Abbreviations: n – number, lupus nephritis – LN, a – < 4000/mm3 or diagnosed in medical history, b – < 1500/mm3 or diagnosis based on medical history, c – ≤ 12 g/dl in women, ≤ 13.5 g/dl in men, or diagnosis based on medical history, d – anemia with a positive direct Coombs test or anemia with a decreased level of haptoglobin or diagnosis based on medical history, e – <100,000/mm3 or diagnosis based on medical history. This evidence concerns the gene HP and anemia (phenotype).