT and all of them were lupus anticoagulant as well as b2 gp-1 antibody positive.17 had become Coombs test negative on treatment while 21/23 had positive western blot test. DISCUSSION & CONCLUSION: There is strong association of anti tTG antibody with idiopathic AIHA. Aetiological association of this finding needs exploration.
