Anti B cell targeted therapy for autoimmune hemolytic anemia in an infant
A 4-month-old male infant, born to non-consanguineous parents, with uneventful perinatal history and thriving well on breast milk, presented with cough for 10 days and pallor for 2 days.\nInfant was pale with mild icterus, without any fever and any significant lymphadenopathy or organomegaly. Hemoglobin (Hb), reticulocyte counts were 3.2 g/dL and 6% respectively. Liver function test was normal, but with indirect hyperbilirubinemia (2.5 mg/dL out of 2.9 mg/dL of total bilirubin). Coagulation profile was normal. Direct Coomb's test (DCT) was strongly positive (4+). High performance liquid chromatography was normal with Hb F being elevated as per age. In urine microscopy, no fresh red blood cell (RBC) but hemolyzed RBCs were seen. There was no Rh or ABO incompatibility setting. Results for anti-nuclear antibodies (ANA) and for retrovirus were negative.\nHb level increased to 7.9 g% after packed RBC transfusion (15 mL/kg). However, his repeat Hb 24 h later dropped to 5.8 g% with agglutination in the smear and repeat DCT being again positive (4+). Immunoglobulin G (IgG) auto antibodies were high and diagnosis of AIHA further confirmed. He was started on IV Ig (2 g/kg/total) and on methylprednisolone (10 mg/kg/day). As Hb improved to 9 g% after 4 days, he was discharged with advice to continue oral prednisolone (2 mg/Kg). While tapering steroids, his Hb dropped to 6.7 g%, with repeat DCT being positive and with evidence of hemolysis in smear. A repeat course of IV Igs (1 g/kg) along with stepping up of prednisolone to 1 mg/kg/day was given as parents were not consenting for administration of rituximab. There was a transient improvement in Hb to 10 g%, which has dropped later to 7.8 g% on tapering steroids.\nHe was started on rituximab as response to steroids and IV Ig was ill sustained, after obtaining the parent's consent. Dose was calculated as per the body weight (by taking the standard recommendation of 375 mg/m2 once a week for 4 weeks) and 85 mg given once a week. Seven days after the 3rd dose, good hematological response (Hb > 10.5 g%, reticulocytes 3%) was observed. Though the patient was covered prophylactically by co-trimoxazole after 3rd dose of rituximab he developed severe pneumocystis carinii pneumonia (PCP). The PCP infection was thought to be secondary to immunosuppressive status because of on-going steroid treatment aggravated by rituximab.\nAfter rituximab treatment, steroids were tapered over a month and continued at a very low dose (0.2 mg kg/day initially and on alternate day later) for another 2 months as per the hematological picture. Currently, he is off steroids for 6 months from last rituximab dose and maintaining a Hb of 9-10 g%. The DCT is negative.