14 November 2023
: Case report 
Immune Checkpoint Inhibitor-Induced Pure Red Cell Aplasia: A Review of 2 Cases in Metastatic Melanoma
Challenging differential diagnosis, Unusual or unexpected effect of treatment, Diagnostic / therapeutic accidents, Rare disease, Adverse events of drug therapy, Clinical situation which can not be reproduced for ethical reasons
Libardo Rueda Prada
12ABCDEFG*, Tatjana Gavrancic12ABCDE, Miguel O. Cadena Sanabria 3DF, Igor Dumic 14CDE, Kirk Bourgeois5B, Rebecca L. King6B, Yiyi Yan 17DEF
DOI: 10.12659/AJCR.941789
Am J Case Rep 2023; 24:e941789
Table 2. Case 2. Summary of laboratory workup and timeline of hospital interventions.
| Time of presentation | First 24 h | Day 1 | Day 2 | Day 3 | Day 4 | 1 month | |
|---|---|---|---|---|---|---|---|
| Hemoglobin (g/dL) | 7.1 | 7.2 | 5.4 | 6.9 | 9.5 | 8.6 | 12.8 |
| Platelet count (×10/L) | 134 | 140 | 93 | 102 | 134 | 119 | 173 |
| White blood cell count (×10/L) | 5.1 | 4.3 | 1.7 | 5.0 | 8.6 | 7.4 | 13.2 |
| Reticulocyte (%) | 0.39 | 3.10 | |||||
| Absolute reticulocytes | 8.8 | 11.1 | 8.8 | 8.8 | 8.8 | 8.8 | 354 |
| Anemia workup | : Iron 18 mcg/dL. Total iron binding capacity 297 mcg/dL. TSAT 6%. Ferritin 14. B12 level 320 ng/L. Folate level 7.3 mcg/L. 2–3 mcg/dL. Total iron binding capacity 192 mcg/dL. TSAT >90%. Ferritin 642. Folate level and B12 level was not repeated | ||||||
| DIC workup | D-dimer 555 ng/mL. Fibrinogen 111 mg/dL. PT 11.6 sec. INR 1.1. aPTT 32 sec | ||||||
| Hemolysis workup | No schistocytes on peripheral blood smear. LDH 877 U/L. Total bilirubin 1.7 mg/dL (indirect 1.3 mg/dL). Haptoglobin < 14 mg/dL. Direct Coombs negative. G6PD normal. ANA normal. Paroxysmal nocturnal hemoglobinuria antigen normal | ||||||
| Infectious workup | Parvovirus B19 serology and PCR negative. Hepatitis A, B, C serology was negative for active infection. HSV 1 and 2 PCR negative. HIV antigen and antibody screen negative | ||||||
| Reference ranges: Reticulocyte (%) 0.60–2.71. Absolute reticulocyte 30.4–110.9×10/L. Iron 35–145 mcg/dL. Total iron binding capacity 250–400 mcg/dL. TSAT 14–50%. Ferritin 11–307 mcg/L. B12 level 180–914 ng/L. Folate level ≥4.0 mcg/L. D-dimer ≤500 ng/mL. Fibrinogen 200–393 mg/dL. PT 9.4–12.5 sec. INR 0.9–1.1. aPTT 25–37 sec. LDH 122–222 U/L. Total bilirubin ≤1.2 mg/dL. Haptoglobin 30–200 mg/dL. ANA – antinuclear antibody; DIC – disseminated intravascular coagulation; LDH – lactate dehydrogenase; HSV – herpes simplex virus; PRBC – packed red blood cells; PT – prothrombin time; aPTT – activated partial thromboplastin time; TSAT – transferrin saturation. | |||||||